Jump to content
The Klipsch Audio Community
Jeffrey D. Medwin

KT88 Direct-Coupled Design

Recommended Posts

            5-4-19  Progress Photos

 

Had some time, to do things. 

 

Got the switching system ( 120 VAC Line ) installed, and was able to experimentally determine how much resistance I needed to add, to the 8 Ampere rated  ( Rectifer Tubes' ) filament transformer, while it was operating at a 6 A. ( lower current, two rectifier tubes at 3 Amperes each  ) load, and at a higher ( 125VAC ) line voltage.  Only 115 VAC of line-input is what Hammond had originally designed it for.

 

Rectifier tubes with a 5 volt ( nominal ) filament design, can not work well, for very long, ..........at 8.68 Volts !!

 

My solution, of adding a giant power resistor of 25 Ohms into each end of the Transformer's Primary's winding, is only a temporary one, to get the amp  / prototype " up and running ". 

 

Adding 50 Ohms of total series resistances, to a power supply, is one of the worst things one can do.  The added DCR will degrade dynamic contrasting, which is one of the amp's main design goals I seek to maintain.   Yes, after adding 50 Ohms as shown,  the amp will play, and the rectifier filaments will be fine at 4.89 VAC, but this use of 50 additional Ohms will only be temporary. 

 

When I discuss the History of a L.S.E.S. supply, I will be quoting a 1986 letter from Dr. Charles E. Halijac, audiophile, deceased Dean of the College of E.E. at the University of Alabama, where he explains how and why lowest DCR is best - and necessary,  in a tube amp's power supply.  Stay tuned for that LSES History Post !! 

 

 

 

                                        898300903_SNIP1.JPG.a26dcdfbd3d0d023f37a8ed734731962.JPG

 

 

 

                                        1531176341_SNIP2.JPG.468268662d59f7f70264123207269705.JPG

 

 

 

                                         1944957957_SNIP32.jpg.e9013c8e894be8a945ca98300a7d3e15.jpg

 

 

 

                                          1296700189_SNIP4.JPG.d0f3b73d8f86133357bac647ed7b9496.JPG

 

 

 

Notice ( photo below) that the CL-90 thermistor ( current-inrush-limiter for slow start-ups ) is tilted 45 degrees in relationship to the chassis.   This is a very good, common sense thing to do.  If the thermistor were vertically orientated, NEITHER side would get a natural convection cooling. If the thermistor was horizontally orientated, ONE side only would get the majority of natural convection cooling.  The 45 degree orientation is long-term-best.   Lay Out, Lay Out, Lay Out !! 

     1333029967_P1010016editedFINAL3.thumb.jpg.b17688ea4fed277876e7d627a0df3537.jpg

 

 

 

             Does anyone know of a Manufacturer who makes a standard off-the-shelf filament transformer that will load at 4.8 to 6.15 VAC with a nominal 6 Ampere ( two 5U4GBs) load, from a 125 VAC Line Input?   Hammond does not.   I could always "contract"  for a custom transformer build, and will do so, once this is running.

Share this post


Link to post
Share on other sites

      5-5-19 Progress Photos

 

All three GTO ( Gate Turn Off )  bypass caps ( Arcotronics 5 uF at 1200 VDC, 64 A. continuous, 1.500 PEAK ) are installed.  Short ground return.  C1 wired .

 

This below is NOT an ordinary tube amplifier design, taught in E.E. classes the last 100 years !! 

 

   480688641_P1010018dated.thumb.jpg.8f35826615f3ead81bdfed32f2f4e775.jpg

 

 

                      1696203792_P1010018dated4snip.jpg.7db4275dbcdbb1f567bb85854ac565ed.jpg

  

Above :  Power Supply Filtering is two 5U4GBs recitifiers, inputting into L1, a Hammond 159ZA 6 Ohm , 1 Ampere choke, filtering both ( stereo ) channels,.  L1 feeds C1, a WIMA DC LINK 35 uF industrial film cap, bypassed with a 5 uF "GTO" high-peak-current industrial film cap.  L1 and C1 are shared by both channels.

 

This stereo amp's Supply / Filter does a "Y" after L1/C1, and feeds each channel separately.  Employed is a second L/C , designated  L2 / C2 for each channel. 

 

L1 is always the same as L2, in make and values, or else there will be audible skews heard in a good SE amp.  ( We hear it as a  A CAT AND DOG FIGHT WHENEVER these two Ls in series are NOT THE SAME !! ). C2 is usually a 50 uF value, a WIMA DC LINK MKP4 film.  No single film cap over 50 uF is used.  

 

Visually, in a stereo amp, I employ this filter configuration  :   

 

                                                                                                                                          L2/C2     ( left channel )               KT88, 2A3, etc.        

                                              L1/C1         ( doing both channels ) feeds 

                                                                                                                                          L2/C2    ( right channel )              KT88, 2A3, etc.      

 

 

I add a 5 uF "GTO" bypass cap to C1 and each C2.  This GTO  supplies the Output / Finals tube with current ( peaks ) on music's transient / pulsed-nature signal demands.  No other cap type, other than a "GTO" can do these instant peaks !  The above use of " GTO " caps is 100%  "my baby" since 2015, and it is not an essential component of a L.S.E.S. supply ( Low Stored Energy Supply ).

 

In the end, we are all listening to a music-modulated power supply.  How good is the  power supply ? 

 

Does the supply's design allow the Vacuum Tube's control grid, to follow the music?? 

 

Due to the nature of Ls and Cs,  a low value L and low value C supply,  ( as in this fully developed LSES supply - a " fast " supply  ) has a chance to supply the tube the best, and it is totally audible. More, in a future post on this !! 

 

1488426395_P1010020edited.thumb.jpg.8e7d93b4902dd1c9518cfa788d5bd35a.jpg

  

 

                                        XLO large spade lugs ( 8 AWG ) for GTO caps - and a very short distance to 8 AWG Mil Spec ground bus.

 

Isn't it rather interesting, much of what we are doing thus far, and see in the photos above, is Power Supply related !!  

Share this post


Link to post
Share on other sites

 Not enough can be said about the use of GTO's in the power supply .....

 

  Willie

Share this post


Link to post
Share on other sites
On 5/7/2019 at 7:52 PM, drummerwill said:

 Not enough can be said about the use of GTO's in the power supply .....

 

  Willie

 

Willie, 

 

 I will do a post on that, within a week or two..  Thank you, for contributing.

 

 

Share this post


Link to post
Share on other sites

Hello everyone,

 

Here is some "history"  :

 

 

                                                 Five clues, over my life-time, that led me to use, and champion, a L.S.E.S. Power Supply

 

 

Clue One. Meeting Robert Fulton of Fulton Musical Industries, 1978.

 

I grew up with high efficiency ALTEC Professional Speaker systems since I came home from the Hospital as a baby. My Dad had a 604 initially, later, also a 604B.

 

At age 34, I attended an audio seminar at Mission Bay Audio ( Dr. Tom Johnson's store ) in San Diego, CA, in 1978, where Robert W. Fulton was the guest speaker. As I heard him, I felt he was gifted, and likely the best person I have ever met in the entire audio field. I thought to myself – that, IF this is the case, “ I should not ignore him”. We two developed a superb relationship for a decade, from 1978 to 1988, the year he passed away.

 

                                                                                                   http://fultonmusicalindustries.com/biography.html

 

                                                                                                     http://fultonmusicalindustries.com/index.html

 

In about 1979, I built my first tube amp,. It was an AudioNote kit, for a Los Angeles, CA. record reviewer friend, Neil G. Levenson. ( Fanfare, the magazine for serious record collectors ). Push Pull 2A3s, it was completed by me on Neil's living room floor over one weekend, primarily so we could both hear 2A3s for the first time.

 

In about 1980, I was told by Mr. Fulton that I could build a much better Push Pull triode amp than the AudioNote kit. It would use NO feedback, and be more “ musically correct ”. For about two years, I worked out its design and implementation, with my experienced / gifted friend, Robert Fulton, directing and mentoring.

 

The amp, used 6SN7s and Push-Pull-Parallel tubes, 6B4Gs,. It was built on six chassis , as monoblocks, and weighed over 400 pounds !! The “ Triode Music Amp, or TMA ”, became my first all-from-scratch design and build. Each mono channel had three separate supplies, double choke-cap filtered ( L1/C1/L2/C2) and then, each B+ was actively double-regulated.

 

 

                                               620314892_OneChannelOnly200pounds..JPG.4d8da205d4ce9472aaac27bc46d0a68d.JPG

 

 

                                                                               155168815_TwoChannelsfilledtheVW-1988.JPG.d286569aa3dbfde585634524887ae585.JPG

 

                                                                                     6 Chassis,   both channels,  in a V.W. Vanagon, Jacksonville, 1988

 

 

 

                                                           1165148678_audiobottom2.JPG.d6e52a4447d45454bd3462b5466023eb.JPG

 

                                           Minneapolis 1986 in Mr. Fulton's Living Room.  Under the Deck / Audio Chassis.  Some " first amp design and build, eh ??"

 

 

                                                           385431263_RawSupplyBottom3.JPG.d57879d36e4060133f8a015d365a2900.JPG

 

                             Main Power supply , below deck.  There was also a Pre-Regulator Chassis - 9 regulated DC  Ef supplies., ......six chassis for Stereo. 

 

 

 

 

I recall VIVIDLY, Robert's first piece of advice to me, on this new design.

 

He told me …

 

“ Jeffrey, the chokes have to all be 20 Ohms or less, in DCR ( resistance ), if you can find them.”

 

He went on to explain to me :

 

“Because the 6B4G/2A3 family of DHT tubes is a direct-access-to-the-music device, and it requires such a choke.”.

 

Such advice, coming from Robert W. Fulton, I did not take lightly, because I knew he knew what he was doing !!! …......

 

“ Twenty Ohms or less, if you can find them ”.

 

The best I could do - was accumulate a large number of 24 Ohm DCR chokes, 3 Henries, from Phil at Fair Radio Sales, in Lima Ohio These nicely potted chokes, cost only $8.00 each, surplus-priced.

 

A few years later, in the early 1980s, I indoctrinated Herb Reichert ( currently a Sterophile Reviewer, then a fellow DIYer ) into low DCR. One will see the same exact potted choke in his “ Flesh and Blood” amp photos.

 

 

Clue number two, 1989, Dr.Chales E. Halijac,

 

 

In the late 1980s, Mr. Fulton became progressively sick from cancer. I fortunately developed a vibrant new audio-friend. This new audio-friend became my second ( and present ) Audio Mentor. His name is Dennis Fraker, from Livingston, Montana. Dennis was both an avid audiophile, and had vast experience in the movie theatre business. For many years, he was a Theatre Owner and was also a trusted Technician for many other movie theatre owners.

 

It was Dennis, in the 1980's, who introduced me to Dr. Halijac. Charles Halijac was an audiophile and also - Dean of the Electronic Engineering School at the University of Alabama.

 

In the late 1980s, I was constantly experimenting with DIY amps. I applied low DCR concepts to their power supplies, just to HEAR and learn what that did. On a modest Dynaco ST35 amp, I added four rectifier tubes to its supply, to hear the result. I liked it, and wrote to Dr. Halijac , a letter - explaining this experiment. The letter he wrote back to me, ( below ) served as my SECOND clue. Dr Halijac reinforced what Mr. Fulton had previously told me, about DCRs in power supplies needing to be kept low. Here is Dr. Halijac's 1989 letter, confirming Mr. Fulton's earliest advice :

 

1989

Dear Jeffrey,

This letter is concerned with the power supply and the use of chokes.

A choke must have some internal resistance and its non-standard figure of merit is the ratio R over L. The best choke is the one with the smallest figure of merit and the best power supply has the least series resistance.

It is not too difficult to obtain R over L = 10 but one can easily obtain R over L = 30 or more. The latter should be avoided but the ongoing shows that in a way it is unavoidable.

The choke input filter controls the diode by timing and not by ohmic losses. ( JM : current vs: voltage wave forms ) The best place for a choke is at the input and the worst place is at the other end of a power supply filter chain because resistances tend to be higher there.

Suppose we start with your case and R over L = 10. When diode ( 5U4GB) and transformer resistances are taken into account we have :


 

15 ( choke ) + 70 ( rectifier ) + 70 ( power transformer resistances )
--------------------------------------------------------------------------------- = 103
1.5 ( HY )


 

( the 70 ohm power transformer resistance is a guess )


 

If four 5U4GB are placed in parallel one has :


 

15 + (0.25 ) ( 70 ) + 70 
__________________ = 68
1.5


 

Both figure of merit are way above the original 10 but your listening experiment told you that 68 was alright; this actual figure of merit is the best you can do because the largest power transformer was used and the smallest resistance available choke was used. You can see that stock power supplies are not anywhere near being the best cases *.

Most tube and transistor electronic engineers are unconscious about power supplies, but good.


* Also the best cases need not have zero internal resistance - a utopian goal. One strives for minimal non-zero resistance !!

 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

 

Dr. Halijac would have Stancor custom-make his chokes. His favorite choke design value was “ One Henry at 8 Ohms DCR.” This – was back in the 1980s. Charles is no longer living.

 

 

Clue Number Three, 2004 and 2005. RMAF shows, Mr. Dennis Fraker :

 

Throughout the 1980's onward, I remained in-touch, with Dennis Fraker. In 1989, Dennis developed his own first Direct Coupled 2A3 amplifier. He took a pair of monoblocks to RMAF in Denver Colorado, ( Rocky Mountain Audio Fest ) in 2004. Late, after-hours, he took part in a tube Amplifier Auditioning session. This was in Terry Cain's room, with all the best tube amps. Dennis' DC 2A3 amp was generally considered # 1 by those attending. The high-end amp builders present gave him a standing ovation, when they first previewed / heard these new Serious Stereo 2A3 mono amps.

 

Dennis came to RMAF the next year, 2005, not as a visitor, but as a new Manufacturer and Exhibitor, with his amps, a low-loss attenuator, and GPA 604 coaxial speakers in his MLTL enclosures. People can accurately read on line – all about 2005 RMAF - and Dennis' Serious Stereo room, from this Six Moons review by Stephaen Harrell:

 

                                                                       https://6moons.com/industryfeatures/rmaf05stephaen/rmaf05_2.html

 

 

Once I read that Six Moons review on-line, I called Dennis to find out what was going on, design – wise with his 2A3 mps. He tells me, his amps are using small mass TEN Ohm chokes ( two per mono block ) and all the capacitors were film ( or oil ) caps, none more than 50 uF in value. He called the supply a “ Low Stored Energy Supply “, and he explained the theory of it, as best as I could understand him.  Hey, Hey Hey, this was an extension of what Messers Fulton and Halijac had been getting at, except talented / experienced Dennis Fraker was far more complete.  He fully-developed a L.S.E.S. tube amp supply, that worked like gang-busters !! .

 

I decided then, that ( just like me “not ignoring Mr. Fulton in 1978 ” ) , it was time for me “ to not ignore Dennis Fraker, …...in 2005.”

 

In about 2006, I decided to share “ the good news ” about “ L.S.E.S. ” with audio friends online, on Audio Asylum's “ Tube DIY “ Forum. Me, an audio amateur and not being trained as an E.E, did not do the subject justice. I presented the information on LSES in an odd way. My manner and elite attitude was also offensive to many conventionally trained EEs and conventional, by-the-book, thinkers.

 

I also had less overall experience in L.S.E.S. in these early years, versus now. So, some of my early suggestions were not the best, to launch this new-to-others concept / design idea.

 

I personally made it a point, 2006 on, to visit the Serious Stereo room at Denver's RMAF show, every year Dennis and Serious Stereo exhibited there. I dd so, to visit my mentor, hear what else was new and good elsewhere, and to get a handle on Dennis' amps, and how they were playing back music.

 

Serious Stereo's in-the-room playback at RMAF varied from year to year,. This was largely a function of a limited pre-show available time and energy, the two Fraker brothers had, to optimize speaker placement, and do their system's set-up.

 

No one else in audio visited Dennis – eleven out of twelve years in Denver. Certain years were well above average and some years - it was really great in my opinion !! Six Moons ( Stephaen - 2005) and Reichert ( Stereophile -2016 ) heard the hotel room-display in years when the system was performing at close to the amps' full potential.

 

Dennis' use of a L.S.E.S. Power Supply in the 2A3 amps, since 1989, is a constant !! For me and my own DIY amp builds, since 2006, it is the same constant .

 

 

Clue Number Four, Tube DIY Forum Posts, Audio Asylum, John Swenson and John L. Hasquin. 2006-2010.

 

From my crude 2006 postings on Audio Asylum, two sharp EEs, DIYers, experimenters, took the ball and ran with it, despite my inept presentation of LSES . Unlike the vast majority of A.A. Forum readers, these two actually built and listened to LSES supplies. Both fellas came to EE conclusions as a result of their building and direct listening. Their Forum posts and explanations, helped me, an amateur, to better understand the mechanisms at work with a L.S.E.S. supply.

 

People often times have a hard time thinking out of the box.  E.E. Dean, Dr. Halijac said it “so well” - writing in 1989 :

 

Most tube and transistor electronic engineers are unconscious about power supplies, but good.”

 

 

                                                                                         ----------------------------------------------------------------------------------------

 

 

 

Clue Number five, “ destroying ” a Yamomoto A-08 Type 45 SE amp, 2015.

 

In 2015, after reading glowing comments for years about Type 45 SE amps, I applied most of Dennis Fraker's design ideas to a Type 45 Finals tube amplifier build.

 

Once built, I transported this new amp to Kansas City, my old friend Randy's system, to compare it to his Yamomoto A-08 Type 45 amp.

 

Here is a review of that Yamomoto amp of Randy's, on line:

 

                                                                                          http://www.6moons.com/audioreviews/yamamoto2/45.html

 

Both amps are two stage, and both use Type 45 Finals tubes. Randy has an absolutely huge listening space, ( an entire 1911 Firehouse station, built of stone, for horse-drawn fire gear ). Randy had one or two pairs of ALTEC A-2s for speakers. This is like an ALTEC VOTT on steroids, for large venues. It uses two 15 woofers, front-horn-loaded and direct radiating per enclosure, and a large multi-cellular horn on top, driven by a ALTEC 291 two inch compression driver.

 

The first thing we two did was to rewire Randy's speakers, from the Yamomoto -08 amp, up to the drivers' terminals, with Mil Spec wire, m22759/11 12. We used similar 16 AWG wire – crossover to the tweeter driver terminals. We felt good about doing that change !!

 

Next, we did some serious amp comparing, my Type 45 DC amp ( with L.S.E.S. supply, etc. ) to his two stage Yamomoto A-08 Type 45 amp. Frankly, there was NO comparison, and we both heard it instantly, and neither of us could deny what we were hearing. My Type 45 build absolutely murdered the Yamomoto A-08, in about every music-performance parameter we could think of. This comparison gave us lots of amplifier design reassurance, that we were on the right track, amp building – wise.

 

It helped me, to have Dennis Fraker as my amp-building mentor!! The blatant trouncing of that Yamomoto A-08 will remain in Randy's and in my mind, for as long as we live !! It was, for me at least, hilarious.

 

In another post, I will quote key parts of John L. Hasquin's comments on L.S.E.S. supplies - to promote your fuller understanding, in EE terms, not just subjectively.

 

I may even do a third post, suggesting how, in 2019, one may specifically and conservatively go about applying L.S.E.S. to a DIYer's own builds, if Dennis will allow me, so some can actually hear and enjoy it.

 

Sorry if I rambled !!

 


 

Share this post


Link to post
Share on other sites

 

Below, are thirteen selected out-croppings of John L. Hasquin's posts on The Audio Asylum, Tube DIY Forum, circa 2006-2010. Kindly be aware :  I selected what reflects MY biases regarding teaching friends about L.S.E.S. This will give a Non E.E., a pretty good background. John explains it so much more clearly than I can and do .

 

More disclosures, to be intellectually honest :

 

John L. Hasquin started on his journey, apparently from my own Audio Asylum postings. Another very bright E.E. ( Henry Pasternak ) also read my posts about Dennis Fraker's L.S.E.S.   Henry then used PSUD 2 simulations, and came up with a power supply he called “ The Flywheel ”, a theoretically “ dynamite” way of re-applying Dennis Fraker's L.S.E.S. Power Supply ideas. Henry's post and work seemed to be theoretical only. All of Dennis' SE 2A3 DC amp builds , however,  were fully-using L.S.E.S.,.............. 17 years prior to any of my own Audio Asylum posts.

 

E.E.s John Swenson and John L. Hasquin, most definitely DID build and adopt Flywheel supplies. There were certain things that the L.S.E.S. originator, Mr. Dennis Fraker, does not care for, about a Flywheel design. Perhaps Dennis will be able to report up here and comment, if he cares to do so.

 

For a quickie background - please first see a topic labeled ( 6 ) dated 2-08-2008,  below. Then, have fun, relax, read them all. I truly love the way John L. Hasqin writes .

 

 

 

(1) on 3-08-2007

 

                                                                 1.....3-8-07.jpg.2b161d706a530ceef2488ace75f9ca94.jpg

 

 

(2) on 3-14-2007

 

 

 

                                                                508753495_2...............3-14-07.jpg.777b7a50fbf4c43e1557c8159bd5a5fa.jpg

 

 

 

(3) on 12-16-2007

 

                                                                1778910399_3First..................12-16-07.JPG.d37dda4d09808c88f979ba2fd0ecddaf.JPG

 

 

(4) on 12-16-2007

 

                                                                 1300226509_4........12-16-07.JPG.a821ea83dfccbab3cd8b3c7fdd4e05e1.JPG

 

 

 

(5) on 12-16-07

 

 

                                                                   2036678886_5....12-16-07laterintheday.JPG.8255b6db39be6ab6843cdb358bbb1206.JPG

 

(6) on 2-08-2008

 

                                                                   6......2-8-08.JPG.aa9788d10c0a7b20aa753e20bef41eb0.JPG

 

 

(7) on 4-09-2008

 

                                                                   506668166_7..........................4-9-081of2.JPG.e7c705e51f3b4db61baa0c51b160ac10.JPG

                                                                   557722139_7........................4-9-082of2.JPG.82a6a6313676f92dfdc93e5fbbbb730d.JPG

 

 

(8)  on 9-16-2008

 

After describing a “Flywheel” JLH addresses HIS last L/C section, which IS a L.S.E.S set of values :

 

                                                                 8......................9-16-08.JPG.0014eaad87945508c628764524053dba.JPG

 

(9) on 9-28-08

 

 

                                                                 2033788340_8......9-28-081of2-Copy.JPG.7c8fcb1566f768810e2ede361fc88bd9.JPG

                                                                298982778_8........9-28-082of2.JPG.3965b83c0e8de53c20a0c905c2de1814.JPG

 

(10) on 6-30-09

 

                                                                 10.........6-30-09.JPG.a36a5c046831b4d03399a3a4d18e4f1b.JPG

 

(11) on 7-1-2009

 

                                                                  11..........7-1-09.JPG.da6693687682de16100384453ce5dd97.JPG

 

 

 

(12) on 2-15-10

 

                                                                  12.................2-15-10.JPG.075c6d966214bed08ba1475324f7a9d9.JPG

 

(13) on 4-16-10

 

                                                                 958096832_13.............4-16-101of2.JPG.0ed44f631bd542d96ef3433f33a1b079.JPG

                                                                    1227627789_14............4-16-102of3.JPG.b82f006fe36a113060e71ce7fb834c26.JPG

                                                                 

                                                                   15............4-16-10     3 of 3.JPG

 

 

If anyone seeks to read all of John L. Hasquin's posts, and all of John Swenson's posts from this era, unedited by me, please contact me though Klipsch Forums Private Mail, as I have time-sequenced compilations of both I'd be happy to to email to you, if you include your private email return address

 

L.S.E.S. is all Dennis Fraker's idea.. I tried to select really germane John L. Hasquin posts to share with you all, while trying to assist, and be helpful. Fun stuff, eh !!?? The proof of the pudding is in the listening.   It is totally lovely to hear L.S.E.S. in my amps.   Thank you for this, Dennis.

Share this post


Link to post
Share on other sites

Here is the third of three parts, L.S.E.S. for DIYers, etc.:

 

 

 

A Low Stored Energy Supply ( L.S.E.S.) consists of two specially chosen  L/C ( choke / capacitor) sections connected in series ( L1/C1/L2/C2).   The L.S.E.S. filter parts are smaller and purposely-sized to provide fast discharging and recharging of their parts.  The L.S.E.S. design's goal is to not have the B+ filter parts compete with the vacuum tube - when its control grid signals the tube to play back peak currents, and fast / complex pulsed information, inherent in music.

 

A L.S.E.S power supply filtering approach offers a performance and music-listening advantage, over any conventional filter.

 

A conventional audio amplifier power supply filter may be considered as having two very large filter parts, a choke and a capacitor, acting as storage tanks. The large sizes of conventional chokes ( in Henrys and in high DC Resistance ) and the low impedance nature ( current gobbling ) of capacitors, “ robs ” the vacuum tube's needs, on fast repetitive music signals.

 

Larger filter parts, ( taught to E.E.s - and used routinely - the last 100 years ), prevents the tube from following what it's music control grid, is asking or telling the vacuum tube to do - to amplify music accurately.

 

Subjectively, a fast-acting L.S.E.S supply plays music back in the time, pace and with the full dynamics of the music. Conventional ( slower ) supplies plays music back in the timing and pace of its “too large” parts, superimposed - over the original music signal's playback.

 

If anyone compares one conventionally built amplifier against the other, its virtually impossible to hear this timing and dynamics difference I speak-of herein. Throw a decent L.S.E.S. two stage amp in the mix, on a good system, and it trounces all the others, very obviously. That was my experience - doing a Yamomoto A-08  " A - B "  comparison in 2015.  Picky music people who use Serious Stereo 2A3 amps in their home's system, also know this performance difference today.

 

Do you want to hear your amplifier play back in the time-frame of the music, be dynamically–engaging to hear …....or in the time-frame of an always slightly out-of-time, thumb-printed, dynamically-unreal sounding audio amplifier??   This, folks,  IS  the L.S.E.S. difference !!

 

 

 

 

 

 

                                                                      How a DIYer may build a L.S.E.S. amp,  2019, on :

 

 

First of all, it will be necessary to model any L.S.E.S. configuration, in PSUD2 simulations, to evaluate the ripple and voltages that one's filter combination choices inherently produces. The L.S.E.S. filter must be applied thoughtfully to your circuit's current and operating voltage needs.

 

Duncan Amps' PSUD2 is user-friendly, a great tool. Don't be afraid of it !! Download it for free. You just input the parts choices that comprise the power supply : a power transformer, rectifier system, chokes , capacitors, and sometimes resistors. ( Use PSUD's formula for your Power Transformer's effective DCR, to most precisely model the supply. )

 

To save a DIYer from potential pitfalls and trouble, I will herein suggest some of the best parts and design techniques to use, for highest performance, and the least possible troubles, while retaining reasonable costs :

 

We have found that in all cases, L1 must be the same as L2, in size, construction, etc.

 

When L1 is not the same as L2, in L.S.E.S. there is an unwanted audible skewing of the sound, in any good S.E. amp circuit, ….very audible. This skewing was recently well-described to me by Mr. Dennis Fraker, as “ a continuous cat and dog fight”. Very good.

 

I should very importantly note, the above-paragraph's skewing sonic result has been consistently derived by Dennis, since 1989, ( and I, much later ) from listening tests. This audible skewing likely will NOT be easily seen on any Oscilloscope, nor be evident in any PSUD 2 simulations.

 

So very simply, totally avoid this pitfall - by always having L1 equaling L2, both chokes being the same.

 

I find the basic single L.S.E.S. Filter ( L1/C1/L2/C2) can be adequate for total amplifier loads up to about 70 to 80 mA.

 

If an amplifier application requires a higher total current, intelligently use more separate L.S.E.S. Filters. ** Avoid adding L/C sections in series to the Finals, above two sections. **

 

Similar to the loss of performance one experiences with a three stage tube amp ( versus two stages ), performance suffers - with B+ filters to the Finals using anything more than two L/C sections. KISS.

 

If a stereo amplifier – is drawing more than 80 mA. of total current, two L.S.E.S. Filters should be employed, one for each channel :

 

                                                                                              L1/C1/L2/C2 left channel               ( 80 mA. maximum )

                 Power Transformer / Rectifier /

                                                                                              L1/C1/L2/C2 right channel              (80 mA. maximum)

 

 

Another reasonable-sounding technique, needing less parts and chassis space, is to use a “split ” L.S.E.S, approach ( as seen in the 2019 KT88 build ) .

 

With a “ split or “Y” approach ”, L1/C1 is used / shared, by both channels, and the output of C1 is then fed individually per channel, each channel using a separate L2/C2, ( ie: L2/C2 Left, L2/C2 Right ). In a stereo amp. It would look like this :

 

                                                                                                                                                                           L2/C2 left channel ( 80 mA. max.)

                  Power XFR / Rectifier /                                 L1/C1 ( both channels)

                                                                                                                                                                           L2/C2 right channel ( 80 mA. max.)

 

 

 

 

                                                                                         What choke is good to use??

'

 

I have a choke suggestion in 2019, that I wish I had been using in 2006 !!

 

Hammond, for a long time, has made a 159ZA, rated 300 mHY at 1 full Ampere and only six Ohms in DCR. In 2019, this is typically ideal for L1 and L2. ( PSUD2 it at 340 mHY, its lightly-loaded ).

 

A choke, in a L.S.E.S. Design, ignores what E.E.s call “ critical inductance ” and so, it must have a large enough core, for current spikes to be contained within the choke, and NOT passed-on to the the rest of the audio circuit. Each 159ZA, operated at 70 to 80 mA. will easily absorb spikes in its 1,000 mA. rated core. And the choke's 6 Ohms of low DCR is TRULY wonderful to hear.

 

Realize, two 159ZA s in series, two L/C sections, will only be 12 Ohms total DCR.

 

Conventional amp designs, that most listeners use / own today, are usually consisting of a single large choke, 80 to 100 Ohms total in resistance, which is very poor in delivering energy on time. Avoid this !! Compare 80-100 Ohms, with just 12 Ohms total in this suggested L.S.E.S. implementation.

 

Recall Mr. Robert Fulton advised in 1979 – four decades ago “ The chokes need to be 20 Ohms or less, if you can find them”. Well, we can !!

 

Some comments on use of 6 Ohm 159ZA chokes :

 

            (1) Hammond's leads are too thin and are inadequate for L.S.E.S. use, and should be replaced with Mil Spec m22759/11 16 wire,                                  doubled-up,  two for each lead.    See this post for DIY photos :

 

        https://community.klipsch.com/index.php?/topic/182623-kt88-direct-     coupled-design/&do=findComment&comment=2372560

 

           (2) On initial fire up, a 159ZA choke will have a recessed / distant sounding midrange, lacking a bit in colors / harmonic structure. Worry                    not, it changes in nature after 10, 20, 50, and 75 hours, all for the better. This choke NEEDS to break in. Full break in takes 75 to 200                      hours of music playback

 

           (3) This 159ZA with its 1 Ampere larger core mass - loads a 5U4GB Electro Harmonix tube rectifier better than, say Hammond's 159ZB,                     etc. The 159ZA is perceived as playing back audibly with lower in distortion. Yes, the 159ZA controls the 5U4GB better                                               than a Hammond 600 mA. 320 mHY at 7.8 Ohm rated 159ZB, ….and all other chokes I have personally tried.

 

 

           (4) Two 159ZAs ( L1 + L2 ) seem to provide a better rendition of precise depth-imaging, events and placement of instruments in the                             recording site's Z axis.   Also, it seems to be the best so far experienced in low-frequency resolution, low end clarity. All good stuff !!

 

 

---------------------------------------------------------------------------------------------

 

 

                                                                                  What wire do I use, to do L.S.E.S.??

 

 

 

John L. Hasquin, describes L.S.E.S. as a source-feed supply, and the wire plays an important part, maintaining transfer efficiency, especially if maximum dynamic contrasting is sought.

 

I suggest using Military Specified m22759/11 wire, in various gauges, throughout the supply, which starts with the line cord.

 

The line cord and ground can be 10 or 12 AWG, JVH's “ Flavor 2 ”.

 

Leads to the AC switches, fuse, and the main power transformer's primary winding need to be 12 AWG.

 

The ends of the High Voltage secondary can be either 14, 16 or even 18 AWG.

 

The center tap of the power transformer's High Voltage winding is likely best as a single long run of 8 AWG Mil Spec, starting less than one inch out of the winding, and positioned all the way to the front of the chassis' star ground location, as the ground bus. ( Usually it will be under two feet long ).

 

The 5 VCT winding of the tube rectifier can be 14 AWG on the ends, and doubled-up 16 for the center tap, feeding L1.

 

Wire for leads into the L1, L2, a 159ZA can be doubled-up 16 AWG. ( I will experiment with doubled-up 14 AWG there - in 2020 ).

 

Ask for Steve at Apex Junior, in California, USA - a long-time, honest surplus electronics dealer, to obtain decent prices and many color and AWG choices in m22759/11 wire. 866 427-3957. Cost varies with silver prices, versus his published list, but not drastically. Its a bargain, given the military-build quality, and performance.

 

              861294207_ApexJuniorSTEVE1866427-3957.thumb.JPG.ff1f5177a599188d0e38a1d00f9654a1.JPG

 

 

   

 

                                                                 What about caps ??    Types first, …............then, uF Value:

 

 

 

In 2019, I can only suggest using WIMA DC LINK MKP4 caps , with FOUR PINS, not two, as the C1 and C2 main caps. I use these as main caps in most amplifier locations. These are high quality MODERN film caps, extremely low in ESR, and VERY good sounding.

 

These sell for INDUSTRIAL prices, not audiophile prices !  Only use the WIMA brand – and only ones having four lead-out pins .

 

The WIMAs play back in the same league as the Blackgate Electron Transfer WKZ 47 + 47 uF cap at 500 VDC. Don't believe me?? A-B the two - in a great L.S.E.S. amp !!

 

Sonically, WIMA DC LINKS impress me as having NO storage-time effect, when doing pulsed information ( the Steve Clarke drum solo playback ). GE Silicone 2 holds WIMAs down in a chassis nicely, as shown in this KT88 amp build.

 

 

                                                                                                Capacitor uF values :

 

 

After over a dozen years of DIY L.S.E.S. building, and PSUD 2 simulating power supplies, I almost always find C1 equals 35 uF ( plus or minus 5 uF ) and C2 equals 50 uF ( plus or minus 5 uF), in all my L.S.E.S. Supplies !!!

 

My mentor and I when PSUD 2 simulating, are looking, not for the fastest settle time, but we seek a gradual and nicely PSUD 2 “ shaped ” smooth step-response, with a reasonable settle time. Sort of like a race car with broad- band engine response, powerful at at all RPMs, not an engine tuned to have maximum usable power only in a narrow band - at the highest RPM.

 

Additionally, we also want the B+ filter to have the least amount of parts as possible, to get the job done for the Finals. Attention.. This means only TWO L/C sections in series, as in L1/C1/L2/C2. KISS design!! This rules-out a more complex ( than L.S.E.S.) “ Flywheel ” per Mr. Pasternak..

 

John Hasquin commented on 7-1-2007:

 

" There is nothing ambiguous about dynamic impedance or low DCR power supplies. It is a less invasive way to achieve a low impedance power supply with the least amount of components. As most have found, the less junk you put in the signal path and power supply, generally the better the amplifier sounds. "              (JLH )  ( Jeff's emphasis )

 

 

In PSUD 2, AC ripple at C2, for a low mu triode Finals tube's plate supply, will simulate at up to 850 to 900 mVAC, and it will be perfectly acceptable in performance. A Pentode Final's plate supply is even more tolerant of high C2 VAC ripple, John L. Hasquin, EE, suggests on 12-16-2007, in this A.A. Post :

 

The question of power supply ripple is an over rated and over discussed issue. Pentode circuits are nearly immuned to the plate supply ripple. Just take a look at the plate characteristics. They are almost horizontal, which means a relative large change in plate voltage has little effect on plate current. The screen grid supply is a whole different story. The pentode is very sensitive to variations in screen grid voltage” ( JLH )

 

Ripple at C3, ( feeding the front end Input / Driver stage in tube amps ), needs to be low, and WELL thought out.   B+ design also should be WELL thought out for a Pentode G2 ( screen grid ) supply - as John mentions, and as done with this thread's KT88 amp.

 

I incorporate simplest ( one part !! ) SHUNT regulation, in both these amplifier areas, as taught to me to do by my Audio Mentor, Mr. Dennis Fraker. Please view the two larger ARCOL aluminum bodied Chassis-Mount Power Resistors, mounted inside each side-wall of that KT88 amp chassis.

 

Just remember, as a DIYer, you first clearly define the circuit's VDC and VAC goals, and simulate it all in PSUD2, before building, to be sure you will get what you need. Enjoy !! Thank you, again, Mr. Dennis Fraker.

 

 

Jeffrey D, Medwin                     5-12-2019

 

 

 

 

                       

 

 

 

 

                                                                       

 

 

 

 

Share this post


Link to post
Share on other sites

Jeff, as you know, there's a heated discussion about your build on AA in which Dennis made some assertions yesterday which made the little remaining hair on my head start to fall out!  He asserted that published tube data is all wrong since it doesn't account for thermal stresses within the tubes, and that his simplistic method of generating plate curves (using a variable B supply and some batteries) provides the only correct data.  My traditionally trained brain just can't accept this.  Since you are using Dennis' parameters in this build, I thought it fair to ask you to please post his plate curves along with a detailed explanation of how he knows what is going on inside the tube thermally, what corrections he has made to allow for this, and why he does so.   I can't imagine that he has a sufficient background in electronics, metallurgy, physics, etc. to justify his claims (his statement about the 75TL really got me- Eitel and McCullough should have hired him to do all of their engineering when they had the chance!).

 

Those who want to know a bit more about this very involved topic may enjoy this article:

 

https://www.john-a-harper.com/tubes201/

 

Is there any chance you can convince Dennis to sign on here to explain all of this?  I'm willing to consider his points of view if he can back them up with some proof.

 

 

Maynard

 

 

Share this post


Link to post
Share on other sites
On 5/12/2019 at 7:31 AM, tube fanatic said:

Jeff, as you know, there's a heated discussion about your build on AA in which Dennis made some assertions yesterday which made the little remaining hair on my head start to fall out!  He asserted that published tube data is all wrong since it doesn't account for thermal stresses within the tubes, and that his simplistic method of generating plate curves (using a variable B supply and some batteries) provides the only correct data.  My traditionally trained brain just can't accept this.  Since you are using Dennis' parameters in this build, I thought it fair to ask you to please post his plate curves along with a detailed explanation of how he knows what is going on inside the tube thermally, what corrections he has made to allow for this, and why he does so.   I can't imagine that he has a sufficient background in electronics, metallurgy, physics, etc. to justify his claims (his statement about the 75TL really got me- Eitel and McCullough should have hired him to do all of their engineering when they had the chance!).

 

Those who want to know a bit more about this very involved topic may enjoy this article:

 

https://www.john-a-harper.com/tubes201/

 

Is there any chance you can convince Dennis to sign on here to explain all of this?  I'm willing to consider his points of view if he can back them up with some proof.

 

 

Maynard

 

 

 

 

 Hi Maynard, 

 

So far, I didn't read that, nor do I particularly have any interest to read about the head banging between Dennis and the conventional EEs on that " Audio Asylum " ( well named ) Forum.

 

If you have questions, please ask Dennis, his phone number is posted on the Serious Stereo Web site.  He returns all calls, and is a VERY nice person to speak with.  Alternately, you can approach him in writing on that Forum.  

 

When you talk about "proof", I think Dennis probably makes the best sounding SE tube amps - ever made in the history of audio, Maynard.  I have heard his monoblock pairs, the past 11 out of 12 years at RMAF shows, various set-ups, and have a VERY good idea as to how capable his design and builds are.   The reviewer from Six Moons Audio (  Stephaen Harrell, in 2005  ) and Stereophile Magazine (  Herb Reichert in 2016 ) who essentially gave him, and his Display Room, Best Sound of Show, ought to be enough "proof" that Dennis's talent and understanding goes well-beyond the normal person into audio..

 

My first Mentor, Mr. Robert Fulton," nailed" all of this topic in two sentences he wrote / published in 1978 on wire in audio  ( First Choice In Listening "Those Funny Little Wires ").  At the end of one paragraph he chose to write :

 

                                                                                         " In science, what is obvious is not necessarily true ". 

 

At the end of his two page discourse on wire in audio, he concluded his message to us by choosing to write :

 

                                                                                        " Scientists do not pursue the truth, it pursues them. "

 

Regarding Dennis :  Unfortunately, you likely have not heard Dennis Fraker's work at all, have you ??  I certainly have. I know that those fellows he is banging heads with on AA,  not one of them, ever heard his work as I have.  The proof, is not in any theory - article Maynard, and the proof is not found in what people, including you Maynard,  think they "know" to be true..  The real proof is found..... in the pudding,  and that Maynard, to me,  is all that matters in the end.

 

I would prefer to have this thread focused on design / build aspects of this 2019 SE DC KT88 amp !! 

 

The contents and ideas I expressed on this thread's particular page, page eight, regarding L.S.E.S., are more important than much of what many people will ever see or learn, in audio.  As a non-E.E., I stand on the shoulders of two of the nicest and most extra-ordinary men I have ever met in audio,  Messers Robert Fulton and Dennis Fraker.   I shared information openly herein for two reasons : (1) to go public, go on record / best foot forward - for posterity and (2) for the 1% , or maybe only zero point 1%, of the readers who will get off their rear ends, actually build it, hear it, and enjoy it, ..........around this world.   

 

Non commercial.   'Hoping to serve others, ........................Who teaches us to do that  !

 

Respectfully submitted to you Maynard, with sincerity,

 

Jeffrey

 

Robert on Audio Wire, 1978, page 1 of 2.pdf

 

 

Robert on Audio Wire, 1978 page 2 of 2.pdf

Share this post


Link to post
Share on other sites
On 5/12/2019 at 7:31 AM, tube fanatic said:

Is there any chance you can convince Dennis to sign on here to explain all of this?  I'm willing to consider his points of view if he can back them up with some proof.

Not going to happen Maynard.  You just have to accept it because he said so.

  • Haha 1

Share this post


Link to post
Share on other sites

                           5-13-19   Progress Photos

 

Today was interesting.  I decided to use 8 AWG as grounds, not just for the ground bus, but for all three GTO bypass caps, and for grounds of C1, and C2 left and C2 right.  

 

How does one join two 8 AWG ground wires, one to another, in a SE audio amp, with limited build space??

 

Its virtually impossible to solder two 8 AWG wires well, with my 300 Watt Weller iron.  I did not want to add any lugs, to interfere with the wires connecting one to another.  No one I know of has ever faced this before in audio amp building.

 

Here is what I did.  I tinned each 8 AWG wire, where two were to meet. I then attached them, typically 90 degrees from each other.  I used a long , stripped end of similar Mil Spec wire, but in 16 AWG, and wrapped this 16 AWG around the two larger wires, where they intersect.  Then, I twisted the unattached ends of the 16 AWG, with a precision pliers, until the two larger wires were securely in contact with each other.  Next, I soldered this entire joint with my 300 Watt Weller D650.

 

I will live with this work, kept intact over night, and see how I feel about it, when I see it again in the morning.   This initial idea may be the best option, and Standard Operating Procedure for " intersecting two 8s " in the future !!  Fun stuff huh ??  Any other truly good ideas are welcomed.

 

 

 

160750521_P1010056explainedFINALREV3.thumb.jpg.41cc250c05f4e0d94f5e2eab88b7633b.jpg

 

 

Well, I certainly like the look of this Brass capacitor support plate, clear-coated.   ' Have to connect the pictured GTO to the main C2 , positive to positive, next.  The Orange wire on C2 positive goes to the Magnequest DS-025 output transformer's primary winding, and that single blue wire comes from the output transformer's primary ( the winding's other end ) , and goes to the KT88 tube socket's Plate Pin.

 

 

 

 

P1010051.thumb.JPG.a201224eeac8e5a709c41b8055418648.JPG

 

                          Frankly, I am anticipating this SINGLE 8 AWG ground bus will sound good, after living with, hearing, the "trio" of 12+12+14, equaling 8 AWG.

 

 

P1010054.thumb.JPG.63a068477057d74df63f49c29fc8a750.JPG

 

                                                                                                                   I can't figure out - any other way to do this !! 

 

 

 

436967465_P1010048USE.thumb.jpg.5fafecc1765d1db847d755154077947a.jpg

 

 

 

More, later.  Thanks - for looking.                    Mr.John Gerndt, ace DIYer, I am now starting to clean flux off of soldered joints.  Thank you, for that suggestion.

 

 

 

 

Share this post


Link to post
Share on other sites

                  5-14-19  Progress Photos

 

Have both channels wired, up to and including C2,  the caps that run the Finals' B+.  Slow but sure, careful.

 

 

 

                                          356300610_P1010072USEfirstBEST.thumb.jpg.a34424abd77fc0b29885b0794b321498.jpg

 

                                                                                                  Smile, for the Camera !!

 

 

 

 

257374920_P1010063USE.thumb.jpg.2e28f3d965ba2ae96924ec24766f6fad.jpg

 

 

                                                    Above      Pre-Soldering  :      m22759/11 16 wrapped tightly around both large m22759/11 8.

 

 

 

798899383_P1010070USEBEST.thumb.jpg.8a5036623f68046afc9301b21ea8b54c.jpg

 

 

 Soldered and de-fluxed.  Short Finals' cathode resistors' return to Ground Bus.  A critical build area !!    Rk's return wire,  type AND amount, determined by ear.

 

 

 

 

32011444_P1010074USE.thumb.jpg.4f63e3dd31360b718b44aed2e44fcdd2.jpg

 

 

Much more to do !  Have a great day !!

 

 

 

Share this post


Link to post
Share on other sites
7 hours ago, Jeffrey D. Medwin said:

This initial idea may be the best option, and Standard Operating Procedure for " intersecting two 8s " in the future !!  Fun stuff huh ??  Any other truly good ideas are welcomed.

 

A split bolt connector?

Share this post


Link to post
Share on other sites

Jeff, what is the purpose of removing the flux from the solder connections?  Other than cosmetics, I have always believed that it is not necessary unless used on printed circuit boards which will have elevated temperatures in the 200+ deg. F range.  For hard wired audio amps, such a temperature under the chassis is very unlikely (I sincerely hope so anyway!).  Just wondering.......

 

 

Maynard

Share this post


Link to post
Share on other sites
1 hour ago, tube fanatic said:

Jeff, what is the purpose of removing the flux from the solder connections?  Other than cosmetics, I have always believed that it is not necessary unless used on printed circuit boards which will have elevated temperatures in the 200+ deg. F range.  For hard wired audio amps, such a temperature under the chassis is very unlikely (I sincerely hope so anyway!).  Just wondering.......

 

 

Maynard

 

 

Hi Maynard !!

 

Purpose :  I am not sure, need to ask DIYer John Gerndt.  He likely may have A-Bed this.  I have not.

 

I am removing flux on this build, because of cosmetics, as I am showing all these below-the-deck photos.

 

Maynard, I have been labeling parts a LOT, because you or I may know whats for what, but the average viewer, looking at a mass of parts,  should be able to make more sense out of the build. 

 

I hope I am not overdoing labeling by being repetitive. !!!  I feel its better communication !  What say you , re Photos??

 

Jeffrey

Share this post


Link to post
Share on other sites

The pics and labeling are terrific and are reminiscent of some of the electronics magazines from back in the day.

 

Maynard

Share this post


Link to post
Share on other sites

 

  Thanks Jeff  for the detailed view of your latest build . It truly does

appear to be well thought out and executed version of your builds.

   So I'd also like to add " not enough can be said"  the use of

GTO's as Bypasses in the Power supply .

 

  Willie

Share this post


Link to post
Share on other sites
17 hours ago, drummerwill said:

 

  Thanks Jeff  for the detailed view of your latest build . It truly does

appear to be well thought out and executed version of your builds.

   So I'd also like to add " not enough can be said"  the use of

GTO's as Bypasses in the Power supply .

 

  Willie

 

Why do you consider GTO bypasses so wonderful in an audio application?  Is it purely subjective, or is there a scientific explanation?  Those following the build may be curious.  

 

Maynard

Share this post


Link to post
Share on other sites

 

On 5/15/2019 at 7:42 AM, tube fanatic said:

 

Why do you consider GTO bypasses so wonderful in an audio application?  Is it purely subjective, or is there a scientific explanation?  Those following the build may be curious.  

 

Maynard

 

 

Maynard, and Willie ( Drummerwill ), 

 

Give me 48 to 72 hours maximum, and I will respond to GTOs........... on several levels,. 

 

 I'll start with the USA GTO history in audio amps, supply published data sheets, good photos, and describe  ( in my own words, as a NON E.E. ), what I believe is happening " scientifically" , when we use GTOs, ................... particularly friends,  when applied in  L.S. E. S. - designed tube amps and well-wired, high efficiency audio systems.  

 

To the best of my knowledge, no one has discussed GTO's use on line, in audio amps.  I believe it is very much cutting-edge Maynard.   The audio public is totally unaware.  That is pretty funny.  We will debut the subject here, in this Forum's thread.    

 

It started in about 2015, in the USA, fortuitously with me experimenting. 

 

Myself, and Willie ( Drumerwill ) are likely the ONLY people in the world to have applied GTOs , properly executed, in a well-made LSES style tube amps Maynard. 

 

Dennis Fraker was sent GTOs from my supply, maybe three years ago, and he has not yet gotten a opportunity to experiment with them.   He will.

 

With the new use of 8 AWG single-run Mil Spec wiring, ( and the way in which I am operating my 2018  6005 SE DC amp / A7-8, the last three nights ),  I believe the case for GTOs has become even more compelling, ( Willie ) ....just from what I am  most-recently hearing !!!  These GTOs also have applications in speaker crossovers.

 

Willie, if you care to, maybe you can compose your own subjective experiences, ( downstairs and upstairs systems ), and post them, so its not just one man's opinion.. 

 

I'll be done preparing a thorough GTO post soon - within 72 hours.  Why in the heck would I ever insist on adding three of those " big things " in recent amp builds, the last few years  ???  Coming up soon !! 

 

I have limited computer-on-line time each day.  I also maintain a job, am not retired like most people my age.

 

Much FUN ahead.  The best............ is yet to come ...my audio friends !!    Thanks everyone, for looking.

 

 

Jeffrey

 

             2005272802_GTOSnippedDESCRIPTIONedited2.thumb.jpg.fd699430bca25f86e02e21974633c321.jpg

 

 

                                                                                                    Music IS pulsed information!!  

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

BS... you are on the "cutting edge and the audio public is totally unaware" ... just more delusional self grandstanding nonsense 

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.

×
×
  • Create New...