Jump to content

Klipschorns with 300b amplifiers


sns109

Recommended Posts

Hello, this is my first post, although visit these forums often. I recently acquired a 300B SET amp to audition as a summer replacement for my two 845 SET amps which are space heaters. Both of my 845 amps have wonderful tonal balance, articulate bass, reasonably extended highs, fully involving mid range. This is the third summer replacement amp auditioned, the first two class a/b solid state, both nice enough but lacking the palpable, meat on the bones quality of my SETs. The 300B has a nice palpable mid range, highs are a bit rolled which I can probably live with. The big issue for me is lack of articulation in bass, this along with more rolled off highs gives a rather dark presentation.

 

Overly loose, warm bass has always bothered me, articulate bass is an absolute requirement for me. I suspect a 300b amp may be inherently unsuitable for me. Looking at the impedance curve of Klipschorns, below 8 ohms between aprox. 40hz to 225hz along with steep impedance curve is too much for this amp. No separate taps on amp, assuming 8 ohm on non-separate tap tube amp. It seems the 845 SETs with their 8 ohm taps overcome this limitation, the 300b tube can't handle it. I'm in midst of one mod which may or may not address bass issue in that I replaced the Russian K40Y9 coupling caps with VH Audio Vcaps.

 

Assuming this 300b isn't satisfactory for me, what amps do you guys think would work for me? At this point I'm planning on auditioning First Watt J2 or F7, another intriguing option would be AGD Audion GaN Tube monoblocks, class D amplifier that supposedly replicates SET amp sound to quite a degree. The class A solid state amps will also be hot, albeit not to the same degree as the 845's. Any other class D amps close to SET sound?

Link to comment
Share on other sites

I have to say I'm extremely particular when it comes to bass, once I hear a less than articulate bass my attention is forever distracted by it. Many other listeners seem not to be bothered by bass that bothers me.  My 300b is a cottage built unit, guy builds them in batches of ten,  power supply has 1000uf capacitance of  Vishay/BC components, hand turned output transformers which I'm assuming don't have 4ohm tap available. I'm using NOS Mullard F32 rectifiers, NOS RCA long grey plate 12au7, NOS Amperex Bugle Boy 6267 and Shuguang Treasure Black Bottle 300b. The Shuguang are reportedly at the lower end of the best in the articulate family of 300b tubes.

 

I previously built the Latino Dynaco clone amp. Granted it was in a different system, but I was never impressed with resolution of the unit in comparison with my 845's. And that was with some better quality parts than supplied with kit and top line tubes. I've owned several push pulls over the years, EL34 my favorite tubes in these,  while nice I still prefer SET sound.

 

I did own Wright Sound 2A3 monoblocks many years ago, I was using those with Omega and EL Jordan single driver speakers. My recollection was they did some very special things in the mids,  couldn't tell much about bass and highs as they are rolled in single driver speakers. I did obtain greater amounts of bass with these speakers with some Cary SLM 100 and conrad Johnson MV-55 I was running at the time. I'm afraid I wouldn't be satisfied with 2A3 bass, the 845 amps spoil me with great amount of drive, articulation, micro and macro dynamics. I find 845 and Klipshorns magical combo, life like presentation. If I didn't have the heat problem these would be my final solution.

 

I've heard similar reactions to many long term reviews of class D amps. I'm just wondering if the new GaNfets are an advancement?

Thanks guys, keep coming with ideas and possible solutions. Scott

Link to comment
Share on other sites

The specific amp I acquired is Tube Fantasy, individual in China builds these from his home. I purchased these based on the experience of some trusted users over on Audiogon, they've successfully used this guy's amps on Zu speakers.  While I know Zu speakers present a different load to the amplifier, I purchased based on build quality. Really rather funny, but the Chinese builder writes with better English grammar than many Americans. He appears to be knowledgeable and honest in my conversations with him. Also, having the amps in hand, they are quality built. 

 

I still believe my bass issues come from the rather difficult load Klipschorns present in bass. I suspect I'll need a 4ohm tap with any SET amp other than 845 to satisfy my bass needs. The 845 amps simply muscle themselves past this liability, assuming their single taps are 8ohm. BTW, 845's are Coincident Turbo 845 SE and Art Audio Carissa Signature. Running Coincident Statement line stage.

 

Being new to 300b amps. Is 1000uf of capacitance in 300b power supply (my 845's have tons more capacitance) sufficient to provide quality bass? Drive and micro and macro dynamics seem pretty nice, although not to the level of my 845's.

Link to comment
Share on other sites

The GAN (gallium nitride) FET class D amps I speak of are a rather new technology for audio. Technics SE-R1, and at a lower price level, the AGD Audion, LSA Electronics Voyager, Java Hifi and soon to come GAN amps from NuPrime, Nuforce and a few others. These FET's switch at much higher speed, supposedly eliminating some of the liabilities of older devices. Based on initial reviews the GAN amps sound less dry and sterile than other class D. If true, could be a game changer for class D.

Link to comment
Share on other sites

Thanks Jeffrey,

You make a lot of sense.

 

All caps electrolytic in this amp with exception of coupling cap. I replaced the Russian cap with the Vcap, as good a result as I could have expected, opened up top end, much better tonal balance now. Also, higher resolution, blacker background thing with the Vcap vs. Russian. The increased detail also distracts my attention from bass.

 

The power supply consists of four 100uf Vishay/BC component caps and one Epcos/TDK 600uf cap, also has choke. This is for each channel.

 

I have no doubt silver content in wire would help with bass, assume this is all copper. I may change out wire if I decide to keep amp.

 

This is my first foray into relatively low power SET with Klipschorn. You are correct in regard to crossover sucking power, the impedance curve is a bear from aprox. 32 to 225 hz. I hear macro dynamic compression in more complex passages, doubt this amp can ever overcome that limitation. The 845 amps are simply beautiful with the Klipschorns, absolutely no sins of commission. I've  tuned my entire system for over two years for perfect compatibility with the 845 amps, quite possible I don't find a sympathetic alternative amp.

 

At this point, I may have to go with a push pull if I stay with tubes, otherwise the class A solid state or the new GAN fet class D's if I continue to hear good things.

Link to comment
Share on other sites

BTW, my Klipschorns are modded, only stock piece is bass cabinet. Crites cast frame woofer, John Allen A55g mid, B&C DE120 tweeter, Volti mid horn, tweeter mounted on custom baffle in line with mid driver, Duelund silk/oil tin plate copper internal wiring, Furutech wire to woofer, Vampire binding posts, upgraded tag strip, Jupiter VT and Audyn True Copper Max, Duelund Silver bypass caps in Crites AA crossover with diode protection circuit removed. Result is much more natural timbre, greater transparency, resolution,  bigger sound stage, life size images, dynamics wide open. I never like to say never, but it is likely these are last speakers I'll ever have in main system.

Link to comment
Share on other sites

  Yeah, I did all the mods myself. While I can solder, replacing parts and building kits is the extent of my abilities. I could measure DCR on choke, however, where would I take measurement from? 

 

No schematic, pretty simple circuit. I will get pictures to you tomorrow.

 

I only thought silver would help by thinning out bass to some extent, I agree silver has much more affect on highs.

 

I appreciate the offer to help, hopefully something can be done to improve amp. Again, I'll get pictures out to you tomorrow.

Link to comment
Share on other sites

  • 5 months later...
On 2/4/2020 at 10:58 AM, Jeffrey D. Medwin said:

 

 

Amp OFF, voltages drained.  Each lead of the choke, is connected to the positive lead of a supply cap.  Put the probes on those two caps - where the choke leads are attached to..  Ohms scale. 

 

EDIT on 2-6-20, 

 

The amp owner measured the choke at 111 Ohms, over five times too high.. 

The wiring inside the amp is very poor IMHO, ...........as is every resistor..

Layout is sophomoric,, two-dimensional, not three, excessively long leads everywhere, tie wrapped together. 

Imagine an RCA Jack's input wires bundled and tie-wrapped together with the speaker leads, for about a thirteen inch span. !!!

Every cap inside appears to be an electrolytic, including Rk bypass caps .  We will decide in a week or two, what to do !!

So, what did you to the amps? I am interested as I have similar ones, pair of tube fantasy 300 B SET,  driving the RF-7 III's, they do sound really nice with no mod. and not too expensive tubes. 

  • Like 1
Link to comment
Share on other sites

  • 2 weeks later...
On 2/4/2020 at 12:05 AM, sns109 said:

  Yeah, I did all the mods myself. While I can solder, replacing parts and building kits is the extent of my abilities. I could measure DCR on choke, however, where would I take measurement from? 

 

No schematic, pretty simple circuit. I will get pictures to you tomorrow.

 

I only thought silver would help by thinning out bass to some extent, I agree silver has much more affect on highs.

 

I appreciate the offer to help, hopefully something can be done to improve amp. Again, I'll get pictures out to you tomorrow.

It appears you have some electronic skills so you may want to try building one of the SE SS Firstwatt clones. There is a new build that should be published soon that uses a V-fet  that has the curves of a triode tube which I think may sound much like Nelson's SIT amplifiers which were highly praised as having the 300b sound with more power which would equate to better bass. To the best of my limited knowledge the Firstwatt SIT amplifiers are the only SS amplifiers that have a true SET sound. All other mosfets have a pentode curve. 

 

The 845 tube is one remarkable tube. 

Edited by henry4841
Link to comment
Share on other sites

  • 2 months later...
On 8/1/2020 at 6:49 PM, pallpoul said:

So, what did you to the amps? I am interested as I have similar ones, pair of tube fantasy 300 B SET,  driving the RF-7 III's, they do sound really nice with no mod. and not too expensive tubes. 

+1.....      I have a pair of Tube Fantasy's too and would be interested in any mods to improve the performance. I'm a new owner and don't have many hours on them. A pair of GL300B's are due to arrive today to replace the previous defective ones. I'm using Telefunken EF86, Phillips NOS 12au7 and Mullard GZ34 to complete the tube complement. I'm bi-amping my speakers.

 

 

Edited by Chad
removed broken image
Link to comment
Share on other sites

  • 2 weeks later...

Schiit markets their Aegirs amp as class A like'ish. any body has had experience with them driving Klipsch horns ? i am tempted to try a pair, with a Shiit freya +.  any advise?  Now i am using a fire bottle SE 45 amp, with a matching Dennis Had pre amp. sounds good, nd can get loud if needed. 

Link to comment
Share on other sites

3 hours ago, Jeffrey D. Medwin said:

 

 

The Klispch speakers are generally hard to drive, with a SE power amp.  It's got high transfer efficiency losses, often a three way crossover to drive through, which is a killer for a sub 2 Watt amp to handle.  As I reported earlier above, you have to match the speaker to the amp. 

 

 

An acceptable push-pull tube amp, could be built for Klipsch speakers, but no one has ever done that in audio to date. 

 

Jeff Medwin


Jeffrey,  in regard to your first point, it is totally untrue in my experience. As to your second point above, back in the day I built many wonderful push-pull tube amps for use with Klipsch speakers.  
 

How do you come to these conclusions?

 

Maynard

  • Like 2
Link to comment
Share on other sites

  • Moderators
14 hours ago, Jeffrey D. Medwin said:

The better sounding SE tube amps, will be low powered, two Watts or less often,  and be used with two-way efficient speakers, with little or no crossover circuitry to get in the way.

 

What does this mean? 

 

The only way to go is a two way with no networks? So Jubilees are.out, Khorns, La Scalas, Cornwalls, 396s, all out?

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...