tube fanatic
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Marty, do you have the model number? If not, tell me what the audio output tube(s) are and I can help you out-- Maynard
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Daughters tend to think things like tats are "cool"..... Until they "grow up" and discover the "tramp stamp" sends the wrong message to wealthy prospective "mates for life", LOL!!!
Well, she already has her other half and they both have tattoos and are planning on having some more done. He also thinks they're cool, and he's almost 38!!! I jokingly told my wife that I should have a tube imprinted on my butt and she told me to go ahead if that's what I want. Guess I'm just not "with it!!!!!"
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Somehow, at my age, I don't think it would be appropriate!!!
http://www.flickr.com/photos/tattooculture/4037519369/in/set-72157622647926510
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I just might order it, it could be fun for a first build. Would it move the woofer in a La Scala?
Hey Sterling! You will be amazed at how loudly the LSs can play with such little power. For a first project, this looks like a good bet imo. Best regards-- Maynard
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Craters & Freighters is wonderful. I've shipped large, heavy speakers across the country with them and they do an amazing job. Their packing would survive an airplane drop! All it takes is a phone call and they do the rest. Worth whatever they charge!
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My first point to point wiring amplifier was this:
http://diyaudioprojects.com/Tubes/50EH5/50EH5.htm
I found doing the point to point project let me understand what was going on much better than the kit on a board.
It's amazing just how nice a single tube "spud" amp can sound. I have a friend who built one a long time ago when he got bored one weekend (his usual designs are complex variants on the single ended theme.) Tubes like the 50EH5 or 60FX5 are great choices in that the voltage output of the typical CD player is sufficient to drive them to near full output. And with some negative feedback applied between the plate and grid, the frequency response can be tailored to suit one's listening taste.
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Erik, I sent you an email regarding an AK10A breadboard with a Model L speaker, etc. Please post if for some reason it didn't reach you. Maynard
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Thankfully, I haven't gotten into clocks!!! Given how much I spend on the amplifier and radio stuff I'd get brained with the frying pan if I even brought it up. Vintage communications receivers are amazing and I've restored dozens over the years, mostly for ham operator collectors, many of whom keep at least one vintage station set up. The modern digital ham equipment can of course do many things that the old "boatanchors" can't, but their performance is still breathtaking especially when considering their age (The Hammarlund HQ-180 is still one of the best receivers ever made imo.) I have a friend who has a huge collection of radios from the 20s, including many breadboards, which he's slowly liquidating. If he has an AK breadboard with the 01As for sale, I'll email you with the particulars. And to me nothing compares with the smell of an old wood cabinet radio on a cold winter night when the tubes are nice and warm (my wife has caught me many times with my nose near the back of the radios inhaling the fragrance!!!) Guess I really am nuts.................
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Over the years I have spent so much time experimenting that I often neglect music listening. Our system has also at times been so complicated -- switchable battery bias, standby switches, remote power supplies, etc, that my poor wife was so confused by the insanity that she was afraid to play a record unless I was at home so I could show her the fifteen switches that had to be thrown, and the order to throw them in, before music would come out of the speakers. Erik
Tell your wife that she isn't the only one who has had to live with the insanity that you outlined above! My wife won't even go near the equipment that I use as she doesn't want to be responsible if something blows up (we have a small system in the living room which she uses- tube amp with 1 switch, a tuner, and a pair of KLH 20s.) And I won't even get into the antique radio insanity which is almost as bad. At least she's not afraid to use those. Perhaps a new forum can be started for spouses of insane audiophiles.................... Regards-- Maynard
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Not sure I understand why Deckert is mentioning brand and year of manufacture?????
I think on the brand names its a smart thing to do. Reason is that I find different brands of tubes have different internal resistance and as a result, behave differently..and sometimes are even difficult to bias correctly. For example I have an amp that was designed around the Sovtek 6550, american 6550's are to hot for it, asian 6550's are too hot for it. It will run any EL-34 and only EI KT-90's, EH KT-90's are too hot for it.Interesting point. I haven't run into all that much variance among the US made NOS tubes. I've never used modern replacements (too stubborn not to stay with what I have always used!), but have read that they can perform quite differently. Guess from a marketing standpoint it's a plus in case someone happens to have any of the tubes Deckert mentioned.
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The new Tori boast a lot of tube options
1944 RCA Gray Glass 6Y6G
1949 Raytheon 6V6GT
1951 National Union 6V6GT
1950 Sylvania Gray Glass 6Y6G
1950 National Union 6V6GT
1955 Sylvania JAN-CHS-6V6GTY
1959 Tung-Sol 6L6WGB
1960 Canada G.E. 6L6-GB
1961 Raytheon 6V6GT
1962 Ken-Rad 6V6GT
1964 Sylvania 6V6GT
1970 Sylvania 6L6G
1972 RCA / Amperex 5881
1979 Philips JAN-6L6-WGB
1961 CBS-Hytron 6L6WGB
CEI 6L6GB
5881
International
6V6GTA
Ken-Rad Black Top 6Y6G
Sylvania Gray Glass 6Y6G
Westinghouse
6V6GTA
Tung-Sol Type41 6K6
RCA
6K6GT
G.E.
6K6GT
1940 RCA
Type 41 6K6
Sylvania
6F6GT
1961 G. E.
6F6 Metal
USSR
6F6M-1
Ken-Rad
6F6 Metal
6L6 Black Plates
Shuguang
6L6
RCA
Metal 6L6
RCA-Tung-Sol
6L6
Amperex EL37-6L6
Ken-Rad
6L6 Metal
USSR
6L6
1957 G.E. Black Plate 6L6-HP
G.E. Double "00" Getter 6L6GC
Tung-Sol
6L6
G.E.
5881
Sylvania JAN-CHS 5932 Black PlateNot sure I understand why Deckert is mentioning brand and year of manufacture?????
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Hi Erik- Just wondering if you have poked around under the chassis to see if Deckert is using variable degeneration for the treble roll-off feature that he discusses in the promotion:
"Finally there is
a treble control that has been carefully crafted to take edge off the
top end, from barely detectible to substantial so that you can enjoy
listening to sub-par recordings or internet streams without going nuts
as well as trim the shout right out of your single driver crossoverless
speakers in bright rooms."Also, have you by chance measured the filament, bias, plate, and screen voltages if tubes like the 6Y6 are swapped in as he says is reasonable to do? As you know, the filament draw of those is far greater than that of the 6V6, so I'd imagine that the voltage to the filament string sags a bit if they are used. I'm also scratching my head about the different impedance requirement of the 6Y6 vs. the 6V6 as well as the fact that the tube can't be run at the same voltages as the 6V6.
Anyway, enjoy the amp! It sure is gorgeous. Hope you can indulge my curiousity. Regards--- Maynard
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" I kinda like the 'all tube design' with a bridge rectifier... "
That's fine as long as you use fast rectifiers for low noise, and a plate-voltage delay to avoid stripping the emissive material from the tube plates during warm-up.
The typical "receiving" tubes used in amps like this are not prone to cathode stripping from having plate (and screen with pentodes) voltage applied before the cathode is up to temperature. Even tubes like the 6V6, 6L6, and so on are not prone to this effect either. Amps which use rectifiers such as a 5U4, 5Y3, etc. (which ramp up the B+ well before the other tubes are at opeating temperature) do not demonstrate a higher rate of tube failure than amps which use a cathode type rectifier which heats at a rate similar to the other tubes in use.
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and only, 2 months shipping!
I don't know where they are located, but even if it's China, delivery can be fairly rapid. For the price though, even a 2 month wait would be worth it. A Hammond aluminum chassis for an amp like that runs around $25, and the transformers alone would push the cost well above what's being offered. Also, even if someone messes things up while building it, the financial loss isn't huge.
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A friend sent me this link. Even if it doesn't sound that terrific, for the price it's an unbeatable way to gain some experience with building your own tube amp:
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ml
The point is that it's not just amplifier performance into a resistive load that matters. Speakers typically behave like complex impedance devices electrically (...and acoustically): they have dips and peaks in their input impedance curves vs. frequency--sometimes these are dramatic changes such as in the Khorn's input impedance curve, shown above. This causes issues when amps with higher than 0.3 Ohm output impedance are used to drive them - FR issues among other things. If you use an amplifier with higher output impedance than this with a Khorn, it means that you will have to EQ your Khorns to achieve the same FR as using an amplifier driving them with 0.03 or less output impedance.
Totally agree about the varying speaker impedance issues (wish I had access to some Audio Precision equipment)! However, with speakers that dip to say 3.2+ ohms, the amp can be kept very "happy" by using its 4 ohm tap. The dip of a few tenths of an ohm isn't going to cause anything objectionable at the frequencies at which it occurs, assuming that its output impedance isn't nuts (again, I've never encountered output impedances of 15-30 ohms as you indicated in a previous post.) The higher speaker impedances at other frequencies will then, to a certain point, actually lower the amp's distortion somewhat. Granted, this must be considered in view of the somewhat reduced output power which goes along with it. Anyway, this discussion is fun. Hopefully, those following along will come away with some sense of what this insanity (and being an audiophile tweaker definitely fits the profile imho- this statement is not directed at you Chris; I'm as guilty of the syndrome in my own way!) is about and be able to draw their conclusions from more of a scientific viewpoint. Be glad to continue babbling if that's the prevailing consensus. A nice day to all--- Maynard
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Perhaps it appears that way, but I feel that there may be SETs out there that minimize the negative performance issues mentioned above and that probably sound as good as or perhaps better as the F3s. You are probably going to find that those amps may be extremely expensive relatively speaking, however, and their performance will be constantly changing by small degrees, but measurably as the tubes burn-in and subsequently age, and those amps will have extremely long warm-up times measured in hours, not minutes as in the case of the FET amps. These are performance issues that I consider in my assessment of one amp design vs. another.
Just to put in a few more cents worth of my thoughts Chris. Your comment above about SETs which minimize negative performance issues being extremely expensive is absolutely wrong. It should be obvious that it doesn't cost a huge amount at all to build triode amps using excellent quality output transformers. What's wrong with an almost totally flat audio band frequency response, with low distortion, as George demonstrated in the example I cited previously? The cost of duplicating such an amp is in the hundreds, certainly not extremely expensive by audiophile standards. Sure, the performance may change incrementally as the tubes age, but is that going to be audible in most cases? Definitely not! And why do you think that extremely long warm up times are needed? It takes all of 1-2 minutes for tubes to come up to operating temperature and stabilize. I have spent a large portion of my life servicing tube type radios and TVs as well as tube type audio equipment, and have never encountered the need for hours long warm up for circuits to stabilize and perform as desired. Can you explain the basis of your assertion about this? I'm not trying to be ornery (although my wife says that such behavior is natural for me!!!), but would like to know the basis of your thinking. Regards-- Maynard
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These are supposed to be the best of the modern KT88s: http://www.euroaudioteam.com/en/eat-kt88-diamond-valve-000011.html
Yeah, but they're like $1k a quad, or maybe even a PAIR as I recall. Redonkulous.You are sure right about that! I read an interesting article about the factory around a year ago. Talk about hand crafting taken to the ultimate degree. The folks building these tubes are true artisans. Quality does have its price..............
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These are supposed to be the best of the modern KT88s: http://www.euroaudioteam.com/en/eat-kt88-diamond-valve-000011.html
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Although all the advice posted is accurate, we've collectively overlooked the fact that stereo FM sensitivity is less than mono, i.e., it takes a stronger signal to get a stereo output with acceptably low noise. I would try a RF preamp ahead of your tuner. They used to be very common, but I guess now can be found your favorite online auction site. Try to find one whose gain is adjustable. Another fact is, of course, the antenna. My experience has been that older FM tube tuners-with certain exceptions-do not have the sensitivity of modern solid-state tuners. I'd also see if anyone in your area has the same model receiver or a tube tuner of equal quality and swap it out with yours to hear any difference. I suspect your problem is a mixture of inadequate antenna and a RF front end that is just not strong enough for your location.
Your point is well taken which is why I recommended trying a new 6CW4 and 6AQ8. In my experience nuvistors didn't have an incredibly long service life and sometimes tested "normal" but were inadequate for the job. Mixer tubes also can test ok but need replacement. Regrettably, both of these tubes are a bit costly.
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This is not the type of equipment on which to learn how to do an FM stereo alignment! You will need to buy (building one is an extremely advanced project) an FM multiplex/sweep generator. That isn't going to be inexpensive. In addition, you will need to have a good understanding of how to use/interpret what you see on the 'scope. Where are you located? I may be able to help you find someone qualified to do this for you.
I am in Parkersburg, WV.
I will likely just ship it off to http://www.radioxtuners.com/. They were recomended by forum member USNRET in another thread. He has been very satisfied with his results.
I'm not familiar with them but looking at their site, they're just what you need. Another alternative is Bob Eslinger:
http://www.oldradiodoc.com/main.html
He's an ace at doing this stuff also and has a lifetime of experience to draw from. Good luck and be sure to post the results after you get it back!
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So, since you asked, why does Craig build PP tube amps and not SET tube amps?
I think that he has answered that question on the forums, quite clearly. I was a bit surprised by the clarity of his response:
http://forums.klipsch.com/forums/p/158381/1674209.aspx#1674209
Chris
I thought that this topic was over! Craig's statement is a reflection of his design philosophy and is no more or less correct than anyone elses. Every amp designer has his/her group of followers who consider the sound of their equipment to be absolute perfection. Craig has his, I have mine, Deckert has one, Pass has one, and so on.
In case those following this topic didn't click on a link I had provided previously (http://www.tubelab.com/BudgetOPT.htm), here's an excerpt from it:
Electra-Print:
These are the reference transformer, I have found nothing better for this
amp.
Best sound is achieved at 50 mA with 300B's. Distortion measures 2.3% at 4.5
watts
(mostly 2nd harmonic), frequency response is 14Hz to 28.7KHz, and visible
clipping
appears just over 5 watts. Specs measured at 1watt: Frequency response 3.6Hz
to 29.1KHz,
distortion 0.91%. This transformer is only rated for 10 watts, but it is 5
times the size of the others.
No visible saturation effects were seen at 5 watts and any frequency above
20Hz. The sound is excellent,
this is the amp that I use daily.
This is a frequency response
plot of the amplifier operating at 1 watt with 300B tubes through the
Electra-Print transformers. Response is ruler flat across the audio band,
except for about 1 db of loss at 20 KHz.Distortion at 1 watt. Mostly
second harmonic, but the third and fourth are clearly visible.Remember that this was obtained using a 300B triode. The distortion figures are wonderful, and the frequency response is similarly wonderful (don't compare this to a SS amp though- apples and oranges.) Even at 4.5 watts out, 2.3% distortion is just fine and well within the accepted design parameters for vintage amps. The 0.91% at 1 watt isn't even worth discussing, and for those using high efficiency speakers, that much power per channel is often far more than is needed for the desired listening level. It should be obvious from this (at least it is to me and my fellow SET enthusiasts) that the magical SET sound is caused by something which we are not measuring. In the shop we used to do all kinds of level matched listening comparisons with different amp configurations (SET, SEP, P-P, SS, Loftin-White to name only a few) in an effort to try to figure out just what was going on sonically and to quantify it with objective measurements. All it did was take us in circles as each configuration had its sonic virtues and negatives. Using a particular amp design to resolve a sonic issue which is disturbing is in my opinion no different from using the tone controls of a vintage amp or receiver to accomplish the same thing. Any modification to the frequency response is a departure from what is in the recording (I say this with all respect for your philosophy Chris.) Heck, even using very high capacitance interconnects will affect the frequency response and sound with some equipment. This issue was debated long before I got involved in audio in 1960 and is likely to continue well into the future. We're not going to solve it!
So, my advice to anyone who has been following this topic is to buy what you find pleasing to listen to. If your friend doesn't like the sound of your system, tell him/her to go home and listen to what they like! You may not enjoy the sound of their system either.......................
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The MPX circuitry is prone to interference, etc. on older tube tuners. It's difficult to get around it unless you use a really good, isolated FM antenna. Noted this on many FM tuners, including TU-99, 919, 9900. 719, 719, and the Macs. I live in the sticks, and until I isolated the antenna it was an issue.
I had planned on a better antenna. I will make sure I buy one with good isolation charicteristics.
The problem is not in the preamp or amplifier sections. To troubleshoot and properly align the front end and multiplex circuitry you need to have some fairly sophisticated test equipment. Unless you are experienced in doing this, I suggest that you refer it to a qualified repair person. It's easy to mess things up very quickly! That said, you could try replacing the 6CW4 and 6AQ8 in the front end. Even though the stereo light is illuminated, you may still not have sufficient signal to get a really good lock on the station.
I was pretty sure it was either the FM front end or the multiplex circuitry. I am the type of guy who really enjoys learning. I learn by doing. I am content listening to mono, but I really want to know why she's only fireing on 7 cylinders. I had an electronics repair shop test all the tubes and they tested OK. I don't know how good the tester he used was, or if it was properly calibrated. He said an old timer gave it to him, and he only uses it occasionally. I am going to get a better antenna, and we can see if that extra signal helps.
if your tuner uses exposed variable capacitors (the evenly spaced aluminum fins that move as you tune stations ) you could air blast them with canned air to blow off all the dust.
While I was cleaning potentiometers, I sprayed those fins. They didn't look at all dusty. This receiver is actually very clean.
Sensitivity has more to do with the ability to pick up the station, not the quality of FM decoding.
The stereo FM signal is not a simple RF analog of a stereo audio signal. The main FM signal is actually the L+R channel signals combined. That makes it compatible with older monaural FM demodulators. To get stereo FM, a difference signal (Left minus Right) is modulated onto the sidebands of the main signal. You can't hear them directly. The FM tuner demodulates (removes the FM carrier) this sideband signal, then takes the mono (L+R) signal and combines with the difference signal (L-R) which elimintes the right channel info. It also inverts the difference signal and combines with the mono signal (L+R) -(L-R) which negates the left channel. Those two derived channels become the Left and Right analog audio.
Since you're receiving the monoaural signal OK, and the stereo light is on (which means the tuner is seeing the sidebands), somewhere in the tuner there is something going wrong with the inversion and summing process. On older equipment, the tuner is usually made of discrete components, meaning that something may be broken or mialigned that can be corrected. On newer equipment, FM demodulation is usually performed in a single integrated circuit that is not repairable.
A technician with the proper FM alignment equipment can probably repair and/or realign your tuner.
Nicely said. In answer to my question above, the consensus seems to be signal improvement( in case the side bands aren't quite strong enough), FM front end alignment, and then multiplex alignment. I can easily do the antenna part. That may be the only problem. As for the rest, I would have to build, buy or borrow an FM signal generator, an Oscilloscope and a VTVM at the very least. Or try to find a qualified tech in my little town.
This is not the type of equipment on which to learn how to do an FM stereo alignment! You will need to buy (building one is an extremely advanced project) an FM multiplex/sweep generator. That isn't going to be inexpensive. In addition, you will need to have a good understanding of how to use/interpret what you see on the 'scope. Where are you located? I may be able to help you find someone qualified to do this for you.
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I haven't heard either of the bookshelf speakers. I use RF-15s which are a predecessor of the RF-52 II and they are absolutely amazing in terms of smoothness, imaging, and bass output. A description of the room in which they are used is in my profile. Given the size of your room, either speaker type should work just fine (the bookshelf speakers will, of course, need to be elevated on stands.) So, it will probably be more a decision about appearance and location than anything else.
Is There A Simple Way To Measure Nominal Speaker Impedance
in Technical/Restorations
Posted
Marty, if that's an AC/DC radio there are some very definite electrical safety concerns which you should be aware of (especially if you're going to do an kind of testing or measuring while it's powered up.) Feel free to email if you want me to explain the concerns and how to address them.