OT: Show us your DIY tube amps

Lowohms, I am interested in any investigation/analysis of your claims as long as it is published in a professional journal and is peer reviewed. Please direct me to any such papers.

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Lowohms, with the 0.47uF capacitor removed you now have a Series-inductance input filter with the 72mH input inductor being way below the minimum required value required for the effective DC operation of this rectifier circuit.

For members of this forum you can check out:

Section 8. of this reference download: http://www.itermoionici.it/letteratu...s-Handbook.pdf (24.5 MB)

Chapters 30. & 31. of this reference download: http://www.ax84.com/rdh4.html (Brings up index with links to chapters)

Both publications have impeccable credibility.

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Originally Posted by mah

Lowohms, I am interested in any investigation/analysis of your claims as long as it is published in a professional journal and is peer reviewed. Please direct me to any such papers.

- - - Updated - - -

Lowohms, with the 0.47uF capacitor removed you now have a Series-inductance input filter with the 72mH input inductor being way below the minimum required value required for the effective DC operation of this rectifier circuit.

For members of this forum you can check out:

Section 8. of this reference download: http://www.itermoionici.it/letteratu...s-Handbook.pdf (24.5 MB)

Chapter 30. of this reference download: AX84.com - The Cooperative Tube Guitar Amp Project (Brings up index with links to chapters)

Both publications have impeccable credibility.

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Hi mah,

Seems like you are still hung up over L1/C1 whereas I have told you we must consider the entire filter to the Finals L1/C1/L2/C2, and the power transformer and rectifiers too !!

Fred Terman and the Aussie who wrote RDH4 have been around forever, what, about 70 years ?? People have been building tube amp power supplies this way all that time. It is really a shame, because none of those books' supplies work well in tube audio. The supplies ( in both quoted references ) are only OK for industrial applications, or maybe for an amplifier to call the pigs at the State Fair. To honor the music in my living room, frankly, those ideas don't work well at all.

Guess what, we found a much better way to do it. It has only been publicly disclosed for about 5 years, where I wrote about it on the Tube DIY Asylum, with great controversy from some EEs who were narrowly educated and unable to think in an open manner.

You seem to want to only see a certain type of material, from your stipulation

"as long as it is published in a professional journal and is peer reviewed".

Well mah, this is new and none of it is published in any such stipulated journal!!!! Sorry sir. :-)

What I can send you is a series of chronological postings by two EEs, ( who also happen to be VERY SHARP audiophiles ), that have built and experimented with this new approach I introduced, and posted their findings, engineering explanations, and listening experiences.

These two well-known and well-respected EEs are John Swenson and John L. Hasquin, and I would liken them on the AA Forum, or on any horn speaker design forum, to be somewhat like GM is here on the Altec Forum. ( well, no one is quite like GM, GM is very special !! )

Anyway, IF you are open to learn something new, you, or really any other Altec Forum member may send me a private email address, and their "moniker" here, so I know who has responded. I will promptly send back via email attachments a Word and/or PDF file, of their complied chronological postings on the subject.

Besides the postings of Swenson and Hasquin, one of my chief protagonists, Henry Pasternak, ( who I believe is a college EE professor ), was able to come up with a proper explanation of the " sub-critical L1, small C1 combination", in his case, 35 mHY and 20 uF . He later went on to post his measuring experiments of it on AA. He showed us all it produced a better result than a conventional L-Critical L1 as espoused by the two references you elected to post. Unfortunately for Henry, he never has heard the circuit, he just showed us his proof of concept. Poor guy, IMHO, he missed the best thing, not the reason "why", nor the numbers on his DMM, but hearing WHAT it does !!

So its up to you, or any one else. If you want to learn about this, just contact me with a send-to address and your moniker. I am drlowmu AT gee male dottie commie. I personally feel that this is the biggest advance in tube audio design I have ever experienced in my lifetime. I have no real financial interest in this. I am happy to share it as an amateur, with others. I KNOW it will transform a low powered tube amp into an instrument that will play the Altec speakers with great bass, ultra wide dynamic contrasts, and unprecedented speed. Just the things that most low powered single ended amps today don't do !!

BTW, off subject, I am a big fan of no loop feedback amps, for correct timing of music playback. That is heavenly on any high efficiency speaker. Write to me and I will respond.

LowOhms

LowOhms you are big on rhetoric and bereft of substantiation.

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Originally Posted by mah

LowOhms you are big on rhetoric and bereft of substantiation.

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Hardly mah, baloney. You are quick to criticize and get personal when I challenge your training and belief system.

I nicely gave you a chance to look at information from sharp EEs, instead you chose to launch a personal attack on ME, without even reading their information.

That is not nice.

Whatever I claim is "backed up", is in the public domain, and I can put people in touch with other audio enthusiasts who have built these supply circuits and amps, and listen to them. They will vouch for my accuracy.

Alternatively, if you would like a direct learn-by-doing experience, you can bring any SE low powered amp you build to my home, ( employing Terman or RDH4 power supply principles ), and you will easily hear what I have claimed.

So lets just agree to disagree, and we will leave it at that, This is going no wheres. Have a great weekend.

LowOhms

I had already moved on.

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Originally Posted by LowOhms

Hardly mah, baloney. You are quick to criticize and get personal when I challenge your training and belief system.

I nicely gave you a chance to look at information from sharp EEs, instead you chose to launch a personal attack on ME, without even reading their information.

That is not nice.

Whatever I claim is "backed up", is in the public domain, and I can put people in touch with other audio enthusiasts who have built these supply circuits and amps, and listen to them. They will vouch for my accuracy.

Alternatively, if you would like a direct learn-by-doing experience, you can bring any SE low powered amp you build to my home, ( employing Terman or RDH4 power supply principles ), and you will easily hear what I have claimed.

So lets just agree to disagree, and we will leave it at that, This is going no wheres. Have a great weekend.

LowOhms

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Originally Posted by mah

I had already moved on.

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No need for arguments fellas..

Arguments are rare unless LowOhms is here.

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Originally Posted by Old Guy

Arguments are rare unless LowOhms is here.

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Yeah, I see that even the way he states his opinions can be pretty inflammatory......

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Originally Posted by LowOhms

.....none of those books' supplies work well in tube audio. The supplies ( in both quoted references ) are only OK for industrial applications, or maybe for an amplifier to call the pigs at the State Fair.

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:O

"BTW, off subject, I am a big fan of no loop feedback amps, for correct timing of music playback. That is heavenly on any high efficiency speaker. Write to me and I will respond.

LowOhms "

This I agree with. none of my amps have global feedback. Distortion, freq response stand on thier own merit. Although I prefer PP circuits.
SE, sorry, just not enough poop for the music and SPL's I like.

Ron

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Originally Posted by RonSSS

"BTW, off subject, I am a big fan of no loop feedback amps, for correct timing of music playback. That is heavenly on any high efficiency speaker. Write to me and I will respond.

LowOhms "

This I agree with. none of my amps have global feedback. Distortion, freq response stand on thier own merit. Although I prefer PP circuits.
SE, sorry, just not enough poop for the music and SPL's I like.

Ron

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If Nelson Pass hadn't rescued me from the vacuum, i'd still be enrolled in the Stewie Hegeman school of thought. Heck, i may even enroll in some summer classes. ;)

Ok, Designer of the Citation II. Multiple feedback loops. Beyond that, you lost me completely.

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Originally Posted by RonSSS

"BTW, off subject, I am a big fan of no loop feedback amps, for correct timing of music playback. That is heavenly on any high efficiency speaker. Write to me and I will respond.

LowOhms "

This I agree with. none of my amps have global feedback. Distortion, freq response stand on thier own merit. Although I prefer PP circuits.
SE, sorry, just not enough poop for the music and SPL's I like.

Ron

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Hi Ron,

A P-P amp is a far easier task to design and DIY build, and P-P is forgiving to less than optimal executions.

In SE amps, the entire supply is IN the audio circuit, and it needs to be executed impeccably, which 99.99999 percent of existing SE amps ( and amp designers ) do not know how to do.

The P-P amp "messes" with the circuit too much. It has to split the phase 180 degrees, and then put it all back together, hopefully intact, at the P-P output transformer . Its a processor.

The SE amp does not have to invert the signal 180 degrees, and IF ( a big word ) the rest of the SE amp's execution is state of the art, then it will creme any P-P amp, easily. That is why we build em and use them on high efficiency speakers. Its a sub 2 Watt amp with about a 500 Watt "on-time" power supply, backing it up, zero negative feedback - of course. And its killer on Altecs.

I do NOT deny anyone's experience with P-P and SE Ron. I understand it fully.

I just wanted to share my very unusual experiences with any others who are open to DIY amp builds for Altec speakers. Cheers,

LowMu

Since I have some dynaco iron, I've been researching some designs, and came across this which looks really promising:

Jeff Yourison's El-Cheapo

A lot of tech talk in this thread. Here is my 2A3 SE amp running two tubes in parallel each channel. It was built by a gentleman by the name of Henry Hyde. Henry would not sell the amp while alive but left instructions in his will to sell it to me. The big iron is by Magnequest. I was working in Indonesia and went down to a small wood shop in a jungle village. Had them make this this custom hand carved cabinet out of a local variety of wood called 'iron wood' (not sure what it is). I dig the art deco look. I bi-amp using a big Crown for the low end. My technical observation about this amp is "sounds pretty good".

A real 'beauty' inside and out! What's the rest of the sound system?

Iron wood is a fairly generic name for the collection of the world's densest/hardest woods with the original being native to the Sonoran Desert: Ironwood Information

FWIW, this list doesn't show any in Indonesia per se, so no clue what yours might be: Ironwood - Wikipedia, the free encyclopedia

GM

It's a beauty, but I'm not crazy about surrounding a tube amp in a wooden case. It can hold in too much heat. It looks like that baby needs to breathe.

I left the high efficiency arena a few years back and bought a set of Infinity Kappa 9's. These sound great in their own way but require the equivalent of several arc welders to drive them. I used two Hafler 9505 amps which are really quite impressive, to drive each speaker's HF and a Crown K2 for LF. The Crown puts out 1200 wpc at lower impedance and all three amps would clip at higher sound levels.

Now I'm dusting off the tube gear and have a nice 12A7 preamp that was built by the same gentleman who built my 2A3. Bought a variac and some used vintage tubes. Picked up a nice set of Santiagos on the cheap and have collected all the components to build a set of A-7's. Have a large stack of teak wood I brought back from Indonesia and has been curing for nearly 10 years, so who knows?

Next up- going green. I am assembling 12VDC components and solar cells for my solar powered system. I will make amends for the huge carbon footprint left by my old Infinities.

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Originally Posted by TubesNhorns

I left the high efficiency arena a few years back and bought a set of Infinity Kappa 9's. These sound great in their own way but require the equivalent of several arc welders to drive them. I used two Hafler 9505 amps which are really quite impressive, to drive each speaker's HF and a Crown K2 for LF. The Crown puts out 1200 wpc at lower impedance and all three amps would clip at higher sound levels.

Now I'm dusting off the tube gear and have a nice 12A7 preamp that was built by the same gentleman who built my 2A3. Bought a variac and some used vintage tubes. Picked up a nice set of Santiagos on the cheap and have collected all the components to build a set of A-7's. Have a large stack of teak wood I brought back from Indonesia and has been curing for nearly 10 years, so who knows?

Next up- going green. I am assembling 12VDC components and solar cells for my solar powered system. I will make amends for the huge carbon footprint left by my old Infinities.

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ooooohhhh teak. definately measure twice cut once