Very fine workmanship from Amplitude

[Painful Reality]

This person has professional metal working ability from automobile restoration/painting, and has been working with tube and television equipment since most of us were kids. His workmanship, including chassis painting (powder coated here) wiring -- all of it, is really among the best I have seen.

Erik

It that's amongst the best powder coating you've ever seen, I suggest you have an appointment with an optometrist A.S.A.P.

I'd rate it amongst the worst I've seen. Unless the "see through" effect was wanted, it looks like a botched job.

Rest is cool though. If you like the retro art deco look.

[NOSValves]

Speedball:

"So is the switch close to that a bad thing"

A power switch and an IEC connector have the same blood type (type 'AC'), which is why they have been put close together. Some builders don't worry about installing power switches in the front of the chassis for the sake of conveniene. However, since the high impedance first voltage gain stages into (some) amplifiers are often also up near the front of the chassis, many builders really prefer to have any AC carrying wires, even if they are shielded or twisted for minimal hum, away from those high impedance sources. High impedance circuits, particularly where signal levels are low, tend to be less immune to noise problems associated with 60Hz AC hum, RFI, EMI, etc.

I once built a version of the AES (Audio Electronics Supply -- division of Cary Audio) AE-1 preamp (which I still use), and installed the switch at the back of the chassis in the exact same location as this amp from Audiogon. I had worked on two factory-built AE-1 preamps, and found both of them to be reasonably quiet, but still nevertheless noise-prone. The factory chassis had power supply and signal circuitry practically on top of one another, as well as AC power switch wiring very, very close to the first stage of the preamp. I will not say the preamp I made is a better preamp, but it is more quiet in terms of background noise than the two factory examples I had here. I also used a larger chassis for the same reason.

Where to install the power switch can be a matter of personal style and/or building practices. I have been taught to keep, if possible, any AC carrying components as far away from signal related parts as possible. Even my old RCA Tube Receiving manual discusses the importance of good wiring practice, including neatness and separation of power supply and signal wiring, in high fidelity circuits.

Erik

Erik,

You been living in the noise prone SET world to long. My amps for instance range from a low .8mV on the output to a high of 1.2mV this depending on how quiet the front end tubes themselves are most of this noise on the outputs is tube hiss not hum in fact you can stick your head in the woofer cabinet on my Lascalas with my amps and hear nothing! These PP are not humming SET amps that you have to spend countless hours moving wires a 1/4" one way or the other. Its very easy to get a PP amp for all intensive purposes dead silent. Ask anyone that owns my amps and a good portion of the vintage amps I rebuild. I just finished an EICO HF89 stereo power amp yesterday this amp has .9mV on one channel and 1.1 mV on the other it has what I would call a sloppy original wiring job by the kit builder along with numorous errors(anyone can do it right). When it comes to Push Pull if you spend all your time on the same noise issues as you do on SET you will cut yourself extremely short. Spend the time where it counts on the front end to get as perfect as possible phase inversion and amplification. Tune feedback for what your desired frequency response with a scope, distortion analyzer and your ears.

Craig

[NOSValves]

Max,

Frankly I had a stencil company all lined up to letter the VRD plates they did various digital demos on there PC for me and I personally thought no matter what font, style or size it was a step backwords. I like the nice clean look myself.

Craig

[AnalOg]

Here is another interpretation, using all new parts and refurbished power and OPTs, of the ST70. These are built by the same person who did the brief modifcations on the Baldwin I have. This person has professional metal working ability from automobile restoration/painting, and has been working with tube and television equipment since most of us were kids. His workmanship, including chassis painting (powder coated here) wiring -- all of it, is really among the best I have seen. He also installs the meters you see on the front panel of this amp. There is another Dyna 70 available for under $700 that doesn't have the meter.

Dee's awesome new MKIIIs were from the same builder.

http://cgi.audiogon.com/cgi-bin/cl.pl?ampstube&1134664996

Erik

I'm sorry but that amp looks like one of those antique clocks you place on the center of a fireplace, and with a bad coating job to boot.

Tom

[sfogg]

Craig,

"You been living in the noise prone SET world to long. My amps for instance range from a low .8mV on the output to a high of 1.2mV "

The SE-OTLs Erik has had in his system are rated to 0.2mv of noise.

After slightly tweaking of wiring position in the one I had it was closer to 0.1mv.

Shawn

[NOSValves]

Craig, "You been living in the noise prone SET world to long. My amps for instance range from a low .8mV on the output to a high of 1.2mV " The SE-OTLs Erik has had in his system are rated to 0.2mv of noise. After slightly tweaking of wiring position in the one I had it was closer to 0.1mv. Shawn

Wow!!! That really makes a difference EWWWWWWWWWWW You can't hear the amp even with a super duper hearing aid. BFD

Shawn do you have some desire or true love for Erik. Can Erik not stand up like a man and have a discussion without you coming to his rescue? My god.

Craig

[jt1stcav]

C'mon now, Craig...ol' DeanG usually comes to your aid once in awhile (or is it the other way around?)...[]

[sfogg]

" Wow!!! That really makes a difference EWWWWWWWWWWW You can't hear the amp even with a super duper hearing aid. BFD"

The point was that you, wrongly, claimed Erik had no experience with

quiet amps. The reality he has had experience with amps that are

quieter then your reference.

BTW, you can hear a difference in those noise floors. My Dynacos are

right around 0.8mv and the difference in noise between them and the

SE-OTL was audible.

Of course it should be since it is about 11dB of a lower noise floor.

IOW, the 0.8mv has a noise floor that is over twice as loud. For an amp

with 1.2mv of noise it is closer to 15dB a higher noise floor.

Get some experience with a quieter amp or a quieter room.

Shawn

[Erik Mandaville]

Shawn:

It's true about the SE OTLs. Having a noise floor that is as low as possible has always been an important factor to me, and like you, I found that some small amount of experimentation with wire positioning was effective in bringing background noise to an even lower level.

The stereo T-16 that I had here for a couple of weeks was a marvelous amplifier. It wasn't a surprise, though, because I think Bruce is a talented designer. OTLs really have a sound that is different from both solid state and conventional transformer-coupled amplifiers, and I am kind of kicking myself now that I didn't hold on to the T-16 when I had the chance.

OTLs have been brought up recently here. This is Transcendent's latest and most powerful monoblock, the so-called 'Beast'[] The name notwithstanding, I think this might also be a great amplifier for those with less efficient speakers, or those with big horns in a very, very large listening area -- for example, if one happened to purchase an auditorium for use as a home theater or music listening space.

http://www.transcendentsound.com/Beast%20OTL.htm

These are surely more expensive than his other products, but for the price of the kit, compared to what I have been told is 'real' hi-fidelity amplification, it is not out of proportion -- particularly compared to some other examples of output transformerless technology.

Craig: I have listened to MANY directly-heated single ended amps, and the DRDs from Welborne Labs exhibited vanishingly low noise. I'm sure you don't remember the fact that the Moth 2A3 amp I made uses regulated DC on ALL heater/filaments, including the 2A3s. Except for some power transformer mechanical hum, which I have reduced greatly with simple rubber grommet dampening, the noise element of that amp is truly on par with the Teac. It sounds virtually inert. In fact, the Teac has slightly louder HF hiss from the tweeter, but that was never a problem since our listening position if quite away back from the speakers.

The paint work on the Dynacos is flawless -- opinions regarding that are incorrect. This person also does professional auto-body work, although the powder-coating is 'farmed out' to a powder coating facility. What is shown here (I don't care of the red color) is an example of a wrinkle-texture finish. Again, this person has been working with tube equipment since I was a child, and I'm 42.

Erik

[Marvel]

I do like the size of the Welborne chassis. At least you have a bit

more room to work under there. The ST-70 chassis is pretty tight and

doesn't give a lot of room for experimentation.

Bruce

[NOSValves]

" Wow!!! That really makes a difference EWWWWWWWWWWW You can't hear the amp even with a super duper hearing aid. BFD"

The point was that you, wrongly, claimed Erik had no experience with quiet amps. The reality he has had experience with amps that are quieter then your reference.

BTW, you can hear a difference in those noise floors. My Dynacos are right around 0.8mv and the difference in noise between them and the SE-OTL was audible.

Of course it should be since it is about 11dB of a lower noise floor. IOW, the 0.8mv has a noise floor that is over twice as loud. For an amp with 1.2mv of noise it is closer to 15dB a higher noise floor.

Get some experience with a quieter amp or a quieter room.

Shawn

No the point I made is he spends to much time on getting the noise floor as silent as possible while ignoring other aspects of the designs that actually will make a larger difference in what people hear not what they don't hear. The noise floor in the Dynaco you mentioned "ON ITS OWN" is completely inaudible at even 3' from the 104db speaker. I would bet what your experiencing in your system is noise from the other components being amplified by the Dynaco. What is the input sensitivity of the Dynaco compared to the OTL there is where I bet the real difference lies.

Test the Dynaco for .8mV on the output again hook it to a normal full range Klispch Lascala/Khorn and install shorting plugs in the input of the dynaco just to insure no stray noise sneaks into the open RCA jacks. Sit down in your sweet spot and tell me you can hear a thing. If you can you have super human hearing. I can see spending time trying to get the hum out of a hum prone designs like SET where it is absoltely audible by the normal human being. This is not the case in the PP world.

Craig

[sfogg]

"The noise floor in the Dynaco you mentioned "ON ITS OWN" is completely inaudible "

To you in your system perhaps, not to me in mine.

"I would bet what your experiencing in your system is noise from the other components being amplified by the Dynaco.""

Nope, you would have already lost that bet.

You have fairly noisy components (not including a phono stage) if they are louder then your amps. If you have gain to spare in your pre-amp put some attenuation between the pre-amp and your amp and knock you components noise floor down further.

"Test the Dynaco for .8mV on the output again hook it to your system and install shorting plugs in the input just to insure no stray noise sneals into the open RCS jack. Sit down in your sweet spot and tell me you can hear a thing."

Been there done that... I can hear the Dynaco's noise.

Like I said... get some experience with a quieter amp and/or a quieter room.

Shawn

[NOSValves]

C'mon now, Craig...ol' DeanG usually comes to your aid once in awhile (or is it the other way around?)...[]

Actually there is a huge difference when Dean steps in. At the point he enters I'm being slammed by numerous people. This situation is just me and Erik. He makes the comments about things that pertain to me and I respond. This particular subject stems from an earlier post by him that was off the topic at the time he mentioned it (trying to side track another discussion) so at the time I let it slide. The subject reappeared so I thought it was the time to hash the issue out.

My point is proven ironically by Shawn. He states his Dynaco has .8mV on the output this amplifier if its a ST70 has the power switch on the rear and the inputs on the front connected to the front end through a 1" wire absolutely optimal for minimum noise floor according to the cheap seats crowd. It has the same residue noise as a supposed none optimal amplifier with the power switch on the front and the input on the back with 12" shielded wire. There is no difference............... Quality shielded input wire does the job perfectly.

No issue I rest my case.

Craig

[NOSValves]

"The noise floor in the Dynaco you mentioned "ON ITS OWN" is completely inaudible " To you in your system perhaps, not to me in mine. "I would bet what your experiencing in your system is noise from the other components being amplified by the Dynaco."" Nope, you would have already lost that bet. You have fairly noisy components (not including a phono stage) if they are louder then your amps. If you have gain to spare in your pre-amp put some attenuation between the pre-amp and your amp and knock you components noise floor down further. "Test the Dynaco for .8mV on the output again hook it to your system and install shorting plugs in the input just to insure no stray noise sneals into the open RCS jack. Sit down in your sweet spot and tell me you can hear a thing." Been there done that... I can hear the Dynaco's noise. Like I said... get some experience with a quieter amp and/or a quieter room. Shawn

First off Shawn your asuming to much here. I have no noise issue with my system. Check your anal meter its pegging again.

Craig

[NOSValves]

Shawn,

You must be super man to do the suggested test that fast. Complete hogwash.

Craig

[sfogg]

Craig,

"First off Shawn your asuming to much here. I have no noise issue with my system. Check your anal meter its pegging again."

I didn't assume anything. I said *IF* your components are louder then your amps.....

You were the one making assumptions about my systems noise.

"You must be super man to do the suggested test that fast. Complete hogwash. "

I said I have been there done that.

In other words I have already done that test before Craig. Like I said I heard the Dynaco's noise.

You aren't exactly suggesting a difficult test to try....

Shawn

[NOSValves]

From what I understand in your system it would be a monumental task. Isn't your system tri-amped with 6 different amps? Maybe I'm confusing your system with someone else.

Craig

[3dzapper]

Craig,(or anybody) have you ever tried applying DC to the heaters of the small signal tubes in a Dynaco using the existing transformer?

Rick

[sfogg]

"Isn't your system tri-amped with 6 different amps? Maybe I'm confusing your system with someone else."

Three identical amps (one per speaker) and that went in place as of a few weeks ago.

Noise has become a bigger issue since then not a lesser issue as every driver is now run at its full efficiency from any noise an amp has.

" From what I understand in your system it would be a monumental task."

First, it would still be easy just to wire an amp into any driver to check its noise on that driver. Re-balancing the system after changing amps would take more time but a simple noise test would be easy.

Second, I did the test before I was tri-amping.

Shawn

[NOSValves]

Rick,

It couldn't really be done. you would have to use a separate filament transformer. The small signal tubes would draw to much current off say the bias winding or the B+. Nope never tried it because these is ZERO 60hz or 120Hz hum !! I mean ZERO well maybe that is a slight exaggeration. But a good percentage of residue noise is just simply tube and resistor hiss. Nothing audible comes out of the woofer at all when there working correctly. I'm speaking of units I have modified and rebuilt.

Craig