Doge 6210 - another great headphone amp

[tuatara]

Originally Posted by Roam

The question then becomes: Why do we keep using these designs over & over & over again? Why do we continue to build 300B amps based on designs from the 1940's? Why aren't much better and more recent tubes used, tubes which were invented after those 40's amps were designed?
.

Simple answer probably, the people who buy these amps like the way they sound. A lot of use grew up using 40s valve gear and designs as part of our everyday life and its a very comforting position to be able to go back to the tried and familiar.

I wouldn't have a clue what the circuit designs in my two valve head amps are, the fact is for me and others who have tried these amps, they work and work very well. The sum is usually greater than the parts and specs alone never tell the whole story.

[creeky]

Originally Posted by Roam

The question then becomes: Why do we keep using these designs over & over & over again? Why do we continue to build 300B amps based on designs from the 1940's? Why aren't much better and more recent tubes used, tubes which were invented after those 40's amps were designed?

First off I don't claim to be a know it all in this subject so excuse me if what I’m about to say is a load of old tripe :0)

My guess would be people reuse these old circuit and tube combos because they give the classic "tube" sound. Surely if you wanted an amp which gave you flat frequency response curves and lower distortion you would opt for a good solid state design so as to avoid the issues associated with tube equipment.

[drarthurwells]

Originally Posted by creeky

First off I don't claim to be a know it all in this subject so excuse me if what I’m about to say is a load of old tripe :0)

My guess would be people reuse these old circuit and tube combos because they give the classic "tube" sound. Surely if you wanted an amp which gave you flat frequency response curves and lower distortion you would opt for a good solid state design so as to avoid the issues associated with tube equipment.

Well, I would say you do know what you are talking about, based on the following:

To know that you know what you know,
and to know that you do not know what you do not know...
that is true knowledge.
-Confucious-

To not know what you do know when you know it, and to not know what you don't know when you don't know it, and to know what you don't know when you know it, and to not know when you don't know when you don't know it,.....that is true ignorance.
-Art-

lol

[hciman77]

Originally Posted by creeky

Surely if you wanted an amp which gave you flat frequency response curves and lower distortion you would opt for a good solid state design so as to avoid the issues associated with tube equipment.

A casual skim through Stereophile's online reviews shows that there are several Tube amps that measure pretty flat from ~20 - 20k. I have to say this surprised me but there you go. By the same token there are some with FR curves that are frankly shocking like the Cary 300SEI amp, but there are badly non-linear SS amps too.

[Roam]

Originally Posted by hciman77

A casual skim through Stereophile's online reviews shows that there are several Tube amps that measure pretty flat from ~20 - 20k. I have to say this surprised me but there you go.

It's not really surprising for me since I know how easy it is to achieve such a frequency response. What is disappointing is that the vast majority of tube amplifiers do not measure like this.

By the same token there are some with FR curves that are frankly shocking like the Cary 300SEI amp, but there are badly non-linear SS amps too.

Today's object lesson: Recall what I said earlier regarding 300B amplifiers with inadequate underpowered driver stages, based mostly on a 6SL7 & 6SN7 mix or the 12AX7 & 12AU7. In short, a 1940's bandwidth limited circuit. Now look at the tube complement of the Cary 300SEI, that's why it measures as poorly as it does.

[creeky]

Originally Posted by hciman77

A casual skim through Stereophile's online reviews shows that there are several Tube amps that measure pretty flat from ~20 - 20k. I have to say this surprised me but there you go. By the same token there are some with FR curves that are frankly shocking like the Cary 300SEI amp, but there are badly non-linear SS amps too.

Hello Hciman77,

Of course it is possible to achieve almost flat frequency response curves with tube based equipment however it always makes me wonder why someone would bother with such an amp. Up until now (perhaps wrongly) I have assumed the only point in buying tube based equipment was to get the much touted tube sound. If I was in the market for an amplifier with almost perfect freq response curves and low distortion figures I wouldn't even be looking at tube based equipment. Sure you can build tube amps which have those characteristics however a good solid state amplifier can also have those characteristics with the added benefit of not having to put up with the problems associated with tube amps i.e. no extra expense replacing worn tubes.

[hciman77]

Originally Posted by creeky

Hello Hciman77,

Of course it is possible to achieve almost flat frequency response curves with tube based equipment however it always makes me wonder why someone would bother with such an amp. Up until now (perhaps wrongly) I have assumed the only point in buying tube based equipment was to get the much touted tube sound. If I was in the market for an amplifier with almost perfect freq response curves and low distortion figures I wouldn't even be looking at tube based equipment. Sure you can build tube amps which have those characteristics however a good solid state amplifier can also have those characteristics with the added benefit of not having to put up with the problems associated with tube amps i.e. no extra expense replacing worn tubes.

Hello Creeky,
Does tubes perfromance degrade gracefully like a cartrdige or do they just go from working to not working ?

[creeky]

Originally Posted by hciman77

Hello Creeky,
Does tubes perfromance degrade gracefully like a cartrdige or do they just go from working to not working ?

Hello again,

It depends really, you get the odd one or two tubes that go out with a bang however that is fairly rare, in most cases they age gracefully. Only had to replace two tubes myself. They were worn when I started using them, Ii the end they became really microphonic and started hissing.

[drarthurwells]

Originally Posted by Skylab

Roam, you may well know more about this than the rest of us, but it's a real shame that we won't learn from you, since you are so incredibly and unnecessarily obnoxious in your posts.

If you have something to contribute, please try to behave in a civil fashion. Otherwise, please leave this place alone.

Originally Posted by drarthurwells

He tells it like he sees it, without reservation.

Give me that anyday over the sneaky and passive-aggressive snipes, concealing deceit and venom, more frequently seen.

Roam is a breath of fresh air.

I am sure most commerical amp designs are compromised in design integrity by cost cutting needs.

The trick is to get good sound in spite of design and part limitations.

Originally Posted by Skylab

I respectfully disagree that he is a "breath of fresh air" - hurling insults is not needed. But perhaps I am in the minority. In any case I don't care that much - I'm out of this discussion.

I didn't mean to suggest that you were wrong about Roam - I believe as you do that he is rude in some posts, and think most people would agree.

I just like an up-front and direct person who speaks his mind regardless of how little this mind produces or how wrong it is. Roam is telling the truth as he sees it with no deceit - what he says may be false but not knowingly so on his part.


Roam finds very few amps that meet his personal and idealized design characteristics. Obviously many audio engineers, who are paid to produce amps that sound good (where nobody would pay Roam to do this) would not agree with Roam's personal design requirements.

I know two amps, that Roam says have terrible designs, the Bada 12 and the Doge, have superb sound.

Some amps control the tubes so much that the amp imposes its own sound on the tubes, so that changing tubes does not result in big sound changes.

The Bada 12 and Doge change sound drastically with tube changes - the design of the amp allows the sound of the tubes to come out and not be choked. In such amps, the tubes used are more important to the sound than the amp - you can dial in the sound you want good or bad.

I enjoy the point of view that Roam offers on amp design as entertaining, but don't believe for one moment that his remarks on design define how the amp actually sounds.

Departures from Roam's ideals of amp designs, which Roam calls stupid and idiotic designs, might have been purposefully accomplished by audio engineers, to achieve some positive sonic effect which Roam doesn't appreciate.

If it were Mark Levison or Nelson Pass saying the things Roam said, I would pay attention.

[drarthurwells]

Originally Posted by hciman77

Hello Creeky,
Does tubes perfromance degrade gracefully like a cartrdige or do they just go from working to not working ?

The parts are in a vacuum. Electron-generation ability slowly degrades over time, and some gradual power degradation occurs, but this does not necessarily make the sound worse.

[tyrion]

Keep this thread civil without the personal attacks and it will remain open. Any other personal attacks and it will be closed.

I tried to go back and clean up the mess in this thread and it is hopeless. This thread derailed long ago. It's time to put it out of its misery.