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Tube and SS amps. - Page 3

post #31 of 47
2/12/10 at 2:36am
hmmm never even heard those phones...got a bit carried away with hijacking the thread.

There ya have it sir - Solid state it is for you then. They're very good - transparent and speedy too - rock on!

Agreed - always felt amps should high light a phones strength and not try to compensate for weaknesses - you're only highlighting the bad which is not good.
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post #32 of 47
2/20/10 at 12:04pm
There are differences between tubes and SS devices in terms of their use as amplifiers. They require different circuits, and parts. This means they WILL sound different.

As for better, or worse - that depends on the circuit or amp design. It's not a question of whether tubes or SS are better. It's about what AMP is better, and moreover, what amp is better for a given pair of headphones.
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post #33 of 47
2/20/10 at 1:50pm
Quote:
Originally Posted by Skylab View Post
There are differences between tubes and SS devices in terms of their use as amplifiers. They require different circuits, and parts.
Not really.

An N type solid state transistor is not fundamentally any different than a vacuum tube triode and can be used in most all of the same same circuit topologies.

What sets them apart more than anything is that whereas tubes are stuck using electrons for conduction, transistors can use either electrons or holes, allowing transistors to have compliments of opposite polarity, i.e. NPN/PNP or N-channel/P-channel for field effect devices.

So while transistors can be used in most all tube topologies, tubes can't be used in most all transistor topologies.

se
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post #34 of 47
2/20/10 at 1:55pm
Are you suggesting that the same type of power supply needed for a tube amp is needed, or even advisable, for a transistor amp? And what is the transistor equivalent of a cathode-follower circuit? I am asking genuinely here - I know more about tube circuits (just from having read up on it from interest) than SS circuits.
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post #35 of 47
2/20/10 at 2:20pm
Quote:
Originally Posted by Skylab View Post
Are you suggesting that the same type of power supply needed for a tube amp is needed, or even advisable, for a transistor amp?
Not sure what you mean by "type" of power supply.

Quote:
And what is the transistor equivalent of a cathode-follower circuit?
That would be either an emitter follower (for bipolar junction transistors) or a source follower (for field effect devices).

Both transistors and triodes are three terminal devices and each terminal serves the same basic function.

A change in voltage on a tube's grid causes a change in current flowing from the tube's cathode to its plate.

The same occurs in transistors, except instead of calling it a grid, it's called a base in a bipolar junction transistor and a gate in a field effect transistor. The cathode is the emitter or source and the plate is the collector or drain.



And tubes and transistors share the same fundamental amplifying configurations: Common cathode/emitter/source, common grid/base/gate, and common plate/collector/drain (also known as a cathode/emitter/source follower).

se
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post #36 of 47
2/20/10 at 2:31pm
OK thanks - I learned something useful today
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post #37 of 47
2/20/10 at 2:50pm
Quote:
Originally Posted by Skylab View Post
OK thanks - I learned something useful today
You're welcome!

And to try and answer your power supply question, both tubes and transistors require a DC power supply. It doesn't matter how you get there, as long as it provides the proper voltage and current for the given circuit. Both tube and transistor amps typically use the same type of supply, which is your basic capacitor input supply (i.e. power transformer -> rectifier -> reservoir -> capacitors). Of course tubes also require a filament supply, but there isn't any type of power supply that's just for tubes or for transistors.

se
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post #38 of 47
2/20/10 at 4:39pm
Quote:
Originally Posted by Koyaan I. Sqatsi View Post
but there isn't any type of power supply that's just for tubes or for transistors.
Maybe about voltage, there are more tube circuit that use really high voltage than transistors.
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post #39 of 47
2/20/10 at 4:54pm
Quote:
Originally Posted by bidoux View Post
Maybe about voltage, there are more tube circuit that use really high voltage than transistors.
Sure. But I don't see the voltage as a "type" if you know what I mean. By type I think battery, linear, switchmode, etc.

se
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post #40 of 47
2/20/10 at 9:51pm
Understood. What I meant was the much higher voltage, but I understand why you would say that is not a "type". I'm not aware of any SS amps that have lethal voltages inside them, But I did think the circuits were more different than they apparently are. I guess I need to learn a little more about SS circuits, once I finish learning about tube circuits. I've been reading "Tube Audio Design", but I have to read each chapter like 6 times to really get it.

Anyway, do think there are some sonic benefits to tube amps, but there are some negatives, too. Tube-rolling can allow a little bit of ability to flavor the sound, although it can be expensive
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post #41 of 47
2/20/10 at 10:17pm
Do tube amps with the tubes exposed sound different from the ones that are enclosed and out of site? Why are the tubes exposed in such a vulnerable way. The only thing I can think of is sexiness or that it actually adds to the sound (psychoacoustic sexiness or otherwise)?
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post #42 of 47
2/20/10 at 10:21pm
Having the tubes exposed is a very effective method of ensuring they have adequate ventilation, which is often a good idea
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post #43 of 47
2/20/10 at 10:28pm
Quote:
Originally Posted by Skylab View Post
Understood. What I meant was the much higher voltage, but I understand why you would say that is not a "type". But I did think the circuits were more different than they apparently are.
Nope. Other than typically higher voltages, they're the same.

Though you will more likely find things like choke regulated supplies used for tube amps, but that has absolutely nothing to do with whether or not the supply's being used for a tube circuit. Its benefits would be the same for tube or solid state amps.

Quote:
I guess I need to learn a little more about SS circuits, once I finish learning about tube circuits. I've been reading "Tube Audio Design", but I have to read each chapter like 6 times to really get it.
Who's the author of that?

You might also want to check out Morgan Jones' Valve Amplifiers.

But I know what you mean. I never came at any of this from an academic perspective so I've had to do my share of re-reading over the years too.

Quote:
Anyway, do think there are some sonic benefits to tube amps, but there are some negatives, too. Tube-rolling can allow a little bit of ability to flavor the sound, although it can be expensive
Oh sure. Don't get me wrong. I wasn't trying to say that tube amps sound worse than solid state amps or that you could replace tubes with transistors and get an amp that sounds that same. Was simply pointing out that both tubes and transistors can be used in the same topologies is all.

se
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post #44 of 47
2/20/10 at 10:31pm
Quote:
Originally Posted by Skylab View Post
Having the tubes exposed is a very effective method of ensuring they have adequate ventilation, which is often a good idea
And of course they do look sexier that way.

se
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post #45 of 47
2/20/10 at 11:58pm
Quote:
Originally Posted by Koyaan I. Sqatsi View Post

Who's the author of that?
Bruce Rosenblit:

Amazon.com: Beginner's Guide to Tube Audio Design (9781882580132): Bruce Rozenblit: Books

Good book; even dummies like me can get it (after multiple readings )

I will check out the one you recommended too, thanks.

Quote:
Originally Posted by Koyaan I. Sqatsi View Post
And of course they do look sexier that way.
That they do
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