Audio valve amplifiers

Wizard · 2009-12-03T21:46:15+00:00

My first valve amp has now got me interested in valve amps for normal audio. Look at this for a novel idea. Old meets new:

Audio valve amplifiers

singemonkey

I fully agree that it's pointless getting a super high-quality amp for an ipod. Tossing pearls before swine. :?

But what does a tube amp do for your audio? Will it actually improve the sound? Or does it colour it significantly?

RobK

singemonkey wrote: I fully agree that it's pointless getting a super high-quality amp for an ipod. Tossing pearls before swine. :?

But what does a tube amp do for your audio? Will it actually improve the sound? Or does it colour it significantly?

I don't think it's pointless for an ipod. Might not make much difference, but it won't make the sound quality any worse.

Besides, it doesn't have to be built only for the ipod. You could plug a decent CD player or maybe even a turntable.

I have no idea what it would do to the sound, but they really look cool ?

AlanRatcliffe

aja wrote: London bridge?

That's one of them, but if you're seriously interested, I have one on the Tyne that's all mine too. I have one in the US, but unfortunately that's over troubled water. Purveyor of fine bridges, that's me... ?

RobK

Alan Ratcliffe wrote:
aja wrote: London bridge?
That's one of them, but if you're seriously interested, I have one on the Tyne that's all mine too. I have one in the US, but unfortunately that's over troubled water. Purveyor of fine bridges, that's me... ?

Would you consider a swap for a couple thousand acres of prime land on Mars?

aja

RobK wrote:
Alan Ratcliffe wrote:
aja wrote: London bridge?
That's one of them, but if you're seriously interested, I have one on the Tyne that's all mine too. I have one in the US, but unfortunately that's over troubled water. Purveyor of fine bridges, that's me... ?
Would you consider a swap for a couple thousand acres of prime land on Mars?

Hmm, what's the view like from up there?

Wizard

It was perhaps a bad idea to use an iPod example.
I'm actually interested in insights on valve amplifiers being used for hi-fi.
I've read that scientific measurement can't distinguish between solid state and valve when run within tolerance.
People report that valves are "quieter" between notes than solid state ... and suggests that this is something that hasn't been measured appropriately by the scientific measures.
This is possibly a class A / crossover distortion thing.

General wisdom is that valves overdrive in a way which is much more human ear friendly than solid state - a feature obviously used for active effect in overdriven guitar amplifiers.

So ... are valve hi-fi amps available? At reasonable price? And what are they like?
How hard are they to build?

singemonkey

Wizard wrote: People report that valves are "quieter" between notes than solid state ... and suggests that this is something that hasn't been measured appropriately by the scientific measures.

Or that people are hearing stuff that isn't there ? There's the old excuse much beloved by the lucrative alternative medicine industry: "If you found no effect, it's because you were doing the test wrong."

Wizard wrote: General wisdom is that valves overdrive in a way which is much more human ear friendly than solid state - a feature obviously used for active effect in overdriven guitar amplifiers.

Mmm... I love that creamy distortion on Vivaldi's Four Seasons when I crank up the volume ?

CDee

Wizard wrote: So ... are valve hi-fi amps available? At reasonable price? And what are they like?
How hard are they to build?

Something like this? http://diyaudioprojects.com/Tubes/6T9-Tube-Amp-Kit/

Gearhead

As a proud 300B audio amp owner I can say that most people do hear the difference when they hear my setup (my speakers aren't bad either, speakers are more important than amp). The thing mentioned most is that the sound is more direct or transparent.
In essence the thing about not being able to measure difference between amps is absolute nonsense. If you measure a small sine signal maybe, but audio is much more than that. The biggest difference between sand and vacuum is that the linearity of tubes is much better and for a larger range. This leads to two things: for starters the harmonics produced are nasty high order for transistors versus low order 'musical' for valves. If you don't turn up the volume too much the distortion is not going to be enough to hear this, but then we don't always play everything at volume 1, now do we? The second result is that audio designers know this and apply negative feedback to compensate. The feedback used will be roughly as much as or more than the input signal. Theoretically this should give you the 'perfect' output signal, if it weren't for the fact that there is a time delay between the feedback and the original signal. The amp is always too late to completely compensate for its own mistakes, a phenomenon called tim (transient intermodulation distortion). And that is what you hear. The feedback also eats away at the maximum signal you get from a given output power - one of the reasons why you need a lot more power in transistor amps.

I herewith challenge anyone to bring a solid state amp to my place so we can A/B compare in a double blind test. If we agree which amp sounds better and it turns out to be yours, you can pick any one of my guitars to take home.

@Wizard: don't worry about the Ipod, there are seriously audiophile upgrades for it 8)

Wizard

@ Gearhead: So what does this uber valve amp arrangement cost?

Gearhead

Well, I bought my amp in Shanghai (less than 1000km from where it is made) for R3900, which I consider a very good deal. You pay the same money just to buy new output tubes (cheapest you can find) never mind the rest of the amp. In fact, you would have a hard time buying the components for that price.
http://www.yarland.com/en/product_19.asp mine is brushed alu faceplate.
The downside to all this is the enormous price tag for getting new tubes; I saw some nice NOS 300B the other day for $1200 a pair and you pay $900 for a set of Western Electrics. Hope these Shuguangs last a bit still ?

My CD player (Shanling CDT80) is just such a cutie; went for R3800 in Hong Kong and has only tube amplification. The newer models are better looking but the same technology: http://us.shanling.com/en/product.asp

The customs guy at OR Tambo I showed the receipt to did not believe me straight away. Only when he asked how many channels and how much power it was, and I answered 2x7W did he let me go ?
At full power it is so loud the neighbours complain so I think 7W and high efficiency speakers is plenty....

Wizard

nice amp Gearhead ....................