Nov 8, 2016

The more vacuum tubes the better the amp?

I am new to the audiophile community and I was wondering if the amount of tubes on an amp matters. What does having more tubes in you amp do? Less?
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Something that EniGmA1987 didn't mention is that sometimes tube based amps will also use tubes in the linear power supplies as tubes are actually very precise and stable for this use. In this case the extra tubes aren't really involved in the audio.
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If that is the case there will be a minimum of two (one (usually larger) in the power supply and however many in the amplifier) Many tube amps use solid state components in the power supply and if propper care is put into the design it should work just as well.

Also, some amplifiers use seperate tubes for either channel while some use a single tube for both, using seperate tubes should lower the amount of crosstalk between channels.

The amplifier class can also play a role in this. a class a amplifier can be made with fewer tubes than a class ab, but is better sonically (though a class ab amp can deliver much more power)
Bigall
Cool. Thanks!
more tubes generally equal more power output. Typically a headphone amp doesnt really *need* more than 1 pre amp and 1 power tube, though the power output can leave a bit to be desired sometimes. 2 tubes or each offer some of the best balance between cost and power capability. That isnt always 100% true of course, but generally speaking.

When looking at a tube amp, you need to look at the power output in the impedance range your headphones use, as well as the amp's output impedance. Tube amps are almost always designed for high impedance headphones (200ohms or more), and solid state amps generally work best with low impedance headphones (200 ohms or less). That is where they can control the headphones the best and have their power output optimized for.
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EniGmA1987
it will also depends on if you're amp is for driving speakers or headphones.
When driving speakers with larger amps, you need to separate out as the other replies did in 3 stages
1. power supply
2. signal stage
3. power stage

In power supply stage, tube will typically have a more stable operational characteristics which give a lusher sound. However good transistor power stage can give a much better instant power or current draw which is critical to have the bigger dynamic range with a quicker sound without muddying the sound stage

For signal stage, a good tube signal stage like the re-issued McIntosh series gives a good warm sound and has a great harmonic ring to the tone. However, with digital musical and greater dynamic range and finer details, sometimes you may actually wanted that little extra zing in some transistor design to balance out the output stage

For output stage, usually more tubes the bigger the power as mentioned. Not always the case though. Some tubes like 211 single tube can give more than enough power to play with. Also it matters if it's single ended or push-pull. Single ended tend to have sweeter sounding and lush mids and usually have fewer tubes and thus single ended. But when you use something that's power hungry then you'll typically need to have push-pull design which almost by default double the tube number. It'll definitely give your more authority and power but when overly done, you'll loose the actual sweetness of the sound.

Then when talking about tube power, it also matter to have transformer or not (OTL). Output transformer matches speakers easily but at the same time can introduce it's own sound to the over all system regardless of some of the tube used. But with OTL which means output transformer less, it'll sound open and fast like transistor amps, but 1 little mistakes, the whole amp is fried and has the reputation of not being stable.

So in short, does more tube means better? For one thing, more tube means more expensive in most cases but not necessary better.
EniGmA1987
Thanks for the extremely detailed response!

Currently I have the Audio-Technica AD900X and the Beyerdynamic Custom One Pro Plus. I know these don't need an amp but I am looking for another set of open back headphones to round out my collection. I listen to a lot of rock and soul, but also some electronic. I love getting rich vocals and I was wondering if you had any suggestions of headphones as well as amp or DACs. From your response it seems like I would want a single ended tube amp, but what do you think?

I have around $300 to play with. If your suggestions are a little above that is fine too.
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