Pre amp or Power amp tubes. Which effects tone the most?

markj

I'm thinking of changing my poweramp valves to some NOS 6V6's.  Philips 6V6 gt JAN to be exact, in a Gartone Bluesman. As the title says which alters the tone the most.

ICBM

Preamp valves affect the tone more.

Power amp valves affect the dynamics and presence more.

VerodaClient

And I think the preamp in slot 1 (or v1) affects the tone the most

Philtre

I dip the pins of my valves in unicorn tears. The tone is amazing.

Nerine

The circuit. 

Maynehead

ICBM said:

Preamp valves affect the tone more.

Power amp valves affect the dynamics and presence more.

Unless the power valves are worn, in which case changing them will result in a noticeable improvement in tone.

HAL9000

I'm (slightly) intrigued by the Boss Nextone amps which have voicings for four differently valved power amps. Since most of the tone-shaping happens in the pre amp stage I always thought the majority of options would be there. Obviously I'm wrong, but I'd like to understand why, if you're giving different valve emulations, it should be at the power amp rather than the pre amp stage (or even have options at both).

ICBM

HAL9000 said:

I'm (slightly) intrigued by the Boss Nextone amps which have voicings for four differently valved power amps. Since most of the tone-shaping happens in the pre amp stage I always thought the majority of options would be there. Obviously I'm wrong, but I'd like to understand why, if you're giving different valve emulations, it should be at the power amp rather than the pre amp stage (or even have options at both).

Because there is a huge myth that the power valve type determines the tone of the amp - for example you will often see amps described as ‘EL84 amps’ or ‘6L6 amps’, implying ‘Vox sounding’ or ‘Fender sounding’. In fact the power valve type makes almost no difference - some, but only subtly. You can easily have amps which sound like the ‘wrong’ valve type. By far the most important factor is the amp circuit.

So the amps with ‘power valve’ emulation take these small differences and magnify them drastically, and add the characteristics of the typical circuit that historically was associated with those types, because that’s what people expect.

For example the typical ‘6V6’ sound is usually based on the Fender Deluxe - not the Laney AOR30 which also used them but sounds completely different. You won’t find an ‘EL84’ sound that’s based on a Mesa Studio 22 either...

HAL9000

So, the 'power valve emulation' stuff is just marketing speak to suit what people believe? Whilst the reality is that it is actually whole amps being emulated? 

ICBM

HAL9000 said:

So, the 'power valve emulation' stuff is just marketing speak to suit what people believe? Whilst the reality is that it is actually whole amps being emulated? 

Certainly a large part of the power stage design, even if the preamp emulation is separate.

Things like the bias type, negative feedback, transformer ratios, the way the screens are supplied, and the power supply regulation and filtering all have a larger effect than the valve type, and are what really give different power amps their sound.

Describing valve amps by the type of power valve they use is like describing guitars by the fingerboard wood - it does make a small difference, although it’s so far down the list of what matters that it’s almost irrelevant... but easy to see, so assumed to be important.

Here are half a dozen EL84 amps, for example... Marshall 2061, Fender Blues Junior, Mesa Studio 22, Peavey Classic 30, Orange Tiny Terror, Mesa Mini Rectifier. None of them sound anything like a Vox - or like each other!

Or 6L6 amps... Mesa/Boogie MkI, Soldano SLO, Mesa Dual Rectifier, Marshall JTM60, Engl Screamer, Supro Thunderbird. None of those sound like a Fender Super Reverb either.

HAL9000

Thanks @ICBM ;

gringopig

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