Pre-Amp Tube Question....

gordon_39422

gordon_39422

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What are the benefits/effects of having matched preamp tubes?

More specifically, in a single channel amp with added gain stages, such as the Fender Hot Rod Deluxe....

I have been playing with different tube configurations, and have notice several sites offer matched preamp tubes. I understand the need for matched power tubes. However, if V1, and V2 are used at different points of the signal path, what would the effects be with a matched set....

If you were seeking a pristine tone, and stepped down to 12AT7's in all 3 positions, would a matched pair in V1, and V2 result in a cleaner tone that with standard 12AT7's?

Of course, the Phase Inverter is balanced, BTW....

Thanks for the input,
Allen
 
Re: Pre-Amp Tube Question....

I think that matching the pre-amp tubes don't do much, except for matching by brand. It shouldn't matter much with pre-amp tubes.
 
Re: Pre-Amp Tube Question....

If you mean matched sections of individual dual triodes ala 12A*7 family---that's one thing (it doesn't matter), If you are talking about matched triodes, that's another (can't see how that would matter either). And a balanced PI tube doesn't matter either in a unbalanced PI circuit...this matching stuff is more 'important' for audiophile applications than for guitar amps.
 
Re: Pre-Amp Tube Question....

Unless you're an audiophile; none. And it's rather pointless considering tubes drifts out of match rather quickly when you use them.

A perfectly balanced phase inverter could theoretically sound worse, as it would eliminate some of the harmonics in the guitar tone that are easy on the ear. However if you've been using a phase inverter tube that was advertised as balanced, chances are by now it's drifted out of balance anyway.
 
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Re: Pre-Amp Tube Question....

You don't want matched preamp tubes. You want matched output tubes.

There's alot that can be done to shape the tone by using a slightly differant preamp tube in the differant positions.

Not all 12ax7's sound the same...and that knowledge can be used to shape the tone.

You should buy a few differant 12ax7's and experiment so you're familiar with that.

Lew
 
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