Tube preamp

woody357 · #1 07-28-2010, 03:49 PM

Does having one 12AX7 tube in the preamp really makes that much of a difference?

levis76 · #2 07-28-2010, 04:07 PM

It sure does.

I have a Hartke HA3500, which has separate gain knobs for the tube and solid state preamps. The tube pre has one 12AX7 tube and it sounds a lot different than the ss pre. I won't say better, because that is subjective, but it makes a huge difference in the overall tone of the amp.

Tube selection makes a big difference as well. No one can tell you what tube will sound good to you, it's truly a trial and error process. Same brand and model tubes even have subtle differences, which gives you an almost infinite pallette of tones to choose from. The only limiting factor is your budget.

Good thing pre tubes are fairly inexpensive. Have fun, that is what it's all about, right?

Bassmec · #3 07-28-2010, 04:47 PM

Quote:

Originally Posted by woody357

Does having one 12AX7 tube in the preamp really makes that much of a difference?

It depends on the design of pre amp, you wont get much from some of the ridiculous starved plate single dual triode hybrid rubbish we see today, and no it takes far more tube circuitry to achieve a totally satisfying tube tone, the best ones have an output transformer of some sort.

RickenBoogie · #4 07-28-2010, 04:53 PM

+1 it's not so much about the one tube as it is the overall design of the circuit. There are tubey sounding amps without ANY tubes, and some the other way around. You can't make a generalization like that.

woody357 · #5 07-28-2010, 06:19 PM

Quote:

Originally Posted by RickenBoogie

+1 it's not so much about the one tube as it is the overall design of the circuit. There are tubey sounding amps without ANY tubes, and some the other way around. You can't make a generalization like that.

It was a simple question, how about this "which head that uses a single tube preamp sounds more like a tube head"

craig.p · #6 07-28-2010, 06:29 PM

Ah, but that's complicating it, Woody, because much of a tube head's sound can be traceable to its output stage, not its preamp circuit. That's where the larger nonlinearities are apt to occur, at least from what I've seen.

RickenBoogie · #7 07-28-2010, 06:35 PM

True, and that can't really be replicated without a tube power section and/or a big iron transformer. But, many here at TB, myself included, consider the Mesa Walkabout to be one of the "tubiest" sounding hybrid amps available. Of course though, they have 2 12AX7's in them, and are also used in the driver stage.