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Registered Member #105
Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408
Im looking for a good PREAMPLIFIER circuit to build with some tubes that I recently aquired, and since I don't have any pairs of power tubes. Anyone have some favorites that they would point me to? I really don't know where to start. I;m figuring on using the 12AX7s, I think. That way i can hear the difference between some mullards and gibson tubes.
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
aaaahhhh....well guitar has its own set of problems
1. What type of sound are you looking for?
you have to figure this out first before you can narrow things down because there are too many variants out there. For me, I have to change my Fender to Hiwatt because that's what David Gilmore uses.
Registered Member #105
Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408
I just want a little bit of a reverby sound, but really, I've never owned a tube amp, so I really won't know the difference too much. I don't want a highly distorted sound though, I know that for sure. Maybe a bit of a bluesy tone...
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
They're not problems, they're opportunities If you want a reverby sound from a tube amplifier, you'll need a spring reverb tank as well as a driver tube and transformer for it. Many reverb units use a 6V6 for the driver. In my experiments with tube guitar amps, I never bothered fitting a reverb tank, because I like more of a dirty grinding sound and reverb just seems to get in the way of it.
Strictly speaking, using digital reverb is cheating, since it's not made out of tubes but it's a lot more versatile. If you get fed up with reverb you can press a couple of buttons and have chorus or delay or whatever instead. I modified one of my amps to interface with an old Digitech effects unit instead of a reverb tank. I think the Alesis Picoverb is actually cheaper than a reverb tank too...
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
if you don't have the 6V6 you can double up the plates on the 12AX7 into the reverb transformer. This is very common because the 6V6 is seen as 'more valuable' in the power portion of the amp rather then a transformer driver. But both work equally well.
Registered Member #105
Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408
I am so new to this stuff- i'd like to learn some theory, too. I have a tube amplifier book that has a bunch of schematics for some marshall, mesa boogy, fender, vox amplifiers, but I don't know where to cut off the signal for the preamplifier. I guess the optimal amp would use OA2's as the rectifiers, and using the AX7's as the preamplifier, and after thinking twice about it, I think Ill drop the reverb for simplicities sake, since this is my first tube amplifier.
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12AX7 preamplifier
If you want a reverby sound from a tube amplifier, you'll need a spring reverb tank as well as a driver tube and transformer for it. Many reverb units use a 6V6 for the driver. In my experiments with tube guitar amps, I never bothered fitting a reverb tank, because I like more of a dirty grinding sound and reverb just seems to get in the way of it.
but it's a lot more versatile. If you get fed up with reverb you can press a couple of buttons and have chorus or delay or whatever instead. I modified one of my amps to interface with an old Digitech effects unit instead of a reverb tank. I think the Alesis Picoverb is actually cheaper than a reverb tank too...