Tube Amp Archive

As a general statement I think the p.i.gives an amp a certain character as much or more so than the output tubes and possibly the preamp. i experimented with a vox, Marshall and orange pi fed by various preamps into various output tubes configurations and was surprised to find the pi appeared to giv...

I only used 6sl7 (vintage used) in one low watt project and had trouble with microphonics. You might want to consider another tube for a high wattage bass amp. Maybe new tubes would be fine though.

I’m trying to follow along and learn so forgive me if my question seems trivial. Where does the B+/2 come from in the equations above? I understand most of the other numbers but this one has me lost.

Is that an actual dumble or a copy?

Does anyone else have any experience,or advise to offer on the post pi cathode follower? I've read quite a lot on the matter but its mostly theoretical information. I'd like to hear from anyone else that has implemented this into a 100-200 watt amp. Also any comments on the use and level of nfb in a...

Couple of questions if you don't mind. At the junction of the 82k and 100k PI resistors is that a 10k balance pot? Your chassis picture seems to show two resistors from the first stage coupling caps to ground. Is that correct? What value? The local NFB, is that actually on v2? Can you explain the sw...

check the actual values of the pi cathode and tail resistors. looks like it could be a 1k instead of 10k.

i have two smaller ones that i use for work in the field. they work well but they have a "window" on the side where you light them and it will melt the insulation on the wires and components or your fingers if you are not careful.
very handy but not a replacement for an electrical iron.

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A while back I built a "monster bass" head. I used four KT88's for about 200 watts of pure tone. The output transformer was a behemoth 30 pound Hammond Hi-Fi transformer that could go down to 20 hz at full power! I also used a toroid power transformer. The front end was similar to a Marshall super ...

i am curious if you are doing any mods to the circuit. which preamp did you use?

doctord02 wrote:I'm in the process of building a 4 x KT88 Hiwatt DR201 inspired bass amp myself.

i'd like to hear details about this build

look at some of the ampeg models like the V4 V9 and SVT.

was this a bass or guitar amp? what style music do you play?