Tube Amp Archive

Thanks. I figured as much but couldnt think if I had ever seen it before.

non-reverse wrote: ↑Wed Sep 03, 2025 7:39 pm The tubes are all old and there is at least one 6v6 in it (I can't tell what the other power tube is, the label has worn off). .

6L6? There should be no 6V6 tubes in his amp.

Is there anything wrong with using two cathode resistors (and caps) in the power section of an amp? Specifically this is for a 4xEL84 amp, and each pair would get their own resistor like so: https://live.staticflickr.com/65535/54763689309_1959e706ac_c.jpg Reasons for this would are 1) ability to use...

Jumping from 5E3 and Pro Reverb to orange and Marshall is quite a jump! Ha....for comparison sake i'm just saying to focus on cathodyne vs LTPI and how to switch between the two of them. There are no pitfalls but you need to consider how you will switch the NFB. You'll probably need more than just ...

pdf64 wrote: ↑Tue Aug 12, 2025 5:24 pm But the output stages are rather different too.

I know, but those are details for another conversation. For the sake of discussion we can pretend the two amps I mentioned were an Orange OR120 and a Marshall 1959. The point is determining if there are pitfalls to switching in this location.

Hi All, A friend asked me recently if it would be possible to build a two channel amp where one is 5E3-ish and one is Pro Reverb-ish. Obviously on most two-channel amps the phase inverter is shared and thus the signal is blended before the PI. These two circuits, however, have very different PIs so ...

Mark wrote: ↑Thu Apr 10, 2025 2:01 am The output valves are 6GW8’s which are a 12AX7 and an EL-84 in one envelope.

No. Its a high-mu triode and a pentode in one envelope. Its like half of a 12AX7 and some other pentode that is dissimilar from an EL84.

I tried this by looking toward the AC30. I added the following RC filter b/w C5 and R9, but all it did was make the thumping brighter. https://live.staticflickr.com/65535/54309476815_a268a9eeb2_w.jpg You need to filter out lows even more if you want to get rid off the thumping. With those capacitor...

You need to filter out the LFO signal after V1B. Third or fourth order RC high pass filter is probably required to get rid off all the thumping when intensity is all the way up. I tried this by looking toward the AC30. I added the following RC filter b/w C5 and R9, but all it did was make the thump...

Hi All, I'm working on a build and having some tremolo issues. The details of the build are: AB165 Bassman preamp. Normal channel only. ECL84 push-pull power amp. I'm taking a lot of inspiration from the SoLow Watt project here, among others. I've built a few amps with this power section and find th...

Issue resolved! The problem was the board being too close to the jacks. I put some shielding tape on a piece of card stock, grounded via an alligator clip, and put it between the jacks and the board and that solved the distortion on the scope. I was able to pull it out and watch the distortion reapp...

Compare your V2 wiring to Fender's wiring. Your jumper between pins 1 and 6 goes directly across the socket while Fender's jumper loops around the socket, close to the chassis. Make your jumper look like Fender's jumper and see if some of your issues disappear. Good observation, and will definitely...

Compare your V2 wiring to Fender's wiring. Your jumper between pins 1 and 6 goes directly across the socket while Fender's jumper loops around the socket, close to the chassis. Make your jumper look like Fender's jumper and see if some of your issues disappear. Good observation, and will definitely...

I see that you've got the wires to your reverb control tucked in with your tone stack wires. Maybe try separating those? Good looking build! Thanks! Not my first rodeo, which is what makes this so puzzling. At this point i'm testing without V2-V4 even installed so its hard to believe the reverb con...

Pics! Board and control panel: https://live.staticflickr.com/65535/53971453615_51d3c56ac8_b.jpg https://live.staticflickr.com/65535/53971453610_d8cfcd1efe_b.jpg https://live.staticflickr.com/65535/53971453605_d310fb9b74_b.jpg Board and tube sockets (the jack between V2 and V3 is for footswitch): htt...