Tube Amp Archive

Hey guys, just got back from vacation. Just to clarify, I didn't have the jumper on when I measured the plate voltages, there is still almost no plate voltage on one of the plates. I only had it on there when I took resistance readings, which is why I got the resistance of half of the OT to centerta...

I had left a bleeder wire clipped on the centertap to ground and forgot to take it off before I made the measurements! Both pin 3 measurements show open now, no reading. Time for me to step away and go to bed now.

blackeye, yes I made my measurements directly off the lead where it is soldered to the socket pin. I also measured resistance from the side of the socket where the tube pin inserts with no difference in the resistance from the side where the lead is soldered. Very puzzling indeed.

Resistance for Pin 3 to ground on the problem socket is 98 ohms. It is 89 ohms on the other socket. There are no carbon traces on the tube socket, it looks clean. Also, I have had the amp plugged into my current limiter lamp during this process and it hasn't lit the filament at any point, so I don't...

Ok guys, I swapped the plate leads. Surprisingly, I get the same plate voltages I did before on the same tubes, the low plate voltage did not go to the other side. I really expected the OT to be the cause.

Sorry, I left out Pin 8. It is 24v on each tube.

Here are the voltages for each tube-- Tube 1- Pin 3: 1v, Pin 4: 341v, Pin 5: 0v Tube 2- Pin 3: 330v, Pin 4: 339v, Pin 5: 0v I used a new Hammond 1760J for the output transformer in the build, but I do like to play it at close to full volume at times.

I noticed one of the 6L6 power tubes being physically much cooler on my home-built Gibson EH150 style amp. I decided to check the plate dissipation and noticed right away that the power tube in question only had a few volts on the plate, while it's partner had about 30 extra compared to the last tim...

Thanks for the help. I have some 1K 5-watt resistors that I can use. One more question. Because pin 4 on each of the 6l6 tubes is run together, would it be acceptable to use just one 1K 5-watt resistor between the node and the two power tubes?

I was given a Laney AOR 30 chassis that looks to be complete with the exception of the output transformer and one of the pots. Does anyone know what kind of output transformer I need? Specifically, what the primary impedance needs to be. The amp has 2 6V6 output tubes, which I believe are in push-pu...

I finished my EH150 build and am very happy with the result. I built it exactly to Tino's specs, but had some questions about changes that might help reliability. I wanted to know if I should add a 22K resistor to elevate standby above ground as suggested by one of the members here and also should I...

Thanks for the help, Colossal! I'm not necessarily going for the Charlie Christian sound (although I do like it). To be honest I was inspired by Johan Segeborn's youtube video of what I believe he said was an EH-185. It seemed to have a pretty unique distortion, and I thought it would be cool to do ...

I am about to start an EH-150 build using the Tino Zottola book. I would like to know what resistor and pot combo I should use in the voltage divider circuit on the overdrive channel instead of the 100K resistor. I was hoping you guys with completed builds could tell me what works best and what sort...