DRRI Build High Pitch Squeal

[onenotetom]

Got my DRRI all wired up and as soon as the tubes warm up it sounds like a bottle rocket going off. This is with no guitar hooked up and all pots full counterclockwise. I reviewed all of the wiring to the schematic and checked all solder connections. I moved some wires away from others. I swapped the phase inverter 12ax7 with another new one. All of the tubes are new.

None of the changes made any difference. Here are some wiring picks. The grey wire (labeled FB on the board) going to the speaker jack has an additional 150 ohm resistor soldered in line by the previous owner. Is my heater wiring causing the noise?

My research suggests swapping out the tubes. Which ones should I start with? I do not have a spare rectifier tube. Any other suggestions?

[printer2]

You may have to reverse the leads on the transformer. Just added NFB to mine tonight and when I started adding the NFB, well you know the sound. I swapped the primary leads of the transformer as it was easier for me but either swapping the primary or the secondary should do it.

[onenotetom]

Thanks for the quick response Printer2. The leads on the power transformer (Yellow and Red) or the leads on the output transformer (green and black)?

[Telenut62]

The output jacks would seem be to correctly wired according to the schematic...

http://ampwares.com/schematics/65_Deluxe_Reverb_RI.pdf

[onenotetom]

Most of the wiring was pretty simple as the board is marked. On the wires that plug into the board the colors are marked and the wires that go from the board to the tube sockets they are numbered. The rest I followed the schematic and also compared to pictures of DRRI's that I downloaded. Now I get to try and learn how it really works.

[onenotetom]

Okay, I figured out that you were talking about the power transformer. Going to the board I have 2 greens, a black and a white, a red with yellow stripe and a red with blue stripe. Can I switch the 2 reds without causing damage?

[printer2]

Originally Posted by onenotetom

Okay, I figured out that you were talking about the power transformer. Going to the board I have 2 greens, a black and a white, a red with yellow stripe and a red with blue stripe. Can I switch the 2 reds without causing damage?

No, not the power transformer, the output transformer leads. If the leads are correct as compared to the schematic the problem might be somewhere else.

[onenotetom]

My output transformer brown and blue are going to the wrong tubes compared to the schematic. Will reverse these and report back. Thanks.

[onenotetom]

Thanks printer2, that fixed the squeal. The normal channel works well, the vibrato channel has issues. I have ideas as to where to look so will tackle those in the morning.