Dumble - help needed urgently!

[Mousey Dung]

All three relays should have a diode connected across the coil, with the banded end connected to the the positive side. It's not obvious from the layout how this is done, except for in the case of the right-most (mid) relay the diode is soldered to the eyelets. The chatter you are hearing is likely a relay, I don't know what else it could be.

Then that's probably it. The diodes at the PAB and OD relays aren't connected across the coils. Will fix that now!

[jelle]

No.

The diode is only to be connected across the coils. Not to the cathode of the reverb recovery stage.

Not sure how this would affect the clean channel only though.

Something else must be going on as well.

Please post detailed pics.

[Mousey Dung]

This is a very complicated amp for a beginner to build. I would argue that it is too complicated as a kit build for the public.

You could be right. Nevertheless, I really think I would have managed just fine with some proper instructions and a general parts ID list. I saw some examples of instructions for some other models he was selling and thought that this one would come with similar instructions too.

Well, I am trying to help you here, otherwise I would not be spending my time posting here. The comment is not a personal one. This is a technical issue, don't you agree?

Alright, thanks, and I really do appreciate your help.

[Mousey Dung]

No.

The diode is only to be connected across the coils. Not to the cathode of the reverb recovery stage.

I'll attach the diode to the coils without going to eyelets and report back...

[ToneMerc]

You could be right. Nevertheless, I really think I would have managed just fine with some proper instructions and a general parts ID list. I saw some examples of instructions for some other models and thought that this one would come with similar instructions too.

Jelle, is 100% correct, read again what I said back on page 3, this layout is a very complex build.

TM

[Mousey Dung]

OK, I left the diode by the PAB connected to the eyelet beneath (with the 25 uF cap and 2.2 K resistor), because that appears to my untrained eyes to be right.

I removed the positive leg of the diode at the OD relay from the eyelet under it and connected it across the coil and now the hum thing and rattling (when I turn down the master volume) is GONE!

Flipping the switches around does not result in any nasty surprises.

All that remains is an occasional slight crackling noise, like that of a dusty pot (only I'm not turning anything). I've dialed the knobs a bit to see if the noise results, flipped and shifted the switches to see if anything results in the crackling -- it doesn't.

UPDATE: The faint crackling seems to have stopped. Perhaps it was bits of debris left of the circuit from the build?

[martin manning]

The PAB relay diode definitely does not go to the eyelet with the 25uF and 2k2. Connect it like the other ones.

[ToneMerc]

OK, I left the diode by the PAB connected to the eyelet beneath (with the 25 uF cap and 2.2 K resistor), because that appears to my untrained eyes to be right.

I removed the positive leg of the diode at the OD relay from the eyelet under it and connected it across the coil and now the hum thing and rattling (when I turn down the master volume) is GONE!

Flipping the switches around does not result in any nasty surprises.

All that remains is an occasional slight crackling noise, like that of a dusty pot (only I'm not turning anything). I've dialed the knobs a bit to see if the noise results, flipped and shifted the switches to see if anything results in the crackling -- it doesn't.

UPDATE: The faint crackling seems to have stopped. Perhaps it was bits of debris left of the circuit from the build?

So is it full functioning now?

TM

[Mousey Dung]

The PAB relay diode definitely does not go to the eyelet with the 25uF and 2k2. Connect it like the other ones.

Oki! Will do so and report back in a few minutes.

[Mousey Dung]

What do these eight trimmers on the preamp board do?

[martin manning]

I would systematically go through the controls and switches to see if they are all functional. Have you got reverb?

Where did the tube voltages settle out? It would be a good idea to get a set of measurements from the power supplies and the tube pins.

Eight Timmers:
Upper left is a cut control that reduces high frequencies when the PAB is engaged by shunting across the PI outputs.
Lower left is the PI balance (center it for now; there is a sticky on setting that).
Next one to the right is a variable negative feedback level.
The 1M on the PAB relay is the variable lift that determines the amount of boost in PAB.
The three HRM trimmers in the center of the board are middle (the top one), bass (left), and treble (right) controls for the OD.
The lower right is the OD entrance level, which basically determines the minimum amount of distortion that you can get in OD.

[Mousey Dung]

The PAB relay diode definitely does not go to the eyelet with the 25uF and 2k2. Connect it like the other ones.

Oki! Will do so and report back in a few minutes.

Reconnected PAB diode so it's just across the coil and not connected to the eyelet beneath. Everything fine now, except for occasional "dusty" crackling noises.

[Mousey Dung]

So is it full functioning now?

Just some occasional random faint crackling noises similar to the turns of a "dusty" pot.

[ToneMerc]

What do these eight trimmers on the preamp board do?

1. Hi-freq trim or cut control
2. PI trimmer
3. Soul Control- adustable negative feedback
4. PAB variable megaboost
5. HRM mid control
6. HRM bass contol
7. HRM treble control
8. OD trigger

TM

[ToneMerc]

So is it full functioning now?

Just some occasional random faint crackling noises similar to the turns of a "dusty" pot.

So all switching functions are 100% correct? What are you doing for a footswitch? If all functions are correct, I would document voltages and then start to chase crackling gremblins with a shakedown test of the wiring.

TM