Yes a layout for the build - but, still, why not both?
However, I don't agree that layouts are good for mods as then it seems much harder to comprehend what the changes really are and what they are doing.

And where is the attachment button?
None of the icons I see seem to be for attachments.

Once again a schematic would be helpful to see where everything is.

The Drive pot varies signal from the output of the tube's 1st stage to the input of the effect.

The IN pot varies the signal from an effect to the tube's 2nd stage input.

The Out pot varies the signal from the tube's 2nd stage output back to the amp.

With nothing plugged into the c'lator's effect loop, the loop's in/out is internally jumped.

I'm pretty sure he has them, but just doesn't post them.
I don't know why, as would be of benefit to anyone trying to build one of his kits.

I personally prefer having a schematic  too, especially when comparing circuits.
It's in the mail...

See if there the Recovery Input cable has a ground shield that is grounded to the front buss wire that runs along the top of the pots. If so, try cutting it so is not connected to the buss.

PS:
At first you described the problem as 'noise', but later as 'hum'
Just for future reference, most people regard noise as 'hiss' or 'static' etc. and hum differently.

Umm... if you don't know what I'm taking about then shouldn't you also not know what Mcinku is talking about?



In the event you mean you don't even understand the concept of adjusting the pate voltages, then it is this:
[Someone please correct me if I am wrong].
The power supply generates a high voltage that is successively dropped through string of resistors in series - and the voltages that go to the plate resistors come off the taps (B3, B4, B5) between those resistors. The values of those resistors are supposed to be selected so as to drop the voltage to the desired level. But that apparently doesn't always happen. Either that or people have determined that the noted voltages produce the best tones etc.

On my HRM, that is modded more towards an OTS, the voltages were much higher than those 'golden' voltages I mentioned. I didn't have enough 2 watt resistors to totally adjust the entire voltage divider string - so I just raised the first 3.3k resistor [delivering the B3 voltage to the PI phase inverter tubes] by adding 2.7K which lowered B3 to 300 volts at the PI tube plate. My B4 voltage was still a bit high at 210 and my B5 voltage a bit low at 183; but the amp sounded much better.

Checking the plate voltages also allows you to see how balanced your tubes are. If they are not, then the voltages can be quite disparate.

Hope this clarifies.

I read where Scott mentioned that the PI is typically around 250 compared to 300 on the OTS.

I was referring to the OTS and HRM amps.

But I also did not know the Bluesmaster was substantially different.

How so, and why?

Take this for what it's worth, as (IMHO) I leaned the hard way by doing everything else but.

For BLOOM, the plate voltages need to be right
I believe the recommended values are:
V1@190
V2@200
PI @300

but you may find that others also work.

One thing you want to do is to adjust your PS dropping resistors to get the voltages right. I leaned the hard way by doing everything else but.

Edited:
mcinku informs that the optimal Bluesmaster voltages are not the same as the OTS, but I don't know what they are. Perhaps someone can post them.

When a low frequency exposes something it's generally because it causes a physical vibration that causes the problem to manifest.

Have you tried pounding on the amp with your fist to see if that also causes the problem to happen?
It could be a bad solder joint or even a tube that is reacting to vibration.

This is why I just do not understand why everyone posts the LAYOUT and not the schematic; nor why Nik doesn't include schematics.

With just a layout, one has to not only envision what each part is about but which parts are different. But with a schematic the part's function is evident and it's much easier to follow the circuit flow.

Having both together can be very useful - especially when trying to build a board. But if only one is available to understand the circuit and any modifications, after something is built, the schematic seems the most explanatory - otherwise I'm sure layouts would have been the diagrams supplied with all electronic devices for the past 90 years rather than schematics.

I would have taken a hammer to my HRM long ago if not for having a schematic.

What kind of OT do you have?

I found that an vintage RCA short plate in V1 with JJ's elsewhere sounds OK for my tastes.

I tried a long plate in V!, but it seemed too smooth. Putting them in V2 or PI made the amp even smoother - more like a Marshall than Dumble.

Yes. Just try every combo you can, because even similar tubes will sound different in the same spot.

Are those tubes you have definitely NOS?

I wouldn't count on anything but trying it with a slow blow.

However, if you disconnected all the secondaries from the circuitry, so that the only connection to the transformer is the AC, and it still blows (with the correct fuse) - then the transformer is bad.

I envy you guys. The only German I know comes from watching Nena vids from the 80s. Hast Du etwas Zeit für mich. LOL.

Oh yeah I forgot, my French, Michele my belle... sont les mot qui vont tres bien ensemble.