BM HRM layout (edit)

[larsmuller]

Does anybody know if there is a HRM BM layout?

edit: I found one...

[dogears]

Well done but a bunch of inaccuracies....

There is no cap feeding the HRM. This is important.

The CL2 can be a .01 or a .02. Try both. Both have been in the real deals.

Clean master bright cap is 47pf. Although maybe 30pf suits you better.

Only use 47pf bright cap on OD master if you plan on using the loop.

OD1 coupler can be .002 (some may prefer .001, but most don't)

I'd use a 180-K feeding a 50K trimmer on the pre-od network. Most like the trimmer set very low....

Mid pot is 50K.

[larsmuller]

Well done but a bunch of inaccuracies....

There is no cap feeding the HRM. This is important.

The CL2 can be a .01 or a .02. Try both. Both have been in the real deals.

Clean master bright cap is 47pf. Although maybe 30pf suits you better.

Only use 47pf bright cap on OD master if you plan on using the loop.

OD1 coupler can be .002 (some may prefer .001, but most don't)

I'd use a 180-K feeding a 50K trimmer on the pre-od network. Most like the trimmer set very low....

Mid pot is 50K.

Hey Dogears,

Thnx alot!

A few questions though,...

What do you mean by "There is no cap feeding the HRM."?

I see a Orange Drop Treble cap....shouldn't it be ceramic?

Does it need a choke? Or can I use a resitor (just like the dlite), is this the Dumble way, do you think RF's Dumble got a choke?

grtz

[dogears]

I see a .01 on the board that connects to the HRM board. In the real Bluesmasters, the plate resistor connects directly to the HRM board.

I have two BM amps. One with choke and one with resistor. I prefer the choke in this circuit.... YMMV.

The midboost cap is an OD. The treble cap is ceramic and on the midboost switch.

Well done but a bunch of inaccuracies....

There is no cap feeding the HRM. This is important.

The CL2 can be a .01 or a .02. Try both. Both have been in the real deals.

Clean master bright cap is 47pf. Although maybe 30pf suits you better.

Only use 47pf bright cap on OD master if you plan on using the loop.

OD1 coupler can be .002 (some may prefer .001, but most don't)

I'd use a 180-K feeding a 50K trimmer on the pre-od network. Most like the trimmer set very low....

Mid pot is 50K.

Hey Dogears,

Thnx alot!

A few questions though,...

What do you mean by "There is no cap feeding the HRM."?

I see a Orange Drop Treble cap....shouldn't it be ceramic?

Does it need a choke? Or can I use a resitor (just like the dlite), is this the Dumble way, do you think RF's Dumble got a choke?

grtz

[Bob-I]

One more thing. The lead dress on V2 is wrong. The lead to pin 8 should wrap around the tube socket on the other side, parallel with both pin 1 and 3. This is important and makes a difference.

[Funkalicousgroove]

Clean master bright is actually 68pf, Bright switch cap should be 100-120pf

[larsmuller]

One more thing. The lead dress on V2 is wrong. The lead to pin 8 should wrap around the tube socket on the other side, parallel with both pin 1 and 3. This is important and makes a difference.

Thnx! So just like it is on V1?

[larsmuller]

I modified the layout....should be better....

[Bob-I]

The HRM area is a little confusing I can't tell where the wires are going, plus the .01 is still there. It may be that it's not connected to the HRM but I can't tell.

Also, look at the pics in this thread https://tubeamparchive.com/viewtopic.php?t=393

It may be a tad picky but the leads on plates and cathodes are touching. I've found that it makes a difference.

The rest looks good. You might consider listing alternate values that dogears mentioned for the couplers.

[mdroberts1243]

Just a heads-up... I wouldn't trust much about this layout myself... and I did the original.

This layout was done based on posted pictures of Funk's chassis and boards before I got my delivery from Funk. It is incomplete and represents early thoughts as I was in the process of trying to cobble together a schematic for the BM from reams of threads discussing it in a round-about way... for instance there are a number of posts suggesting a coupling capacitor between OD2 and the HRM (not normal by any means).

Once I had boards and chassis in hand I switched to directly wiring the beast and didn't work with the layout any further.

I have passed on the original Visio files to interested parties that intended to update and finish the job but no results to date.

I'd still love to have a 'reference' schematic for the BM a la #124, etc. I did the best I could with the information I was able to glean from forum discussions.