What parts are bluesmaster and which are HRM?

[JamesO]

I'm moving my current build from #124 to a non-hrm Bluesmaster. After looking at the layouts for HRM ODS 102 and the Bluesmaster HRM, three areas look HRM-specific.

Because I'm doing non-hrm, I'm wondering if I should . . .

- Leave the 220k OD enterance, instead of the BM HRM's 470k/47pF to 120 OD In network?

- Leave the .005uF to 150k to OD volume, instead of the BM HRM's .01uF to 100k to OD volume?

- Leave the 120 and 110k w/ 5k trimmer B3 enterance, instead of the BM HRM's 110 and 100k w/ 10k trimmer?

In other words, should I leave everything as is other than the pot layout, tonestack, and PI? .001uF's on the bias circuit?

[heisthl]

If I'm understanding you right you want a Bluesmaster front end, a Bluesmaster PI and a non-HRM OD? If so you will not have a OD master (you'll have a level or Ratio instead). The issue you will have is a little too much signal and a little too much bass entering the non-HRM OD section, compounded by a PI that has less low end clarity. If you try the Bluesmaster entrance to the OD and don't like it, I would recommend using the LNFB on V1B and at the relay common adding a resistor (470K to 1meg is probably a good value) to ground with a cap (.02 or .047) in series to the 220k entrance trimmer (100k) feed. This will cut down the level and the amount of bass so the OD will still sing nicely. You can compensate for the slight decrease in OD output by using a 33k feeding a 250k level pot instead of the more traditional 150k feeding the 100k pot. You may have to drop the PI entrance cap to .01 or even as far as .003 for clarity in the low notes.

[JamesO]

Thanks.