Bluesmaster CLEAN optimized for STRAT (Blackface cap values)

[bluesfendermanblues]

I really enjoy my 50W Bluesmaster clone, that gets a lot of positive feedback from band mates and audience about its (OD+PAB) lead sound.

However, being mainly a strat player, I was never very impressed with the (strat pos 2 and 4) clean tone of amp with my strat. Too much bass and not shimmery at all.

The amp is setup exactly like Tony's schematic and always used wtih a Dumbleator. V2a is 2n (as per Dogears suggestion).
OD Trim is set at 20k
HRM board: Mid: 4.3k, Bass: 30.1K, Treb: 90.1K.
PAB is 22M - aka megaboost.

My guitar has SD Antiqueties in neck/mid pos. Solos are mainly played on the bridge PU, which is a SD Twangbanger (that sounds very similar to bridge PU in a Fender 52' Tele RI) and I use use OD+PAB for solos.

What really provoked me was sitting in with a new band, where the rythm guitarist played a Bogner Alchemy and his Clean sounds were way more fendery and open, than my clean sound.

This got me thinking, it must be possible to get a nice clean (STRAT) sound out of this amp. The obvious would be converting the the tonestack to blackface specs!

I did the following:
Changed the 22n bass cap to 100n
Changed the 22n mid cap to 47n
Changed the Slope resistor from 47K to 100K
Didn't change plate or cathode resistors.

Really enjoy this change on the clean sound with the strat - it's standard blackface sound, even if the plate resistors are BM values.

lead sound (OD + PAB) is NOT affected by this change.
OD (without PAB), which was also a bit bass heavy, now sounds nice with the neck pickup for blues lead.

I don't claim to have rediscovered the holy grail of amps, but I hope this can inspire other BM/Strat players.

As always your mileage may vary, but to these ol' ears this is a nice(r) clean sound.

[dcribbs1412]

Thanks for the info
I may give this a shot
any pics of your build?

[bluesfendermanblues]

Thanks for the info
I may give this a shot
any pics of your build?

Not any of the updated version, but some with the ol' 2x22n + slope

[dcribbs1412]

Thanks blues
on the OD relay
from left to right
1 is coil
2 is the loop
3 is OD
4 is clean master?
5 is ground?
6 is ?
7 is ?

I see you have the mid boost on relay also
OK blues I think I got it
looked a little closer and I think I have it
will give it a go asap
Thanks again for posting shots

[SoundPerf]

OD Trim is set at 20k
HRM board: Mid: 4.3k, Bass: 30.1K, Treb: 90.1K.

What are the measurement points for these resistance measurements of the trimmers on the HRM board? Are these measured in circuit?

Thanks!

[glasman]

Very cool. Been doing something similar for a while as well.

A lot of room on the mid cap and slope resistor. I keep .01, .02 .033, .04, .05, .06 .082 and .1s around to tweak the stacks to match a particular guitar and customers requirements.

Gary

[bluesfendermanblues]

Thanks blues
on the OD relay
from left to right
1 is coil
2 is the loop
3 is OD
4 is clean master?
5 is ground?
6 is ?
7 is ?

I see you have the mid boost on relay also
OK blues I think I got it
looked a little closer and I think I have it
will give it a go asap
Thanks again for posting shots

Check Tony's layout:

https://tubeamparchive.com/download/file.php?id=15545

IMO, It much easier to the relay details on the layout, than on my photos.

[bluesfendermanblues]

OD Trim is set at 20k
HRM board: Mid: 4.3k, Bass: 30.1K, Treb: 90.1K.

What are the measurement points for these resistance measurements of the trimmers on the HRM board? Are these measured in circuit?

Thanks!

Here ya go...

BTW the mid trim sound range is 3.2k-4.8k - with 4k being the mean value or starting point. I have plenty of midrange sound with the presented HRM trim values. Maybe I will up the HRM slope to 47K

Also the Mid boost is 2n+390p, I guess 1n + 500p would be a better mid boost.

[bluesfendermanblues]

Very cool. Been doing something similar for a while as well.

A lot of room on the mid cap and slope resistor. I keep .01, .02 .033, .04, .05, .06 .082 and .1s around to tweak the stacks to match a particular guitar and customers requirements.

Gary

Gary, great to hear that you also tweak the tone stack for clean. And why shouldn't we, because the lead sound (OD + PAB), which is the signature of these fine amps is unaltered.

BTW, After playing the amp at a rehersal tonight, I will probably lower the slope to 68k.

[dcribbs1412]

Blues and Gary
thanks for the info

[jelle]

What's the cap across the 100K NFB doing there?

Have you been studying ancient marshalls?

Jelle

[bluesfendermanblues]

What's the cap across the 100K NFB doing there?

Have you been studying ancient marshalls?

Jelle

Actually yes! and old HiFi tube amps, where a cap in parallel with the GNFB resistor is mandatory. Keeps HF swing out of The OT.

[dimitris]

You have a capacitor paralleled with the 100k NFB resistor.What's that for?
Edit :Just saw your answer

[glasman]

What's the cap across the 100K NFB doing there?

Have you been studying ancient marshalls?

Jelle

Take a look at the PV 5150. Interesting take in the FB loop as well.

But the Ubershal takes the GRAND PRIZE for complex feedback networks R's C's and L's. Nothing else I've seen comes close.

[SoundPerf]

Blues, thanks for the great reply. Time to do some analysis.