Bluesmaster pre with non-hrm overdrive

[10thTx]

I'm thinking maybe the PAB should look more like this?

Can someone confirm please?

With respect, 10thtx

[10thTx]

Looks like there may be another possible error on the schematic with the clean to OD relay switchin?

Can someone confirm that the correction I drew is accurate, please?

With respect, 10thtx

[Dr d]

Erwins drawing is fine, I think. The PAB relay allows the mid to go straight to ground or via a 72k lift. The 22m is there for anti popping I think. Same as Mdroberts bluesmaster drawing. Channel switching is fine also. The unconnected line should just go to the 0.02uf cap out of cl2.

[Dr d]

Hi Erwin, does it still sound as good with a strat? I guess you could always install a switch to bypass the 4m7/0.02 combo in the OD entrance.

[10thTx]

The 22m is there for anti popping I think.

How does that prevent anti-popping if the 22M is only connected to itself?

Maybe I am missing something here or not understanding what he has
drawn?

The unconnected line should just go to the 0.02uf cap out of cl2.

OK, got it. That makes sense. The master volume is after the clean/od switching prior to the FX & LTPI.

It could have been drawn to connect the two DPDT (relay) posts or two wires from the .02 to those two DPDT posts.


with respect, 10thtx

[Dr d]

Just looked at Tonys Bluesmaster layout. The 22m is connected either side of mid wiper and bottom of bass pot so that they are disconnected when PAB is engaged. In Erwins drawing, the 22m could probably be omitted?

[10thTx]

Just looked at Tonys Bluesmaster layout. The 22m is connected either side of mid wiper and bottom of bass pot so that they are disconnected when PAB is engaged. In Erwins drawing, the 22m could probably be omitted?

So maybe something like this?

With respect, 10thtx

[wokkel]

Biggest improvement was changing the cap on the mid boost: it was a ceramic , now it is a silver mica.

Hi Erwin,

could you elaborate what was the improvement? (Assuming you used the same value).

Thanks,
Harald

[erwin_ve]

Just looked at Tonys Bluesmaster layout. The 22m is connected either side of mid wiper and bottom of bass pot so that they are disconnected when PAB is engaged. In Erwins drawing, the 22m could probably be omitted?

So maybe something like this?

With respect, 10thtx

Tony's layout is correct, my schematic has some flaws. Thnx for updating Jeff!

[erwin_ve]

Biggest improvement was changing the cap on the mid boost: it was a ceramic , now it is a silver mica.

Hi Erwin,

could you elaborate what was the improvement? (Assuming you used the same value).

Thanks,
Harald

Yes same value; with the ceramic the sound was flabby, fuzzy and squashed.
The siver mica had a firm low-end, felt really open and had transperant high end.
I don't know what the deal is with ceramics; I certainly lack knowledge on that part. Maybe ceramic is picking up some magnetics in that area or construction types have something to do with it.
I've been doing swaps with silver mica since 1,5 year and in my limited experience they seem to be more consistent sound wise compared to ceramic.

[PaisleyTube]

@Erwin

I always try using the largest ceramic caps as possible (sometimes using 1kV or 2kV types) if such caps are required regarding tone/circuit.

As soon as I did see " '68 ES 335" I thought of mr. G. His amp did get a MM OT last saturday over here, he was amazed by the impact of that. I guess there will come some more mods and maybe some tube-swaps in the near future. If I do understand correctly the preamp is like a bluesmaster and the rest is non-hrm.

That '68 ES335 is a great sounding one, not really bas-heavy imo (my R7 does have way more low-end without being muddy); it's a very transparanet one, not as mellow/jazzy as a '67 from a buddy.

grz from Vleuten

Chris

[erwin_ve]

@Erwin

I always try using the largest ceramic caps as possible (sometimes using 1kV or 2kV types) if such caps are required regarding tone/circuit.

As soon as I did see " '68 ES 335" I thought of mr. G. His amp did get a MM OT last saturday over here, he was amazed by the impact of that. I guess there will come some more mods and maybe some tube-swaps in the near future. If I do understand correctly the preamp is like a bluesmaster and the rest is non-hrm.

That '68 ES335 is a great sounding one, not really bas-heavy imo (my R7 does have way more low-end without being muddy); it's a very transparanet one, not as mellow/jazzy as a '67 from a buddy.

grz from Vleuten

Chris

Hi Chris, Nice to hear from you! Indeed Mr. G. Do you know why the higher voltage ceramics rates sound better. I like a better undrerstanding on this subject.
Edit: do you think it's plausible that some ceramics are more prone to picking up magnetics than others?
Erwin

[PaisleyTube]

I truly don't know , I just use my ears and comments from clients. Ceramic caps are also (way more) sensitive to chassis-vibrations/etc.

Lots of iconic amps from the past did use ceramic caps and most of the time those caps are larger than the modern ones of the same voltage-rating cer. caps..... size does matter

In a warm sounding (or "very mid-focussed") amp SM caps can work greatly imo but in a brighter toned amp those SM caps can be harsh sounding.

Ps I did remove the 0.02/4M7 combination becuase the low-end was way better with the new OT and the amp did lack some "push"/low-end-power with that RC-combi, also did remove the mv-brightcap and the 0.001 or 0.002 on the fx-send; it's easier to dial in the mv-control without effecting the sound too much and the "blanket" was gone.

[erwin_ve]

I truly don't know , I just use my ears and comments from clients. Ceramic caps are also (way more) sensitive to chassis-vibrations/etc.

Lots of iconic amps from the past did use ceramic caps and most of the time those caps are larger than the modern ones of the same voltage-rating cer. caps..... size does matter

In a warm sounding (or "very mid-focussed") amp SM caps can work greatly imo but in a brighter toned amp those SM caps can be harsh sounding.

Ps I did remove the 0.02/4M7 combination becuase the low-end was way better with the new OT and the amp did lack some "push"/low-end-power with that RC-combi, also did remove the mv-brightcap and the 0.001 or 0.002 on the fx-send; it's easier to dial in the mv-control without effecting the sound too much and the "blanket" was gone.

Cool, Thanks!

[gsb]

Hi,

I know it is old thread but.. I have laying around set up for jtm45 -power tranny ,choke ,OT from good German winder.Young family player want the amp but after some tracks from BM he want BM amp.Power tranny has 325-0-325V ,and 0T is made for kt 66. 6.6k and 8k(Shinrock).My idea was to use kt66 in cathode bias?I have also complet set of Mustards caps Nos. Are they to use in that build?What kind of resistors are used ?

thanks for help and advice
gsb