Is there a Rev. B Schematic for 2004 Blues Deluxe Reissue?

[pcb777]

I bought a Blues Deluxe Reissue used; it is the 2004 model as clearly written on the circuit board. However, the (2004) schematics show a different power supply biasing arrangement for the power/output tube grid biasing (C- ) than my amp actually has. (Note: I am using the schematics for the 2004 model, not the 1993 schematics. They are different due to a slight redesign in 2004.) My amp has what appears to be a combination of the Blues Deville and Blues Deluxe power supply configurations. Looking at the Blues Deluxe schematic for the power supply, the changes are:
a. Capacitor C37 replaces jumper W2 as on Blues Deville
b. Diode D10 runs from C37/D15 to GND as on Blues Deville
c. R76 is 72k, not 1.5k
d. R77 is 68k, not 100k

Note that although the voltage at TP41 is -106Vdc, there is still -50Vdc at the R76/R82 junction per the schematic.

The problem I am encountering which led me to investigate all of this is that after putting in new power tubes, the minimum biasing I could obtain was 120mA (120mV on the 1 ohm cathode resistor). After changing R77 from 68k to 200k, I am able to get the 60mA which the schematic says to adjust to. However I want to know if the 68k originally on there was a mistake by the assemblers or if something else is wrong with my amp.

[Enzo]

The assemblers are computer coltrolled machines.

I have encountered this very power supply change too, I just followed what I found in the various schematics you listed.

Just a thought, is the 1 ohmer still 1 ohm?

[pcb777]

The assemblers are computer coltrolled machines.

I have encountered this very power supply change too, I just followed what I found in the various schematics you listed.

Just a thought, is the 1 ohmer still 1 ohm?

Yes- 1 ohm. If you found the same change in the p/s it must be a revision- they decided to change it from half rectification (one diode) to full (2 diodes). Maybe to cut down on the ripple.

[Enzo]

More likely to use one board design for more models. Half wave is only a ripple problem when you try to draw current from it. Bias supplies draw little current. Half wave bias supplies have been working quite well for decades and decades. Longer than most members of this board have been alive.

[peppercalhoun]

hey,new to this thread,and,evidently a hack at this stage. I installed a Fromel kit on a 2004 BDR,replaced the power and pre amp tubes,speaker,caps-filter and tone stack,removed the resistor next to the reverb control -all part of the mod.My issue is a noise that was there before the mod and I assumed,wrongly,that by replacing the caps and resistors in the power supply,this noise would have gone away since the noise I hear has been related to the components I replaced in more than one discussion. now to the noise,cable plugged in or not,volume down or up,EQ at any position,reverb on or off,and without any predictability ,a thunderstorms recreates itself through this amp,and very loudly!!! I plugged the amp into a furman a/c line regulator with no other electronic devices around and...same thing.I have removed the board twice since the mod,retouched all of the connections I've made as well as any other dirty,hazy,or otherwise suspect solder joints,checked that the wire connections are in their respective locations,etc.. but no relief from this unpredictable noise. Any ideas?

[peppercalhoun]

and,by the way,i didn't see any links here for the schematic for the Blues Deluxe Reissue,so here is one http://www.blueguitar.org/new/schem/...le_reissue.pdf