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Post subject: Is there a Rev. B Schematic for 2004 Blues Deluxe Reissue?
Posted: Mon Jul 11, 2011 5:36 am
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I bought a Blues Deluxe Reissue used; it is the 2004 model. However, these 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.


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Post subject: Re: Is there a Rev. B Schematic for 2004 Blues Deluxe Reissu
Posted: Mon Jul 11, 2011 9:52 am
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The schematic in this service manual matches my BDRI purchased in 2009.

http://www.blueguitar.org/new/schem/fen ... eissue.pdf

a. I cannot find a C37 in the schematic for the Deville or the Deluxe.
b. I cannot find a D10 in the schematic for the Deville or the Deluxe.
c. R76 is shown as 10K ohm in the Deville and 100K ohm in the Deluxe.
d. R77 is 100K ohm in both schematics.
e. TP41 shows -73 volts in the Deville and -53 volts in the Deluxe.

I have no trouble biasing my BDRI to 83 mV with JJ 6L6GC tubes.

I am not sure what schematic you are looking at.

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Post subject: Re: Is there a Rev. B Schematic for 2004 Blues Deluxe Reissu
Posted: Mon Jul 11, 2011 10:31 am
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Hi pcb777,

What kind of test point reading did you have with the old tubes? Is there a better adjustment range with the old tubes? :idea:

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Post subject: Re: Is there a Rev. B Schematic for 2004 Blues Deluxe Reissu
Posted: Wed Jul 13, 2011 4:21 pm
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bluesky636 wrote:
The schematic in this service manual matches my BDRI purchased in 2009.

http://www.blueguitar.org/new/schem/fen ... eissue.pdf

a. I cannot find a C37 in the schematic for the Deville or the Deluxe.
b. I cannot find a D10 in the schematic for the Deville or the Deluxe.
c. R76 is shown as 10K ohm in the Deville and 100K ohm in the Deluxe.
d. R77 is 100K ohm in both schematics.
e. TP41 shows -73 volts in the Deville and -53 volts in the Deluxe.

I have no trouble biasing my BDRI to 83 mV with JJ 6L6GC tubes.

I am not sure what schematic you are looking at.

These components are in the power supply, sheet 2 of the schematics in the manual you quoted. According to the manual, tubes should be biased to 60mV, not 83mV.


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Post subject: Re: Is there a Rev. B Schematic for 2004 Blues Deluxe Reissu
Posted: Wed Jul 13, 2011 5:08 pm
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Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
pcb777 wrote:
bluesky636 wrote:
The schematic in this service manual matches my BDRI purchased in 2009.

http://www.blueguitar.org/new/schem/fen ... eissue.pdf

a. I cannot find a C37 in the schematic for the Deville or the Deluxe.
b. I cannot find a D10 in the schematic for the Deville or the Deluxe.
c. R76 is shown as 10K ohm in the Deville and 100K ohm in the Deluxe.
d. R77 is 100K ohm in both schematics.
e. TP41 shows -73 volts in the Deville and -53 volts in the Deluxe.

I have no trouble biasing my BDRI to 83 mV with JJ 6L6GC tubes.

I am not sure what schematic you are looking at.

These components are in the power supply, sheet 2 of the schematics in the manual you quoted. According to the manual, tubes should be biased to 60mV, not 83mV.


Ok. I found C37 and D10 in the Deville. Are you claiming that those components are present in your Deluxe?

Are you claiming that the values for R76 and R77 in the schematic are different than what is in your amp?

I will be opening up my BDRI this week to change speakers so I will look to see what my actual configuration is.

I still don't know what the schematic is that you are looking at.

Yes, Fender biases the stock Groove Tubes to 60 mV which is very cold and not necessarily the best for tone. I am running JJ 6L6GCs which can be biased hotter and sound better. Perhaps you need to learn more about biasing. Here are some good places to start:

http://www.aikenamps.com/WhatIsBiasing.htm

http://www.aikenamps.com/Why70percent.html

http://www.justinholton.com/hotrod/bias.html

http://www.eurotubes.com/euro-Fender-HRDV.htm

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