I got the amp all put together over the holidays. Changing those 26 year old filter capacitors significantly changed the sound. More musical. Less muddy. Greater detail.
The amp could use a bias checkup but I am having a terrible time finding documentation on adjusting it. I have a GFA-555 service manual but it contains the procedure for a PS board unlike mine. They may be similar enough that the procedure also pertains to it but I would like to run it by the forum. Hopefully some of the past Adcom techs will chime in or others who have the same board as mine.
Here is my board along with the link to the schematic:
Link to schematic: ftp://www.civilwarmedicalbooks.com/bias/hfe_adcom_gfa-555_schematics.pdf
My GFA-555 PS board:
Here is the link to the only GFA-555 service manual I can find which has the bias alignment procedure in it. Remember the board in this manual differs from mine:
ftp://www.civilwarmedicalbooks.com/bias/Adcom_GFA-555_service_manual(1).pdf
Here is board the top link refers to:
The amp could use a bias checkup but I am having a terrible time finding documentation on adjusting it. I have a GFA-555 service manual but it contains the procedure for a PS board unlike mine. They may be similar enough that the procedure also pertains to it but I would like to run it by the forum. Hopefully some of the past Adcom techs will chime in or others who have the same board as mine.
Here is my board along with the link to the schematic:
Link to schematic: ftp://www.civilwarmedicalbooks.com/bias/hfe_adcom_gfa-555_schematics.pdf
My GFA-555 PS board:
An externally hosted image should be here but it was not working when we last tested it.
Here is the link to the only GFA-555 service manual I can find which has the bias alignment procedure in it. Remember the board in this manual differs from mine:
ftp://www.civilwarmedicalbooks.com/bias/Adcom_GFA-555_service_manual(1).pdf
Here is board the top link refers to:
An externally hosted image should be here but it was not working when we last tested it.
Screwed the links up in the previous post. Here they are corrected:
Here is my board along with the link to the schematic:
Link to schematic: www.civilwarmedicalbooks.com/b...schematics.pdf
Here is the link to the only GFA-555 service manual I can find which has the bias alignment procedure in it. Remember the board in this manual differs from mine:
www.civilwarmedicalbooks.com/bias/Adcom_GFA-555_service_manual(1).pdf
Here is my board along with the link to the schematic:
Link to schematic: www.civilwarmedicalbooks.com/b...schematics.pdf
Here is the link to the only GFA-555 service manual I can find which has the bias alignment procedure in it. Remember the board in this manual differs from mine:
www.civilwarmedicalbooks.com/bias/Adcom_GFA-555_service_manual(1).pdf
I guess you've seen the stuff here:
Adcom GFA-555 | Owners Manual, Service Manual, Schematics, Free Download | HiFi Engine
Adcom GFA-555 | Owners Manual, Service Manual, Schematics, Free Download | HiFi Engine
Thank you gootee. I guess I got that wrong 2 times. Here is the procedure outlined in the Adcom service manual:
An externally hosted image should be here but it was not working when we last tested it.
This procedure is for this board:
An externally hosted image should be here but it was not working when we last tested it.
The schematic to my board is here:
http://www.civilwarmedicalbooks.com/bias/hfe_adcom_gfa-555_schematics.pdf
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