Dear folks,
I am new to this hobby so please bear with my plebe ignorance.
I just purchased a used Adcom GFA-5800. It works and sounds pretty good, but currently not up to the audio quality of my Nuforce STA-200.
I figure it needs some component replacements because of age. I tried looking around to see if there are any upgrade kits that I can install myself. I've built the Transcendent tube amps kits GGP which I upgraded, and the SE-OTL amp, and the BPS, as well as other electronic stuff, so I believe I can physically do it.
However, I am not at a superior level because I need electronic expertise to tell me what to change, and their new values.
I've also sent Big Sky Audio in Montana to see how much it will cost that way as well, but shipping one way is about $85 from California to Montana via UPS, not to mention the cost of the service. Maybe this is a better, easier way to go.
I have found the schematics (service manual) for the Adcom GFA-5800 amp. I was wondering if anyone has a list of parts replacement and upgrades that I can do? I've been searching the internet for DIY information, but found nothing. If you know of some upgrade guide specifically written for the Adcom GFA-5800 somewhere on the internet that is written step by step, I would greatly appreciate it if you can send me the URL link.
I've attached the service manual to this post.
I am new to this hobby so please bear with my plebe ignorance.
I just purchased a used Adcom GFA-5800. It works and sounds pretty good, but currently not up to the audio quality of my Nuforce STA-200.
I figure it needs some component replacements because of age. I tried looking around to see if there are any upgrade kits that I can install myself. I've built the Transcendent tube amps kits GGP which I upgraded, and the SE-OTL amp, and the BPS, as well as other electronic stuff, so I believe I can physically do it.
However, I am not at a superior level because I need electronic expertise to tell me what to change, and their new values.
I've also sent Big Sky Audio in Montana to see how much it will cost that way as well, but shipping one way is about $85 from California to Montana via UPS, not to mention the cost of the service. Maybe this is a better, easier way to go.
I have found the schematics (service manual) for the Adcom GFA-5800 amp. I was wondering if anyone has a list of parts replacement and upgrades that I can do? I've been searching the internet for DIY information, but found nothing. If you know of some upgrade guide specifically written for the Adcom GFA-5800 somewhere on the internet that is written step by step, I would greatly appreciate it if you can send me the URL link.
I've attached the service manual to this post.
pictures will help
besides that , consider replacing all smaller electrolytic caps .... for big ones it would be wise to at least test them for ESR, then replace if necessary
check all bolts and screws for tightness , especially those on mosfet cans
if you have laser temp gun or something decently precise , check temp. of all mosfets and compare ; if there are bigger differences than ,say, 5C - consider dissmantling them (one by one) , cleaning of old thermal goo and laying new one
inspect all solder joints , clean/wick/suck suspicious ones , resolder
check Iq and offset
besides that , consider replacing all smaller electrolytic caps .... for big ones it would be wise to at least test them for ESR, then replace if necessary
check all bolts and screws for tightness , especially those on mosfet cans
if you have laser temp gun or something decently precise , check temp. of all mosfets and compare ; if there are bigger differences than ,say, 5C - consider dissmantling them (one by one) , cleaning of old thermal goo and laying new one
inspect all solder joints , clean/wick/suck suspicious ones , resolder
check Iq and offset
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I also noticed a strange behavior. If I turn off the amp overnight and turn it back on, the distortion light on the left channel glows dimly. After it warms up, it disappears. Does anyone know what this means? I figure it must be a filter cap that is going bad.
Big Sky doesn't work on GFA-5800
I just got word from Big Sky Audio in Montana.
Rick Krzemien has informed me that they do not do upgrade work on the Adcom GFA-5800 anymore. 🙁
I just got word from Big Sky Audio in Montana.
Rick Krzemien has informed me that they do not do upgrade work on the Adcom GFA-5800 anymore. 🙁
hopefully you can find someone locally with serious ESR meter , to check big caps
if not , it's your choice - replace them or leave in
small ESR meters ( measure it all gadgets of nowadays) aren't serious enough
if not , it's your choice - replace them or leave in
small ESR meters ( measure it all gadgets of nowadays) aren't serious enough
Just replace them all, and sleep better at night know with absolute certainty you have eliminated any possible issue with caps being a problem now or in the near future.
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