Adcom GFA 5400 Worth Repair?

[Deonild]

Hi all,

I picked up an Adcom GFA 5400 2 channel power amp. The amp has a distortion/static that I hear with the music, no static when no music is playing, distortion not noticeable during very light musical parts. Distortion increases with volume and the amp has a distortion LED that flickers at medium-high volume. Verified its not due to source, preamp, speakers, cables or power. Any ideas what the root cause could be?

I have some knowledge of parts/repairs, have soldered new MOSFETs onto a DIY-style headphone amp, however thinking I would bring this to a professional repair shop if there's a possibility it could be something worth repairing. Do the symptoms sound like any common issue? Something expensive for sure like $300? Could it be over $500 repair job? Any feedback is appreciated.

Thanks!

 

[BoredSysAdmin]

Did you had a chance to find it's siblings on ebay?
http://www.ebay.com/itm/272881118226
That listing is one of most expensive, tells me that paying $500 or even $300 for repair would not be good investment.
Good news is that both service manual and schematics are easily available online. I'd seek help for someone who could guide to troubleshoot it and don't be shy to look for youtube videos - that's how I fixed my Onkyo AVR and partially my Panasonic plasma TV (partially since doing surface mount level solder for ICs is above my skillset)

 

[Deonild]

If the repair cost may be just a few hundred I would look into repairing it. My significant other would not appreciate my bringing home expensive brand new equipment, however I could get away with putting some money into used equipment. Looking at new "budget high-end" components like Parasound 2100/2125 preamp and poweramp, that'd be close to $1400. So if Adcom may be similar audio quality and I hope well under that total price, it's good for me. I've never had stereo components repaired so want to see if this is something that could be a common issue/repair for older amps.

 

[BoredSysAdmin]

If the repair cost may be just a few hundred I would look into repairing it.

Somehow I got a feeling that you didn't clicked the url I gave before. Let me spell it out for, if I wasn't clear.
If you could could replace it for couple of hundred, why pay couple of hundred for a repair?
I think the repair would only make sense if it's at or under $100
Speaking of budget hi-end component, don't discount Emotiva and Outlaw

 

[PENG]

Repair is going to cost >$300 for sure and for an old amp like that you probably want to replace the capacitors so it could push it up to $500 or more, not worth it. They may charge $100 to $150 just to figure out what's wrong and give you a firm quote and if you go ahead, that $100-$150 will of course be deducted from the total cost.

 

[Deonild]

Thanks Bored and Peng. I don't like the idea of shipping heavy breakable stuff so buying that one didn't occur to me, hah. But that makes sense if it arrives and works better! I found a repair shop that does free estimates, will see which will come out cheaper.

 

[lovinthehd]

Why buy another old amp that could be in the same situation in the near future?

 

[MrBoat]

I have the GFA 5500 that a roommate that was audio rich/money poor gave me in exchange for his rent when he was moving. My cousin needed an amp so I let him use it. He paid to have it gone through and caps upgraded/replaced to the tune of about $400. It sounds great but now I don't have the heart, or need to ask him for it back. Only agreement is he can't sell it or trade it away.

By the time I got it back, even if it was now, I'd be wondering how long again before needing more work. So unless it's a complete refurb, it's going to be kind of one of those ongoing maintenance things with mis-aged, consumable components in the chain.

 

[PENG]

I have the GFA 5500 that a roommate that was audio rich/money poor gave me in exchange for his rent when he was moving. My cousin needed an amp so I let him use it. He paid to have it gone through and caps upgraded/replaced to the tune of about $400. It sounds great but now I don't have the heart, or need to ask him for it back. Only agreement is he can't sell it or trade it away.

By the time I got it back, even if it was now, I'd be wondering how long again before needing more work. So unless it's a complete refurb, it's going to be kind of one of those ongoing maintenance things with mis-aged, consumable components in the chain.

If the $400 is US$, that's about the numbers I mentioned earlier, sometimes I forgot the conversion factor from C$ to US$. Those big caps are surprisingly expensive.

 

[Deonild]

Found a stereo repair guy who diagnosed it for free. Even brought me in back and hooked it up to an oscilloscope. Said he'll repair it for $160-$180 with a warranty, saw he had a few other Adcom amps there so he must be familiar with them. Going to have it done.

He said the amp will be fine for me, but he didn't have nice things to say about the preamp I bought haha, Adcom GTP-500II. Hopefully these Adcom's, with an ext dac, will be a noticeable enough improvement for me, over using a cheap avr for 2 channel music.

Thanks again for the help all.

 

[M Code]

Found a stereo repair guy who diagnosed it for free. Even brought me in back and hooked it up to an oscilloscope. Said he'll repair it for $160-$180 with a warranty, saw he had a few other Adcom amps there so he must be familiar with them. Going to have it done.

He said the amp will be fine for me, but he didn't have nice things to say about the preamp I bought haha, Adcom GTP-500II. Hopefully these Adcom's, with an ext dac, will be a noticeable enough improvement for me, over using a cheap avr for 2 channel music.

Thanks again for the help all.

Sounds like a reasonable deal..
Today most repair techs charge $85-100 just for a quick checkout, but often this can be applied toward the repair. U didn't say what the warranty was 90 days? 1 year? Make sure to confirm this..

Just my $0.02...

 

[MrBoat]

If the $400 is US$, that's about the numbers I mentioned earlier, sometimes I forgot the conversion factor from C$ to US$. Those big caps are surprisingly expensive.

IIRC, all the caps on the outputs were upgraded to better ones than stock, and the reason he got it done for that price is because the tech is a gearhead and digs doing the upgrades. The labor wasn't that much, or at least I can't imagine working for that just considering overhead and my time for what I do, comparatively.

The guy ran temperature scans and everything on it for that price and I have to admit it's a potent amp.

The preamp is an adcom gfp 750. He bought that himself after.

I still prefer my Denon 3805 with bass management and pure direct gets me pretty much the same effect in a much smaller pkg. My home is too small for 200 wpc.

 

[PENG]

IIRC, all the caps on the outputs were upgraded to better ones than stock, and the reason he got it done for that price is because the tech is a gearhead and digs doing the upgrades. The labor wasn't that much, or at least I can't imagine working for that just considering overhead and my time for what I do, comparatively.

The guy ran temperature scans and everything on it for that price and I have to admit it's a potent amp.

The preamp is an adcom gfp 750. He bought that himself after.

I still prefer my Denon 3805 with bass management and pure direct gets me pretty much the same effect in a much smaller pkg. My home is too small for 200 wpc.

If the GFA5500 were like my GFA555 then the caps won't be cheap as they were pretty big, prbably around 30,000 uF total per channel if I remember right. I can't complain about Adcom because my first pairs of separates are the GFP565 and 555 that lasted me over 20 years, only then the GFA555 lost one channel. By then I have so many amps/preamps so I didn't bother repairing it and used it for the center channel for some time until I needed the space. If I have time, I will locate it (somewhere in the basement) and get it fixed for fun.

My GFP 565 preamp is still in brand new condition as a ready back up for my SC-7. Too bad Adcom is no longer in business. They were like the Monolith/Emotiva/Outlaw in the old days.

 

[Deonild]

Just got the Adcom 5400 back, so glad I got it repaired! Huge sound improvement over using AV receiver. May have paid more than I should have in total for a used amp, but he only charged me $135 for the repair even though estimate was $160. Guess it could have gone bad if I didn't find a good repair shop.

 

[lovinthehd]

Just got the Adcom 5400 back, so glad I got it repaired! Huge sound improvement over using AV receiver. May have paid more than I should have in total for a used amp, but he only charged me $135 for the repair even though estimate was $160. Guess it could have gone bad if I didn't find a good repair shop.

Congrats, just what did he need to do?

 

[Deonild]

Here's the description from invoice:
Adcom 5400: service. Faulty current limiting (+ half of supply rail on left, - half of supply rail on right), both rails corrected for both channels; power switch inoperative (previous tampering, duct tape??), returned to normal operation; bias and null trims cleaned and rinsed; output stages nulled to 0mV after thermal stabilisation, cover in place (final was +/- 1.4mV); output stages biased at 10kHz into 4 at 1w output, and all x-over notch eliminated. Both channels operating as designed. 1 year warranty.

He gave me the little piece of duct tape : )

Also, I took the repair tech's advice to get a different preamp. Found a vintage Harman Kardon Citation Eleven (gave some business to a audio shop he works with). Sounds great with the Adcom amp and my JBL L60T speakers! Did test the GTP-500II preamp before trading it in, and it was a little bright compared to the HK, may have been too bright with my speakers. Very happy with this setup! Not sure of forum rules for recommending repair shops, if anyone needs a repair shop recommendation in Chicago PM me.

 

[Swerd]

Glad to read about your repaired amp .

Not sure of forum rules for recommending repair shops, if anyone needs a repair shop recommendation in Chicago PM me.

I'd go ahead and name the repair shop. I went through a similar repair of an older amp last spring. I was happy with the results and recommended the repair shop:

https://forums.audioholics.com/forums/threads/household-electrical-problem.107460/page-7#post-1191398​

I'm not a moderator, but if it were a problem, they would speak up.

 

[Deonild]

Cool, Stereo Rehab on Devon avenue in Chicago. He spends time with every customer to test their gear when picking up Fri-Sat, so there was about a half hour line when I came right as he was opening. One guy in line came from Indiana.