Adcom GFA-555 Modded, and gone through

ben62670

Well I have another piece to go. This one is an Adcom GFA-555 with all new electrolytic caps, bridge rectifiers, drivers, cap mod on top of main filter caps, and better power cord. The PS cap mod is small 12uf caps on top of the main PS caps. Big computer caps aren't as smooth as the smaller ones, and many guys add these to clean up the highs.


$400 shipped with a pair of Silver IC's

I'll post pics later

Ben

ben62670

Bump for the evening crowd.

george daniel

I can't believe this is still sitting here,,especially with people looking for amps to power newly aquired speakers.Good luck with the sale Ben.

Systems

How much power does this have Ben? 8ohm & 4ohm? Bridgable and stable at low ohms ?

Chuck




pssst....its a bump too.

heiney9

stereo_luver wrote: »

How much power does this have Ben? 8ohm & 4ohm? Bridgable and stable at low ohms ?

Chuck




pssst....its a bump too.

200 wpc @8
350 wpc @4
will run admirably into a 2 ohm load

Stable into low impedance when bridged (except a no..no.. with SDA's when bridged)

H9

Ricardo

This is a great amp, and with new caps it will last 20 more years.

Someone needs to grab this, soon.

ben62670

The mods don't add any power. They tighten the bass, clean up the mids, and highs. Thanks guys for the props. This amp is definitely sweeter than a stock 555.
Ben

ben62670

Guys modded. Not stock. Gone through. With IC's. Ebay is going to get it soon.

george daniel

With all the people posting questions about their newly aquired SDA's and need for an amp,this is a no brainer.This amp will have you covered,if this goes to Audiogon,it won't last one day I tell you,one day.Good luck with the sale Ben,,I can't believe that its still here.

ben62670

Thanks George.
I'll sell the amp without IC's, and you guys pay shipping for $300
Ben

leroyjr1

Any pictures?

Thanks

schwarcw

I think if Adcom added meters to their amps they would sell a boat load.

RuSsMaN

Adboms are cool. I've had 2 555's modded to near 800w cont on the bench.

ben62670

RuSsMaN wrote: »

Adboms are cool. I've had 2 555's modded to near 800w cont on the bench.

They must have beefed the toridal? Is that each channel, and at what ohms?
Ben

RuSsMaN

Dual power trannies, much higher voltage on the rails (obviously) all per channel, continuous at 4 ohm. We ended up setting fire to both on Danny's Alpha Line Source (a speaker you cannot blow up).

Cheers,
Russ

ben62670

RuSsMaN wrote: »

Dual power trannies, much higher voltage on the rails (obviously) all per channel, continuous at 4 ohm. We ended up setting fire to both on Danny's Alpha Line Source (a speaker you cannot blow up).

Cheers,
Russ

Don't encourage me. I have a spare 555 tranny on the shelf!

heiney9

RuSsMaN wrote: »

Dual power trannies, much higher voltage on the rails (obviously) all per channel, continuous at 4 ohm. We ended up setting fire to both on Danny's Alpha Line Source (a speaker you cannot blow up).

Cheers,
Russ

There are several hobbyist's that are very knowledgeable about circuit design, etc over at DIYaudio that run the **** out of their Adcom's. It's a very robust design right out of the gates and I know several people who run them "hot" w/o issue. But you've got to have some working knowledge to keep from destroying things.

The best testament is when Stereophile took an Adcom 555 II and ran the Scintilla speaker, which dips below 2 ohms, to a very commendable level w/o the 555 II even hiccuping. They were using the factory supplied fan system and IIRC, they put slightly higher rated rail fuses in.

H9

ben62670

Sold

Systems

Good for you Ben.

Chuck

george daniel

Hopefully someone here picked it up,,I just felt compelled to say that.;)