Adcom GFA-555 II South Africa

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Mods and gents please excuse me if this is posted in the wrong space.

I recently purchased a 555 II amp of eBay after doing a fair amount of research. Trying to get some decent vintage, quality gear. I unscrewed the top plate, the amp and all internals look better than expected especially for an amp this old.

What I'm getting at is that I am in way over my head and do not want to mess around with the amp. The reason I bought it was mostly because of the ratings, it being bulletproof and because I could not get anything remotely similar in quality in Pretoria, South Africa. Prices over here are ridiculous as well and the rand dollar exchange sucks.

Do anyone on here know where in the Pretoria / Johannesburg area I could get in touch with someone with experience to test and maybe repair this amp if needed. The amp switches on and was sold as is, estate find - I don't know the working condition and do not plan to blow up my speakers.

Be gentle please. :dunno:
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I can't help with local help, but for avoiding speaker damage, it is easy to check for DC offset on the speaker terminals if you have access to a simple digital voltmeter (or multimeter) that goes down to a 200mv or 300mv scale, which is something handy to have if you don't already have one.

With speakers disconnected, and no inputs to the amp attached, turn on the amp, let it settle for 5 min or so, and then measure the voltage between the two left speaker terminals (marked + and -, or + and 0, or red and black), and after you are done with that, the two right ones. Make sure to use the millivolt scale.

Generally, if that number is 50 mv or less, you are in decent shape and it is safe to connect your speakers.

But for this line of Adcom amps, there is a servo circuit that zeros the DC-offset, and if that is working, you will get a reading of 1 mv or less, which tells you that that part is working well. Generally, you should not get a reading of 0.0 mv on the millivolt scale; if you do, check to make sure your meter is working properly, or if you are making proper contact with the speaker terminals with the test leads (might has to lightly scratch them on the metal of the binding posts).

Good luck. I have the 535 II and 545 II amps, and love them.
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.