Adcom GFA-585 Limited Edition pop on power up

Mtg06405

Member
2019-01-31 7:00 pm
Hi everyone,

I recently purchased an Adcom GFA-585 Limited Edition power amplifier and have a question about a click in the speakers I hear on initial power up.


I heard about the leaking Elna capacitors nightmare that causes all sorts of problems with DC offsets at the speakers and pops on start up, so that's why I'm asking about this.

The previous owner said that all the problem capacitors were changed about 10 years ago before any leakage damaged anything, and that the DC offsets at the speaker output was 0 - 2mV.

It sounded like a good deal, and I had been looking for a nice example of one of these to drive my Polk SDA SRS 1.2 speakers, so I decided to get it.

When it arrived, before hooking it up I confirmed the DC offsets were good right from initial power up and did not drift even after about an hour and a half.

I removed the top cover for an inspection and there is absolutely no sign of any electrolyte leakage inside, no repairs on any of the circuit boards, and the capacitors had been changed to a brand called Shoei, which I am not really familiar with, but at least they weren't leaking.

So then I thought it was pretty safe to hook up to my speakers and give a listen.

I notice a little "click" sound in the speakers on initial power up, and again when powering the amplifier down. Aside from this, it seems to work fine and sounds great.

I'm just looking to check in with other owners to see if this is normal or not, given the reputation this amp has for lasting issues even after the caps have been changed.

Again, there's absolutely no other evidence of any problems, no hack or jury rigged repairs.

I have also heard that the electrolyte can seep into to boards and cause problems to pop up later.

So am I OK? Should the speakers remain dead silent on power up and power down, or is some noise to be expected?

I should probably add that I investigated the possibility of the Softstart/ Bias delay board being the possibility culprit, but I think that has been ruled out.
 

Mtg06405

Member
2019-01-31 7:00 pm
Interesting

This is definitely a slight "pop" or "click" sound when first turned on or off.

I had a GFA5800 years ago that made more of a bass "thump" when it was first turned on, but I don't think that had any soft start in it, but I could be wrong on that.

I just wanted to determine whether this is an issue or not. I might consider using an outboard speaker protection relay anyway, because as some people have pointed out- accidents can and do happen, and with the power supply that this amplifier has, it could easily destroy the Polks I have hooked to it