[michaeljmarkus]

Hi there
I'm brand new, so I hope I'm in the right place, and asking an appropriate question. Please forgive me, and feel free to correct me if i'm not. 

I recently purchased a 2nd hand Bryston 4BST amplifier for use in my home studio, powering a pair of Dynaudio M1's. It's easily the best setup I've personally ever had.. and I love it.. but recently the inputs on the Bryston have been intermittently cutting in and out, as well as noisy..  and before I do anything, I wanted to make sure I wasn't about to make a terrible mistake.
My instinct is to get a can of compressed air and try using it to clean any dust out of the amplifier inputs.

The problem is far more persistent in the xlr/quarter inch inputs.. where the right side cuts out every few minutes.. the problem can be temporarily rectified by gently 'jiggling' the cable (i'm using 1/4" 'instrument' cables) at the input slightly. Unfortunately my Audio Interface (my main source) does not have XLR outputs to test with. Thankfully it does have a pair of RCA outputs, with which I'm able to maintain a more stable signal.. but I do still get intermittent noise, and today I heard the right side cut out briefly as well.   I've tested with alternative sound sources and cables and encountered the same problems.. and as I mentioned above, I noticed that lightly touching the base of the cable where it connects to the amplifier input either exacerbates or corrects the problem.

Am I on the right track to try compressed air or perhaps some type of contact cleaner? or should I instead seek a qualified technician to service this amplifier?

thank you kindly.
michael

[Grit]

The problem with compressed air is that you might force something further inside the amplifier and not correct the problem.

How old is the amp? 15-ish years?

For what it's worth, I'd send the amp in and have it serviced. Bryston can most likely take it apart, clean out any dust build-up, replace worn capacitors, and re-solder any loose connections. I'll bet they can even give you an estimate or range before you ship it.

- Garrett

[Armaegis]

Some compressed air is unlikely to do any harm in a 4B. That plus a bottle of contact cleaner will run you $10 and they're always handy to have around the house, so it's worth a shot.

The sound cutting intermittently out like that though almost makes me think it's a bad solder joint somewhere.

[michaeljmarkus]

thank you both Grit and Armaegis!

Armaegis, you are right, it certainly can't hurt to have air and contact cleaner on hand (I think my wife tossed my last supply when we moved last year.. of course)

and Grit, thank you for that. I spoke to Bryston who informed me that amp was still covered under their awesome warranty.. if only I had the packaging it would have cost only shipping to Vermont (where, to my surprise, they maintain an American service center).. but even with the cost of the packing, not to mention being without the amp for a few weeks, it'll be well worth getting 'er all tiptop while she's still covered under warranty.

thank you both kindly.
I really appreciate it.
yours,
Michael

[Grit]

No problem, and glad to hear you're getting it done. I'm sure you'll love the results!