So last week my vintage Mc2100 amp was shipped back from a recap, and when I hook it up the left channel doesn't play anything but some low-level hum noise. Subbing the Eico or Heathkit amps into the EXACT SAME setup works perfectly, so it must be the 2100, right? Wrong!

Not 1 hour after dropping off the amp at the highly recommended local McAmp guy (that I found out about after the recap), I come to the striking realization: wait, didn't I have a bizarre channel-out problem with some interconnects and the AT-HA2002 a few years back? The center pin on the old-style HGA silver lace RCA Lok connectors was a bit too skinny, and for some reason wouldn't make internal contact on ONE of the HA2002's jacks. Worked fine with my other gear, though. Wait...aren't those the SAME ICs I'm using on my amps these days??

So inevitably I get a call a few hours later and the amp measures totally-super-kickass-like up to 150 Watts both channels (they sure don't make 105 Watt/ch amps like they used to). So after a 3-year hiatus the wonky ICs strike again, on the 2100's left RCA. I swear I need to throw those damned ICs away.

On a related note, I need to be more thorough dammit. Normally I troubleshoot this crap before I solicit outside help. I'm just in a situation now where I've got far more gear than interconnects. Normally I am way more thorough, dammit. I wouldn't have my job if I wasn't WAY more thorough than this. HGA connectors still suck, dammit (the locking mechanism is a joke too - you have to tighten them way past "10" to get any grip on some jacks).

Oh well, at least my amp is OK. I'll probably pick her up this weekend.

Damn, another haunted amp.

It's possible that using the IC's in one place squished them down (I'm using technical terminology here, feel free to instruct me to "dumb it down"), so that now they're too small for other gear -- like the MC2100. I know I've had that problem before. If you're lucky, the middle pin is made up of four pieces, and you can spread it out again, with a utility blade or something.

It's possible that using the IC's in one place squished them down (I'm using technical terminology here, feel free to instruct me to "dumb it down"), so that now they're too small for other gear -- like the MC2100. I know I've had that problem before. If you're lucky, the middle pin is made up of four pieces, and you can spread it out again, with a utility blade or something.

Now that you mention it this seems likely, though probably from the previous owner. The pins are 2-piece and they're pressed together pretty close. I guess, enough to have issue with about 1 in every 20 RCA jacks. Ah, now I see the beauty of XLR connectors.

I've not yet had a complaint with Audioquest cables and they look/sound nice; maybe I'll pick up a pair that's not too expensive.

I'm with you mulveling, I am not a fan of the LOK RCA connectors. I used them once early in my career, never again.

I've seen locking rcas rip connectors from expensive devices, and wouldn't ever use one.