Replace pwr cord w/IEC socket on vintage gear?

I have a Sumo 9 that has gone through a full rebuild and has an IEC power connector cord in place of the original captive cord. With just a budget Volex 17604 power cord I'm getting really good results with it in my 2nd system. I'm tempted to spend more money on different power cords but I'm controlling myself. If it isn't broke I'm not fixing it. Kudos to Mike Bettinger at GasAudio.net. That guy really knows Sumo gear.

I installed an IEC jack and replaced some wiring on a Harman Kardon amp I got off ebay. It was a nice little project and the results were well worth the hour it took. Go for it.

In my opinion installing an IEC on vintage equipment is a mistake and it does devalue the equipment. I personally would not buy a vintage amplifier with an IEC modification. Besides, the amplifier was voiced with the existing power cord.

In fact, at one time I owned two sets of Quicksilver Silver 90's. One set had the original power cord and the other an IEC with an aftermarket cord. Guess which one sounded better. The one with the stock power cord.

With vintage equipment it is more important to make sure the polarity is correct when you plug it into the wall outlet.

06-27-11: Rrog
In my opinion installing an IEC on vintage equipment is a mistake and it does devalue the equipment. I personally would not buy a vintage amplifier with an IEC modification. Besides, the amplifier was voiced with the existing power cord.

You may have a point there. I don't know how much consideration Heathkit put into the power cord, but it *is* a bit odd, even for that era. It's a high current design amp with a massive power supply--40 lbs for a rated 125 wpc. The power cord is a 2-conductor (no ground) small diameter cord. It reminds me of the stock used for extension cords for Christmas tree lights.

When I first plugged this amp in, it sounded pretty thin, but I figured that the capacitors had to charge up. So I stopped the music and let it warm up and charge up. That helped immensely.

The thing is, I've now left the amp on about 30 hours, playing music for at least 8 of those, and the sound is so superb I don't think I want to mess with it after all. When I posted this thread 12 hrs ago, there was still a slight edge that I figured a fatter cord might fix. But now--geez you guys will think I'm crazy--its tonal balance, low noise, speed, dynamics, and low level detail remind me the most of an early '90s class AB Rowland Research amp. And for a 30-year-old amp I picked up for $219, that's good company to be in.

I'm playing an album I've had for 15 years, that I've heard many times on many systems, and through Sennheiser HD580s, and this amp is revealing low level cues and details I didn't know existed. But it presents them in a totally natural perspective, not in a hyper-detailed way. It just makes everything sound more real than I ever heard this recording before.

I don't think the amp was voiced for the stock power cord. The amp probably wasn't voiced at all. It was spec'd out, and well spec'd out at that. Heathkit offered some excellent products. It's fine to replace the power cord, particularly if it's frayed or totally wimpy, but swapping power cords to find the right one kinda' goes against the vintage vibe, if you know what I mean. Just stick an Acme or Volex on it -- it's more along the lines of what the designers at Heathkit would do.