I talked to Steve. I'm amazed a guy like that just answers the phone! He had some suggestions around my system that is quite complicated. He said it might be blown fuses. Anyway, I checked, the fuses are fine. My tech suggested getting rca to xlr cables. I got a specific kind he recommended, something to do with pins that I didn't follow. Anyway, long and short, using rcas is catastrophically noisy, using the xlr inputs with xlr to rca cables and the amp is up and running and sounding great.
McCormack DNA 500 loud hum
So I just picked up a McCormack DNA 500 and the damn thing just hums loudly in one channel when coupled with my cyrus preamp. I took it in and the tech said it's because the rcas aren't grounded as they enter the same Jensen transformers as the balanced connection, this can result in really bad humming. He's going to ground them but I just can't believe that I can't run this amp stock with my cyrus preamp? That preamp shouldn't have any problems with this amp. Any one have detailed knowledge of these a,ps that can guide me or my technician?
11 responses Add your response
It not the caps, that would just make a mild hum and they all look in good condition. An amp this old is unlikely to have cap problems. This is a loud open circuit sound, like if you (very stupidly) remove one rca while the amp is on, like I've done on other amps on occasion. I was worried for my speakers it was that loud. |
Yeah, I agree. I own a DNA 225 and it's amazing. I read a lot about the DNA 500 and know about Steve's reputation and if this was a problem someone would have encountered it. But my technician is a really knowledgeable guy and he says the RCAs should have been grounded and it's a poor design so I'm in a quandary. For now I'm going to use XLR to RCA cables and use the XLR connections on the DNA. Hopefully that will solve the problem. |
yes, call Patrick, Steve and Patrick are two of the most helpful people you will meet. Prices are fair by audio standards, and their work is top shelf reliable! www.smcaudio.com such a beautiful brut you have there, I would hate to see her not working. Call Patrick, send her to them, they will make it right! and while your at it get some upgrades,.... you WILL be satisfied. |
I also recommend calling or emailing Steve, (he's actually on here sometimes). I've known Steve since way back in the Mod Squad days. He's a great guy and wouldn't design a product that had problems. I think it might be something else within the interactions of your system. If this was a problem from the design, I would think it would have raised it's ugly head by now. I've owned a few of his products and never had any problems. |