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Johnkenn 14th September 2008 01:27 AM

Can a PS cause a ringing sound in 500 series pres?
I'm waiting on my BAE 500 series rack, but in the meantime, I've had a Mono Gama and a borrowed API 10 space lunchbox. It seems like I'm getting a oscillation from the phantom power. It even happens when I plug a guitar in too. I've tried a borrowed PS and it started doing it after a while too. Can a power supply be the issue?

Player1 14th September 2008 03:24 AM

I'm not sure that the power supply would cause this problem. It's usually some kind of oscillation in the unit. Here's something I read on prodigy recently about the Jensen transformer in these units:
"Posted: Thu Jan 27, 2005 7:50 am Post subject: Very simple tube preamp. I can see two issues with the design. First, there's no termination on the input transformer, and most transformers these days are designed to be used with a specific termination. On the Jensen JT-115K-E, for example, it's 150k. If you don't use the termination, the tranny's likely to ring.

I hope this will help!

Daedalus77 14th September 2008 05:06 AM

Sorry you're having trouble.

I've got an API 10-space rack and stock API power supply, and I've never had any troubles.

I've got API, BAE, Avedis, and Purple mic pres in the rack. No issues.

Sorry if this isn't helpful.