Issue with B&K Power Amp?

[scarpi]

I have a B&K 200.5 series two power amp. For all you B&K owners out there I have a question. My amp is plugged into its own dedicated 20 amp line. I usually use my preamp (Marantz AV 8801) to turn on my amp from standby via a 12 volt trigger. This always works fine with no problems at all. But if I go on vacation and shut off my amp totally using the on/off button on the front panel, when I get home and push the button to turn on the amp into standby mode, it draws so much current at turn on that it blows the 20 amp circuit breaker on the dedicated line. My dealer told me that these amps do that, and the proper way to turn them on is to use the 12 volt trigger which in fact works great without any problems at all. The amp works great and sounds fine. I guess that the 200 watt B&K amps just draw over 20 amps at cold turn on?? Do your B&K 200 watt five or seven channel amps do that? Apparently B&K did not design a soft turn on switch for these amps? Seems to be not too good of a design? Love the amp though and just wondering if any other B&K owners have seen the same issue with their amps. Thanks...Don

[John Holmes]

I do still own a Reference 50 but have never owned a B&K amp. I've never heard of the issue you described from others but, that doesn't mean others haven't had the same problem. There is/was a company that repairs B&K product. Opened not long after B&K shut doors. My understanding is that several of the original techs work there.

I believe the company name is Eastern Elite Audio Video. Could call or drop them an email.

[Dmantis]

I have Installed many 200.5 amps and never heard of this issue. Something is wrong with the amp. A 20 amp circuit is more then enough power to power that amp from off and fill the caps. I'd get it checked out.

[scarpi]

Thanks for the reply Dmantis. It's nice to have someone with your experience on the forum. This has been happening since the amp was new. I bought the amp on 7/9/08. I told my dealer about the issue then, and he told me that B&K amps have a tendency to do that from his experience, so I just considered it normal. He told me to use a 12 volt trigger from my preamp to turn on the amp from standby and that will eliminate the issue. I did that, and it always works fine that way. Since B&K is now out of business, and the amp has no other issues, based on your experience, do you think I really need to send it out to someone for service? It really isn't a problem that it does this since I don't typically use it that way. My only concern, since you think it is a real problem and not "normal" as I was told in 08, is will it cause a problem being left on standby like a short or fire when I'm not home? That's my only concern now. The amp sounds fine. And I do appreciate your input. Thanks.......Don.

[Glen B]

I guess that the 200 watt B&K amps just draw over 20 amps at cold turn on??

Not just over 20 amps inrush current but probably more like 100 amps or greater (you read that right) for a few milliseconds. A 15A or 20A breaker can pass many times its nominal rating momentarily without tripping. It all depends on the amount of current, duration, and breaker trip curve. It would be interesting to find out exactly what kind of inrush current your B&K amp is drawing. It may also be worth it to try the amp on a different circuit, just in case the breaker on the original citrcuit is defective. I have a window air conditioner rated at 12 running amps that draws 200 amps at startup on a 15A line according to my Fluke 335 clamp-on meter, and has never popped the circuit breaker.

[scarpi]

Hi Glen B. I initially did have it on a different circuit (the living room circuit through a Panamax power conditioner). At that time it caused the Panamax to shut down the circuit when I turned on the amp from the on/off button, so that's when I decided to give it its own 20 amp line. Like I said though, it turns on fine using a 12 volt trigger from my preamp.