My RM10 is feeling much better now!

RTMerkel · « **on:** 4 Feb 2009, 01:06 am »

This duplicates a pair of emails I sent to Music Reference over the weekend… but maybe this a better venue for discussing a possibly sick amp?

BTW: Roger, your answering machine message appears to be waaaaay out of date

I have a pair of RM-10's that I run in mono block mode, one of which appears to be sick and may require service.

Back in ‘06 this same amp blew one of the fuses which I didn't discover until I tried to adjust the output tube bias. Replaced the blown fuse and it appeared fine… until this weekend when I ran it few hours when it went silent. Sure enough, both fuses had blown.

I replaced both fuses and powered on the amp to see if I could adjust the bias. Turned it on and saw a flash and heard a click or pop in the speaker. I powered the amp down and noticed that the two right most EL84 little symmetric burn spots. I assume that’s two EL84’s down, sigh…

I installed the original tubes that came with the amp, which I purchased used. The EL84's are not matched pairs. Anyhow I replaced all six tubes, and turned the bias pots fully counter-clockwise and powered on the amp. It appeared to behave at first as I was able to set the bias for both channels just under 250 mV. However the left channel voltage keep rising. I was distracted for a moment, or so it seemed, and when I looked again the left EL84 was quite red and the voltage was above 1V!!!

I powered down the amp, back to full counter-clockwise and for the heck of it swapped V4 & 6 (the 2nd to the left and left most EL84s) and tried again. The left bias very quickly was above 400 mV so I gave up.

So.. I assume that my problem is more that problematic tubes and needs to “go home” to RAM labs for inspection and repair and replacement of some/all of it’s tubes. Would that be correct?

Thanks, Randy Merkel

RTMerkel · « **Reply #1 on:** 7 Feb 2009, 07:56 pm »

In the past week I've sent two emails to Music Reference, left two telephone messages, and this message here... and absolutely nothing! The web page is still up, but hasn't been updated since 8/2005.

I wonder if Music Reference still in business? Perhaps Mr. Modjeski is on vacation? Does anybody know?

I'm tempted to just ship the amp to Music Reference, with signature required, but I don't have a shipping address.

What to do?

Randy

tybee · « **Reply #2 on:** 7 Feb 2009, 09:03 pm »

Roger is notorious for not answering his emails promptly, but he has always answered my phone calls to him within the first two rings during normal business hours. I have talked with him directly twice this year. From his website, I call Technical Support: (805) 687 - 2236.

Hope this helps.

RTMerkel · « **Reply #3 on:** 8 Feb 2009, 01:06 am »

That's the number I called on Tuesday and Thursday and was greeted by a message talking about Memorable Day and reduced hours. Left messages, not returned.

I have an address from 2006 so I'm just going to UPS the amp and hope for the best!

Randy

6BQ5 · « **Reply #4 on:** 9 Feb 2009, 05:22 am »

Doesn't inspire much confidence in MR as a company does it?
A big shame.

rbwalt · « **Reply #5 on:** 10 Feb 2009, 03:21 pm »

yes roger can be hard to get a hold of from time to time. calling him is the best way to reach him as he does get behind on his e-mails. yes Music Reference is still in business. roger has been very busy building and designing new products that people want. so keep after him.by the way roger is one of the very best audio designers out there today. easily in the top 3.

rob w.

RTMerkel · « **Reply #6 on:** 12 Feb 2009, 09:55 pm »

Got a hold of Roger around 1pm on the telephone. He opened my box and started checking out my poor old RM10 while I was talking to him. The driver tubes are gone as well as some bias resisters! Don't know what the 'root cause' is yet, but it should be repaired today.

Looks like a happy ending is coming... along with a mild credit card bill

Randy

Roger A. Modjeski · « **Reply #7 on:** 1 Mar 2009, 01:03 am »

A note of caution to owners of all tube amps. When the tubes have a lot of hours on them there are usually visible signs. Randy's tubes were well worn and showed signs of having been very very hot. Although my amps are less prone to resistor damage than most, it can happen as it did in Randy's amp.

See upcoming post on "Tube Wear"

Randy, Your amp went out this week. Did you get it yet?

RTMerkel · « **Reply #8 on:** 3 Mar 2009, 03:49 am »

Roger,

It arrived mid week. I replaced the tubes on the second amp, biased them both at 300 mV and both are running fine.. all is well again.

Should I assume from your comments that you'll be using photos of my old tubes in your Tube Wear discussion?

Thanks again,

Randy