Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems 557 problems?

For the past couple of weeks I have been having problems with the sound dropping out for a few seconds and then back in again and then out a few seconds later etc, etc, etc on my 557 . It is fine until I have the volume up around 65 and there is a loud passage in the music and then this starts. I have previously run it up to around the mid 80's without a problem. I have checked all the leads, swapped them around and finally substituted in my old 541 to eliminate the possibility of a problem with the 561 processor. I have also plugged in my old M30 to the 561 outputs, they play just fine.

While researching it I came across this topic on one of the older forums. The symptoms sound exactly like the ones I am experiencing other than the fact that I am not using the balanced inputs.

http://www.meridianunplugged.com/ubb/ultimatebb.php?ubb=get_topic;f=6;t=000818#000000

My question is this. Has anyone else experienced this and is the only cure a trip back to M? I tried emailing them a few days ago, but have yet to receive a reply. I would like to get to the bottom of this as soon as possible as I am just putting the finishing touches to a HTPC and would like to get everything hooked up in the next couple of weeks.

I had a similar problem but there is one significant difference:

In my misshap the amp was dead once it cut off and wouldn't work unless reset from the power switch - also the green led on the front slowly faded to off and stayed this way - this behaviour would indicate an overload detection.

Since yours is going off and then comes back on by itself, I would rather think that this is the thermal protection kicking in.

I'm afraid a call to M is in order.
Best of luck.

Thanks for the reply. The green LED stays permanently lit and it appears to work fine other than the sound dropping out for a couple of seconds. The amp is definatley not overheating, just warm to the touch and it occurs immediately from start up, no chance for any heat to build up.

I tried an email to M but no response yet. I will give them a couple of days before following up.

The symptoms are consistent with thermal protection kick-in. If you say the amp is cold then you probably have a faulty protection module.
M should clear that up, as I am only guessing around.

I had a pal with a 557 and he had accidently moved the bridging switch on the back.
Worth a look.

Cheers, Chris

Dear Furrner,
It sounds like it might be a trip for you down I75 to the big "ATL" to Meridian USA! Before you head South or you despatch your beloved 557 from your grasp, it might be worth thinking about something: Have you plugged in any new equipment nearby to the 557 which might be power hungry?

The reason I ask is that the 557 can be hungry for Amps itself - it contains a 1.6kVA transformer - this equates to nearly 15 Amps of current draw in the USA when the amp is working hard. If you have added another device which is consuming current from the same power circuit, then the 557 may not be getting enough, causing a drop-out. This could be why you used to be able to go above 80, but now have problems at 65. The average power circuit breaker in a US home is rated at 15 Amps ......(unless for the range, A/C, water heater etc) and so you could be near the limit there too ......

If you have added other equipment, try removing it and see if the amp has the same problems.

I moved from the UK less than a year ago and had Meridian change the transformer in my 557 to 110V before I left. My 557 now runs hotter than before, even at idle, because it is drawing more than twice as much current as it was when in the UK (240V there). This could mean that thermal protection is more likely to kick in for a US 557.

I am amazed at the instability of US domestic power - turn on the vacuum cleaner and the lights dim, the heating element of the iron kicks in and the light go dim, the air conditioner starts and the lights flicker. How is a device like the 557 expected to deliver top performance under these conditions? It's no wonder that all the hi-fi and home theater dealers in Atlanta offer power conditioners!! (I do not have one, but I am seriously thinking about it)

Thanks for all the replies guys.

Chris, I checked the bridge switch, not the problem.

I have also tried plugging the Amp in to a seperate wall outlet, but still have exactly the same problem. The only change in electrical devices has been the move to an LCD TV, but this has not been in use when I have problems.

I came over here from the England about 5 years ago (hence the screen name) and had the Amp converted to 110 V by Meridian. It does run a little warmer over here, but certainly not enough to make the thermal trip a problem.

I finally recieved a reply from them last Friday. "This may be a biasing issue with one of the Amplifier modules but we would need to examine the unit to determine the exact cause", so it looks like I will have to make the trip down I-75 to drop it off. Unfortunately I am working a 60 hour week at the moment, and will be for the next couple of months at least. I don't trust UPS/USPS/FEDEX, so I will have to learn to appreciate the more subtle nuances of my music collection.

I will post back with the cure when it is fixed for future reference should anyone else have a similar problem.

Furrner