Either all my amps have problems or .... ??

[seebert]

10N20 and 10P20 sources in the USA anyone? Or alternatives?

Found this source in the UK - same transistors as in the Muse amp?

http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=ECX10N20R

http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=ECX10P20R

Thanks, Mike.

 

[tvrgeek]

Ordered mine from England. Only $8 postage.

Is ListenUp still on the mall in Boulder? They should know of a repair shop. Basement Sound Gallery? There used to be a used dealer there too. ADL and Christman are long gone, as was Gerry's shop. There was a good shop in Longmont I think, but that was years ago. The shop in the 'Springs turned out to be selling more than amps.

 

[seebert]

Hello TVR ...sorry again for the delay in answering ... I have more bad days than good nowadays: PTS, florid cervical spinal spondylosis and generalised rheumatoid arthritis plus 'silver stars' eyesight and tinnitus sometimes just win out over my resolve. I know I was (am) one of the lucky ones who came back in (roughly speaking) one piece so no complaints.

I've had a very close look at the Muse160 amp and it's obviously been repaired in the past; I see a few odd new resistors and some other 'bright' soldering on some other components including some of those power transistors. Repairs were well done but I'm now thinking that it'd be better to get the amp to a real repair tech rather than me messing with it - it's a fine sounding amp that I've only had for a very short time. I'm pretty sure the seller didn't know of any problems with it - he's an old guy like myself who bought it and then decided to stick with valves after all.

I know this forum is all about DIY and I'd love to be able to amass the knowledge needed to enjoy the hobby but with zero formal training in this area (I do have other degrees but they're far removed from electronics) I think it better that I start with building (say) a small Hirago or other basic hi-quality amp for the fun of the hobby rather than 'spoiling' good gear that a proficient tech could probably repair very quickly and easily.

Right now I still have a 'part working' Audire 2 amp that I can't take any further along the repair path and now I have a 'broken' Muse160 amp that didn't come cheap; I feel like the village idiot trying to be something he's not. Listen up are still around (at least in Denver which is about 130 miles away) but I can't drive now so my wife has to do it all - it makes looking around for repair shops 'painful' in more ways than one. I'll give Listen Up a call and also Jon at vintage audio repair - but shipping heavy amps is costly and it's a h*** of a decision to make as to whether or not the overall cost of repair is going to be worth it. Apart from having a genuine interest in audio electronics that's obviously why I try to do repairs but as I also said above I finally get it that I just don't know enough to do the job properly and apart from the forum there's nobody else even remotely locally that I can ask for advice on a regular basis.

Ordered mine from England. Only $8 postage.

That's cheaper than the manditory handling charge of $20 of the US supplier - a good deal !! But heck I've found out that I don't even know how to test those transistors. I think by now I've wasted enough money by jumping in where I can't swim

I'm really grateful for all the help I've had from the forum members but I can also understand their frustration at being asked to 'answer' complex questions in an oversimplified way to a layperson such as myself; it'd be like me trying to explain just a part of (for example) the Kreb's cycle in the kind of detail that made complete 'practical' sense when the questioner has no real understanding of biochemistry. I just don't have the brain function speed or the time left left to assimilate a full course in this electronics discipline.

Everyone grows old and it's no fun so ya'll try to do it as slowly as you can

 

[RayCtech]

I have more bad days than good nowadays: PTS, florid cervical spinal spondylosis and generalised rheumatoid arthritis plus 'silver stars' eyesight and tinnitus sometimes just win out over my resolve. I know I was (am) one of the lucky ones who came back in (roughly speaking) one piece so no complaints.

seebert I may have some good news.
I will send you a PM.

 

[seebert]

Thanks RayCtech - PM sent.

 

[Tino]

I wanted to say that I have a similar problem. I have a Threshold SA3 and a Soundcraftsmen PM860 and since moving to my new place, I have a more noticable buzz not just in the transformer, but audible from the speakers even from a few feet away (with or without signal connected ot the amp).

Sometimes the buzz is louder, sometimes softer and once in a while I'll be present as the buzzing slowly gets louder then softer. Most of the time it happens at night. I've tried turning EVERY braker off in the house as well as trying the amp in a different circuit.

Basically i'm going crazy.....

Hi all. Going slowly insane. I thought I had a fault with a Threshold amp - a buzzing/rattling power transformer - quite loud. Changed it out to a different Threshold - quiet for a moment and then the transformer noise just like the first amp. Changed it out again for a Muse160 and ... quiet at first then the buzz/rattle.

BUT it is not constant I've found. Sometimes the noise goes away, sometimes I switch on an there's no transformer noise for quite a time but the time varies from minutes to an hour or so. It just comes and goes.

I don't know if this is in any way related (I can't see how it could be) but all of these previously heat stable amps are heating up on one side more than the other by a definite amount that's easily felt by hand; not red hot but way hotter than the other channel.

There is no (hum/buzz etc) noise through the speakers. No distortion.

I have both an anti-surge strip and a Panamax 4300 - amp noise as above. I've tried plugging into the mains directly and it makes zero difference - the transformer noise (and heat) problems stay the same.

Live in a tiny town (500 residents) with medieval facilities and get brown outs pretty often but checked the line voltage and it's 122VAC with and without the noise. There are be some big 'farm factory grain do-somethings'
a block away but nothing much else. The local emergency radio controller lives and transmits from next door and have had problems with RF in the past but that doesn't seem to be the issue here I don't think.

ANY ideas please - I'm just about ready to go off bang.

Thanks, Mike.

 

[djk]

DC on the mains can come from any house sharing the same transformer out on the pole.

When a neighbor turns on his hair-dryer/halogen floor-lamp/space-heater/crock-pot on 'low' it sticks a diode in series with one side of the line and this produces the DC on everyone's line.