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Wear and tear on amplifiers

I had a Musical Fidelity A-100 in the 90s. Supposedly 50WPC, but more likely 10-15WPC in class A. Even so, the heatsinking was barely adequate. It relied on a pair of small fans inside to force air through sideways. These fans became less and less effective as they got covered with inhaled fluff and detritus. It gave up the magic smoke after about two years.
 
James said:
That would work only in there are perforations on opposing sides of the casework. Otherwise, air just won't flow.
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There are some on the bottom of the case, as a nodding recognition of the problem, I was thinking of having a fan suck the air out rather than at the moment blow in
 
James said:
I had a Musical Fidelity A-100 in the 90s. Supposedly 50WPC, but more likely 10-15WPC in class A. Even so, the heatsinking was barely adequate. It relied on a pair of small fans inside to force air through sideways. These fans became less and less effective as they got covered with inhaled fluff and detritus. It gave up the magic smoke after about two years.
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That is so sad, the original design I believe was done by Tim P. of E.A.R. and had better cooling.
 
I tried adding cooling and music together, but I got a big shock.

A-1m-violin-shaped-swimmi-003.jpg


Nearly as bad as when I drilled throw 400VAC 3 Phase cable trunking, I had good bang that day.
 
CJ14 said:
That is so sad, the original design I believe was done by Tim P. of E.A.R. and had better cooling.
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The original A-1 did not rely on forced cooling, but it is also rated for a lower output of 20-25WPC. Again, I suspect only the first 10W might be class A.
 
I just saw an original A1 on eBay, offered at $1,030 USD. Yikes, and all the more so because the amp is filthy, the seller couldn’t even be bothered to give it a quick cleaning.
 
Subito said:
A mere $62.80 USD, because we all know that darn amp is just so heavy:

https://www.ebay.com/itm/2747917351...d=link&campid=5338728743&toolid=20001&mkevt=1
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That’s a nice sounding amp but half of this price would be fair IMO.
Also, although it’s in good working condition, I would replace all of the electrolytic caps with higher voltage and temperature range right away and make sure there’s enough thermal paste where needed.
Doing so and making sure the heat it generates can dissipate, you can have a very good amplifier for a while.
 
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A1 is 20W and kinda class A. A100 50W and never had better cooling. Towards the end of it's life the cooling fans were reduced to one from the two originally used and it ran less class A. Original type replacement fans are not available. There is no real issue with vol controls... only slightly noisier or less reliable than normal.
 
Gervais Cote said:
True, but if you replace it with a ALPS Blue like done here, it’s problem solved for ever :

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LOL! They are standard fitment in all but early one's! The vol control in these and several other MF amps (and a few others going back to 70's Cambridge Audio amps) works in a different way to "normal" vol controls (it's active) and slight DC present on the control exacerbates noise from wear. It's usually only an annoyance whilst actually turning the control and can be ignored if one is not bothered by this. I have not found vol controls used in this way to be much less reliable than in standard circuitry.
 
chartz said:
Oh, like Quad preamps then?
The Alps blue is nothing special by the way!
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Some Quad pre amps used a bigger better black Alps pot which doesn't seem to be available anywhere unfortunately.
The Alps Blue has long been the "industry standard" and for good reason. It has very good tracking between the channels, is quiet, long lasting and has a decent "feel" to it. If you want something that sounds much better get a switched attenuator.
 
That’s what I commonly use anyway. Very cheap and reliable. And the balance one has a centre tap I like too. They can be easily opened in case they need some cleaning – which they never seem to need anyway!
By the way, I need a switched one for my 33… what happened to Sithnamara?
The better black ones aren’t available unfortunately, as you say. That eBay seller had them once.
 
Try the stepped attenuators on ebay for 18 euros. Less low level grunge and much more clarity. I fitted 2 to my Sugden A21SE to give me a balance control. Lost the remote control of course, but I won´t be going back to the Alps
 
Alps quality as gone way down in the last few year, and the stupid idiots have shortened the shafts, so I have to make them longer.
 
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