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PostPosted: 03 Sep 2008, 07:55 
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Joined: 29 Jul 2008, 08:12
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Location: Wiltshire, UK
I almost forgot to mention; the switch on thump is tiny and there is NO hum at all. The only noise from the amplifier is the fan which runs very slowly and is barely audible. This give no noise over the speakers. And in what I am told is good amplifier practise, the input to the amplifier is grounded only at the input sockets to avoid earth loops. :D


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PostPosted: 03 Sep 2008, 08:00 
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Joined: 28 May 2008, 21:53
Posts: 4577
Location: Winnipeg, CANADA
Hi John,

Great work. That came together rather nicely. Is the fan necessary?

Cheers

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PostPosted: 03 Sep 2008, 08:06 
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Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
Is that fan manually variable speed or are you controlling it with a thermistor?
Nice job by the way. Last night I started building with everything I had laying around as well. Should be done today sometime.
Glad to hear its sounding great.
Ri

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PostPosted: 03 Sep 2008, 08:18 
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Joined: 29 Jul 2008, 08:12
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Location: Wiltshire, UK
The unit got built into an old instrument case and the heatsinks are internal when the lid is on, so to err on the side of caution, we've put the fan in just in case. If it's really necessary, I don't know but I'm sure in long term-use it'll get a little too warm.

The fan is manually adjustable, there's a trim pot on the controller board.

I already have tweaks in mind and other ideas that I'd like to try.

Not necessarily in order these are things I'd like to do:

Transplant the unit into a nicer case with a pair of heatsinks on each side.
Try alternative caps and resistors to see what I think sounds better.
Dispense with the tacky spring-clip speaker terminals and put on decent binding posts.
Lose the RCA inputs and use either XLR or DIN connections.
Nicer cables within the case. A lot of builders seem to be a big fan of pure silver, so this is another avenue to explore.
Lose the volume pot and control the volume with an external pre-amp


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PostPosted: 03 Sep 2008, 10:48 
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Joined: 29 Jul 2008, 08:12
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Location: Wiltshire, UK
I made a discovery this afternoon. Those capacitors a couple of you guys were interested in are polystyrene. I accitentally stumbled upon them on hificollective, Suflex apparently were the manufacturer here in the UK. but they are now long gone.

http://www.hificollective.co.uk/compone ... yrene.html

Sure, they're espensive I just hope they either ship overseas or you can find somewhere locally that sells them! :D


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PostPosted: 03 Sep 2008, 12:15 
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Location: Winnipeg, CANADA
Yep, that is what i thought they were. They are supposed to be pretty good for audio.

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PostPosted: 03 Sep 2008, 14:28 
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Joined: 29 Jul 2008, 08:12
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Location: Wiltshire, UK
If you want some, let me know by PM what values you're after and what quantities, and I'll get some sent your way, I've got loads of them scattered about. :)


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PostPosted: 30 Oct 2008, 18:31 
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Joined: 14 Oct 2008, 17:35
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Location: Dartmouth, Nova Scotia
That is a really nice build. Some day I plan on building a class A amp, but I was thinking of the 8 watt mosfet amp, as they are very simple and I have just about all of the parts to build one.

Well done job I must say. 8-)

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PostPosted: 31 Oct 2008, 04:18 
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Joined: 29 Jul 2008, 08:12
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Location: Wiltshire, UK
This amplifier had me shocked, and still does. I'd rather listen to this than a Naim Nait, and that's a damn good amplifier in it's own right too.


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PostPosted: 31 Oct 2008, 15:20 
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Location: Dartmouth, Nova Scotia
Keep up the good work! I think you should try adding a simple tube preamp to the amplifier, it would be a good addition to the already nice sound of your class A amp.

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