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Another NCC build on the way

PigletsDad said:
The fins always need to run vertically, so the air flows up past them, so it would be way too tall for your box.
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On the face of it this makes sense :confused:

But why then, do Sugden with their their A21A run the heatsink fins horizontally? Surely class A operation produces far more heat than the class AB of the NCC amps.

The A21A I had here for a while run very hot without issues.

John R.
 
chiily said:
Mike, they are not like the SOA protection which , I think, is some form of current limiter on the amp board. The KT4700 use a relay to turn the music on and off. Les recommends them, he uses them in his £3k Voyager amps so they can't be all bad.

The good thing about the KT4700 is that not only do they delay the output of the amp by 6 sec so no turn on thump, but they also protect against DC offset and short cct of the speaker terminals. For me these features are essential esp if your drivers are either too expensive or no longer manufactured.
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Yeah I know they are totally different to the SOA. I was just wondering if the sense circuitry might effect the sound in some way but if Les 'ses they're good then they're good for me too :) Cheers mate.
 
James, what are the values of the PEH resevoir caps attached to the M-cap boards?
 
Yes James, I was looking at those very same ones. They are very good. It is a very elegant solution to stack them like that. I have a space problem within my Pesante NCC case and this may be the way to go instead of the usual rectifier boards. My power transformers will be 300VA 35-0-35V I'm wondering if 20,000uF a side is enough?

Again, question: where did you get the mounting brackets for stacking the Caps. Are they just general fixing hardware or special types?
 
20kuf per side was all I had space for - they ain't small! Oh, and they ain't cheap either - no way could I afford 8 of them.

The brackets were lying around in the garage - leftovers from some stackable shelves. Anything from B&Q would do I reckon.
 
OK thanks again James.

I am actually cutting pieces of paper to match the footprints of boards and transformers to try and layout the inside of the amp!

Even paper tubes for the PEH caps. Beats mowing the lawn...
 
John R said:
On the face of it this makes sense :confused:

But why then, do Sugden with their their A21A run the heatsink fins horizontally? Surely class A operation produces far more heat than the class AB of the NCC amps.

The A21A I had here for a while run very hot without issues.

John R.
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You would have to ask Sugden why they did it, but running very hot may have something to do with blocking the airflow on the heatsink!

I have seen numbers somewhere showing a 30% difference for one particular type; if you look at the price of big sinks, that is very expensive amount of cooling to buy back!
 
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