A Power Amp for Paul

[Radford Revival]

Lovely. Neat as a new pin Will. With workmanship like this, and an amplifier like this, it does make you wonder if people seeking one of the best PP amplifiers out there at the minute ought to look closer to home than places such as Italy, Germany, America or God forbid, China!

Many thanks Paul. This entire thread is a ruse by the way, I'm actually re-casing a Chinese eBay amp for you

[The Black Adder]

Looking very nice, Will.

[Reffc]

Many thanks Paul. This entire thread is a ruse by the way, I'm actually re-casing a Chinese eBay amp for you

Like this one?

[Radford Revival]

Looking very nice, Will.

Many thanks

A note about the protection circuit.

It's extremely simple - but quite effective. It just watches the cathode current of each output valve. Because the average current in a Class-AB amplifier varies, it employs a time constant to ignore short term high current spikes from music, et cetera, but trigger on a longer term overcurrent / fault. There is actually a more accurate way to implement such a circuit, that will more or less ignore music current swings and only trigger on a fault, but the additional complexity would be hard to justify, when this already works quite well, and just consists of resistors, diodes and capacitors.

As well as this, each valve has a rapid response trip for severe faults that will bypass the time constant, to reduce any potential damage as much as possible.

[spendorman]

I was going to ask for more details about the protection, but you have beaten me to it, thank you.

[spendorman]

Lovely. Neat as a new pin Will. With workmanship like this, and an amplifier like this, it does make you wonder if people seeking one of the best PP amplifiers out there at the minute ought to look closer to home than places such as Italy, Germany, America or God forbid, China!

+1

[southall-1998]

Nice pictures, Will.

Do you also build ''Integrated'' versions of these Radfords too? Or, at least a Radford, with built in volume pot?

S.

[Radford Revival]

Nice pictures, Will.

Do you also build ''Integrated'' versions of these Radfords too? Or, at least a Radford, with built in volume pot?

S.

Thanks Shane.

Not at the present. It's a good idea but unfortunately not something we currently offer - future projects will likely feature an integrated type amplifier.

[Radford Revival]

Just for the record it is currently around about 9:40pm and I've been soldering on and off since this morning, and have now stopped for the day. The amp is getting there now but these things aren't half labour intensive to build. I'm tired!

[southall-1998]

Thanks Shane.

Not at the present. It's a good idea but unfortunately not something we currently offer - future projects will likely feature an integrated type amplifier.

Thanks, Will. Wish I could come over someday, and hear the STA15!

S.