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Graham_W · 23rd Jul 2021, 7:57 pm

Thank you all for your comments, all very useful.
I intend the amplifier to be used with a turntable. I agree that some form of preamp will be necessary as apart from the PEN3520's there is only the AC/HL triode. The phase splitting is somehow done by the cylindrical transformer twixt the AC/HL and PEN3520's.
I can see the similarities with the QAP12 so maybe mine is an early Quad. Can't beat a pair of KT66's though!
The battery is of the '800' type and I remember the style from my youth. Not much left of it except to say it is an Exide and has the price of 1 shilling.
Yes, it has seen some 'improvements' at some time. One of them you can see is a pair of flying leads connected to the PEN3520 anodes, presumably at sometime connected to a meter of some sort. I'm hoping it can be sorted though and look forward to seeing how it performs, at a guess all 7 watts of it.

Regards
Graham

23rd Jul 2021, 7:57 pm	#9
Graham_W Triode Join Date: Feb 2021 Location: Dunstable, Bedfordshire, UK. Posts: 12	Re: PEN3520 Amplifier project Thank you all for your comments, all very useful. I intend the amplifier to be used with a turntable. I agree that some form of preamp will be necessary as apart from the PEN3520's there is only the AC/HL triode. The phase splitting is somehow done by the cylindrical transformer twixt the AC/HL and PEN3520's. I can see the similarities with the QAP12 so maybe mine is an early Quad. Can't beat a pair of KT66's though! The battery is of the '800' type and I remember the style from my youth. Not much left of it except to say it is an Exide and has the price of 1 shilling. Yes, it has seen some 'improvements' at some time. One of them you can see is a pair of flying leads connected to the PEN3520 anodes, presumably at sometime connected to a meter of some sort. I'm hoping it can be sorted though and look forward to seeing how it performs, at a guess all 7 watts of it. Regards Graham