Internal views and some technical info on this classic english amplifier.
This is the original mk1 amplifier which was brought to me for repair by my father-in-law. It has a short circuit output stage on one channel,probably caused by a short circuit on the speaker wiring or using too low impedance speakers.



It has a super size mains transformer to be able to supply high current on demand,something which a lot of modern amplifiers fall short on. The output transistors are of the TO3 type and are TE01019 (BDY77).this is an N.P.N device rated in my book at 150v,16a which is pretty hefty. I am told that it is difficult to obtain any of the above transistors but you can use the
MJ15003 type which is the same TO3 package and is rated at pretty much the same amount. The drivers are SML1101
(40872),here you could use BD244C/TIP42C.
The power supply is rated at +50v,-50v using 2 10,000uf electrolytics across the split rail power supply. If you have a hum in the background these capacitors are likely to be the culprits.




FRONT VIEW


REAR VIEW


PARTNERED WITH THE QUAD 33 PRE AMP

For more information on quad equipment please go to my links page.