Hacker GP42 Capacitor Values

[gram065]

Having recently bought a Hacker GP42 to go with my Cavalier GP15 I have been drawn into the world of recapping. A number of capacitors have been replaced on both my machines and information on the forum has helped a great deal but I've got 3 questions that at the moment I don't understand and wondered if someone could help. Preferable an answer in as near layman's terms as possible as electronics is very much a mystery!

1. Although the amp in the two machines looks basically identical the output transformer on the GP15 has a Supermold capacitor at the back of it. This isn't present on the GP42. What was its purpose? Also I've read that Supermolds are unreliable so should I replace it? (To be honest the record player is working fine by the way...just curiosity)

2. The capacitors C3, C5, C9 and C10 are all rated as 50mf in the Gondolier service data. As everything else apart from the Supermold at the back of the transformer on the Cavalier appear the same I wondered if the capacitors at these positions on the Cavalier should be the same? The reason for asking is that the original capacitors have been replaced but using capacitors of 100mf. value.

3. Finally, in the service data for the GP42 whilst capacitance values are given, apart from the capacitor at C6 no voltage is stated. On replacing capacitors I know voltage is often printed on the capacitor being replaced but as I don't want to remove them until I receive new ones how would I know the voltage to look out for? (The capacitor at C8 on both the Cavalier and Gondolier are so positioned that no information is visible).

Bit long winded that...sorry!

[ukcol]

If the Supermould is electrically connected to the output transformer primary it is probably there for tone correction. Supermoulds should be replaced on sight.

The modern replacement for a 50uF capacitor is 47uF. Probably the 100uF capacitors were to hand when they were fitted and this doubling in value of the cathode decoupling capacitors is not likely to make a significant difference to the amplifier's performance.

Capacitors are available in a number of working voltages. You should chose a capacitor with a working voltage that exceeds the voltage that will be applied to it in the circuit. With non-electrolytic capacitors you can chose as high a working voltage as you like but there will be a cost and physical size penalty if you go too high. With electrolytic capacitors again choose a working voltage higher than the expected circuit voltage but electrolytics are more reliable run at a voltage that is a significant proportion of its rated working voltage. For example, don't use a 450 volt electrolytic to replace a 63 volt one.

[gram065]

Hello, Colin..Thanks for your post...I think I'm beginning to understand a bit more about capacitor replacement! Many thanks again
Graham