02-10-2013, 07:58 PM
(This post was last modified: 02-10-2013, 08:00 PM by Robert Darwent.)
Rob,
Assuming Lawrence is correct about all the voltages throughout the schematic being higher due to a higher input voltage from the mains transformer, then it is improbable that they are all 'mistakes' even allowing for the differences in the expected mains voltages you mention.
The two schematics may appear virtually identical (ie; the symbol for the mains transformer is the same on both) but the likely explanation is that the mains transformer is physically different in the two models, with one wound to give 315 volts whilst the other is wound to give 365 volts.
If this does turn out to be the case, then you will need to change the mains transformer as well as halving the value of the reservoir capacitor, not just change the capacitor alone.
IMHO you would better restoring the amplifier using like-for-like component values and get it working reliably first before experimenting with trying to convert it to another model straight away.
Regards
Assuming Lawrence is correct about all the voltages throughout the schematic being higher due to a higher input voltage from the mains transformer, then it is improbable that they are all 'mistakes' even allowing for the differences in the expected mains voltages you mention.
The two schematics may appear virtually identical (ie; the symbol for the mains transformer is the same on both) but the likely explanation is that the mains transformer is physically different in the two models, with one wound to give 315 volts whilst the other is wound to give 365 volts.
If this does turn out to be the case, then you will need to change the mains transformer as well as halving the value of the reservoir capacitor, not just change the capacitor alone.
IMHO you would better restoring the amplifier using like-for-like component values and get it working reliably first before experimenting with trying to convert it to another model straight away.
Regards
