Tweaker's Asylum

Posted by JOEY (i) on June 19, 2001 at 09:50:31

Hello All,

I was recently very lucky, picking up a Dynaco PAS 3 preamp at a radio swap meet. Like all tweakers I looked inside to see what to change (improve?). At the least I thought I will change caps in the signal path, but after examining these closely, I noticed that they appear quite large in size for their capacitance value (values range from .002 uF/400v to .1 uF/400v). The caps are labelled "GEN INST IMP" (General Instrument?) and then with value. They are black in colour with yellow writing. They appear to have a moulded thermosetting platic case.

I know these are old caps, but given their size and capacitance and voltage rating these caps are likely to be plastic film caps, probably film and foil construction (polystyrene, polcarbonate, or polypropylene?)(too large for mylar). These are all guesses and I would appreciate anyone with any knowledge of this preamp to advise:

1. What type of caps they are? and

2. Any good mods for this preamp.

Thanks in advance.

JOEY