Question about older C-J D capacitors...
Posted: Tue Oct 16, 2012 11:44 am
Hello, all,
I own a Premier Three preamp, which was updated by conrad-johnson back in 1990 to include the 1986 "revised" stepped balance control, silver wiring and power supply capacitor upgrades. Other than those revisions the preamp is completely stock.
I have a question about the film capacitors installed in the older "vintage" c-j components.
All of the capacitors in my preamp are film caps (except for three electrolytics in the heater supply and relay-timing circuits), and all are marked "C-J D" (for conrad-johnson design) except for three metalized polypropylene caps that replaced electrolytics in the original power supply.
Most of the C-J D caps are white with yellow ends, but seven are all-yellow.
I had always understood (from older reviews and product literature) that all of the caps in the signal path of the Premier Three were polystyrene film-and-foil type.
After some recent net-surfing of various audio forums I now wonder if there might be a difference between the older white C-J D caps and the yellow ones. It is possible that the yellow caps are actually polypropylene rather than polystyrene.
There are seven of the yellow film caps in my Premier Three. Five of these (marked 1uf/600V) are in the power supply, but two are actually in the signal path (one in each channel).
These two caps (see the circled caps in the photo and schematic) are located at the input of the line stage, after the balance control. They are located on the smaller circuit board that mounts the mode switch and volume/balance controls, rather than on the main board. They are marked .5uf/100V and correspond to C32 in the schematic and parts list.
Does anyone know for sure if these two caps are polystyrene (perhaps "metalized" polystyrene rather than film-and-foil), or if they might be polypropylene?
Thanks for any info you might have about these "vintage" caps!
Ken
I own a Premier Three preamp, which was updated by conrad-johnson back in 1990 to include the 1986 "revised" stepped balance control, silver wiring and power supply capacitor upgrades. Other than those revisions the preamp is completely stock.
I have a question about the film capacitors installed in the older "vintage" c-j components.
All of the capacitors in my preamp are film caps (except for three electrolytics in the heater supply and relay-timing circuits), and all are marked "C-J D" (for conrad-johnson design) except for three metalized polypropylene caps that replaced electrolytics in the original power supply.
Most of the C-J D caps are white with yellow ends, but seven are all-yellow.
I had always understood (from older reviews and product literature) that all of the caps in the signal path of the Premier Three were polystyrene film-and-foil type.
After some recent net-surfing of various audio forums I now wonder if there might be a difference between the older white C-J D caps and the yellow ones. It is possible that the yellow caps are actually polypropylene rather than polystyrene.
There are seven of the yellow film caps in my Premier Three. Five of these (marked 1uf/600V) are in the power supply, but two are actually in the signal path (one in each channel).
These two caps (see the circled caps in the photo and schematic) are located at the input of the line stage, after the balance control. They are located on the smaller circuit board that mounts the mode switch and volume/balance controls, rather than on the main board. They are marked .5uf/100V and correspond to C32 in the schematic and parts list.
Does anyone know for sure if these two caps are polystyrene (perhaps "metalized" polystyrene rather than film-and-foil), or if they might be polypropylene?
Thanks for any info you might have about these "vintage" caps!
Ken