Patient: Marantz 7200 (Class A+AB), 20 yrs old
Symptom: annoying hum
Investigations results: filtering caps should be replaced
Debate: I have the possibility to replace old 12mF caps with 33 or even 47mF caps. Do you anticipate any problems if I will do so?
Symptom: annoying hum
Investigations results: filtering caps should be replaced
Debate: I have the possibility to replace old 12mF caps with 33 or even 47mF caps. Do you anticipate any problems if I will do so?
The increased peak current of bigger capacitors could be too much for the rectifier diodes,
so I would at least check them for their (peak) current rating.
so I would at least check them for their (peak) current rating.
I concur with Jon. Its a bad idea to increase the value.
If the originals are the cause of your hum (have you proved this by further diagnostics?) then replace with similar value or if you can not get 12k then fit either 10 or 15k but no more.
If the originals are the cause of your hum (have you proved this by further diagnostics?) then replace with similar value or if you can not get 12k then fit either 10 or 15k but no more.
It didn't hum when new.
If it hums when old, put new parts in.
12mFd (12,000uFd) seems like plenty for most power amps. It's not exact, 10m or 15m would be fine.
But 4X the value does look excessive, maybe risky.
If I build a garden shed, and the plans call for 12cm (4.7") rafter beams, and I put in 48cm (19") rafters, I lose headroom (ouch) and increase stress on the walls. It would take a greater depth of snow, but snow on a small roof can only pile-up so deep.
If it hums when old, put new parts in.
12mFd (12,000uFd) seems like plenty for most power amps. It's not exact, 10m or 15m would be fine.
But 4X the value does look excessive, maybe risky.
If I build a garden shed, and the plans call for 12cm (4.7") rafter beams, and I put in 48cm (19") rafters, I lose headroom (ouch) and increase stress on the walls. It would take a greater depth of snow, but snow on a small roof can only pile-up so deep.
