MF A1 PSU Capacitors

[ped]

Hi All,

I'm looking to replace the electrolytics in my A1. The schematic that I've seen for this unit shows 10000uf caps in the psu. When I opened mine it had 2200uf. This amp was serviced many years ago and I suppose it's possible that they didn't have the 10000uf on hand and just used the largest they did have at the time. The amp has seemingly worked fine for many years. Has anyone ever seen an A1 that used 2200uf caps in the psu? Or should I replace them with 10000uf as shown in the schematics?

Any other maintenance/upgrade recommendations?

Thanks,
Paul

 

[DrG]

I would replace them. If you use reasonable quality caps it could only be an improvement.

 

[millwood]

Any other maintenance/upgrade recommendations?

Thanks,
Paul

if it works, why fix it?

depending on the power output, 2200uf per rail isn't out of the norm. I will run 3300uf per rail on 100w output. But using a large cap does help, especially if you often listen at loud levels.

However, the gain is likely marginal and I wouldn't go to 10,000uf: if you do, make sure your rectifiers can handle large in-rush current.

 

[ped]

Hi,

Thanks for the responses.

I borrowed a friend's A1 and took a look inside and it has 10000uf caps, so I would imagine mine originally had them as well. Perhaps 10000uf is over the top for a 20 wpc amp for normal operation, although it makes me wonder if the designer had some other reason for choosing such large values.