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01-22-2019, 07:06 PM
Hi TiCatFan
Two 70uF caps in series provide an inadequate 35uF net capacitance. The operating voltage in this amp is likely 470V considering its vintage, and the series-caps have a net voltage rating of 700V. The turn-on surge is nowhere near 700V, nor is it likely over 500V, so it should be safe to use a single 500V to replace both of the stock caps.
I would use a snap-mount cap of 100uF - 500V and use a zip-tie to secure it. A modern cap with these ratings and a life of 10,000-hours is quite small compared to what is in the amp.
Some players and techs like the sound of series-connected caps as the ESR is higher then. If you prefer to go this route, even for purely aesthetic reasons of replacing two caps with two caps, then use 68uF or 82uF caps - or even a pair of 100uF - and wire them as you see in the amp.
Have you determined that the stock caps are actually bad? If they are working there is no need to replace them despite the fact they are way past 14-years old. A lot of techs change caps in amps simply because they don't know what else to do, it makes them money, and the customer feels okay with it because of all the misinformation he read on the web PLUS the customer understands what recapping is.
Two 70uF caps in series provide an inadequate 35uF net capacitance. The operating voltage in this amp is likely 470V considering its vintage, and the series-caps have a net voltage rating of 700V. The turn-on surge is nowhere near 700V, nor is it likely over 500V, so it should be safe to use a single 500V to replace both of the stock caps.
I would use a snap-mount cap of 100uF - 500V and use a zip-tie to secure it. A modern cap with these ratings and a life of 10,000-hours is quite small compared to what is in the amp.
Some players and techs like the sound of series-connected caps as the ESR is higher then. If you prefer to go this route, even for purely aesthetic reasons of replacing two caps with two caps, then use 68uF or 82uF caps - or even a pair of 100uF - and wire them as you see in the amp.
Have you determined that the stock caps are actually bad? If they are working there is no need to replace them despite the fact they are way past 14-years old. A lot of techs change caps in amps simply because they don't know what else to do, it makes them money, and the customer feels okay with it because of all the misinformation he read on the web PLUS the customer understands what recapping is.
