03-08-2026, 06:04 PM
+1 on what Mike (Morzh) states. The originals were 50WV. The difference between 8,000uF and 8200uF is only about 2.5%. If there is no load on the power supply, the output voltage will be higher.
There is a load on the supply due to the biasing of the amp. If this is a class A amp, there would be a minor difference tween no signal and full tilt boogie. For class AB, the difference is significant.
Certainly with program, the voltage could drop.
I don't know if the load is affected by whether or not a speaker is connected. I assume with amp on, no program that if there is an electrolytic cap in series with the speaker (load) there would be no difference in current. If it is direct coupled, there may or may not be current drawn. I would have to assume no current difference with speaker or without speaker for direct coupling because if there was current the speaker voice coil would be energized and the cone would be sitting at a position different from resting position (a mechanical bias due to other than zero volts on voice coil. My brother borrowed a bass amp and speaker and the speaker blew due to a defect in the amp that caused a "DC bias voltage" to be placed on the speaker, which caused a positive excursion of the voice coil. Add to that the signal from the bass guitar, the voice coil moved outside the magnet and the spider tore.
I told the guy to take it in for service as it was new and I didn't want to tamper with it. Besides, with no advanced test equipment, no schematic and no time, I did not want to bother with it.
I just got finished reading several articles on rating of caps. I was always taught (from the 1940s vintage electronics books and NRI course I learned from) that one needed to choose a working voltage for an electrolytic near the actual voltage. For example for an AC-DC AA5 radio, a 150 WV cap was appropriate, a 350WV cap would not form correctly and the actual capacity would be less, possibly much less than design rated capacity of the cap. These articles, however, recommend to allow at least 10% margin to allow for spikes which could destroy the dielectric. They do talk further about derating, that the WV chosen should be about 120% of the "rail" voltage. So if you could find 63V caps, they would be better. However, the set (granted about 40 years old) was designed with 50WV caps.
My $0.02 worth
There is a load on the supply due to the biasing of the amp. If this is a class A amp, there would be a minor difference tween no signal and full tilt boogie. For class AB, the difference is significant.
Certainly with program, the voltage could drop.
I don't know if the load is affected by whether or not a speaker is connected. I assume with amp on, no program that if there is an electrolytic cap in series with the speaker (load) there would be no difference in current. If it is direct coupled, there may or may not be current drawn. I would have to assume no current difference with speaker or without speaker for direct coupling because if there was current the speaker voice coil would be energized and the cone would be sitting at a position different from resting position (a mechanical bias due to other than zero volts on voice coil. My brother borrowed a bass amp and speaker and the speaker blew due to a defect in the amp that caused a "DC bias voltage" to be placed on the speaker, which caused a positive excursion of the voice coil. Add to that the signal from the bass guitar, the voice coil moved outside the magnet and the spider tore.
I told the guy to take it in for service as it was new and I didn't want to tamper with it. Besides, with no advanced test equipment, no schematic and no time, I did not want to bother with it.
I just got finished reading several articles on rating of caps. I was always taught (from the 1940s vintage electronics books and NRI course I learned from) that one needed to choose a working voltage for an electrolytic near the actual voltage. For example for an AC-DC AA5 radio, a 150 WV cap was appropriate, a 350WV cap would not form correctly and the actual capacity would be less, possibly much less than design rated capacity of the cap. These articles, however, recommend to allow at least 10% margin to allow for spikes which could destroy the dielectric. They do talk further about derating, that the WV chosen should be about 120% of the "rail" voltage. So if you could find 63V caps, they would be better. However, the set (granted about 40 years old) was designed with 50WV caps.
My $0.02 worth
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55
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