Maker Pro
Maker Pro

Pioneer SA8500 Amp phono input noisy

gahamby

Nov 19, 2021
12
Joined
Nov 19, 2021
Messages
12
These caps are really noisy when touched.The blue Sanyos are marked .47/25.
The brown ones I am unsure of. I want to replace all 4 caps. Please advise as to exactly what I should purchase. Thanks GHIMG_0686 copy.jpeg
 

bertus

Moderator
Nov 8, 2019
2,637
Joined
Nov 8, 2019
Messages
2,637
Hello,

The 474K is an 47 X 10⁴ = 0.47 μF 10 % capacitor.
I have not seen many failures of that type of capacitor.
The electrolytic capacitors will have a much higher failure rate.

Bertus
 

gahamby

Nov 19, 2021
12
Joined
Nov 19, 2021
Messages
12
Thanks for the reply. That clears things up. Would the linked item be a suitable replacement?https://www.ebay.com/itm/254027288041
With either phono input selected, even getting a finger close to those caps produces a profound hum. I'm going to be in there so I plan to replace all 4. I will proceed to source the electrolytic caps.
Thanks GH
 

bertus

Moderator
Nov 8, 2019
2,637
Joined
Nov 8, 2019
Messages
2,637
Hello,

A phono preamp is very sensitive.
The hum is an induction from your finger due to mains in the surroundings.
This could be normal behaviour.
You will likely in normal use never touch the capacitors.

Bertus
 

TomB19

Dec 21, 2021
28
Joined
Dec 21, 2021
Messages
28
I'm new here and late to this thread but wish to offer a comment very similar to the point Bertus makes.

Some combinations of cartridge/turntable/amp are known to hum. Grado cartridges are particularly known for humming issues. One of the guys on VinylEngine keeps a spreadsheet of combinations reported to have hum issues.

That's not to say you don't have an opportunity to improve or correct the problem; just that it may be normal. We vinyl guys are all dear to our favourite cartridge. I'm sure you could make a lot of improvement on your system.

Happy listening. :)
 
Top