Studio Projects B3 with intermitent sound

[camarada78]

Hello,

I have here in my bench a SP B3 (transformerless fet condenser) that appears to work for a few seconds than shuts down. A few moments later, it goes back working again and then it stops.

I thought it could be humidity on the capsule but after a few hours on the dehumidifier, it came back identical, the same problem. Any clues?

Any thought?

Thanks have a good day

 

[rock soderstrom]

Any thought?

Do you have a second capsule to check where the problem is? This will help you localise the source of the problem.

 

[Migs 31]

I thought it could be humidity on the capsule but after a few hours on the dehumidifier, it came back identical, the same problem. Any clues?

Any thought?

Thanks have a good day

I had the same problem with an SP B1.
The black rubber base under the capsule had deteriorated and contaminated the diaphragm.
AND one of those black switches seemed to have oxidised. Laying directly on the Hi Z path.

Check the state of that capsule, any tiny black deposits/contaminants?
For the switches, clean them wit DE-Oxit spray cleaner, see if it helps.
Good luck to you!
M

 

[camarada78]

Yes, it has some of these contaminants yes. i will try something that way