Roland Space Echo Mode 4,5,6 Hum

[boombipbass]

Hi all,

I am new to this forum and hope someone could help me out
I have a RE 301 and when I set it to mode 4,5 or 6 it gets a low Hum,

I think it is a capacitator but how to find out which one?

Anyone has some tips on this one?

Thanks!

Larry

[emrr]

Cap hum is generally PSU related and would be a constant regardless of setting.

Two things to check first:

Those switch positions all making good contact? Does cleaning it help?

I'm not looking at a 301 layout right now, but possible that combo uses a head that isn't used in the other combos, and its shield has failed. Or that head is bad.

[Darlington Pair]

Yep, cleaning the heck out of the rotary switch is what I would do, while you're there check the solder connections. I'm a fan of either Stabilant 22 or Dexoit D100l for treating that switch. The reason I think it must be related to the rotary switch is that 4, 5, and 6 are just combinations of heads from 1, 2, and 3 and people tend to use the combo settings less for some reason, unused open switches=dirty switches.

I give my space echoes a good internal cleaning at least once a year and have for 25 years, it's just part of owning a space echo... that and splicing tape.