Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[klaus]

1. As a friendly reminder: only real posters who identify themselves with their real name are allowed to post here.
"Il Caccillo" does not sound like a real name to me. I apologize should I be wrong and indeed names like that are printed in passports.

2. What have you actually learned from the responses you received? It seem to me that you ended up where you started out: replace what seem perfectly fine filter caps in a vintage collector's item worth now thousands of dollars, possibly reduced in value by these alterations.

Again, please correct me if I got this wrong, but were these exchanges over the last month worth the time and space they occupy?

[RuudNL]

The only thing I can add to the discussion about replacing capacitors in microphone power supplies, is that I have replaced the capacitors in a couple of U47 (VF14) power supplies.
These power supplies had developed a significant mains hum, caused by the leak currents of the capacitors.
With the new capacitors, the microphone output is totally hum free now!
(And yes, I agree that you shouldn't replace things just for the sake of replacing them.)

[klaus]

As there is a high quality screw-in, German-made substitution available for NG filtering, the value of the power supply will not suffer as a consequence of replacing filter caps.

If one suspects failure, a simple test is to remove one lead of each of the five capacitors, put it on a capacitance meter and check overall capacity.
if any of them falls below the rated capacitance (47mfd) replace.

[teleric]

Nice infos about the cap values.
I effectively had to repair a Nu67 last year because it blew up the fuse after 10 to 15 mn on.
I had Martin Kantola work on it and it was in fact the filter just after the ac input that produce that.
He change the leaking zener and the main caps for longevity. The mic never sounded better, all else being equal.
Now my other Nu67 blows up the fuse too, and I'll probably start with filter and zener change before switching the big caps.

[klaus]

Regarding fuses:
make sure you use the right amp value for the AC voltage situation you are in. Fuses for 220VAC operation are usually one half the rated amperage than the ones for 110VAC.