Crate Blue Voodoo

[Valvehead]

Working on a BV120 head. Its fighting me every step of the way.....

All new tubes
New filter caps

2 problems, but lets start with the first.--very loud , random ticking sound--like an old typewriter. Its not steady .

All the noise issues go away when V2 is pulled out.

with V2 in, the Master volume on ch 2 affects it.

So im assuming the problem is before v2. Tried different tubes.

I have video of the ticking sound--i hope someone has heard this before--sorry about the quality.

Tick Video by solrizzo | Photobucket

[Chuck H]

How about a schematic???

[Valvehead]

i have a paper one here.....yet after searching for 10 minutes now....cant find one online....there are a couple "attached thumbnails" on here if you look...but i cant open them ????
what a day...

if i have to ill dig out my scanner and try and upload mine

[DrGonz78]

How bout dis one?

crate_bv120_sm.pdf

[Valvehead]

thats her !!

anyone watch the video and heard that sound from an amp ?? i havent !

[Chuck H]

Huh?!? I thought I would see something other than standard amplifiers. I was going to blame it on "the digital effects module" or whatever. But I only see regulat silicooties in there. No, I've never heard that before. It may be something to do with the LDR's and/ or their voltage? Try lifting the voltage of any associated LDRs and see if it stops.

[Enzo]

Just sounded like a bad case of the motorboats to me.

If it is oscillation, pulling V2 breaks the loop. This then would not be a noise being created at some spot, rather it would be feedback between stages, possibly a broken cnnection on a decoupling cap.

[Chuck H]

I thought it sounded asymmetrical. Otherwise I might have thought motorboating as well. It IS hard to be certain from the video.

[Valvehead]

well, i just fired it back up and its silent.... i will have to wait until it starts doing it again

[Valvehead]

I thought it sounded asymmetrical. Otherwise I might have thought motorboating as well. It IS hard to be certain from the video.

its very random--sometimes steady for 1 minute straight, mostly not

[Valvehead]

I will order some new coupling caps, and maybe a couple of those VTL5C6 ? --i did ground the leads of the first 4 and heard no difference in the ticking.... Mouser doesnt seem to have those

[Chuck H]

I think LDR's are "obsolete" because of RoHS. I've read that in a few places. And their availability is also indicative. Some should be available for an elevated price through NOS vendors for domestic use (USA).

[Valvehead]

following up -- thanks boys-the amp is working great and all the noise is gone. I replaced all the coupling caps before V2 and that fixed it .

[Chuck H]

And the winner IS... ENZO! (bing-bing-bing-bing-bing)

[gtrplayr1976]

That sounds like the same noise I have in my new build.