Ulbrick - reverb not working....

[longtallronnie]

Tried replacing the valve and still no worky. Any ideas of where to look next?

[ESBlonde]

I can't find a piccygraph of the insides of one and have no first hand experience. On old fender type combos with the reverb tray in the bottom, they are connected by those hi fi push on plugs. These can and do oxidise, if yours has these then pull them of and push them on an slightly twist/wiggle them to clean the contacts. This is an old simple trick that often gets you going.

Does that help/solve it?

[longtallronnie]

Yep, accutronics jobbie in the bottom with two phono plugs connecting.
Unfortunately I'd already tried that - I had to resolder one t'other day. Of course that could be the problem but the joint appears to be good.

[ICBM]

How old is the amp? Does the Accutronics tank have clear moulded push-connectors on the transducers? The modern ones do, and they cause the failures. Unfortunately it's not the connector itself usually, it's that the very fine coil wire breaks where it passes over the edge of the red plastic bobbin before being soldered to the pins. This is almost impossible to fix, really the only solution is a new tank.

This is a design fault with the modern Accutronics tanks - it often happens spontaneously, I think because the mass of the push-connector vibrating weakens the wire. If so it will be the output end that's broken - for ages I used to keep the dead ones in the hope of getting one where it was the send end, and making one good one out of two broken ones, but every single one has been the output end - the wire must be thinner.

One of my obsessive-upgrades-if-I-can-be-bothered - usually only on my own amps or a friend's - is to remove the push-connectors and solder the wires to the pins, as close as possible to the bobbin - *before* it breaks... then they don't.

[longtallronnie]

I don't think it's that old, I'll have a look when I get home.
Chances are I won't use the reverb that much when gigging but still annoying.

As a side note, any recommendations for 6L6's?

Are Svetlana winged c's worth nearly double the cost of a pair of TAD RCA style black plates for example?

[longtallronnie]

Here's a pic of the output connectors. The wire is tiny but appears intact. I've got continuity on the two leads as well.



Gotta head back to work now so will have a closer look tonight.

[ICBM]

Those are the ones.

You probably won't be able to see the break if it is those thin wires - it will be right down next to the pin on the end of the red plastic bit. Pull the connector off and meter across the two pins directly. Or by 'continuity', do you mean you're measuring the coil resistance at the phono connector? If so the problem is not in the tank, if both ends read OK.

[longtallronnie]

I'd only checked the leads end to end not tip to barrel before I had to get back.Will look again this evening.

Any thoughts on what 6L6's to consider?

[ICBM]

I'd only checked the leads end to end not tip to barrel before I had to get back.Will look again this evening

Ah, I thought you mean the black and blue leads inside the tank.

Any thoughts on what 6L6's to consider?

I've been using JJs from Karltone recently and haven't had any probems. I'm not sure I'd pay twice for Svetlanas than what TADs cost either.

[jpfamps]

Ah, I thought you mean the black and blue leads inside the tank.

I've been using JJs from Karltone recently and haven't had any probems. I'm not sure I'd pay twice for Svetlanas than what TADs cost either.

We ABed some =C= 6L6s against JJs and couldn't much, if any difference. As I've had a lot of problems with =C= EL34s and the extra price of the =C= 6L6s versus the JJs, I've stopped using =C= valves.