JCA20H (Jet City) volume drops in/out...?

[Lukelele]

Having some Jet City dramas...

I was playing my Gretsch through it the other day and there's some problems with the electrics in the guitar anyway but of course that and the desire to play in the moment prompted me to put it back in the rack and pick on a different guitar

So I picked on the ol' LP Standard. And what do you know? Sure the electrics in the Gretsch seem to be shot for no apparent reason but there's notable volume drop-outs on all guitars at the moment.

Tried multiple leads - cos seriously, how can you possibly have the electrics in 4 guitars play up at one time after they were fine the day before right? Just doesn't happen.

I've also tried changing the lead from the head to the cab.

Nothing's helped there.

Model: JCA20H + the standard Jet City cab with Eminence speaker. Bought the amp June 2011.

This makes me sad as:
1) I don't live anywhere near the store that I got it
2) The company (Allans Music & Billy Hyde... I'm in Australia btw) has just gone under (yaaaay alllll the stores are closing! So to get anywhere near decent guitars I now have to travel FURTHER).

Does anybody know what could be causing the problem? I've lived with transistor amps for years. Going valve made me happy. But then this shit comes as part of the deal I believe?

[Basher]

I'd probably try new valves.

After that, you're probably going to have to take it to a pro.

I suppose the other variable is the speaker. Do you have access to another cab you could try?

It might be worth contacting Jet City to see if this is a known issue with that model.

[ICBM]

+1 on the speaker. I've come across a problem with Eminences surprisingly often that can cause variable volume or the speaker to appear completely dead, when it isn't.

On the terminal strip, on many models the cone braids are not soldered to the terminals, they're crimped in little folded metal 'u' shaped grips. These quite often make poor contact. If you can solder, it's worth soldering them up - in fact, I would go further and )if it has them) cut the push-connectors off the speaker wiring and solder these to the terminals as well. If you can't solder, try crimping the little clamps tighter with pliers, and probably tighten the push-connectors as well - where the wires are crimped into them, rather than where they push onto the speaker terminals.

If it's not that it could be valves as Basher said. First, just try gently wiggling them in their sockets - a poor contact can cause signal problems. If that doesn't work, get one spare 12AX7 and a pair of EL84s - you should have these anyway with a valve amp. Replace each preamp valve one at a time with the new one, and if that doesn't fix it, try the power valves - one at a time, but if you find that one is faulty, put *both* the new valves in and keep the good old one as a spare, rather than mix one old and one new.

[Lukelele]

Thanks for the advice guys.

Maybe as a starting point rather than stuffing around with valves and electrical stuff that I know stuff-all about, I could see if I can take the head to a shop and ask if I can try it through another speaker cab.

I mean the set up I use is literally as-is. Guitar straight to amp. And that's all that I have. I never have spares of anything! All me strings are rusty! Rue the day when one breaks, then I buy another set. It's bad, I know, but string prices in Aus are freakin' extortionate. As are valves... and just about everything else!

[ICBM]

Yesterday I discovered that the British Royal Mail has re-zoned the world for parcels prices into four zones...

UK
Europe (including the whole former Soviet Union)
World Zone 1 - The Rest Of The World, except for
World Zone 2 - Australia, New Zealand, Singapore, PNG and the Pacific islands.

WTF? It now costs less (not by much, admittedly) to send something to the back end of Kamchatka or Tierra Del Fuego than it does to Sydney.

[digitalscream]

Get in touch with Jet City - they'll be able to give you some good advice. It usually takes a couple of days for them to get back to you (there's only a few of them working for the company). You can get them on support@jetcityamplification.com - if you have trouble getting hold of them, PM me the email address you used and I'll see what I can do to help.

[Lukelele]

I did get a reply from Jet City.

They said to check the tubes.

But I have worked out since that the source of the problem is somewhere in the connection from the head to the cab.

I had another fiddle with the lead from the head to the cab with some interesting results.

Have fiddled with it since and swapped the lead out (in the 16ohm connection) and will see how it fairs out. If it's still a problem I'll have to take a lookie at those connections/joins/solders and see whether the jack socket or something is loose in the back of the head.