amp help

1nten5e

Tonight at rehearsal we had a power cut in between songs, seems to have done something to my roadking head, it's half as loud as it was, and there's a noise like wind or waves in the background with the occasional popping or clicking......I have an aac file if anyone wants to hear it......any pointers? I dont think its power tubes as its happening on all channels whether set to EL34's or 6L6's

bertie

[total guess] is it valve rectifier ?  as that's a common element  and it does sound valvey [/TG]

ICBM

More likely to be a preamp valve. Rectifiers usually either work perfectly or blow fuses.

I'm not sure of the exact layout of that amp, but there will definitely be some preamp valves that are common to all channels.

1nten5e

ICBM cheers, there's a schematic here

http://www.tonymckenzie.com/rk-2-schematic.pdf

I'm just waiting for it to cool down, V5 sounds noisy with a tap test, I'm guessing it could be that

1nten5e

http://s150.photobucket.com/user/1nten5e/media/2013-11-12090925.mp4.html

ICBM

1nten5e said:

ICBM cheers, there's a schematic here

http://www.tonymckenzie.com/rk-2-schematic.pdf

I'm just waiting for it to cool down, V5 sounds noisy with a tap test, I'm guessing it could be that

Thanks!

V5 is the FX loop valve, so if you bypass the loop and the problem goes away, that's the most likely. All the other valves operate on both channels in some way except V3, so it can't be that. V4 is the reverb so it won't be that either.

1nten5e

It didn't go away when I bypassed the loop on the footswitch, but it does seem to have gone with a spare tube in V5 .....odd

would you recommend sticking with the Mesa tubes or is there something better?

ICBM

1nten5e said:

It didn't go away when I bypassed the loop on the footswitch, but it does seem to have gone with a spare tube in V5 .....odd

would you recommend sticking with the Mesa tubes or is there something better?

Not with the footswitch - that just bypasses the loop connections. You'd have to bypass the whole loop circuit including the Solo function, I assume there's a switch on the back if it's like the Dual Rectifier. It does sound like you've got it if the problem has gone away.

There are a lot better than the Mesa valves, it's hard to know where to start! Mesa are currently using JJ now as far as I know, which I like for power valves but not at all for preamp. If you do try different ones, avoid anything Russian-made - or even JJ if you can - in V3 and V5, which are cathode followers and tend to kill them. (And which may be why that one failed first if there was a voltage spike.) The bog-standard Chinese ones are fine though.

1nten5e

The one I pulled from V5 was a rusky 

1nten5e

Crikey, it's a valve minefield.....I've no idea what to get I'm guessing I should go for a good quality brand in V1 and 2 at the very least

Nerine

I've just wanged some Tung Sols and Genelex in my 800. They sound pretty sublime in that.

ICBM

Nerine said:

I've just wanged some Tung Sols and Genelex in my 800. They sound pretty sublime in that.

Be careful about a Tung Sol in V2, if you have - they're Russian and it may well fail. That's why Vox ship the AC30CCs etc with Tung-Sols in V1 and V3 and a generic Chinese one in V2. (Like the Marshall, V2 is a cathode follower in modern AC30s.)