Is this normal..

super-sonic · Post by **super-sonic** » Fri May 11, 2007 11:46 am

so yeah as the title suggests?

ive got some spare valves for my ac30cc and just wondered if im at a gig and need to change the valves, is this ok, only if temporary? until i can get it re-biased?

i read somewhere that ac30s dont need to be biased? is this crap?

ive only owned fenders before now and used to always get them biased after chnging poweramp valves..

any ideas?

gareth

Post by **Doog** » Fri May 11, 2007 11:53 am

From Voxamps.co.uk:

What is the procedure for changing valves?

First ensure that the mains lead is removed and that the valves are cool then remove the chassis. On current AC30 & AC15 you should remove the captive nuts on the side of the chassis before attempting to slide the chassis out, otherwise you will damage the vinyl on the inside of the amplifier.

Remove old valves and insert new valves. Always make sure that the pins of the new valve are perfectly lined up with the valve based before pushing the valve in. This is especially important for pre-amp valves where the valve and valve base can easily be damaged.

When changing power valves, always replace the whole set and never mix valves from different manufacturers. There is usually no bias adjustment on AC30s and AC15s.

super-sonic · Post by **super-sonic** » Fri May 11, 2007 11:55 am

super-sonic · Post by **super-sonic** » Sat May 12, 2007 1:00 pm

so yeah, after haing a look in the amp.. i have..

4 x Electro harmonix EL84's

1 x sovtek 5ar4

3 x tungsol 12 ax7's

i thought all these ac30s came with crap chinese valves?

im pretty happy with whats in there..

Post by **Mike** » Sat May 12, 2007 1:03 pm

Apparently they are stock with a nice mix as you have found. They actually cherry pick the brands to voice the Vox.

I have put 3 Tung-Sols in V1-3 in my JVM - they sound nice.

super-sonic · Post by **super-sonic** » Sat May 12, 2007 1:06 pm

yeah im actually pleasently supprised!

the tungsols seem great!

ive got some EH 12ax7s in my tool box somewhere and just ordered a spare quartet of EH EL84s and another recifier from hotrox

...just to be safe

Post by **Mike** » Sat May 12, 2007 1:06 pm

super-sonic wrote:i thought all these ac30s came with crap chinese valves?

Oh and just a couple of points:

1) Almost all valves are made in China these days, and most of the branded valves (JJ, GT, TungSol, EH) are of great quality.
2) Chinese production /= Bad. It's just where it's cost effective to produce the components. I'd rather have chinese tubes that british overpriced ones that don't work.

And you've done a wise thing, always smart to have some spares around, although for a mid gig issue I would bring a small backup like a Crate Power Block or an Orange TinyTerror or borrow another band's amp if a tube pops ratehr than replace, I ain't opening my amp up in a venue. Mind you, AC30s are accessable aren't they?

super-sonic · Post by **super-sonic** » Sat May 12, 2007 2:15 pm

Well to be honest.. my ac30 is pretty accessible now (after letting rid of some screws.. i opened up up yesturday out of curiosity and to check the vales out etc.. well it took a goos 30 mins to open up. some of the screwheads got mushed (poor quality) so yeah now ive got an action plan if i ever need to open it up hehe..

one more question..

if i was to get a tiny terror or similar... is there a way to run it through my ac30's speakers in the combo? on the back of the amp theres an external out (mutes internal speakers) and an extension out (for adding a cab etc)

would any of these work? ive seen a guy running a vht head through a twin (using the twin as a cab)

any idea??

gareth

Bacchus · Post by **Bacchus** » Sat May 12, 2007 8:10 pm

Mike wrote:2) Chinese production /= Bad. It's just where it's cost effective to produce the components. I'd rather have chinese tubes that british overpriced ones that don't work.

Aye. I remember being in Deinghamms, or somewhere similar, where they had a coat that was stitched in the UK, and was wile dear. I remember thinking "why the fuck would I pay more for an item that has been made by people who, chances are, are less qualified to be stitching together my clothes than others?"

Crazy.

Post by **Mike** » Sat May 12, 2007 10:09 pm

super-sonic wrote:if i was to get a tiny terror or similar... is there a way to run it through my ac30's speakers in the combo? on the back of the amp theres an external out (mutes internal speakers) and an extension out (for adding a cab etc)

would any of these work? ive seen a guy running a vht head through a twin (using the twin as a cab)

any idea??

gareth

If your combo speaker has a speaker cable you;re in business. Just connect it to the correct output. Tell me what the back of your amp looks like = what speakers, what ohms, one cable? two?

give me some more information and I just might be able to help you

super-sonic · Post by **super-sonic** » Sun May 13, 2007 2:20 am

thats what the back looks like and theres obviously two speaker wires coming from each speaker (one pair = black and white and the other pair = red and yellow)

it has two output jacks (extension for adding a cab) & (external which mutes internals)

running at 16 ohms i think?

the speaker wires are hard wired into the amp, not a jack, like fender amps..

*basically i want to be able to sit a tiny terror, or similar on top for backup and have it running into the speakers of the vox.

any help appriciated..

Post by **Mike** » Sun May 13, 2007 5:51 am

Tricky. The best situation is where the speakers are connected via a jack to the combo amp chassis.

You have two options:

1) Make another lead with speaker clips on one end and a jack on the other and use that for the TT

2) Modify the Vox.

Cut the wires to the chassis and wire the amp side ones to a jack socket you mount on the jack plate. Solder a jack onto the speaker end wires. Plug in and you have the Vox with it's own speakers, unplug and plug into the TT and you're cooking on gas there too...