URGENT - valve change

Lizard · Post by **Lizard** » Sat Oct 23, 2004 11:08 am

Hi. I have an AD30R with all standard valves that have never been changed in the 2 years and a bit that I've had it.

I am playing a gig tonight and need more gain than what the amp can deliver. When purchased I got spare valves:

- 1 pre amp: Ruby ECC83-Cz
- Output: 2 matched Ruby Tubes EL84-CZ

Would it work in my favour to change any of the stock (Dragon) valves for the Ruby and IF SO which positions should I change?? ANY help would be much appreciated!!

Thanks.

Andy H. · Post by **Andy H.** » Sat Oct 23, 2004 11:42 am

Hi Lizard. I'd not particularly recommend swapping just 2 of the EL84s - best to use 4 reasonably closely matched ones. Doesn't mean you can't do it with the AD30 - you can. If you want to try it, just swap one from each side - inner pair or outer pair. Sometimes using slightly unmatched valves can give a different richer distortion.

Better bet would be trying your spare ECC83 (12AX7) to see if it has higher gain then what's in there now. The position that has most effect on the overall sound is usually the first preamp valve position, but I forget which that is - ?? nearest the input jacks end. Try it and see - you can't do any harm anyway.

The usual route to higher gain though would be to shove an overdrive pedal in front of the amp...

Good luck with the gig!

Andy.

irish_admiral · Post by **irish_admiral** » Sat Oct 23, 2004 11:46 am

The dragon valves aren't great, so it would probably be a good idea to change them as they're a couple of years old.

You won't get that much more gain out the amp - some valves will break up earlier than others, but even with 'higher gain' tubes, you can't suddenly turn an AD30 into a Mesa Recto or something...

At any rate, the preamp valve slot closest to the (left) side is the gain stage, and will have the most discernable effect on gain. I wouldn't change only two of the output valves as there's 4 in there, and to get the best sound out of them, you want a matched quad. Go for Harma EL84 STRs, or Electro-Harmonix, as they're the highest gain EL84s I can think of off the top of my head.

If you need it for tonight, you're not going to get a huge amount of extra gain from the tubes - i'd use a pedal and recommend trying to get a couple of Electro-Harmonix or Harma STR preamp tubes (12AX7s) as they're relatively high gain, and sound good.

Don't tell me the best way, just tell me the cheapest way...

Lizard · Post by **Lizard** » Sat Oct 23, 2004 12:31 pm

Thanks. I will try the pre-stage and see if it that helps at all.

Lizard · Post by **Lizard** » Sat Oct 23, 2004 1:03 pm

if I was to try and change one of the pairs would you recommend the inner or outer output tubes?

Lizard · Post by **Lizard** » Sat Oct 23, 2004 1:25 pm

last question hopefully ...

I've just change dthe middle set of output tubes when I noticed that the Ruby tubes have a small sticker round the bass of the tube with the name and model number. i tried to peel it off as this seemed the obvious thing to do but it was real stuck on there as if it was not meant to come off. any ideas? safe to leave it on there?

Andy H. · Post by **Andy H.** » Sat Oct 23, 2004 1:39 pm

Inner or outer pair? Either should be fine.
Label? Should be fine too just leaving it on.
When you power up the amp with the 2 new power valves, just keep a wee eye on all of them to make sure the plates (outer bit of the innards - nearest the glass bottle) aren't glowing red at all. If they aren't and it sounds fine to you then you're fine fine fine!
The word for today is...? <img src=icon_smile_wink.gif border=0 align=middle>

Andy.

URGENT - valve change

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