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valve head help needed


Paul_Victory

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ok so ive got a dsl50 that i bought about a year ago, the valves are starting to go and iv found myself turning up the gain more and more over the past couple of weeks

so im pritty sure its time to change the valves

a few people have suggested these so im gona give them a go

anyway what i need to know is, how do i go about changing them? is it just a case of pullin out the old ones and sloting in the new ones? or is there something i need to do?

i know this sounds like a total novice question but id rather ask than f*ck my amp

cheers

paul

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ok so ive got a dsl50 that i bought about a year ago, the valves are starting to go and iv found myself turning up the gain more and more over the past couple of weeks

so im pritty sure its time to change the valves

a few people have suggested these so im gona give them a go

anyway what i need to know is, how do i go about changing them? is it just a case of pullin out the old ones and sloting in the new ones? or is there something i need to do?

i know this sounds like a total novice question but id rather ask than f*ck my amp

cheers

paul

You'll need to re-bias the amp most likely. Lameguitarist on here told me how to do it a while a go but i'm not sure where i saved the email...

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Phil is right. The poweramp valves will need to be biased. Take it to a pro if you don't know how.

Also, use Watford Valves for their generous assistance, but don't buy from them. You'll more than likely end up having to make another order. They have a very bad rep for sending out valves which are reported dead on arrival.

Hot Rocks in Nottingham are ace. Super cheap, and he's so trustworthy that he'll even send out your tubes before your cheque has even cleared. What a squire.

Are you experience any microphonic feedback or dipping in volume? if it's neither of the two, it could well be something other than the valves. They should last longer than a year unless you're playing shows every night with it.

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think there is a guide on the net about how to bias a DSL 50. If not give me a shout and i will explain it to you. If i remember right the range should be about 40 - 45, 43 being a sweet spot i think. Don't overbias them though as it will burn the tubes out pretty quick and if you set them too cold, about mid to late 30's you will get a very harsh brittle sound.

Make sure you are putting EL34's in the power section. Even if you use the same make as you already had they still need biased. Pre-amp valves are just a easy swap over.

Also after you bias it. leave the amp running for about 30 mins then play it for about an hour and then rebias it. After that do a monthly bias check on it, you would be suprised that new valves bias voltage jump up or down until they burn in.

I always bias an amp every month, even if i havent used it for about 6 months - its fussy but keeps the valve life going that bit longer i think.

I have used those Harma valves and they do sound really good. Very warm sound which is lovely when you bias to the sweet spot. Although i agree with the Watford comment. Had a few of those exact valves last no longer than a month! Not a company that seems to have consistent reliability. Don't worry if you are worried about lethal voltages in an amp.

The DSL has external Bias points on the back so its very easy and quick to bias and you dont have to go poking inside the amp. I once revalved Dan from My Minds Weapon's VH-4 which was an internal bias and has to be done when the amp is running. Nothing more scary than clipping those crocodile clips on to the transformer points near the large and lethal filter caps :D

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it has started to hum alot more than it used to

i bought it a year ago but it was second hand and im not sure how long they were in before that

also alot of the gigging i do is at diy gigs where my amp is not micd so it does tend to get turned up a fair bit

eh, where did you buy it? i traded in a dsl-50 a while back. mine was barely used and in immaculate condition...

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Isnt there high voltage risks involved with biasing amps?, i took mine to bruce millers when i got it retubed, cost me 50 bucks but saved me a possible broken amp/trip to hospital...

id say get a pro unless you know what your doing with electrics....

ok just saw that your amp has an external bias pot thing, ignore my post...

There is enough voltage stored in the large Filter Caps to seriously shock, if not kill you. If you are biasing an amp that has internal trim pots you should seek a qualified tech do do this. you don't have to touch the filter caps as well to be killed. a hand a few centimetres next to them on components can still result in a very nasty shock. There are ways to bleed the caps and make it safe to work inside an amp but biasing needs the amp to be running so rules out bleeding the caps.

Had a shock a few years back when i was replacing fuses in my 5150 and that was just from static on the chassis i think. still hurt.

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