#1
I have had my blackstar S1-45 about 2 and a half years, it has never been regularly used as in gigging until the last 4-5 months, I noticed a few weeks ago it started hissing slightly when the gain was getting towards halfway and beyond, I have just had a band practice tonight and the hissing and feedback was unbearable, even with a digital noise gate, i had to have the noise gate at full capacity for it to make any difference to the hissing and feedback. I messed with all the controls from the DPR to master and channel volume, gain etc, the tone sounded very shrill and thin. My first guess is the obvious of the tubes needs replacing, is there a way to confirm this? or does anybody have any other ideas as to what this problem might be? Any suggestions please guys??
Thanks
#2
The way to confirm it is to change the tube and see if the issue is solved.

It does sound like a tube issue, and you're going to want spare tubes anyway, so might as well get a backup set and see what happens.
#4
Like a lot of modern amps, Blackstar runs the tubes very cold from the factory, so biasing is not strictly necessary. Because of this, and to save money, Blackstar does not provide bias adjust pots in the amp.

So, you're ok without biasing. If you want to bias, you'll need to have the amp modded for bias pots and test points. Then you could bias it yourself in the future with just a multimeter. In general I wouldn't suggest putting that much money into modifying the amp. If you're really concerned about dialing in your tone/power tube response, and you love the amp, sure, go for it. From a tube life perspective, you're fine without it.
#5
try taking a pencil and tapping each tube slightly while its on. if it makes a ringing sound, then replace that tube. If a power tube is damaged, it will make a deepish sound. If no ringing is heard in the preamp tubes, then I would believe that the problem is dirty tube sockets, which can be fixed easily by spraying some contact cleaner into the sockets.
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damn J-Metal, why you so awesome

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Schecter Hellraiser V-1 fr
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#6
to be in honest if it just a case of plug in a play, that would suit me so much more, i was just under the impression that most tube amps need biasing after swapping them out. Even if i changed the whole set i could just plug in and play then?? http://www.watfordvalves.com/product_detail.asp?id=2995 this is what i have my eye on, would be great if i could just swap them myself
#7
you only really need to bias power tubes when your switching them out for some other type of tube. Since youre eyeing an el34 set, you could just plug and play without a problem. But again to your original question. test out your tubes first. chances are that 5 out of 6 of the tubes are in perfect working condition.
Marty Friedman is GOD!

curently in a SEX MACHINEGUNS and X JAPAN phase AND Galneryus AND Anthem phase

damn J-Metal, why you so awesome

My Gear:

Schecter Hellraiser V-1 fr
Ibanez RG321mh
Fender GDC-200sce
Peavey Vypyr 30 w/ sanpera 1