How important is it to bias?

Beecher

Hey Guys,

As you might have seen recently im going preamp crazy these days, so to complement this I want to have a EL34 power section and a 6L6 power section at my disposal to take full advantage of everything. My Laney GH50L head currently is equipped with EL34's but can take 6L6's, theres even a handy Bias flick switch at the back for EL34/6L6 usage. From what I am told though for optimal usage the bias should be fine tuned and here lies the problem. The power tube bias is in a very awkward position and practically requires me to remove the chassis from the head to get at properly. Worst case scenario what am I looking at if I don't fine tune it, will my tubes just burn out faster (at only 30 bills to replace my poweramp tube section thats fine)? Will there be a significant tone impact?

Cheers guys.

Voodu Child

If the bias is slightly out, your tubes will run hot/cold and could either wear out quicker or tone won't be as good as it could.

If the bias is way out, you could damage your amp. Not worth the risk tbh, if you actually know how to adjust the bias yourself, then for the sake of a few minutes work getting the chassis out, i'd definitely do it.

Beecher

voodoo_child wrote:

If the bias is slightly out, your tubes will run hot/cold and could either wear out quicker or tone won't be as good as it could.

If the bias is way out, you could damage your amp. Not worth the risk tbh, if you actually know how to adjust the bias yourself, then for the sake of a few minutes work getting the chassis out, i'd definitely do it.

Bah damn you for making sense! My Mesa has just arrived however so its time to rock out!

Voodu Child

Beecher wrote:

My Mesa has just arrived however so its time to rock out!

B*stard I tells ya, those old Mark series leads are as good as it gets...

It'll take you a while to dial in (most mesa's do, because of how the tone controls all interact), but the results are well worth it.

Congrats:D

Beecher

voodoo_child wrote:

B*stard I tells ya, those old Mark series leads are as good as it gets...

It'll take you a while to dial in (most mesa's do, because of how the tone controls all interact), but the results are well worth it.

Congrats:D

Oh boy Oh boy Oh boy is this fun! Best reason to take a half day off work ever! It sounds significantly different to all my preamps which is great since the Laney/ADA/Marshall arent really a million miles away from each other tone wise. The amount of gain on this is unreal but it still stays quite clear

Voodu Child

Beecher wrote:

It sounds significantly different to all my preamps which is great since the Laney/ADA/Marshall arent really a million miles away from each other tone wise. The amount of gain on this is unreal but it still stays quite clear

I was thinking that, i'd consider the ADA and Laney to be in a kind of marshall-ish ballpark. That's why i was saying i think the just the studio and the JMP on their own would make a great combination, the two of them could cover an awful lot of ground, especially in terms of leads.

Anyways, nicely done, enjoy. And as I said, only go biasing the Laney if you actually know what you're doing. I'd hate for you to electrocute yourself and have all that nice gear going unplayed

bombidol

Just picked up a full set of new tubes for my peavey. Anyone know the craic with bias? whos best to go with, not doin it myself!

Voodu Child

It's not something that's particularly hard to learn to do, but as with all valve-amp servicing & tinkering, the cautious advice is to leave it to a pro (dangerous voltages etc)

Im pretty sure that place near Portobello bridge have a fella that services amps. Alladins amps will do it obviously, but he's pretty pricey, i'd leave him for actual problems and not routine maintenance.

I don't know about any of the main guitar shops, I presume at least one of them must have someone who knows what he's doing. Musician-Inc i'd guess.

SirLemonhead

I think Peavey amps have a fixed bias...

Voodu Child

MasterOfSolos wrote:

I think Peavey amps have a fixed bias...

Some amps certainly are - Mesa/Boogie for one. They require you to use tubes that fall within a very specific operating range.

Laney arent anyway afaik.

bombidol

Talked to Euro tubes, its all plug and play , savage!

Beecher

voodoo_child wrote:

Laney arent anyway afaik.

Nope, just a switch that apparently gets it close depending on the type of tube you are using