Cost to Bias an Amp

[rrgguitarman]

Has anyone had an amp biased lately that can tell me what is the average (fair) cost to bias an amp?

I'm looking to have a Crate GT50 Stealth amp biased.

Thanks.

[Eracer_Team]

you're probably looking at 1hr minimum labour charge plus parts (parts= tubes, resistors, cap's, etc)

You can shop around your area but I bet most Big name store/shops (GC, etal) would charge probably something on the order of 70/hr.

[layboomo]

It varies,but if you buy the tubes from most shops they will cut you a break on a bias. It doesn't take very long for an experienced tech to do it.....my guess would be $50 or $60 plus tubes. Most of the better techs will recommend what many of them call an amp tuneup. Instead of just a bias job they go through and clean all pots jacks and switches,bias the amp and get it all up to spec.

[rrgguitarman]

Most of the better techs will recommend what many of them call an amp tuneup. Instead of just a bias job they go through and clean all pots jacks and switches,bias the amp and get it all up to spec.

 

I was wondering if there was more done than just adjust the amp bias.

I called a couple of places and one guy quoted around $85.00 and the other quoted me a flat $45.00

I will say that the first guy mention the cleaning of the pots but, also said that once he got in there he would call me with an exact amount to finish the job and if I decided not to do it, that it would run $35.00 for the estimate.

It seems that nothing is really black and white.

 

Thanks for your input guys.

 

Is there a problem with just having someone just bias the amp?

[m-theory]

It's impossible to tell over the phone whether or not the amp might need some unseen repair work in order to properly set the bias.

[rrgguitarman]

It's impossible to tell over the phone whether or not the amp might need some unseen repair work in order to properly set the bias.

 

This makes sense.

Thanks.

[layboomo]

 

This makes sense.

Thanks.

 

Most good tech's know that and they also know that unless there is a big problem with the amp for a little labor some resitors,contact cleaner etc...etc...they can bring most amps up to spec for a few $$ in parts and an hours labor. That's why they offer a "set price" tuneup.

[cGil]

Yep, might as well do a little general maintenance while you're in there finding the serious bugs. But measuring and testing an amp and finding the bugs takes bench time. And there really is a fair amount of work involved just to get an amp out of the cab and onto the bench for voltage measurements and then back into the cab again, all without destroying something. Granted, it's not much trouble getting VJr out of the box (unless it's new), but if the amp's any bigger than a VJr head, trust me, it's actually heavy labor that you're expecting someone to provide for you. So try not to get all ruffled over having to pay for an "estimate".

 

Hey, I just finished biasing a Silver Jubilee, and my aching back tells me $40 wasn't nearly enough. Maybe if I hung some neon signs in my window, I could charge more?

 

Gil...

[layboomo]

Yep' date=' might as well do a little general maintenance while you're in there finding the serious bugs. But measuring and testing an amp and finding the bugs takes bench time. And there really is a fair amount of work involved just to get an amp out of the cab and onto the bench for voltage measurements and then back into the cab again, all without destroying something. Granted, it's not much trouble getting VJr out of the box (unless it's new), but if the amp's any bigger than a VJr head, trust me, it's actually heavy labor that you're expecting someone to provide for you. So try not to get all ruffled over having to pay for an "estimate".

 

Hey, I just finished biasing a Silver Jubilee, and my aching back tells me $40 wasn't nearly enough. Maybe if I hung some neon signs in my window, I could charge more?

 

Gil...

 

 

Boy do you have a point there Gil ! I had a few v-4 heads in my younger days one of which was missing the back brace...well without that brace the boat anchor of a chassis is like a jelly fish in the rubber shock mounts. I had tubes and a bias job done on it once and the tech said "if you ever give me that f#cking thing like that again....it'll cost you $200 just for me to open it up!"

[StarGeezers]

Might be time for a tutorial ,so everyone could learn how to bias their own amps ... we know how to bias a VJr. right!!! can't be that hard eh???

[Burstbucker1281734065]

I learned to bias my DSL 50 myself and it was very easy to do. You just need to research your amp a bit to find out how it is done. There are tons of resources. Make sure you know what you are doing and are extremely careful as there are voltages in there that will kill you if you make a mistake. I haven't biased my Vox yet, so I'll have to get up on the curve on that one.

[cGil]

Vox's are cathode biased like a VJr. Just follow the wire from any el84's pin 3 to the cathode bias resistor and bypass cap. The only difference is that it's a P-P amp, so you're tweaking one shared resistor for 2 or 4 tubes instead of one, for which you must compensate in the calculations. I won't go into the math cuz it's late and I'd screw it up for sure. And I'm not having much luck trying to find the link I thought I saw it explained in.

 

Ooops. Found it. If the cathode resistor is shared, use half the normal single tube resistance at twice the rated power capacity for the resistor. http://www.freewebs.com/valvewizard1/pp.html

 

Judging by the AC30-1960 non-TB schemo http://www.schematicheaven.com/voxamps/ac301960.pdf

with a shared 50R resistor, it would be safe to extrapolate that for a 4-tube shared bias resistor, use 1/4 the single tube bias resistance, and maybe 4 times the normal minimum power rating.

 

Gil...