#1
Firstly, what equipment exactly do I need to set the Bias?
I'm reading that I need a voltage meter, but how could I get a reading if It only measures the negative voltage? Or is that now how it works..

I don't own a voltage meter so If someone could point me in the right direction to something that I can use I'd appreciate it.


I'm pretty stuck :P
Schecter C-1 Classic (BKP Painkillers)
Schecter Tempest Custom EMG 81/85)
Jackson DK2M
Boss: Ge-7, DD-7, RV-5, NS-2, SD-1
MXR: KFK 10 Band EQ, Dynacomp, Stereo Chorus
Voodoo Lab Sparke Drive
Bugera 333XL 212 Combo
#2
Go to youtube and do a search, plenty of videos on the subject.
Epi Les Paul-APH1/Mean 90
MIM Strat

Korg DTR1000
ADA MP-1
Mesa/Boogie Quad Pre
Mesa/Boogie Midi Matrix
<power amp>

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#3
I;ve had a look and can't see anything on youtube.
For bugera in particular.
Schecter C-1 Classic (BKP Painkillers)
Schecter Tempest Custom EMG 81/85)
Jackson DK2M
Boss: Ge-7, DD-7, RV-5, NS-2, SD-1
MXR: KFK 10 Band EQ, Dynacomp, Stereo Chorus
Voodoo Lab Sparke Drive
Bugera 333XL 212 Combo
#5
From EUROTUBES.COM...

Bugera amps

Plate Voltage 480

Bias Range 38mA - 42mA DCV (25watt matched quad)

We are getting so many questions about the Bugera amps that I decided to put up a page on them. I don't know how Behringer is getting away with this but these are carbon copies of the Peavey amps in almost every way. The sound quality is pretty good and the build quality is average for today's standards for production amps from what I've seen. The 333 is a XXX clone, the 6260 is a 5150 clone and the 6262 is a 5150 II clone.

The power sections on these amps are all XXX style allowing either 6L6 or EL34 type tubes to be used which is a nice option. We have used the JJ 6L6GC's, EL34's, KT77's and the E34L's. Unlike the Peavey XXX amps we have not encountered any problems running the E34L's. The target market for these amps is obviously the Peavey and Mesa seekers who want the best bang for the buck. The Behringer company is the manufacturer and these are a chinese made product thus the lower cost.

The bias setup is exactly the same as you will find on the XXX right down to the bias test point. This is one place that Behringer should have deviated from the Peavey design and incorporated test points that actually measure the bias current. Unfortunately Behringer stayed with the Peavey bias circuit that measures the negative voltage and NOT the actual plate current. What this means is that you cannot accurately set the bias using the test points. You need to use a bias probe under one of the tubes so that you can actually measure the bias current. DO NOT be fooled into thinking that you can bias the amp accurately as stated in the Bugera manual and on their website. This is a large batch of Barbra Streisand.

The bias pot is located right next to the power tubes so if you use a short bias probe you don’t even have to remove the amp from the chassis making a tube change and a bias adjustment a 10 minute job. We have our own Eurotubes bias probes which can be used with any digital multimeter that reads in DC Milliamps for 25.00 and you can also find short probes on ebay. So I will give the same warning that I give XXX and JSX owners, the bottom line is do not use the factory test points! If you want to do the job right use a bias probe. As for tubes, these amps ship with chinese preamp tubes and 6L6's. The JJ 6L6GC's are what we use most all the time where going with EL34's will cause you to drop quite a bit of low end. For players that want more of a Brit tone we typically go with the JJ E34L's which have a deeper low end and are very tight and punchy. You can also use the KT77's which are a little bigger on the low end than the E34L's but neither are as big on the low end as the JJ 6L6GC's so if you're going for that big chug the JJ 6L6GC's are the ticket. Unfortunately Behringer also copied the power tube spacing from Peavey and placed the tubes too close together to allow running a quad of KT66's or KT88's. When we get the chance we will do some experimenting to see if a pair of big bottle tubes can safely be run in the outside sockets. Stay tuned!
#6
you will need a Bias probe and good multimeter.
like Beerchurch posted from the eurotubes site. do not use the test points on the amp. they are crap basically.
Gear:
Mesa MK IV head
Mesa 4x12 cab(3)
Marshall JCM900 2100 SL-X
BBE 482i
ESP eclispe II
B52 At-100 head
MXR and Boss pedals
Sparow guitars
Peavey 5150 II modded
JJ electronic tubes

BUGERA USERS MILITIA
#7
Biasing the BUgera 6262 head(should be the same for the 6260 as well)

plat voltage on the 6262 is about 480 pV
the 6260 is about 470 pV

The very first step is to open up the back. If its a head you may or may not be able to fit the probe under the tube. If this is the case, the chassis must be removed from the head box.

Since I run KT77s, the very first thing I must do is flip the switch from 6L6 to EL34, as the KT77 can be run in place of EL34 type tubes. If you are running what was already in there DO NOT flip the switch unless your 6l6 tubes will no bias above 35mA, in which case flip to the EL34 mode and bias up to about 40mA there. Next carefully begin seating the tubes in the sockets. Only handle tubes by the bases, with a clean rag. You don't want to get the oils from your hand on the tube. I put the bias probe on the third socket(but any one is fine). Put the bias probe on the third socket and then insert the tube into the bias probe.

Alright before we go any further. MAKE SURE YOU HAVE A SPEAKER LOAD CONNECTED TO THE HEAD, OR THAT THE SPEAKERS IN YOUR COMBO ARE CONNECTED. FAILURE TO DO SO CAN RESULT IN SOME FIREWORKS TO SAY THE LEAST.

Ok, now that you have a speaker load connected, and you have your bias probe and multimeter connected, turn on your multimeter. Set it to the DC amps side, and set it to 200mA. Now turn your amp on standby. You should see 0.0 or 0.1 alternating on your multimeter. After a nice warmup, turn your amp on. You should see those numbers going up. Ok, now I am biasing KT77s, so I need to bias somewhere between 34mA and 39mA. If you are using a different tube (EL34, 6L6, KT66 etc) you can find out where to bias between for your tubes. I want a good warm bias, but still want a little bit of extra life from my tubes, so I am going to shoot for 36-37mA.

i say for 6l6s bias them to about 40mA

Now, locate bias trimpot. It is near the EL34/6L6 switch. Alright, if your bias is a little low, turn it to the left to raise the amount of current. Thats right, the left. Make very small adjustments at a time, as a tiny movement on the trimpot makes a HUGE difference. If the bias is a bit too high, turn it to the right. Make small adjustments, then check your multimeter. Ok, mine is now sitting somewhere 36.2 and 36.5 (as current fluctuates a little). This is in the safe range and close to where I wanted it. BINGO. Now turn your amp off and let everything cool down. Remove the tube from the bias probe and put it in the amp tube socket. Alright. you are done. Now that wasn't so hard was it? I'd be willing to bet some of you guitar geeks even had fun.

And remember if you are biasing 6L6 tubes in the 6l6 mode on the amp and the bias will not go above 35mA even with the trim pot turned all the way up, flip to the EL34 mode and bias it up from them. ITS SAFE TO DO. but remember after you bias it in EL34 mode to leave it in that mode, switching back to 6l6 mode will drop the bias back down
Gear:
Mesa MK IV head
Mesa 4x12 cab(3)
Marshall JCM900 2100 SL-X
BBE 482i
ESP eclispe II
B52 At-100 head
MXR and Boss pedals
Sparow guitars
Peavey 5150 II modded
JJ electronic tubes

BUGERA USERS MILITIA
Last edited by HouseBoy83 at Aug 17, 2009,