Would it be wise to use this bias master when putting in a completely new set of tubes? If so do the tubes still have to be "burned in" or is it a simple plug and play scenario? Any and all help would be appreciated, since I'm no guitar tech, but I don't have the money to be taking thing to a tech for something as common as tube failure.
@Sethsilva13 Tubes are usually "burned in" during the process where the factory or distributor determines which ones get "matched" together. If you are really worried about it, you can just test them periodically.
Whilst your actually changing the tubes everything should be switched off anyway. The only time you have power is for testing so you shouldn't really have your hands in there!
@LiquorWreckedEmGood You've just basically agreed with me in a smart ass fashion hahahaha. Don't fuck around with the inside of an amp...I have heard of a capacitor yes, I work as an electrical engineer. Congratulations on making yourself look a complete dickhead haha.
I was going to order the exact same tubes for my amp. i have 4, but only two are bad, i found some online at guitar center. can i just switch out 2 or do i HAVE to do all 4. also there are three different options for my model 1-3low 4-7medium 8-10high. it is hand written on my current tubes a 6 which means i have to order the medium. is it ok if they give me any number between 4 and 7 or does it have to be a 6.
Thanks - I had very tight 6l6 tubes and was worried about breaking them and did the circular wiggle and they slipped out!
I had a bad hum and crackle issue: I swapped all the 12ax7s and wasn't them, so I took the 2x 6l6s out, put some contact cleaner on pins, swapped over their positions, re-inserted ( and wiggled!) and hum gone and no crackle!
I am a complete newbie when it comes to working on Amps. I'm trying to learn so I can bias my own. I'm confused though. With my Jet City JCA20, this bias video on YouTube says to be sure to check the plate voltage.
The only thing a bias meter, the kind that we see in this video, seems to tell, is what the current bias setting is. How do you know what to set the bias to without knowing all the other factors? The formula over there is:
hello i want to bias my marshall haze 15 watts.....but i dont know the exact factory settings......i read some review they sAID 19each tube ma and 25ma each tube.........so any one who know the exact MA for biasing this amp......but i want to try a the 25 eACH IS TUBE ...AND I SEE SOME LIST THE SAFE MA OF 6V6 POWER TUBES IS A ROUND 18 AND 30 MA...PLS HELP ME
HI, first thanks for the excellent expanations . I recently got a hybrid tube amp and tried to roll some tubes on it. I used an oscilloscope to mornitor the output. It turns out only one out of five tubes I got can get the perfect signal shape without distortion, and I checked the bias voltage for that "good" tube and found it is way below the specified value for the circuit. Does that mean most of my tubes are actually no good or the circuit design is problematic?
hello i have a marshall haze 15 watts...no stand by mode......so do i need to bias 1st my old power tube so i can see the mili volts then im going to write how many m.v...then put the new tube and bias again and put the mili volts same with the old power tubes?????pls help me and my haze dnt have a stand by mode pls help me
Okay forget my question. But listen to my suggestion ALL OF YOU and get your frickn' amp head tubes, whatever, replaced and biased by a tech with a good five + years experience. Do most musicians have the time and electronic skill sets required to DO-IT-YOURSELF? I don't think so. If you just formed a band like I did or have gigs scheduled to play, GET THAT AMP FIXED AND BACK TO MAKING MUSIC. If we could do it ourselves, there would be no need for techs. They need us, we need them. You'll see.
Two questions, 1.) What happens if I bias it, the tube voltages or whatever don't match up? and 2.) what is the best way to drain the amp of all the excess power before I start work on the amp? Thanks a lot in advance.
Opinions vary on what is too far unbalanced with regards to good tone. Some people intentionally unbalance an amp. With regards to a properly functioning output section you would want each side to be within a 3mA of each other. You can usually drain an amp with a 10K 5w cement resistor and a set of test clips. Amp off strap the resistor across the first filter.
@punkmusicmetal best thing for draining power when you turn it off would be to make sure theres a resistor, say 100-200k about 2w accrossthe first capacitor, most amps already have it but it could be too big, a smaller capacitor means more current draw means faster cap drain, but then thats still drawing current when the amps turned on so it cant really be too big...
@stevoe1000 On this one, it's only for one to match the other. Alot of Mesa Boogie amps are prewired so no adjustments are necessary, and I'm not sure about any other amps.
high voltage means less amperes. it's small electronic, small cables and everything, no fucking way that's gonna kill you unless you plugg the amp in and holds two fingers on the 230v side for some time.
Hey, one thing, I´m buying a Bugera 333XL soon, but I wanted to change the Bugera tubes, or whatever they´re, and put a Mesa/Boogie 6L6 STR-440 tubes, will it work nice? the amp comes with 4 EL34 tubes fitted on it, but I can change them and put 6L6, it allows it,
but i wanted to put the M/B ones tell me if it´s possible please,
that looked pretty easy! are there different plugs for different tube sockets with the bias master so you can bias almost every amp? (sorry if i misspelled some words my english isn't that good)
One thing to note you should never pull the tubes out by the glass as what is shown in the video. They should be pulled out by grasping the base of the tube.
on the way to Bias my HIWATT HI-GAIN 50 head the 3rd preamp tube 12ax7 destroyed, first i listened the head playing very low ant it needed to put the master volume up to 6-7 to listen low output, i thought it was a big damage on the head ,but when i replaced one by one the preamp tubes the 3rd 12ax7 this one in front of the 12at7 phase reverse tube was destroyd ..does someone why this happened ?? i biased at 35 mA
on the way to Bias my HIWATT HI-GAIN 50 head the 3rd preamp tube 12ax7 destroyed, first i listened the head playing very low ant it needed to put the master volume up to 6-7 to listen low output, i thought it was a big damage on the head ,but when i replaced one by one the preamp tubes the 3rd 12ax7 this one in front of the 12at7 phase reverse tube was destroyd ..does someone why this happened ?? i biased the head to 35 mA is it good?
on the way to Bias my HIWATT HI-GAIN 50 head the 3rd preamp tube 12ax7 destroyed, first i listened the head playing very low ant it needed to put the master volume up to 6-7 to listen low output, i thought it was a big damage on the head ,but when i replaced one by one the preamp tubes the 3rd 12ax7 this one in front of the 12at7 phase reverse tube was destroyd ..does someone why this happened ??
I'm surprised at all the biasing videos on here. One thing is missing from most of these videos and it's a warning about the fatal voltages insides of the capacitors in tube amps. These capacitors hold voltages high enough to kill. This stuff should really be approached carefully and with a lot of research.
@l4nky2 Ever heard of Ohm's law? High voltage translates to high current, if the resistance is the same (such as the resistance of your body, when you go poking inside your amp).
@joedell71 You mean there is enough current (amps) in it to kill you. Volts aren't what kill you take stun guns for example that hit you with 50,000 Volts. Not to say if the volts are high enough it could literally cook you because it's so hot.
never understood why tube amps need speakers hooked up to power up amp without causing some problem...with no signal present...does the output load exist....there is no current nor is there any voltage present...hence the secondary of output transformer has same load whenever no signal is present. transistor amps......its a different story. well not really.....discrete amps same applies to. not sure of output ic's. next lesson...who started the theory that caps can be "reformed" by ...
Flyback will kill the Output transformer without a load connected .... the power builds up in the output transformer and needs to go somewhere... if there is no speaker load hooked up it will ARC and BURN through the windings of the transformer
does the line 6 spider valve 112 tube amp need to be rebiased? please help. i just bought one off ebay and i have no clue on how to replace tubes or what to do. i heard there are amps that self rebias?
unless u really know what ur doing in biasing a tube amp, u should go to a technician and have him do it for u. its worth the money. if u make a mistake then...u know :[
what does it mean biasing?? should you always do this? and i have a mesa but it has more ttubes so how would i do all of this? i dont see that little screw you were turning in
Biasing is setting the current running through the power tubes. You should do this every time you change tubes.
Actually, in your case, you'll probably want to take your amp to a tech to get it taken care of. There are lethal voltages in your amp, so if you aren't confident in your abilities, there is too much to lose...
Touching tubes is not a complete no no. Operating tubes at high temp for long periods of time with finger grease on them can be a bad idea, but tubes are not light bulbs.
Touching tubes is not a complete no no. Operating tubes at high temp for long periods of time with finger grease on them can be a bad idea, but tubes are not light bulbs.
true and that is basis law for all components in electronics=transistor,mosfet,tube,of ic...all the same...biasing is bringin the component neded in state of condition for optimal working...called "biasing"....
"if" push-pull" design then you will get buuuuuuuuuu "brom" of tubes will run destorted sound oor will glow orange to dead...if single ended then your tube will run,destorted oor die....cheers
I'm fairly new to tube amps. I live far away from any shop so i like to do things myself. When replacing power amp tubes, it u buy a matched set, quartet in my case, do u still have to bias the amp? thanx.
if the amp you have is made for 6l6's and you buy a quartet of new 6l6's no. but if your amp was made for and had 6l6's and you buy el34's you will need to re bias it.
correct. and if you own a mesa that came with 6l6's and there's an el34 switch on the back (or any amp, not a mesa) you can put el34's in and set the switch to el34's.
kt77's will also work in an amp that has an el34 switch because they run similar.
That's completely wrong. I hope that kid didn't take you at your word. The tubes are matched with each other, not the amp. Makes no difference whatsoever what type of tube it is. I've retubed dozens of 6L6 amps and they always need adjustment, some times a LOT of adjustment.
I have a Fender twin amp an everytime I switch it on, after maybe 15 minutes a high pitch ring starts coming thru, is that a sign that it is'nt biased? or is it a easy fix? any suggestions please.
You need new tubes... i'd guess at preamp... there cheaper anyway so yeah :) its always better to replace all of them at once this could be nice and cheap.... if youve only got a coupple.... if you have loads then it may cost you a great deal...
must this be done every single time you change tubes? even if u change to the same tubes?
Sakeroz 1 week ago
This has been flagged as spam show
"Voltages don't kill. Amperes do."
Right, but Voltage is the potential for current to flow.
So yes, THERE ARE DANGEROUS VOLTAGES PRESENT INSIDE GUITAR AMPS, EVEN WHEN THEY ARE OFF.
xenod1066 1 month ago
HE USED HIS BARE HANDS ON THE TUBES *facepalm*
omfg51 2 months ago
Would it be wise to use this bias master when putting in a completely new set of tubes? If so do the tubes still have to be "burned in" or is it a simple plug and play scenario? Any and all help would be appreciated, since I'm no guitar tech, but I don't have the money to be taking thing to a tech for something as common as tube failure.
Sethsilva13 2 months ago
@Sethsilva13 Tubes are usually "burned in" during the process where the factory or distributor determines which ones get "matched" together. If you are really worried about it, you can just test them periodically.
QAeternus 1 month ago
Whilst your actually changing the tubes everything should be switched off anyway. The only time you have power is for testing so you shouldn't really have your hands in there!
Myuralz 2 months ago
@Myuralz
oh, everything should be "switched off" huh?
HAVE YOU EVER HEARD OF A C-A-P-A-C-I-T-O-R?
ONE OF THEM FROM A HIGH-POWER AMP DISCHARGING INTO YOUR BODY CAN KILL YOU, SWITCHED OFF OR NOT.
anybody reading this listen to me. you are a FOOL to fuck around with the inside of a high-power amp.
you won't get a do-over. it will just be all over.
LiquorWreckedEmGood 2 months ago
@LiquorWreckedEmGood You've just basically agreed with me in a smart ass fashion hahahaha. Don't fuck around with the inside of an amp...I have heard of a capacitor yes, I work as an electrical engineer. Congratulations on making yourself look a complete dickhead haha.
Myuralz 2 months ago
@Myuralz
you work as an electrical engineer?
wow.
what model electric train set do you have?
LiquorWreckedEmGood 2 months ago 2
I was going to order the exact same tubes for my amp. i have 4, but only two are bad, i found some online at guitar center. can i just switch out 2 or do i HAVE to do all 4. also there are three different options for my model 1-3low 4-7medium 8-10high. it is hand written on my current tubes a 6 which means i have to order the medium. is it ok if they give me any number between 4 and 7 or does it have to be a 6.
kmcgill794 3 months ago
This has been flagged as spam show
set to mA ??? wtf it has to be set to mV ! ! ! bias is voltage not amps !!
CosmicSPC 4 months ago
hi can u pls help me can i use this tad bias master to read a mV??????????
ichi612 5 months ago
Comment removed
ichi612 5 months ago
Thanks - I had very tight 6l6 tubes and was worried about breaking them and did the circular wiggle and they slipped out!
I had a bad hum and crackle issue: I swapped all the 12ax7s and wasn't them, so I took the 2x 6l6s out, put some contact cleaner on pins, swapped over their positions, re-inserted ( and wiggled!) and hum gone and no crackle!
snotmale 5 months ago
how important is biasing??
would it make a big difference if i just changed my tubes without biasing?
Giggity230 6 months ago
@Giggity230 It usually just effects the performance of the amp. It doesn't damage anything, just doesn't sound as good or get as loud.
jawsrock1 4 months ago
WOW, this seems like a royal pain in the ass. I'll stick with my Randall T2 \m/
TheNohcim 7 months ago
Comment removed
donnyab 7 months ago
This has been flagged as spam show
WOW!
Google Compu-bias. Better yet. Go to their website. Awesome product. Great reviews.
Biggerbyte 10 months ago
Hi guys...
I am a complete newbie when it comes to working on Amps. I'm trying to learn so I can bias my own. I'm confused though. With my Jet City JCA20, this bias video on YouTube says to be sure to check the plate voltage.
The only thing a bias meter, the kind that we see in this video, seems to tell, is what the current bias setting is. How do you know what to set the bias to without knowing all the other factors? The formula over there is:
Tube voltage x factor / plate voltage.
Biggerbyte 10 months ago
hello i want to bias my marshall haze 15 watts.....but i dont know the exact factory settings......i read some review they sAID 19each tube ma and 25ma each tube.........so any one who know the exact MA for biasing this amp......but i want to try a the 25 eACH IS TUBE ...AND I SEE SOME LIST THE SAFE MA OF 6V6 POWER TUBES IS A ROUND 18 AND 30 MA...PLS HELP ME
ichi612 1 year ago
HI, first thanks for the excellent expanations . I recently got a hybrid tube amp and tried to roll some tubes on it. I used an oscilloscope to mornitor the output. It turns out only one out of five tubes I got can get the perfect signal shape without distortion, and I checked the bias voltage for that "good" tube and found it is way below the specified value for the circuit. Does that mean most of my tubes are actually no good or the circuit design is problematic?
LK
lai2ke4 1 year ago
hello i have a marshall haze 15 watts...no stand by mode......so do i need to bias 1st my old power tube so i can see the mili volts then im going to write how many m.v...then put the new tube and bias again and put the mili volts same with the old power tubes?????pls help me and my haze dnt have a stand by mode pls help me
ichi612 1 year ago
what is that meter called again?
alvarez1284 1 year ago
how do you know which tube you are biasing? or the bias is for all the tubes at the same time?
Lubial 1 year ago
do you need to bias your amp?
KyuubiXX243H98 1 year ago
Okay forget my question. But listen to my suggestion ALL OF YOU and get your frickn' amp head tubes, whatever, replaced and biased by a tech with a good five + years experience. Do most musicians have the time and electronic skill sets required to DO-IT-YOURSELF? I don't think so. If you just formed a band like I did or have gigs scheduled to play, GET THAT AMP FIXED AND BACK TO MAKING MUSIC. If we could do it ourselves, there would be no need for techs. They need us, we need them. You'll see.
neutroniumamp 1 year ago
Two questions, 1.) What happens if I bias it, the tube voltages or whatever don't match up? and 2.) what is the best way to drain the amp of all the excess power before I start work on the amp? Thanks a lot in advance.
punkmusicmetal 1 year ago
@punkmusicmetal
Opinions vary on what is too far unbalanced with regards to good tone. Some people intentionally unbalance an amp. With regards to a properly functioning output section you would want each side to be within a 3mA of each other. You can usually drain an amp with a 10K 5w cement resistor and a set of test clips. Amp off strap the resistor across the first filter.
imojotv 1 year ago
@punkmusicmetal best thing for draining power when you turn it off would be to make sure theres a resistor, say 100-200k about 2w accrossthe first capacitor, most amps already have it but it could be too big, a smaller capacitor means more current draw means faster cap drain, but then thats still drawing current when the amps turned on so it cant really be too big...
razorrick1293 1 year ago
Comment removed
neutroniumamp 1 year ago
Do all the tubes have their own knob for setting the bias...or do they use the same one
stevoe1000 1 year ago
@stevoe1000
Same one I think
lostlemming 1 year ago
@stevoe1000 On this one, it's only for one to match the other. Alot of Mesa Boogie amps are prewired so no adjustments are necessary, and I'm not sure about any other amps.
jawsrock1 4 months ago
high voltage means less amperes. it's small electronic, small cables and everything, no fucking way that's gonna kill you unless you plugg the amp in and holds two fingers on the 230v side for some time.
xxRockst4r 1 year ago
What is it with all the supposed techs who use their BARE HANDS to touch the tubes
this is a big mistake! You should always clean the tubes with alcohol and wear gloves!!!
Axeman2006 1 year ago
Hey, one thing, I´m buying a Bugera 333XL soon, but I wanted to change the Bugera tubes, or whatever they´re, and put a Mesa/Boogie 6L6 STR-440 tubes, will it work nice? the amp comes with 4 EL34 tubes fitted on it, but I can change them and put 6L6, it allows it,
but i wanted to put the M/B ones tell me if it´s possible please,
thank you a lot :D
anwerpelut 1 year ago
@anwerpelut
do a youtube search on dingle1 and then ask him about it he has plenty of info on bugera watch his vids as well
666Napalm666Death666 1 year ago
yeah or cause a fire, and those grabbling the glass and rocking the tubes NOT!
I had a Harmon and Kordan am fm stereo tube system, It was beautiful sounding .
Ex wife got angry and smashed the tubes. it was going to cost me 1 grand to repair it.
ShutterbugW 1 year ago
that looked pretty easy! are there different plugs for different tube sockets with the bias master so you can bias almost every amp? (sorry if i misspelled some words my english isn't that good)
jks2 1 year ago
dumb question: only one of my power tubes is glowing. is the other one broken? any help would be great :)
kickit301 1 year ago
please i need a big favor, can you tell me were i get the bias master table sheet
panter7722 1 year ago
One thing to note you should never pull the tubes out by the glass as what is shown in the video. They should be pulled out by grasping the base of the tube.
1dennydog 1 year ago
on the way to Bias my HIWATT HI-GAIN 50 head the 3rd preamp tube 12ax7 destroyed, first i listened the head playing very low ant it needed to put the master volume up to 6-7 to listen low output, i thought it was a big damage on the head ,but when i replaced one by one the preamp tubes the 3rd 12ax7 this one in front of the 12at7 phase reverse tube was destroyd ..does someone why this happened ?? i biased at 35 mA
carpediemgr 1 year ago
on the way to Bias my HIWATT HI-GAIN 50 head the 3rd preamp tube 12ax7 destroyed, first i listened the head playing very low ant it needed to put the master volume up to 6-7 to listen low output, i thought it was a big damage on the head ,but when i replaced one by one the preamp tubes the 3rd 12ax7 this one in front of the 12at7 phase reverse tube was destroyd ..does someone why this happened ?? i biased the head to 35 mA is it good?
carpediemgr 1 year ago
on the way to Bias my HIWATT HI-GAIN 50 head the 3rd preamp tube 12ax7 destroyed, first i listened the head playing very low ant it needed to put the master volume up to 6-7 to listen low output, i thought it was a big damage on the head ,but when i replaced one by one the preamp tubes the 3rd 12ax7 this one in front of the 12at7 phase reverse tube was destroyd ..does someone why this happened ??
carpediemgr 1 year ago
The oils from your fingers will fuck those tubes!!!! You used a glove taking out the bad ones but didnt use a glove installing the new ones!!!!
aheartmanagerie 2 years ago 2
omg, stop touching the tubes. Your wearing the tubes just by touching them with your bear hands.
ALSO USE GLOVE/TOWEL TO TOUCH THE NEW TUBES OR THEY WON"T LAST AS LONG.
Pianoblacks 2 years ago
I'm surprised at all the biasing videos on here. One thing is missing from most of these videos and it's a warning about the fatal voltages insides of the capacitors in tube amps. These capacitors hold voltages high enough to kill. This stuff should really be approached carefully and with a lot of research.
joedell71 2 years ago 34
ohhh I am scared. Screw that I will do it my self. Just need to know what you are doing and thats what this video is teaching.
swollenpickle09 2 years ago
@joedell71
Voltages don't kill. Amperes do.
l4nky2 1 year ago 30
@l4nky2 You mean the wattage?
KissMeImPunk 1 year ago
Comment removed
Moh1Z 1 year ago
@l4nky2 Ever heard of Ohm's law? High voltage translates to high current, if the resistance is the same (such as the resistance of your body, when you go poking inside your amp).
Moh1Z 1 year ago
@l4nky2
either way, hes right, tube amps are dangerous, you have to let it discharge for a while after unplugging it
dumapies 1 year ago
@l4nky2 actually its the combination of volts and amps if you have a ton of volts and not as many amps you can still fry someone.
Ynehc 10 months ago
@Ynehc
Yes the combination. But a high voltage and really amps will not kill you. 1 million volts and 1mA will not kill you. But 230volts and 80mA will.
l4nky2 10 months ago
@l4nky2
yeah but you need dem volts to draw dem amps
donnyab 7 months ago
@joedell71 You mean there is enough current (amps) in it to kill you. Volts aren't what kill you take stun guns for example that hit you with 50,000 Volts. Not to say if the volts are high enough it could literally cook you because it's so hot.
Ponchibego 1 year ago
@joedell71 Better yet for those of us who are players and amateur technicians they shouldn't be approached at all.
MrJackanthony 1 year ago
never understood why tube amps need speakers hooked up to power up amp without causing some problem...with no signal present...does the output load exist....there is no current nor is there any voltage present...hence the secondary of output transformer has same load whenever no signal is present. transistor amps......its a different story. well not really.....discrete amps same applies to. not sure of output ic's. next lesson...who started the theory that caps can be "reformed" by ...
earthhydro 2 years ago
Flyback will kill the Output transformer without a load connected .... the power builds up in the output transformer and needs to go somewhere... if there is no speaker load hooked up it will ARC and BURN through the windings of the transformer
patfurlan 2 years ago
does the line 6 spider valve 112 tube amp need to be rebiased? please help. i just bought one off ebay and i have no clue on how to replace tubes or what to do. i heard there are amps that self rebias?
TheeDevilWearsPrada 2 years ago
unless u really know what ur doing in biasing a tube amp, u should go to a technician and have him do it for u. its worth the money. if u make a mistake then...u know :[
TheeDevilWearsPrada 2 years ago 2
wow, I thought I was gonna be stuck with the expert village explanation. thank you oh thank you
pmz1981 2 years ago 2
what does it mean biasing?? should you always do this? and i have a mesa but it has more ttubes so how would i do all of this? i dont see that little screw you were turning in
Blink182PunkRocker 2 years ago
Biasing is setting the current running through the power tubes. You should do this every time you change tubes.
Actually, in your case, you'll probably want to take your amp to a tech to get it taken care of. There are lethal voltages in your amp, so if you aren't confident in your abilities, there is too much to lose...
blondiebabae 2 years ago
ok will do thanks very much
Blink182PunkRocker 2 years ago
This has been flagged as spam show
Touching tubes is not a complete no no. Operating tubes at high temp for long periods of time with finger grease on them can be a bad idea, but tubes are not light bulbs.
iamthepinkcupcake1 2 years ago
Whoa is he touching the tubes? i always tought that way a huge no no.
mattthom1986 2 years ago
Touching tubes is not a complete no no. Operating tubes at high temp for long periods of time with finger grease on them can be a bad idea, but tubes are not light bulbs.
iamthepinkcupcake1 2 years ago
You're right, just makes them wear out faster. Maybe he wants his customers to keep bringing him business?
dannylerch 2 years ago
what would happen if the amp isn't well biassed?
gungoe 2 years ago
you'll get damaged tubes and damaged output bias. don't even think about playing without a proper bias
Chipstastegood 2 years ago 2
thanks :-). I'd rather have someone tell me than find out myslef :-).
gungoe 2 years ago
true and that is basis law for all components in electronics=transistor,mosfet,tube,of ic...all the same...biasing is bringin the component neded in state of condition for optimal working...called "biasing"....
jigibao 2 years ago
"if" push-pull" design then you will get buuuuuuuuuu "brom" of tubes will run destorted sound oor will glow orange to dead...if single ended then your tube will run,destorted oor die....cheers
jigibao 2 years ago
shouldn't the tubes light up
JimmyPage968 2 years ago
"give them about half a minute"
id give them about 3 full minutes to warm up just to be sure they're warmed up 100 percent.
snapascrew 3 years ago
40 seconds is long enough
warriorxtman 2 years ago
I'm fairly new to tube amps. I live far away from any shop so i like to do things myself. When replacing power amp tubes, it u buy a matched set, quartet in my case, do u still have to bias the amp? thanx.
ahub2010 3 years ago
if the amp you have is made for 6l6's and you buy a quartet of new 6l6's no. but if your amp was made for and had 6l6's and you buy el34's you will need to re bias it.
snapascrew 3 years ago
so as long as you keep the valve type the same all the time, you wouldn't need to rebias?
LukeMadSkillz1984 2 years ago
correct. and if you own a mesa that came with 6l6's and there's an el34 switch on the back (or any amp, not a mesa) you can put el34's in and set the switch to el34's.
kt77's will also work in an amp that has an el34 switch because they run similar.
snapascrew 2 years ago
Nice one, i mean this guy must have kept them the same as he didn't have to rebias them too much.
Thanks man :D
LukeMadSkillz1984 2 years ago
That's completely wrong. I hope that kid didn't take you at your word. The tubes are matched with each other, not the amp. Makes no difference whatsoever what type of tube it is. I've retubed dozens of 6L6 amps and they always need adjustment, some times a LOT of adjustment.
br549sample 2 years ago
From Andy at Mojo:
Probably one of the input gain stages is micro phonic - or the reverb
return. If your amp has had output tubes replaced without proper
biasing no doubt it should be checked. However it sounds likely that
you problem could be solved with preamp tubes.
mojomusicalsupply 3 years ago
Does anyone know if you need to bias a valve amp with 2 power valves, ive heard it only needs to be done with 4 valve amps like this. I have a TSL 60
donjonluc 2 years ago
it depends on the amp. check with the manufacturer, tech, or google. but, yes, even amps with 2 power tubes may need to be biased.
bgkyt1 2 years ago
I have a Fender twin amp an everytime I switch it on, after maybe 15 minutes a high pitch ring starts coming thru, is that a sign that it is'nt biased? or is it a easy fix? any suggestions please.
wellingtonian 3 years ago
Thats the amp calling you ;)
You need new tubes... i'd guess at preamp... there cheaper anyway so yeah :) its always better to replace all of them at once this could be nice and cheap.... if youve only got a coupple.... if you have loads then it may cost you a great deal...
If your unsure always take it to a music shop....
joeab09 3 years ago