I managed to switch my tubes with this video and set the bias myself. Thanks for being very thorough and giving safety warnings, which I think a lot of videos out here lack. It was actually very easy to do. My amp sounds like new again 👌🏾😄
Thanks for the knowledge, this makes it much clearer for me. I always thought that if I didn't set the bias pot to the "absolutely correct" spot (that could only be derived at through an engineering degree) I would blow the amp up entirely. Thusly, I would until recently only buy solid state amps because I didn't want to get someone else to bias my tubes. Now I am learning to do it myself, and this vid provides a nice piece of the puzzle.
I wanted to drop by and say "thank you" for this informative and easy-to-follow tutorial. This saved me some time on restoring my amp, and I learned something new. Thanks again! :)
That bias point is total cathode current.. A little screen current (5%) is included in that number.. So a number like 70mV at the test point is ~ 66mA plate dissipation for two tubes or 33mA for each tube. The B+ voltage with a cold bias (60mV) is 431V. A little OT loss and you have 429V plate. Multiply Volt with mA and you get the plate dissipation at idle. This is 14.16W or 47.2% of max plate dissipation for a 30W 6L6GC tube.. That is too cold,, you want to be above 50% to avoid crossover distortion. Between 50% and 60% is a good number for the hot rod.. Going higher and you will loose a lot of headroom and spank in the bass.. Lets run the bias to 80mV at the test point.. deduct 5% as screen current = 76mA of total plate dissipation.. Multiply with you plate voltage which should be a little lower as you are drawing more current at idle.. So lets say it has dropped to 424V (80mV) from the previous 429V (60mV). Now you get an idle plate dissipation of 16.11W which is 54% of max dissipation.. That should be a good bias... With the Hot rod deville you want to have a lower mV number at the bias test point as the voltages are higher in that amp.. With 60mV at the test point and correct wall voltages and a pair of 30W 6L6GC tubes you should get around ~484V on the plates.. Doing the same math you get that 60mV is 57mA plate dissipation (I assume 5% screen curent). Plate dissipation is (0,0285A x 484V) = 13.8W dissipation (or if screen current is even lower) around 14W which is 46.6% of max dissipation.. Again a little too cold.. Bring it up to 55% if you have a strong 30W 6L6GC tube..
Kennis, want to say thank you for sharing your knowledge on this. I just bought a FHD and it was so flat and dead sounding. Bought a set of matched JJ's and with your help got them biased to were I am so happy now! What a difference :)
Good stuff Kennis. I'm acquiring a USA HRD that most likely needs to have a total tube overhaul, and I'm just glad biasing can be done relative quickly and easily. Having no prior experience because all my other tube amps either have fixed bias (Mesa Boogie ROV25) or are self-biasing (THD Bivalve 30), so this video is super useful!
Thank you for the education on biasing the power tubes. I have a Hot Rod Deluxe and I'm replacing all the garbage GT's with JJ's (both preamp and power) but never knew anything how to check the bias. Looks simple enough, thanks for the video and safety tip!
On an interview the tec guy for Angus ACDC said he runs the valves hot.bias high a bit on the edge...which explains Angus,s eq only on 3 bass treble & mids...great info Thanks...you have saved me a few quid...and amp down time.
Thanks for this... I recently purchased a new Fender Blues Deluxe to replace a 15 year old model that quit working. The new one breaks up/distorts at 1-2 where as the old one would begin to break up at 4-5. I need the amp to play clean (jazz/traditional blues) with my hollow body guitars. This was a good video, a starting point to get the new amp set up to match the old one.
Ahh man THANK YOU!! Have been wanting to switch from SS to tube but this whole bias thing kept me from doing so. Finally got myself a HRD iii and could not believe this is all there was to it!! Thank goodness I have the potentiometer!! Thank you!!!!
You put 6V6 tubes in to replace 6L6s? I hope you get 5 minutes out of them. And I don’t really understand why anyone would want to do that in the first place?
What your adjusting is the bias voltage. It's best to bias it by miliamps, to do that you have to go in series with the B+ to the tubes and use a different setting on your meter. By biasing to a set voltage your current draw will vary from tube to tube. When u find a brand of tube u like u want them to run the same after a change and even tubes of the same brand will vary on current draw because of differences in internal resistance. So by ohm's law the same bias voltage with a different internal resistance will yield different current draw. Not saying what your doing is wrong just what the tube is drawing is the important factor.
+Susannah Tomlin : the voltage reading is fine as it is typically measuring volt-drop across a 1 ohm resistor, either within the bias probe base or in this case, on a purpose designed measuring point on the PCB. In this way, it obviates the need to put your multi-meter in series (always a hassle) with THE mV range relating directly to the mA range.
"What does that even mean" ... a question which should be addressed pointedly at all irritating muso/tech know-it-alls. A handy tutorial as well. Thanks.
Apart from most of this being incredibly 'Average Joe' standard, I did cry a little when he switched the power and standby switch immediately one after another, then stated to let it warm up. Let it warm up with the the power on and the standby off.
That works out real well if one has an adjustment and test point. I haven't looked in my Carvin so I can't say how it's set up, everything sounds fine but it is a older amp so I expect to be servicing it soon, my Bugera is suppose to self baising.
thanks Kennis. I've been playing guitar for years but just take the amp for granted. recently I bought a Blues Jr to run in stereo with my HR DV because i felt things were "lacking". great combo though... Changing out my stock power tubes for the first time as well so I'll look to see if my HR DV 212 has the bias option. Sound like I may have some fun. great info, cheers.
Nice video thanks! Will try it. Now my question: if it's about how it sounds why use the multimeter at all? Why not just plug the guitar and tweak the Bias by ear just like you would any other knob on the amp?
Thank you so much! I have Blues Deluxe Reissue I remember it looking the same internally. Any suggestions on cost effective power attenuators? I live in a small apartment...
I've got a 1984 Laney AOR 100 h with new Mullard EL34s and it sounds a bit flat and cold power Trans died ... and had to send it to Atlanta for repair ... my Groove tubes gone and the mullards in their place ... imagine my disappointment as it's been a year since it was "fixed" and I didn't look and bought a spark 40 to jam on ...I've ordered a set of GT #8 matched Quad EL34Ss that have been sitting in a closet in California since the 90s coming my way ... Hopefully they'll sound better and bias a smidge hotter for that sweet sound I miss so much .... Great vid BTW gonna shortcut like you did and bypass all the crazy math 470 vdc x .0632 ma is about 29 wats per tube X4 voltage drop is 1. 18ish per pair at the anode connection... wish me luck !!! 😂
Thanks for all great info. I’d like to replace the original power tube from my Vox AC4C1 for a Mullard and,Honestly, I’d prefer not to bias it if I don’t need it.once my amp has only one power tube, do I need to bias it ?If i don’t bias it (just replace) how can I check if it is working properly ? Which are the evidence of bad functioning (that it should boas-noites it) ?Thanks !!
Can a Fender Deluxe Reverb be self biased as well or should i take it to tech? Thank you for taking the time to to make these videos. They're really great!
Thanks for the awesome video. Nice having amps with only a pair of power tubes and three pre amp tubes. Saves a lot of $$$ come tube time ahem Mesa Boogie Mark Series.
If you were wondering about the "one hand rule" the reason is this. If you have only one hand in your amp and get shocked, you have a chance of surviving, as the current will hopefully bypass your heart on it's way to the ground. Two hands in the amp and the current will likely go to ground via your heart resulting in death. These things are EXTREMELY DANGEROUS, even if you know what you're doing.
Hi Kennis, great video! .. i have the fender hot rod deluxe western version are they the same as the normal hot rod deluxes? I'm going to replace the valves myself but confused on the term "self-biasing" does that mean you can put the power tubes in and they bias automatically ? or do you still have to bias them? ...do you also ever need to change the 3 little valves? your videos are really helpful thanks.
Great video Kennis! Well done and explained. Several years ago, I biased my Fender Hot Rod Deville 212 while swapping from the 2x 6L6s to 2x KT66s and landed around 80. The amp sounded absolutely great for years but I've learned recently that going "too hot" (over 75) can have the negative effect of shortening your tube's life. Recently, I've experienced some unexpected volume and headroom drops at odd times while jamming, and just the other night, during a gig, it flat out volume dropped and stayed low all night. I had to crank it to 6-7 to have any useful sound (which if you know the 2x12, is a crazy high volume for a small room). I have a question for you: are unexplained volume drops a symptom of dying/tired tubes? (NOTE - I've removed other variables such as my pedal board etc... and have isolated it to my amp). Forgive my ignorance - this has been my only tube amp in 20 years so I lack the experience with other tube amps and troubleshooting.
Thank you for this! I don't wanna take my tube amp to the expert because they're hella heavy for me to carry around 😂 plus it's fun doing this, DIY at home
Just a few clarifications .. Unless your amp is horribly defective (and blowing fuses) the circuits ARE already biased .. What you're doing is adjusting, measuring and/or optimizing the existing bias voltage/power dissipation. Secondly, one must be careful with that term "self bias". "Self Bias" DOES NOT means that you can adjust the bias yourself. Self bias is also known as Cathode Bias. It's referring to the the tube creating it's own bias by virtue of the cathode being lifted from ground via a cathode bias resistor. Outside of replacing the bias resistor with one of a different value, you cannot adjust this bias scheme. The other common method of biasing the output tubes is called "Fixed Bias". This method frequently utilizes an internal potentiometer that allows one to adjust the bias voltage to the output tube(s). This is called fixed bias.
Hello Kennis. Thanks for your very well done informative videos that you do I just got a Bugera v22 and it's got an RCA jack with a biasing potentiometer feature in the back that's accessible without having to open the amp up Upon reading forums and watching a specific how to video on biasing the V22 I have to say that I'm now more lost than I was before getting all of this FYI with the exception of your explanation here I am just wondering if you might be able to simplify for me whether or not the feature on my amp is an effective way to bias it and if there's a general setting bias number for my specific amp or tubes (el84s)once I do decide to upgrade my power tubes Again I really enjoy and appreciate all you do here on youtube so naturally superior as a teacher! Better yet "a mentor"
One thing to keep in mind is the higher the current reading the harder the tubes are working. The harder the tubes are working the shorter the life of the tube. The lower the current setting the easier it is on the power tubes and the longer they will last.
Thanks Kinnis! I'm wondering if the 70mV setting is across the board - or for 6L6s - or for the Deluxe. I've got a Hot Rod Deville 212 and wonder if the 70mV would be the same for my amp? Also, my Fluke 75 has a DC 300mV setting, but not a 200mV. I'm thinking it would still put me in the right range. Thanks for the video and advice.
i really like your tutorials,you're easy to listen to and learn,have you ever looked into an orange amp? do you think it's gonna be similar to bias like you did on vid? thanks
Very informative video. Thanks man. If you have 4 power tubes, when checking the bias test point would the minimum be 120 instead of 60? Or is 60 just for this specific amp?
I have a Fender Deville 410, practically identical to your amp in the video. I went to Radio Shack and bought a milli volt reader w digital display but never got a reading anywhere similar to your video. Can you tell me what the exact model millivolt reader did you use? I would purchase one of those.
Dear Kennis, Thank you for the great video. I own a Fender Hot Rod Deluxe III and followed your video closely. Everything is set correctly with the multimeter (200m DCV) but I only get 30mv from the bias testing point. When I turn the wheel it goes from about 10mv to 55mv. Do you know what the problem here could be? I'm using an almost brand new pair of JJ 6L6s that replaced the original Groove Tubes.
Excellent guide, thank you! I have exactly the same amp and when turning on the standby switch I hear some cracks for the first few minutes and then they disappear. Does this has anything to do with the power tubes?
In short, it can. There's some leftover products from manufacturing that can cause some noise. That said, if it persists, try tube shields especially in your preamp stage and check for environmental sources of electromagnetic energy. I would expect properly biased tubes to quit having break-in issues after you've biased them then flogged them for a good days' work or so. How long that takes is dependent on how hot they are biased and manufacturing and how much you play. Some amps just crackle from worn pots and microphonics. Tl;dr: Yes, but if it persists look elsewhere for the crackle.
Could you assume you have a bad set of tubes if you are getting a low reading when biasing? I got a brand new set of JJ 6L6gc's for my Hot Rod. Attempted to bias after replacing them. Set to 200m, I was reading between 33.0 at the lowest and 68.0 at max, after warming up the tubes for 15 minutes. I put in the old Stovek tubes I was replacing, read between 59.0 and 114.0.
Thanks, very interesting. I have a laney vc-30 and the clean channel is very quiet compared to the drive channel. This happened after a guy revalued it. Would I have a bad valve in the preamp?
I have a Fender quad reverb, where could I get info on how to replace the tubes and set the bias ? Is it also possible to fix the vibrato effekt on my own ?
Thanks for the Video. Why you need to bias your tube Amp: Resistors, capacitors and tube values deteriorate with time. It changes the amp output tube characteristics in terms of current, voltage drop and power dissipation. Bias is really realign these values to tube specs for optimum performance. I highly recommend you check out Uncle Dougs bias video.
I'm getting ready to replace all of my tubes on a Fender Blues Deluxe Reissue. (2-5881s & 3-12AX7A's) Do I need to bias the amp? Some tubes says matched...please advise...confused! Thanks
Very helpful, thank you! Could you provide the necessary info for a Supersonic 22 combo? I will be using Electro Harmonix 6V6's and want it a little on the clean side. Thanks!
Thank you , that was really educational and concise ,, it helped .
7 лет назад
Thanks for great and informative video. I have a question. Could I replace 6L6 tubes with EL84? My amp is Fender Hot Rod Deluxe II and I would like to sound more like Vox AC15. So I think about EL84. If you have any other advices, I really appreciate it. Thanks!
Hey Kennis great video and really informative , I have a question, I use a fender SuperSonic 22 and just replaced my power tubes with jj 6v6s (2ea) and my preamps are jj ecc81( 2ea), and ecc83s (3ea.) would you know the bias value for this amp? I've been trying to get a hold of fender with no response's yet. Thanks
Thanks for the great tutorial! I'm wondering about lowering power? I have a Fender Concert Reverb with a 1/4 power switch. Is there any way to get this thing to 15 or 20 watts safely? I've heard of running on input 2 as well as 6V6 tubes? Different pre-amp tubes? Thoughts? Experience?
I managed to switch my tubes with this video and set the bias myself. Thanks for being very thorough and giving safety warnings, which I think a lot of videos out here lack. It was actually very easy to do. My amp sounds like new again 👌🏾😄
Thanks for the knowledge, this makes it much clearer for me. I always thought that if I didn't set the bias pot to the "absolutely correct" spot (that could only be derived at through an engineering degree) I would blow the amp up entirely. Thusly, I would until recently only buy solid state amps because I didn't want to get someone else to bias my tubes. Now I am learning to do it myself, and this vid provides a nice piece of the puzzle.
EXCELLENT!!! So glad you did this tutorial. I didn’t want to take my HRD to a tech for such a simple maintenance task. You shed light on the mystery.
I wanted to drop by and say "thank you" for this informative and easy-to-follow tutorial. This saved me some time on restoring my amp, and I learned something new. Thanks again! :)
“I’ve got one hand in my pocket, and the other is biasing.”
- Alanis Morrisette
Ive got one hand in my pocket and the other one is jerking my girlfriend off
Great explanation, thanks. I followed your suggestion to set it at 71 and the result was so good for me.
That bias point is total cathode current.. A little screen current (5%) is included in that number..
So a number like 70mV at the test point is ~ 66mA plate dissipation for two tubes or 33mA for each tube. The B+ voltage with a cold bias (60mV) is 431V. A little OT loss and you have 429V plate. Multiply Volt with mA and you get the plate dissipation at idle. This is 14.16W or 47.2% of max plate dissipation for a 30W 6L6GC tube.. That is too cold,, you want to be above 50% to avoid crossover distortion. Between 50% and 60% is a good number for the hot rod.. Going higher and you will loose a lot of headroom and spank in the bass..
Lets run the bias to 80mV at the test point..
deduct 5% as screen current = 76mA of total plate dissipation.. Multiply with you plate voltage which should be a little lower as you are drawing more current at idle.. So lets say it has dropped to 424V (80mV) from the previous 429V (60mV).
Now you get an idle plate dissipation of 16.11W which is 54% of max dissipation.. That should be a good bias...
With the Hot rod deville you want to have a lower mV number at the bias test point as the voltages are higher in that amp..
With 60mV at the test point and correct wall voltages and a pair of 30W 6L6GC tubes you should get around ~484V on the plates..
Doing the same math you get that 60mV is 57mA plate dissipation (I assume 5% screen curent). Plate dissipation is (0,0285A x 484V) = 13.8W dissipation (or if screen current is even lower) around 14W which is 46.6% of max dissipation.. Again a little too cold.. Bring it up to 55% if you have a strong 30W 6L6GC tube..
Kennis, want to say thank you for sharing your knowledge on this. I just bought a FHD and it was so flat and dead sounding. Bought a set of matched JJ's and with your help got them biased to were I am so happy now! What a difference :)
Good stuff Kennis. I'm acquiring a USA HRD that most likely needs to have a total tube overhaul, and I'm just glad biasing can be done relative quickly and easily. Having no prior experience because all my other tube amps either have fixed bias (Mesa Boogie ROV25) or are self-biasing (THD Bivalve 30), so this video is super useful!
Thank you for the education on biasing the power tubes. I have a Hot Rod Deluxe and I'm replacing all the garbage GT's with JJ's (both preamp and power) but never knew anything how to check the bias. Looks simple enough, thanks for the video and safety tip!
Great video. Fender sets this amp at 60mV. Raising it to 70mV gives a better sounding gain. Higher bias shortens valve life.
On an interview the tec guy for Angus ACDC said he runs the valves hot.bias high a bit on the edge...which explains Angus,s eq only on 3 bass treble & mids...great info
Thanks...you have saved me a few quid...and amp down time.
Thanks for this... I recently purchased a new Fender Blues Deluxe to replace a 15 year old model that quit working. The new one breaks up/distorts at 1-2 where as the old one would begin to break up at 4-5. I need the amp to play clean (jazz/traditional blues) with my hollow body guitars. This was a good video, a starting point to get the new amp set up to match the old one.
Thank you for this! Your short video was more helpful than anything I’ve read in the forums.
Ahh man THANK YOU!! Have been wanting to switch from SS to tube but this whole bias thing kept me from doing so. Finally got myself a HRD iii and could not believe this is all there was to it!! Thank goodness I have the potentiometer!! Thank you!!!!
Thank you for posting this video. This really helped me feel more comfortable changing out the power tubes from 6l6 to 6v6 for my Hot Rod Deluxe!
Not recommended.
www.tdpri.com/threads/6v6-and-6l6-interchangeable.52593/
You put 6V6 tubes in to replace 6L6s? I hope you get 5 minutes out of them. And I don’t really understand why anyone would want to do that in the first place?
You have explained so far better then anyone else.
What your adjusting is the bias voltage. It's best to bias it by miliamps, to do that you have to go in series with the B+ to the tubes and use a different setting on your meter. By biasing to a set voltage your current draw will vary from tube to tube. When u find a brand of tube u like u want them to run the same after a change and even tubes of the same brand will vary on current draw because of differences in internal resistance. So by ohm's law the same bias voltage with a different internal resistance will yield different current draw. Not saying what your doing is wrong just what the tube is drawing is the important factor.
+Susannah Tomlin : the voltage reading is fine as it is typically measuring volt-drop across a 1 ohm resistor, either within the bias probe base or in this case, on a purpose designed measuring point on the PCB. In this way, it obviates the need to put your multi-meter in series (always a hassle) with THE mV range relating directly to the mA range.
Thank you for a very instructive video. Changed tubes in my Fender HRDx and set bias to 71....it's like a new amp....
Straight to the point and brought across very well, no Guru secrets like I always thought were involved, Thanx Kennis.
Very easy to follow. Thank you! Never BIASed my Hot Rod Deluxe in 4 yrs I own it. The meter was showing 55. Damn!!
Two hands will direct a lethal dose of current thru your heart and stop it. You are done for.
Great video for someone who knew nothing about biasing tubes! Thanks!
This video is a little biased.
UNDERRATED COMMENT
Quite!!
That's pretty funny 😂
😂 Dad joke of the day !!
lol
If you replace the old tubes with the exact same ones, do they still need to be biased? Thanks, Garry.
"What does that even mean" ... a question which should be addressed pointedly at all irritating muso/tech know-it-alls. A handy tutorial as well. Thanks.
Remember driving thru Mississippi in the 70's. Bias was set high there.
Great vid, thanks.
thanks for "the hand in the pocket rule", as a self taught electronics experimental person, never heard that one before
Great video, really cleared up my confusion with biasing. Thank you.
No, actually it's a crappy video, full of incorrect information.
Most excellent! I wish all how-to videos were as well done and to-the-point as this.
Very explicite, helpful and friendly help sir! I'm changing my tubes for the first time today (Traynor YCS100).
Apart from most of this being incredibly 'Average Joe' standard, I did cry a little when he switched the power and standby switch immediately one after another, then stated to let it warm up. Let it warm up with the the power on and the standby off.
super helpful and straight forward video! looking forward to getting amongst the tubes in my deluxe and having a go
I'm gonna bias my Fender HotRod Deville 212 tonight, thanks to this movie!!
That works out real well if one has an adjustment and test point. I haven't looked in my Carvin so I can't say how it's set up, everything sounds fine but it is a older amp so I expect to be servicing it soon, my Bugera is suppose to self baising.
thanks Kennis. I've been playing guitar for years but just take the amp for granted. recently I bought a Blues Jr to run in stereo with my HR DV because i felt things were "lacking". great combo though... Changing out my stock power tubes for the first time as well so I'll look to see if my HR DV 212 has the bias option. Sound like I may have some fun. great info, cheers.
Greatly done and very informative
What do you not do? CHEAH!
Great vid. All the information I wanted and none of the filler. Thanks for the info.
Thanks Kennis. Great job making your tutorial easy to understand.
really appreciate your effort to make these guides. Very well explained!
Thanks for the tutorial!!! Didn't know it was something I could do by myself...Amp sounds GREAT now!!!
Perfect, thanks. Makes sense and I just happen to have a Hotrod Deluxe so I may just tweak before tomorrow's gig.
Man, Ive been paying 75$ an hour for someone to do this. Thanks man, this is simple.
Cheers! Seems a lot easier than I expected! Good idea hand in pocket rule.
Tube info worth weight in gold! Tech Schools need to copy Kens delivery and info “train”.
Really good video also thanks for hitting on the safety side of things not many do that
Nice video thanks! Will try it.
Now my question: if it's about how it sounds why use the multimeter at all? Why not just plug the guitar and tweak the Bias by ear just like you would any other knob on the amp?
Thank you so much!
I have Blues Deluxe Reissue I remember it looking the same internally.
Any suggestions on cost effective power attenuators? I live in a small apartment...
Best bias video on ytube. If you dont have a real Fender tube amp.
I've got a 1984 Laney AOR 100 h with new Mullard EL34s and it sounds a bit flat and cold power Trans died ... and had to send it to Atlanta for repair ... my Groove tubes gone and the mullards in their place ... imagine my disappointment as it's been a year since it was "fixed" and I didn't look and bought a spark 40 to jam on ...I've ordered a set of GT #8 matched Quad EL34Ss that have been sitting in a closet in California since the 90s coming my way ... Hopefully they'll sound better and bias a smidge hotter for that sweet sound I miss so much .... Great vid BTW gonna shortcut like you did and bypass all the crazy math 470 vdc x .0632 ma is about 29 wats per tube X4 voltage drop is 1. 18ish per pair at the anode connection... wish me luck !!! 😂
Cool, man, thanks. Appreciate the vid. Don't forget, people, you can get a serious shock if you touch the wrong place back there.
Agreed. I made the mistake of that and no joke the tip of my index finger is burned/ melted off because of touching something wrong. Be careful guys.
Great video if one of the pre-amp tubes blows do I need to change the whole set
Best bias video on ytube. Also helps that mine is the blues reissue which is basically the same amp your biasing.
thanks man , you took some worry out of my life lol now my amp sounds great and has been running good.
Very helpful. Do a re cap tutorial???
Thanks for all great info. I’d like to replace the original power tube from my Vox AC4C1 for a Mullard and,Honestly, I’d prefer not to bias it if I don’t need it.once my amp has only one power tube, do I need to bias it ?If i don’t bias it (just replace) how can I check if it is working properly ? Which are the evidence of bad functioning (that it should boas-noites it) ?Thanks !!
Can a Fender Deluxe Reverb be self biased as well or should i take it to tech?
Thank you for taking the time to to make these videos. They're really great!
Thanks for the awesome video. Nice having amps with only a pair of power tubes and three pre amp tubes. Saves a lot of $$$ come tube time ahem Mesa Boogie Mark Series.
If you were wondering about the "one hand rule" the reason is this. If you have only one hand in your amp and get shocked, you have a chance of surviving, as the current will hopefully bypass your heart on it's way to the ground. Two hands in the amp and the current will likely go to ground via your heart resulting in death. These things are EXTREMELY DANGEROUS, even if you know what you're doing.
60,900 deaths per year do to tube amps.
@@aaronm.1998due
I've got one of these amps, so this video was very helpful. Thanks very much
Hi Kennis, great video! .. i have the fender hot rod deluxe western version are they the same as the normal hot rod deluxes? I'm going to replace the valves myself but confused on the term "self-biasing" does that mean you can put the power tubes in and they bias automatically ? or do you still have to bias them? ...do you also ever need to change the 3 little valves?
your videos are really helpful thanks.
Great video Kennis! Well done and explained. Several years ago, I biased my Fender Hot Rod Deville 212 while swapping from the 2x 6L6s to 2x KT66s and landed around 80. The amp sounded absolutely great for years but I've learned recently that going "too hot" (over 75) can have the negative effect of shortening your tube's life. Recently, I've experienced some unexpected volume and headroom drops at odd times while jamming, and just the other night, during a gig, it flat out volume dropped and stayed low all night. I had to crank it to 6-7 to have any useful sound (which if you know the 2x12, is a crazy high volume for a small room). I have a question for you: are unexplained volume drops a symptom of dying/tired tubes? (NOTE - I've removed other variables such as my pedal board etc... and have isolated it to my amp). Forgive my ignorance - this has been my only tube amp in 20 years so I lack the experience with other tube amps and troubleshooting.
Could be that one of your power tubes is blown.
Great video tutorial. I really enjoyed the way everything was explained. Keep up the good work.
I love your videos! Very informative, clear, and concise. Thank You!!
Thank you for this! I don't wanna take my tube amp to the expert because they're hella heavy for me to carry around 😂 plus it's fun doing this, DIY at home
Hi, great video. I have a Bugera V22 Infinium (with auto bias). It bursts the power tubes in days. Could be that auto bias is damaged? Thank you.
hey ken very descriptive video, where is the self bias setting potentnmeter and self testing point on a 59 reissue Bassman? thank u for your videos
Just a few clarifications .. Unless your amp is horribly defective (and blowing fuses) the circuits ARE already biased .. What you're doing is adjusting, measuring and/or optimizing the existing bias voltage/power dissipation. Secondly, one must be careful with that term "self bias". "Self Bias" DOES NOT means that you can adjust the bias yourself. Self bias is also known as Cathode Bias. It's referring to the the tube creating it's own bias by virtue of the cathode being lifted from ground via a cathode bias resistor. Outside of replacing the bias resistor with one of a different value, you cannot adjust this bias scheme. The other common method of biasing the output tubes is called "Fixed Bias". This method frequently utilizes an internal potentiometer that allows one to adjust the bias voltage to the output tube(s). This is called fixed bias.
Very Nice introduction to biasing. Thanks!!
Hello Kennis.
Thanks for your very well done informative videos that you do
I just got a Bugera v22 and it's got an RCA jack with a biasing potentiometer feature in the back that's accessible without having to open the amp up
Upon reading forums and watching a specific how to video on biasing the V22 I have to say that I'm now more lost than I was before getting all of this FYI with the exception of your explanation here
I am just wondering if you might be able to simplify for me whether or not the feature on my amp is an effective way to bias it and if there's a general setting bias number for my specific amp or tubes (el84s)once I do decide to upgrade my power tubes
Again I really enjoy and appreciate all you do here on youtube so naturally superior as a teacher! Better yet "a mentor"
One thing to keep in mind is the higher the current reading the harder the tubes are working. The harder the tubes are working the shorter the life of the tube. The lower the current setting the easier it is on the power tubes and the longer they will last.
Thanks Kinnis! I'm wondering if the 70mV setting is across the board - or for 6L6s - or for the Deluxe. I've got a Hot Rod Deville 212 and wonder if the 70mV would be the same for my amp? Also, my Fluke 75 has a DC 300mV setting, but not a 200mV. I'm thinking it would still put me in the right range. Thanks for the video and advice.
i really like your tutorials,you're easy to listen to and learn,have you ever looked into an orange amp? do you think it's gonna be similar to bias like you did on vid? thanks
i just got that very amp second hand , your video was very helpfull thaks alot!!!!
Very informative video. Thanks man. If you have 4 power tubes, when checking the bias test point would the minimum be 120 instead of 60? Or is 60 just for this specific amp?
Would you be able to do an instructional video on biasing a blues Jr 3?
Wow great how-to explanation.
Is this about same for the Hot-Rod Deville 4x10 2x12 the 1st ones.
Great video! Thank you, for this! About too go bias my hrd, and now i know exactly what too do
Awesome info Kennis. Thanks for making this.
I have a Fender Deville 410, practically identical to your amp in the video. I went to Radio Shack and bought a milli volt reader w digital display but never got a reading anywhere similar to your video. Can you tell me what the exact model millivolt reader did you use? I would purchase one of those.
Dear Kennis,
Thank you for the great video. I own a Fender Hot Rod Deluxe III and followed your video closely. Everything is set correctly with the multimeter (200m DCV) but I only get 30mv from the bias testing point. When I turn the wheel it goes from about 10mv to 55mv. Do you know what the problem here could be?
I'm using an almost brand new pair of JJ 6L6s that replaced the original Groove Tubes.
Should I turn the volume and master knobs all the way down first?
Excellent guide, thank you! I have exactly the same amp and when turning on the standby switch I hear some cracks for the first few minutes and then they disappear. Does this has anything to do with the power tubes?
In short, it can. There's some leftover products from manufacturing that can cause some noise. That said, if it persists, try tube shields especially in your preamp stage and check for environmental sources of electromagnetic energy. I would expect properly biased tubes to quit having break-in issues after you've biased them then flogged them for a good days' work or so. How long that takes is dependent on how hot they are biased and manufacturing and how much you play. Some amps just crackle from worn pots and microphonics.
Tl;dr: Yes, but if it persists look elsewhere for the crackle.
The music on this is mixed bit too loud to hear you easily. But do tubes have to be re-biased before reinstalling if they were removed for shipping?
Could you assume you have a bad set of tubes if you are getting a low reading when biasing? I got a brand new set of JJ 6L6gc's for my Hot Rod. Attempted to bias after replacing them. Set to 200m, I was reading between 33.0 at the lowest and 68.0 at max, after warming up the tubes for 15 minutes. I put in the old Stovek tubes I was replacing, read between 59.0 and 114.0.
Great video. Exactly what I was looking for. Thank you.
Thanks, very interesting. I have a laney vc-30 and the clean channel is very quiet compared to the drive channel. This happened after a guy revalued it. Would I have a bad valve in the preamp?
Excellent video - professionally done !!
I have a Fender quad reverb, where could I get info on how to replace the tubes and set the bias ? Is it also possible to fix the vibrato effekt on my own ?
Thanks for the Video. Why you need to bias your tube Amp: Resistors, capacitors and tube values deteriorate with time. It changes the amp output tube characteristics in terms of current, voltage drop and power dissipation. Bias is really realign these values to tube specs for optimum performance. I highly recommend you check out Uncle Dougs bias video.
I'm getting ready to replace all of my tubes on a Fender Blues Deluxe Reissue. (2-5881s & 3-12AX7A's) Do I need to bias the amp? Some tubes says matched...please advise...confused! Thanks
Great video! Very informative and easy to follow.
Very helpful, thank you! Could you provide the necessary info for a Supersonic 22 combo? I will be using Electro Harmonix 6V6's and want it a little on the clean side. Thanks!
Is it as easy on my VK? great tutorial!!
Thank you , that was really educational and concise ,, it helped .
Thanks for great and informative video. I have a question. Could I replace 6L6 tubes with EL84? My amp is Fender Hot Rod Deluxe II and I would like to sound more like Vox AC15. So I think about EL84. If you have any other advices, I really appreciate it. Thanks!
thank you.
do power tubes need to be replaced at the same time and if so , why ?
Hey Kennis great video and really informative , I have a question, I use a fender SuperSonic 22 and just replaced my power tubes with jj 6v6s (2ea) and my preamps are jj ecc81( 2ea), and ecc83s (3ea.) would you know the bias value for this amp? I've been trying to get a hold of fender with no response's yet. Thanks
Noob question, Do Hand wired amps such as a JTM 45 would have a bias test area/switch?
Thanks for the great tutorial! I'm wondering about lowering power? I have a Fender Concert Reverb with a 1/4 power switch. Is there any way to get this thing to 15 or 20 watts safely? I've heard of running on input 2 as well as 6V6 tubes? Different pre-amp tubes? Thoughts? Experience?