Change power tubes and adjust bias on your Marshall DSL40C - DIY tutorial
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- Опубліковано 6 чер 2019
- **WARNING***
Tube amps have voltages in excess of 450V that can KILL YOU instantly, even when unplugged! The procedure shown here involves working inside the amp while it's pluged and powered so EXTREME caution is mandatory. If you don´t have experience or don´t feel comfortable making this kind of jobs please take your amp to a qualified technician to do it for you. Be safe!!!
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Diagnosing faults, replacing tubes and adjusting bias are skills that can be pretty usefull to any guitar player - at least for those of us who still prefer the warm glow of a couple of glass bulbs shining inside our amps - Here you'll learn how to do it for yourself with normal tools and in the safest way possible. "Safe" here is just a word, you'll never be 100% safe working a couple of millimeters away from live terminals with lethal voltages. Do it at your own risk. Extreme all the safety measures, check and re check before touching anything and allways stay alert! And as I said before, if you have doubts don't take the risk and let a technician do it for you. Is allways better spend some money and stay alive for the next gig!
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#marshall #tubes #bias
From an Electronics point of view you should use plastic screwdrivers specifically made for tasks like tuning pots on PCBs.
For those about to change their own tubes and bias, $5 for the right tool is great piece of mind for both you and your amp.
Thanks for video it has shown me that I will not be doing this on my amp. I’ll take it to a technician. I only even considered doing it myself because of quarantine.
Great to hear that it was useful. This things can be really dangerous and if you're not completely sure is a really wise choice to take it to a technician. Good luck!
Good work . You showed the importance of how to properly handle power tubes . By the BASE . Very good .
Love the video. That repetitive soundtrack was driving me insane though.
Haha Im glad you liked it. Its hard to write 15 minutes of music without being repetitive. Luckily you can always mute the audio if you want. Cheers!
Great tutorial how to set the Bias and change the Power Tubes.
I sent an e-mail to Marshall and Dave Wittering (Senior Service Engineer) told me that the recommendation is 35mV per side:
" Hi Cesar, the Bias should be set for 35mV per side".
Good thing my phone has a volume control on the side that lets me turn off the sound
Great video. Great music. Great jam at the end. Very helpful and informative. Thanks for posting.
Thanks for your comment, I'm glad you liked it!
I used some of your tips for my JCM 2000- it is a different amp-but- you really helped ! Thanks!!
Glad to help!!
Thank you sir for making this video! Very much appreciated!
Thanks, I'm glad to be helpful!
I did this on my Haze 40. The trim pots and test points are identical. It was a little nerve racking but I took my time and was VERY careful. The amp sounded so much better and had less hum after.
Thanks buddy. Worked great.
Maaaaaaate!! This is precisely the noise mine started to make yesterday. Absolute legend.
Then you can bet is a power tubes problem like in this case. A least is easy to solve. I remember the first time mine made that noise, I was playing at low volume and that thing coming out of nowhere at full blast sounded like the armageddon. Almost crapped my pants lol
Don't play your guitar in the shower. Ever.
Great sound your getting from the marshall and Great playing thanks. I needed a refresher course on biasing my new purchase a 2266 vintage modern I just bought and a new pair of kt66 gold lions 🦁 to put in with my nos mullards 12ax7
Great job, your guitar channel is cool, subscribed, cheers !!
Thanks Marcelo, I really appreciate it!
Wow, great video. I am too timid to open my amp but your video was super informative
Thanks! Usually I encourage people to open their stuff and attempt to repair it themselves but with tube amps I you aren't sure better stay away haha. Cheers!!!
Good video. I just bought my own stuff to do this. I am done spending twice as much for someone else to do this. Thanks.
Great video, will be back when i get my tubes 😄
Had same problem with my DSL40, these are a really nice amp.
Yeah, I love mine
Thanks for the info and safety advice. Think I'll leave it to the pro's after watching.
Mines just started making unpleasant harmonic whistling noises, gonna have to do this. Thanks for the video!
I may be a power tube, just remember to follow al the safety measures!!! Cheers and good luck!
this video was very useful in obtaining information about tube amp. I hope I can buy a tube amp (DSL5CR)
I'm glad you found it useful. I've heard lots of people talking really good about the DSL5. Awesome little amp
Most excellent music!
Thanks!!!
Found your video a little bit late but it's the closest to what i am looking for. Eye opening tutorial though. In my case it's an Ibanez TS15H. Needs power tubes replacement. I'd really appreciate it if you could provide me with some guidelines especially with adjusting the BIAS. Thanks.
Is that amp on the tracks we're hearing, it sounds alot like the dsl40c i hav which of coarse is why im here . Good vid ! Also i went to ur home page and listened to a few backing tracks . If those are ur tracks they are pretty nice . Iv helped on a handful here so iv got an idea how much work they can b .Good luck ,, new sub btw .
Hi! Thanks for subbing and for checking the backing tracks! They are all written and recorded by me and In the vast majority indeed it's the DSL through an SM57, only in some rare cases when in looking for a non-marshall sound I use some emulation like Amplitude or Bias
Great video, thank you so much. I have the DSL40CR but is should work the same. I will have to some how get the biasing levels for the CR to see if there the same, I don't see why they wouldn't be but better to make sure then to be sorry in the end if there not. Very cool video, very very very well done. I did graduate from electronics tech school in 1993 and all have to say is, if you have never worked with alot of amps before because that's what kills you, have a professional do it and if your going to do it, have one hand behind your back so the juice won't travel through your heart. Got bit by a flyback transformer once and that rule saved my life. Please use something that is noncondutive to touch that stuff with or you might have a shocking experience.
Don't take this video as a guide, the 40CR is a pretty diferent amp. I didn't worked in one of them but I know it has some more features, I can't remember if it has a dedicated external bias adjustment port, auto bias or another feature that makes this work a lot easier. Please check info on that particular amp and good luck!
Thank you I do appreciate you responding so fast but it was a great video you did a fantastic job. I will move the post so I won't give people the impression they could do this on the CR40.
nice video man! In the latest part, when you are playing, in which channel are you playing? Lead !? great playing btw!
Thanks!!! Yes, is the Ultra Gain channel (red) in the Lead 1 mode. Great for nice lead tones but without getting into high gain territory like with Lead 2 activated
Thanks for the video. How old were the valves/amp? My DSL 15 Valves with Marshall branding only lasted about a year, the GT replacement tubes have lasted years since then with no issue.
They were something like 2 and a half years old. I've had more problems with the factory preamp tubes. Two of them stopped working less than a month after purchasing the amp. Stock tubes are pretty unreliable.
Good video man, I disagree with your setting but it’s a good how to regardless. I set mine at the recommended 36ish. Sounds great to me and doesn’t cook the tubes as fast.
If you’re going to try this at home be aware of shock risk and make sure you’re grounded with one hand in your back pocket. Zapp was a great band but not a fun experience!
Looking to
Just pull
Out the head of the amp. But scared about getting shocked seeing everyone say be careful. I’m not doing anything but pulling out the head of the amp. Please guide me the correct way so I don’t get shocked
@@Koake1002 your amp have a standby? If your amp has been off for a few hours just unpulg it and you should be fine.
Good video !
I too have the same problem, only...smaller on a DSL 1. Small.....;-))
Any special precautions to take?
Thanks for answering....!
Interesting stuff. Those "crumbs" you showed inside the power amp valve, is that a sure sign the valve needs to be replaced? Nice playing, by the way. :-)
Very informative. Do you always have to adjust the bias when replacing new tubes?
Thanks! Only when replacing power amp tubes, no need to re bias when replacing the preamp ones (12ax7)
Great video. Thanks good. It was so easy. Just two quest.
Its the same for an DSL5.?
AND finally. Why 38mV ? Always the same value on any valve. Dsl5 comes with 1xEcc99. 👍
bump
Hello friends! Hope all of you are staying safe! Well I bought my DSL40C in December, 2018. It was brand new purchased from amazon. In these last few weeks it started making popping and distorted noise periodically. There is also increased hum even when guitar jack is not plugged in and it goes away when standby is off. I opened up the Amp and tested tubes, one of the power tubes are microphonic and lights more differently like a hot plating tube, I ordered new JJ matches pair for it and also a multimeter. Going to do biasing myself for the first time and there goes my question:
When I put in the new tubes>>open the chassis>>engage the load(speaker)>>turn on the amp waiting 15mins>>turn on the standby>>
THEN: is there a chance that flow of milivolts will be very high and damage new tubes before I even adjust TRIM POTS?
I read a lot and got all biasing process including safety and everything, but this thing gets me concerned as this is my first time. Please, share your experience with me
Hi! I havent heard of anybody with that problem. It's totally safe to turn on the amp and wait for the tubes to get hot before adjusting bias, just be sure that your speaker is plugged in to avoid damaging the output transformar and you'll be fine. Now I don't remember the exact values but my amp (bought new in 2015) came from the factory biased waaay diferent on each tube, wich may be the cause for their short life. No matter wich bias value you choose, be sure is the same on both tubes.
Inspiring tracks Thank you. I just bought new EL34 tubes, they are matched pair but each one of them has 7 pins instead of 8, is this okay?
Cool video! thank you for putting it out there..... question.... shouldn't you measure the current (mA) though the bias points instead of voltage (mV) to set your bias? I'm new to setting biases myselt but that's what i read everywhere? Is there something i'm not seeing? or that I don't understand?
Your measuring the current in effect because they've done the work for you of putting in a pair of 1 ohm resistors for the measurement. Nice of them to add this!
Good vid. I’ve adjusted the bias on mine and want to replace the tubes. Anything else anyone would recommend for the process or or is that simple?
Thanks! It is that simple, the only things to mention is the mandatory caution when working with tube amps, the need to always replace both tubes together for a matched pair and some people claim that fingerprints on the tubes reduce their life. I don't think it's too important but just in case clean the tubes after installing them and you're done. Cheers!!
Very useful video, thank you! But... where are the values from? Why 38, and why is it "hotter"? And how do i find out values for a different amp, in my case a DSL5C? Thanks!
Thanks! The best source of information is marshallforum.com. Great people with lots of knowledge and glad to help
Nice video ! Have you ever noticed a blue glow inside the tube when you “attack” your guitar ? Do you know if that’s normal ?
A blue glow, kind of like a neon lamp usually indicates that there's some air or another gas inside the tube. It may be a sign that you'll new tubes soon
Should it always be done in full power mode? What if it's switched to half power?
well done ! my DSL head is picking noises like an AM radio, but it lasts a few seconds and then the noise is gone, could it be the power tubes or the preamp tubes, or something else ??
The first suspect always are the tubes, and on the DSLs the factory tubes are absolute crap. I had to replace 2 preamp tubes just a month after purchasing it. The procedure to identify a defective preamp tube is the same, tap them GENTLY with a wodden or plastic stick and see if some of them are microphonic or make some weird noises. The good thing is that there's no need to bias or open the amp so is just plug and play. Cheers!
Is it okay if I haven’t biased my amp after playing it irregularly for about two-ish months since a tube change? Did the tube change myself but did not know about the bias part until now.
I got some JJ tubes Premium and the 6th pin on the tube is missing is that an issue or just an aftermarket configuration?
Can anyone tell me what is a reasonable price a tech should charge me to do this in the U.S. ?
Why need bias if tubes are already matched?
Does it make a difference to the way the amp sounds.
I hat the exact same problem with my DSL40C just before you uploaded this video. It doesent really come across how loud this sound of the broken el34 actually is. Intersetingly tho I didnt see any optical damage on the tube. Where your original "Marshall" tubes from TAD too? I got my replacements also from them. (The owner of TAD lives just a few minutes away from me.)
Absolutely, is incredibly loud! The first time the amp started making that noise I was playing at bedroom volume and that thing at full blast scared the s**t out of me lol. The original Marshall branded tubes came installed from the factory and they must be the cheapest ones they can find. Something like 1 month after I bought the amp (brand new) a 12ax7 from the preamp died, and the power tubes failed after just 2 years. Maybe I just had bad luck but I doub it.
I have the DSL100HR head. Should I turn the amp off in between switching the multi meter probes from right to left? Also my ports are on the top where I don't have to go inside the amplifier. Just wondering because I don't want to get fried.
The R series are an update from this model, im not completely familiar with them but I'm sure you don't need to turn it of to switch probes, just be REALLY carefully to not touch anything else and remember that a tube amp can fry you even when powered off
I seem to have a problem. With my fx loop making odd sounds and doesn't seem to work with either looper or delay. Could it be anything to do with valves? And would it be these or the power or pre amp valves
I bet is the switch to turn the loop on and off. All the switchs on the DSL are crap and prone to false contacts that can cause al kind of weird noises and intermitent failures. Try puting the amp on the floor with the speaker facing down so the fx loop switch points up, then spray some contact cleaner on the space between the pusher of the switch and the chassis an push it a lot, something like 50 times at least and see if that works. I had a similar issue with the clean/crunch switch in the front of mine and solved with that method. Hope that helps!
I've got the near same setup. Except I'm playing on a 1980 335s Pro Deluxe with a factory built in coil tap. I swear that there is no tone that is unachievable for live gigs. Brutal volume.
Do I need to put it on stand by when changing the clip clips? 10:27
Another doubt: I only need to adjust the bias if I change the Power or PRE valves too?
No, yo do all the adjustment with the amp powered (and lots of caution). And biasing is only needed when replacing power tubes, you can switch pre tubes without any adjustment. Cheers!
Is it the same on the old DSL401?
Is this an older model dsl? I’ve seen dsl40c’s with the test point and bias adjustment elsewhere without having to remove the physical amp head from the chassis?
Yes, this is the older model, which is quite different to the actual one
Why not run tubes cooler? Or can you?
Can you explain something to me, I have a few tube amps and some have four power tubes .
Do all four tubes have to be matched together? Or is it, one matched pair and another matched pair?
Iv seen some people say matching tubes isn’t totally important , worst case is tubes burn out a bit faster or the sound isn’t super even?
I’m trying to stock up on some tubes for my amps but need to figure out the basics .
I also just got a bogner and it turns on and makes no sound whatsoever . I have no idea what’s going on with that amp.
But anyways yeah, I mean could I technically buy single tubes and still bias them properly?
How does their plate voltage come into play with bias? Too high voltage means they can’t bias lower? I think I had an issue with some ruby tubes where I had to bias an amp high since the tube couldn’t go lower itself .
This stuff is a bit confusing , I actually think I prefer lower gain in general and more of a crunch and less saturation .
But could you answer some of these questions for me? I really need to figure out how to narrow down what tubes to get and what to look for. I’m not sure if I can just get an el34s for my marshalls or they need to have a certain rating to bias properly?
I can’t seem to find answers to these questions online , I guess because they are so basic lol.
Any help?
Check www.marshallforum.com, there's lots of really amazing people there who knows a lot and they should guide you about your particular amp model. Don't want to give you any advise without being totally sure about it
I noticed the replacement tubes are different than the ones I have. It's groove tubes but mine is GBO performance and matched 5. My old tubes are EL34 and 56 is written on the base. Do you think I should replace with the ones I have? What tubes do you recommend?
If both are EL34 they should work, in my case the ones from the factory where physically a little bigger than the replacements but both worked fine. Groove Tubes tests the tubes and clasifies them with a rating number depending on how easily they overdrive. This should only indicate the sound you might expect and not the reliability
@@InspiringTracks I'm sorry. Do you mean if both the new ones I replace them with are also EL34? I don't see EL34 written anywhere on My replacement tubes. Also, do you recommend getting the preamp tubes replaced at the same time as the power tubes? Or do they have a longer lifespan?
@@alexsanders7404 I always replace the entire set of tubes in my amp, all at the same time. The preamp tubes CAN indeed be replaced at ANY time, and you can do one at a time as needed. But for me, it’s a benchmark. If I do them all simultaneously, it’s easier to keep track of how long they last. Especially if you have multiple tubes amp. I have 4 to maintain.
The guitar on the track is this amp? Would you mind sharing settings?
Yes, It's been a long time since I recorded it but I think I remember that is the Ultra Gain channel in mode 1 (Lead 1 - the less extreme one) with bass around the middle, highs and presence rolled down (is a pretty bright amp) and a little mid boost (around 7-8), recorded with a Shure SM57. The other half of the tone is my amazing SG with classic 57 pickups. Hope that help as a starting point. Cheers!
@@InspiringTracks yes that helps a lot! Thank you very much!!
Hey, thanks for the video!
My amplifier is a Marshall DSL 40C too.
I am brazilian and hear when I lives the voltage is 220v.
My amp is 230v...
In the Last months the amplifier starts a problem.
When it heats, sometimes, the green led that indicate that in the Chanel clean blinks and the sound disappear for a little second e come back.
Do you saw this before?
I am so sad about this...
Tks
Hi, I'm from Argentina so we are neigbors haha. Something similar happened to me. The channel selector switchs are crap and if they arent use frequently they get corroded and start to fail. I solved it by doing this (WITH THE AMP OFF AND UNPLUGGED): The part of the switch that you push is a little cap, pull it and remove it. Then lay the amp on its back (with the speaker pointing up), spray a little amount of contact cleaner on the switch and give it a good amount of push cycles - dont be shy give it 50 - 100 pushes. Repeat on all the switches - Even if works right now they all eventually will fail, they are pure garbage.
Hope that solve your problem
Saludos desde Argentina!
@@InspiringTracks ¡gracias mi amigo! Intentaré lo que sugieres. Tengo esperanzas.
estamos más cerca de lo que imaginaba
Hehehe
Is it necessary to do the bias thing? Can I just change the tubes? Cause I gurantee I would screw up the bias thing
Yes is necessary. It's not that hard but also not that easy (and potentially lethal if you're not careful). If you don't feel comfortable doing it the best advise is to take it to a good technician
I can't find any video about tube removal from my dsl20 head. Just got it today sounded awesome till it stated making a crackling sounds. I learned how to tap the tubes with a wood spoon. Sure enough the preamp tube on the far left, if viewed from the back of the amp, makes a obvious sound through the speaker. So I'm positive that it's a bad tube. Do you know what tune that it. V1 or v3?
Factory tubes on these cheaper Marshalls are garbage. V1 failed on mine just a couple weeks after purchase To determine which preamp tube is bad just use the same method of gently taping them. Alternatively if you have a spare and working 12ax7 you can swap them one by one until you find the faulty one. No need to bias or anything, just plug and play so it's way easier
@@InspiringTracks I've tried 3 different JJ ecc83's in the v1 socket. All make noise when tapped with wooden spoon. Could I have a bad socket.?
DSL1 HR and DSL20 HR don't need to be biased after tube changing says the Marshall support.
I can’t find this info anywhere, where did you see this. Ty in advance
you didn't have the option to do the bias by the tubes? mine has + & - probe holes as well as trim pot hole. no taking apart.
Sadly no. Only way to access the trimpots is taking the chassis apart. IDK if on the new DSL CR models they solved this
I think push hook clips may have made the biasing part easier.
Hey!
0:17 - I can’t understand how the high 450 Voltage can flow without any power...
Do u mean that even unplugged from the power socket Tube DSL is hazardous ?
I’m going to change the speaker so I would like to make sure it won’t hurt me while unplugged from power 😆
Sorry if it’s a dumb question I just wanna make sure 😅
The electrolytic capacitors inside the amp store electric energy and can remain charged with lethal voltages for hours after unplugging, if you accidentally touch one you can get a shock that ranges from painful if you're lucky to death if you don't. They are isolated inside the metal chassis, so if you only want to change the speaker you are safe as long as dont touch the tube sockets
@@InspiringTracks Thank you!
I have a Marshall DSL 40 Creamback, it works fine until every few minutes the sound just dies... the tubes are on and the amp had power, but no sound.
I have to turn the amp off and then on and it comes back to life for another 20 minutes, sometimes a little longer. It happens more when using overdrive or distortion.
What do you think it could be? Tubes?
Thank you for any help
Anybody
What happens if you don’t bias the amp after changing tubes?
Sounds like a faulty preamp tube. Try gently taping them one by one just like shown here and see if you can locate the faulty one. If you still have the factory 12x7's chances are high that at least one of them is dead, I had to replace 2 just one month after buying the amp, they are complete garbage
@@InspiringTracks thank you for answering... yes they are the originals, and you are right, I started having this problem a few months after I bought the amp. It failed me a couple of times while I was doing some solos... ugh
I will check those tubes and see if one of them is blown.
What brand would you recommend? Do I need to bias if it is the pre amp tube and have to change it?
Good vid but pin clip leads are about $5 on amazon
I'm a few weeks away from purchasing the DSL40C-all I got to say is-if it comes out of the box and sounds even close to those initial sounds (popping, humming etc.) it's going right back to Sweetwater. Period. End of story!
While I understand what you did-I would not feel comfortable performing this at all. Spending 1000 bucks on a tube amp should get me one in working order!
Is a speaker change-out easy?
Very easy.. Add a vintage 30 greenback etc and it will really come alive.
You need to check your plate voltage to seebwhatbyour bias needs to be first. The EL34 Ma is around 39. Thats 19.5 per tube. Not 39 on each tube.
The video is almost 3 years old, dont remember the numbers right now but the values used on it are accurate and work great. The amp is still working with the same tubes and didn't had a single issue, with lots of gigs and rehearsals at full blast. The tubes will be toasted almost inmediatly with double the current, which clearly isnt the case
I will make this because have the same problem but I won't bias. I don't wanna die.
You always NEED to bias your power tubes after a swap, otherwise they can sound bad and/or see their lifespan greatly reduced and put extra stress in the rest of the amp. If dont feel comfortable doing it yourself take your amp to a technician to do it for you
@@InspiringTracks I asked to only one I know and he refused to do the job.
Right know is very complicated in my country to go out. I just have 4 hours at week to go to supermarket and everything still closed.
Online shopping no problem thats why I was thinking to change tubes by myself and bias later after lockdown.
@@peregrinacarlos An amp won't kill you as long as you keep yourself insulated from ground (wearing shoes) and only use one hand at a time. At most it'll only be a painful shock. If you want to be extra careful, an electrician's glove comes in handy, so you're totally insulated.
The only way an amp can kill you is if you're dumb enough to not be insulated from ground and using both hands instead of one. I've been shocked 3 or 4 times and while it does hurt, like A LOT, there was no damage done. Though, I do understand why you have to put a disclaimer on the video.
I thought you only had to adjust bias when going with a different model tube not the same size but just a different brand...
You always need to adjust bias when swapping power tubes, the ones that doesn't need to do anything special are the preamp tubes, usually 12ax7. Just swap them and you are ready to go
@@InspiringTracks Unless the amp is cathode biased.
Step 2.5 - write the testament and last will.
Lol. You just need a steady hand and take your precautions
Good video but you never measured your plate voltage ,without knowing your plate voltage you can't bais the amp correctly, so the way you biased you could be at 40% dissapation or you could be at 80% or 90%. 70% is optimal
Great video but; don't ever touch tubes with bare hands, it will shorten tubes life...grease you know...
In the 21st century I can''t believe people are still eFing around with tubes etc just to get a distorted crunchy sound!
Why? They are fun and cool
The DSL40CR is so much easier for biasing it's not even funny. Ditch that 40C and get a 40CR!
Lol I heard really good things about the CR, maybe in the future!
Always keep one hand in your pocket when working on a powered up amp.
Great advise, thanks!!
Thought you weren’t supposed to touch good tubes without gloves due to the oils on our skin. 🤔
Why would you play music in this video?
Why not?
Why would I want to watch a youtube video of someone taking off the back panel of an amp, screw by screw?
Maybe because is a tutorial and not everybody knows how to disassemble an amp?
Why would you watch a UA-cam video about amp repair if you already know everything? jack ass.
Good video. The music choice was weird ish tho lol still I appreciate the video , 😊
Thanks! This video is somewhat old and I didn't have a wide choice of music on the channel yet so I had to work with what I had lol. I recorded several new tracks and now newer videos have a wider and mabe more well fitting music selection. Glad you liked the video anyway!
Chassis