Marshall DSL40CR Power Tube Change and Bias Adjustment | EL34 Tube Replacement | How to Change Tubes
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- Опубліковано 3 лют 2020
- In this episode I demonstrate replacing the power tubes on a Marshall DSL40CR combo amp. I show the bad tube and what's wrong with it before replacing the tubes and biasing them.
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/ @alwaysandy_
Greetings from clarksville!! I got my dsl40 from Nashville as well and love it. Thank you for the awesome video, and teaching how to bias this thing. Pretty informative. Thanks bro 🤘🏼
Clarksville!!!! Congrats, enjoy, cheers!!
I’m getting ready to buy one of these amps and I appreciate your video on this because I have no idea what the biasing of the tube was that looks extremely simple.
It’s not normally so easy to do. Def feature for this amp to me. Cheers!
It’s the way it should be. I love everything about this amp
Awesome video! Thank you! Those probing points are very convenient!
🙏🔥⚡️
You keep coming across my screen and I keep liki6you and your videos...so..Subbed!! LOL
I am pretty sure I want this amp.
Hahaha you rock! Save them dollars like I did, one day you’ll get there. Cheers!
Awesome video, man. Thanks.
Thanks for sharing! You saved me from paying a local tech to do this! 🤘🤘
Awesome! 💥🙏
To the multi-meter store I shall travel now! Thank you for these very well done and super duper skills, intel, etc...~
So how’d it go? Did u get that multimeter?
@@alwaysandy_ Yep sure did, it went very well and adjustments made, also used it on the 100W head!
Thanks for the useful information. Just bought one of those amps on musicians friend. Open box, mint condition. Hopefully it arrives in working order. I'll definitely check the tubes with the digital multimeter.
🤞🤞🤞
@@alwaysandy_ just got the amp. The biases were set to 38.t left and 45.8 right!!! Also is it normal for the amp to make loud white noise/ fuzzy sound? I have no guitar or cable plugged in and I'm cycling though my channels. With the volumes and gain maxed and this amp is loud. Is that normal?
@@J_Braz_ it’s a very loud amp. With volumes high I’d expect some noise sure.
What’s you experience so far?
@@preciseaudioblog I sent it back and got the dsl20hr. Put it on a Harley Benton 212 vintage horizontal cab. Sounds good. And the amp came from zzounds, used for 499. Amp arrived in excellent condition. And this one is much quieter than the 40 watt combo I had. I wish Marshall would have gave the 20 the same functions as the 40, two tones on each gain channel. But oh well. These amps are definitely a little fizzy though. I've been experimenting switching preamp tubes around, v1 v2 v3 ECT.
Thx a lot Andy
Thank you dude, seem simple but don't know why, been waiting for doing it since 2 weeks. everybody freak me out with high voltage. don't wanna die lmao I think I'm gonna take glove too , I'm a average guy who just wanna rock
You prob won’t die 😂 just it like I did, for sure unplug it. Lol cheers!
Hi just bought mine a month ago, its now going back for repair yesterday all good , today no sound ? hopefully can get it fixed really like it.
That’s goofy. I had to return mine once I recall. They’re great amps tho.
@@alwaysandy_ Hi Andy, yes I was really enjoying it, i tested new cables swapped guitars etc. but nothing anyway hope they can sort the problem, cheers Steve
Super helpful video. May I know how do you determine to set it to 35? Is there a specification sheet for that? I have the DSL20 head.
Zidane Chan there may be a data sheet per amp or tube, I don’t recall. I know I checked my bias first which was near 30 if I remember. I likely watched some vids and decided 35 would be fine. Lil more gainy than 30. 🤘
@@alwaysandy_ Thank you very much for sharing!
I have the same amp (DSL40cr), Marshall recommends bias setting between 32 and 38 for this amp model.
DSL don't have to be biased - if you don't believe, ask the Marshall support
I like the KT 77's as replacements for EL 34's
Awesome ❤
hello Andy, good video, but que you tell me if i change the power tube of mine, marshall dsl 20 cr ,i must to do adjustment of bias, because i don't see a bias inside. THANK YOU FOR YOUR ANSWER FROM BORDEAUX FRANCE. DAN.
You don’t have to reset or change the bias, but you can if you have a multimeter or voltage meter. See at 11:15 in the video I demonstrate this.
I’ve never seen how you bias an amp. Gives me hope I can do it myself!! Thank you!! Btw, what if you bias it at 32?? Is it better?
Better to some is not to others. Just different, whatever suits you.
@@alwaysandy_ yea, but is the Bias settings on each tube different? What's the Bias settings on a Celestion Green Back? If you change speaker or change or replace tubes-is there a prerequisite setting for a given tube set to a given model of speaker? I want to go back to a tube configuration and am seriously considering this model. But now I fear that changing out the speaker it comes with to a Celestion. Kinda lost now as to seeing this video. last video I saw had the circuit board exposed and the guy fine tuned 2 settings on the circuit board to bias. This video is confusing. Here's the video I am referring to: ua-cam.com/video/WbUoav53VaA/v-deo.html
@@michaelpal7641 Biasing this amp is as easy as it appears in my video. It has little to do with speaker choice as far as I know. If u change a speaker and font like how it’s biased re-do it. Simple.
@@alwaysandy_ Thanks for the quick response-greatly Appreciated. But the Bias settings I refer to in the other video has the guy taking the Amp itself "Out" and exposing the circuit board, then using Volt meter, he attaches alligator clips to circuit board leads, and uses a small screwdriver to turn the trim pots. That's a definitive "Hell No" for me.
In your vid-you didn't remove the Amp itself-you used the two small red dials above the positions where you inserted the multimeter leads. Looks like something I could do after all. man-I just watched your vid again. Yes-You Rock. Thank you again!!
@@michaelpal7641 The video you are referring to is the older version of this amp. Different circuitry as that model did not have the master volume pots like the new “CR.”
I read somewhere that the plate voltage of this amp is 450V. If I use the standard formula: 25 (el34=25 watt) / 450 * 70% = 38.8 mA. Biasing at 35mA seems a bit cold...
Doesn’t sound cold. That’s my gauge.
Just wondering I just purchased one of these and the first few days it sounded really good now it’s bassy and a little fizzy sounding? Any help is appreciated maybe tubes?
Thanks
Yea that’s be a good idea. Or just return it for another one. If it changed in tone all of the sudden that’s a good reason. Good luck.
Hi, thank you for the video! I have a question mine dsl40 cr bias voltage don’t want to stay in one point, it is basically jumps from 34.5 to 35.5 on both checkpoints, is it normal and what can be a problem here? Thank you in advance!
mine is always changing too... i set ir like 32-33 mV and a week late is was near 40... any clue on why does this happen?
i don't know specifically but i'd guess a variety of things could cause minor variations over time. like room temperature, what you're playing, tube age, tube where-in point. good question.
@@JoaoNuno1995 - AC line voltage fluctuations also cause the bias voltage to change. Usually nothing to worry about though.
You can get a Nasty shock from valve amps when theyre NOT plugged in
Hi Andy! I’m planning to buy one of these. Should I bias the amp when I just buy it? Or I can use it normally? Thank you.
No need to bias unless you know why you’d wanna bias it. If you don’t have a preference just leave it.
@@alwaysandy_ Got it. Thank you.
Are you biasing at low amp setting or high because another vid says to do this on high? Just alittle confused. Thanks!
try both? I don't remember now. i'm curious what variation will be. cheers!
Thanks.
Welcome!!
Hey Andy I just ordered a set of power tubes for this amp and did not think to have them matched does this lead to any problems?
I don’t think so. Google it to make sure maybe? I think it’s advised they match but I’m not sure why. Hmm.
Tubes must be matched
im currently trying to bias mine and the bias knobs dont work. the amp is set at about 75 for both, hot as hell. any advice for if the little red knobs arent working?
Ummm, return it? Take it to a qualified repair shop? Personally I don’t like messing with power tube stuff that seems not normal. If those dials don’t turn something is broken.
It's always on that function of the multimeter for measuring that value?
For me yes! I don’t know much about multimeters tho sorry!
Thank you!
Which version JJ el34 tube did you use for your new replacements? JJ el34 or E34 L or El34II? - Thanks! I'm trying to figure out which version JJ el34 comes stock in my new dsl40cr
Oh I have no idea. Whatever was in the rack at guitar center.
Same here..there seems to be different versions of the el 34
@@michaelsteven1090 the stock el34 tube is the standard JJel34 for the dsl40cr. I'm thinking of trying a pair of the JJ el34II's just to see how they sound in my amp. Though I have to say that I am very happy with the stock JJel34 tubes that it came with.
@@gigmandrew8975 Thanks..I'm looking now and there are NONE available..😡
@@michaelsteven1090 - No Dsl40cr or no tubes?
What is the setting on the voltmeter? I couldn’t tell where the dial was at. you said “this one right over here” I think that’s the one” could you be more specific .
Direct current or amperage or something. I don’t know. I said that. Pause it, screen shot it, look up the symbols you see and try and match. I played with the dial until it was on a setting that displayed the proper range of numbers I’m sure. Trial and error.
I'm confused. You said before you walked to get the meter that you need to "make sure it's on the high power mode". When you came back you offered, that "if we'd left it in the high power mode ..."
Considering I did it once before filming perhaps it was in said mode already when I picked it up.
Not knowing much about Marshall amps but shouldn't the preamp tubes be shielded? I noticed one is but the other 3 are not. I am just going Fender amps who shield all their preamp tubes.
Got me dude. I’ve had amps all over the map on that question. Seems like splitting hairs a little but I’m wrong all the time!
No!
My amp isn’t playing when I plug it through the front but works when I plug it through the return fx loop.. preamp issue?
Sounds like it it. Given you’ve exhausted channel switching and voicings etc. Good luck!
@@alwaysandy_update I took it to a proper amp tech and he said it has a blown transistor and needs new power tubes and the transistor replaced! Just leaving this comment incase anyone else experiences something similar
Did that carpet come from Target? We got the same one haha
I’m gonna say yeah. It’s so very likely! 😂🤣😁🤘🤘🤘🤘
Wish I bought a few spare matched EL34 pairs before they went for $110 a pair...
Yikes! Go to eBay and get Tesla el34s. Original with brown base are amaaazzzing tubes. If ur gonna pay a lot for tubes get these. 😎
I got the same amp, question, why the number 35, and not 40 for example?? just asking..?
Assuming you mean 34...it’s a reference to the type of tube. EL34 is a power type type, another type is 6L6. The numbers refer to specific parts or patterns within the structure of the tubes. Cheers!
Here is the formula. The regular JJel34 is a 25 watt tube. 25 divided into 426 DC volts on mine @ 122.0 vac line voltage x .65 dissipation equals .038, or 38 MV.
Hi, would consider is good quality?
There was only one brand in the store, so really I don’t know. I just use the big well known brands.
Can I replace the EL34 tubes with 5881 tubes on the DSL40CR and than just bias it to 35mV without any problem?
I would assume yes.
No you can not just swap for 5881 the screen resistors would need to be changed first
I let my Marshall freeze out in the garage last winter, apparently im not supposed to do that, so I need new tubes I think.
Ha prob yes. They’re not too costly. Good luck!
You should have turned on the amp after unplugging it to make sure power was drained.
Sure.
Yeah I’ve been capacitor zapped more than once and the modelers have circuitry that can be damaged
@@gitarman666 Modeler?..This amp is a modeler? 😵💫
@@michaelsteven1090
No it’s not, it’s all valve El34s and 12ax7s
Don’t know what I was talking about in that comment,🤪
I have been zapped changing out a JVM output transformer!
I wonder if I was making reference to the printed modual they throw in there instead of point to point wiring from Vietnam, Who knows what I was smoking that day
But Dollar for dollar these are great amps I own 2 DSL40cr, JCM 800, 900 and my JVM410 combo,
That’s everything in my Marshall harem
Several Mesa Boogies and Fenders, some smaller SS orange, Revv and my Soldano SLO 100
Friedman next but I have to sell some guitars first, 😢
@@gitarman666 Thanks for clarifying..I just checked my bias and the left power tube is maxed and barely making 35mV..I need to replace them but can’t find any EL34’s..nobody has them! Are there any other versions of the 34 I can use do you know?
What prevents me from biasing the tubes too HOT?
Nothing! Tubes may not last long tho.
what if the problem is with the preamp tubes?
Replace them!
You never checked plate voltage so this amp is not biased, you want your amp at 60% to 70% dissapation ,more than that and your tube life goes down from there,less than that and your amp will start sounding very crap ish doesn't hurt the tubes though
Does it really matter where the blank pin on the tube ends up?
Absolutely in my experience it matters. I’ve always replaced tubes already there, and if there no ‘missing hole’ in the socket I make note of it.
Octal tubes are keyed it will only go in the correct way
Does it matter what kind of tubes you use? I’ve heard that most people can’t really tell the difference
Depends if you’re one of the ‘most people’. I can tell differences in tubes. Power tubes mostly. All the preamp tubes are good lately just a high gain low gain thing.
@@alwaysandy_ What power tubes do you prefer?
@@SECURITY39 Tesla EL34 from Czech Trinec plant. Can find on eBay
do we need to bias it up also
I don’t think you bias preamp tubes, just power.
thank you sir,,,we just have to replace the preamp tubes 4 at once,,,all together
@@miguelenriquez4780 you can mix up preamp tubes sometimes. They’re not as picky as power amp tubes.
I have both dsl 40 and 100,,both of them are terribly hot,,even the switch button are so hot is it normal,,I think I need to bias both of power tube
@@miguelenriquez4780 hot is normal, trying answers questions. Good luck!
You dont need gloves, just wash your hands before swaping tubes. They are not made from quartz glass so no problem.
they're right there (for me) so I use gloves when handling delicate things, cause there's is really no telling what i haven't washed off of my hands. fair advice though thank you for sharing!!
The octal tube socket will not let you put the tube in the wrong way. ALWAYS bias tubes to the datasheet. improper biasing will f**k up tubes way faster than the shit on your fingers ever could.
Thx for the tip!
To be honest, I'm looking at a new 50w master volume 2203 why ? Because I have been gigging two 79 Marshall 50w master volume 2 x12 combos since 1980 without even a hiccup, spend the money on really good quality and you won't look back, you will have that amp for life, none of this crap about only having it for two months or whatever and it's gone wrong already, these u tube reviews are only about making low cost gear and therefore simply making bread and butter money for the manufacturers.
Some of that I’ll agree with. In reality here, I’m a guy (like many) who has no dollars to spare. This particular amp is a lotta bang for the buck, which is why it’s so popular. “These reviews” are not for Marshall, they’re for me and people like me. I’m a struggling musician and creative designer who makes videos like this to help people spend their hard earned dollars wisely. I get literally nothing from it. Yet. Maybe one day. For now I’m happy helping people as I can. And if Marshall sells amps because of this video - we’ll that’s great cause those people will enjoy those amps. Cheers.
The glove is on the wrong hand for keeping finger oils from getting on the new tubes
You solved it Roj great work
Changed gloves because he handled stuff that has been touched by bare hands then pulled on and adjusted the new glove with bare hands 😳
Good find bro you got me! Deleting ASAP. 😁🙋♂️
Haha all good mate, good video. I’m looking at getting one of these amps so found it interesting 🧤
@@shanecameron9400 hell yea dude ul love! I just got it out the other day and did a lil video with a us strat and a vintage les paul. I still like it. 💥🙏
@@alwaysandy_ got my dsl50 combo today, amazing!! Upgraded from a valvestate, no comparison
@@shanecameron9400 wooooohooooo! Congrats!
Touching your tubes with your bare hands is ok. It's a myth that you shouldn't touch them with your bare hands.
Of course maybe wash them first. You dont want to change out tubes after doing an oil change on your car.
My hands have various not good things on em regularly so I play it safe. But, true!
He never said that. He said he didn’t want to get things in the tube that he touched with his hands
@@SECURITY39 what!!??....... regardless.....it's a myth....
@@ericwilliams538 Touching potentially destructive particles before you touch tubes can hurt your tubes because those particles can attach to the tubes. Therefore you should either wash your hands well before touching the tubes (after you touch those particles) or putt in light gloves OR both. His point has nothing to do with touching the tubes with your bare hands.
@@SECURITY39 good grief, what you're saying is a given, and goes with out saying. Of course if you just changed the oil in your car you don't want to run inside and change out the tubes in your tube amp.....So, again for the 3rd time touching your tubes with your bare hands will not harm your tubes.
I bet you change your light bulbs ( older non LED light bulbs) with out wearing any sort of gloves....and that would basically be the same principle.
Dude tap on them gently with a pencil eraser with the amp on, if you hear the rattle its.microphonic also known as tube rattle. Dont wack the new ones like that you will cause them to fail and or rattle. They are fragile.... 😅😂
🍻
You cannot measure current in parallel. To do this properly test resistance across resistor(the spot you tried to measure current) then measure the voltage drop across same spot. Then follow Olms Law. Please do not follow this procedure. There are much better teachers on youtube like Uncle Doug, El Paso tube amps, Blueglow Electronics any of the previous have proper videos on the subject. This is the biggest problem with the internet anybody can post anything they please right or wrong.
mcsniper77
These are bias reading points provided by Marshall. There is a 1ohm resistor to ground on the cathodes of each power tube. The voltage drop on the 1 ohm resistor is equal to the current flow in milliamps. You are measuring cathode plus plate current, so the readings you set it to will be conservative by a milliamp or two.
@@rjake61 Did you not read my comment or are you daft? Watch the video again his mutlimeter is set to measure current, which is impossible with that style of meter without interrupting the circuit IE placing it in series.
mcsniper77 is correct. You can't read amperage in parallel, only series. The multimeter should be set to milliVolts.
I think I’ve said lots of times I’m not an amp tech or even that smart. I followed steps I’d seen best as I could, and it seemed to work for me. Multimeters and their settings could be a video in itself cause wtf???!!😂😂😂
Hey Mr. Know-it-all. This is EXACTLY the procedure that Marshall designed for this amp.
Question what about the preamp tubes do those not need biasing ? Also isn’t that transformer live?
No to biasing. No idea on transformer.