HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

[Shooter.556]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Don't do it man
It'll kill ya

Your tubes will last about 10 years or so if you do nothing. When you change tubes , let the tech check it.

There's nothing in there worth risking your life for

I am a an industrial electrician by trade
I am really comfy doing this myself. If you get comfortable one time.
Miss one thing
Pow
Lights out

Don't mess with it

Play it
When it breaks take it to a professional
Just like your car

*(Sent from my durned phone!)*

What he said, I am also an industrial electrician by trade, I do controls work.
I've had a 10 tube Phantom HAM radio amp knock my dick in the dirt.o
The only thing that has hurt as bad was a 277v lighting ballast that knocked me off a ladder.

The power in tube amps is deadly, don't mess with one unless you have knowledge of electricity because of what I stated above, a veteran can still get hit. I watched an apprentice die in 07 on a lighting ballast, I took a hit 2 years later and it made the fillings in my teeth hot.
That is my PSA for the day, don't fool with tube amps if you don't have the skills to do it.

 

[Nostalgic Distortion]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

I asked this same question a few months back & for the exact same reason, I live in a rather rural area and the closest tech to me is about 300 miles away. I will give you the same answer that I got, if you have to ask you have no business even trying! Even if you have to ship it to someone who knows their stuff it's well worth it! Some techs are even alright with you just sending the chassis to keep the weight down, obviously remove all tubes & pack it extremely well if you go this route. Knowing what to do won't do you any good @ all if you're dead?

 

[Brandenburg]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

a persons life is a persons life and they can spend it like they choose..SO it doesn't matter how many warning ya give a person, they are still gonna do what they want

as long as a person does the proper amount of research, has a touch of common sense and remembers.. safety 1st.. I see np with someone doing a job like this..basically when your time is up.. its up.. no matter how cautious you are

I personally ....rarely, if ever use this forum or any other forum for advice on how to fix something..not that some of ya dont know ya's sh*t.. i will do my own reading and researching and on the rare occasion im unclear about something, i might ask ..i do have to keep on telling myself though.. thats me and not everyone thinks like that

 

[LLL]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Just say "no".

 

[tman]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

I have been having a tech do it thats pretty close and he has some great equipment that does it accurate and fast. He has taught me how to do it,but I just take the amp to him and all is well.

 

[Brandenburg]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

I have been having a tech do it thats pretty close and he has some great equipment that does it accurate and fast. He has taught me how to do it,but I just take the amp to him and all is well.

i need to work on my amp and i dont wanna but no money to take it to the shop.. 2 things are simple to fix.. replace the speaker jack and the jones-sinch footjack plug.. the other is the damn sustain boost switch and/component that had failed 15 years ago.. i never use it much when it worked but it would be nice to ever so often.. makes playing at bedroom volume easier

 

[Lake Placid Blues]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

i need to work on my amp and i dont wanna but no money to take it to the shop.. 2 things are simple to fix.. replace the speaker jack and the jones-sinch footjack plug.. the other is the damn sustain boost switch and/component that had failed 15 years ago.. i never use it much when it worked but it would be nice to ever so often.. makes playing at bedroom volume easier

Your's is a solid state amp right? That makes it even more important to drain any residual energy in the power supply before working on it-especially working on the output jack. With a tube amp its easy. Just locate the v1A plate terminal at the end of the line and jumper it to ground. This drains the power supply slowly through the plate resistor (no sparks, arcs, or mini lightning bolts). I can't tell you how to do it to your SS amp. But any short circuits or arcs will destroy solid state components, such as your output transistors. Do you you have a schematic for it?

Randall made a high gain all tube amp, RGT-100, that was a pretty good amp.

 

[ken361]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

I wanted to learn to bias but I rather buy those plugin ones and stick the tube in and do it that way instead of using the test points, cant afford nothing now not working. Any ways the amps been running great all weekend jamming loud no problems so far!! If the distortion sound crappy when I put the new tubes in then I would of had a tech look at it. It plays the same!!

 

[tman]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Thats what my tech uses. No test points. He uses the plugin kind and its nice, simple, and quick.

 

[Shooter.556]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

I wanted to learn to bias but I rather buy those plugin ones and stick the tube in and do it that way instead of using the test points, cant afford nothing now not working. Any ways the amps been running great all weekend jamming loud no problems so far!! If the distortion sound crappy when I put the new tubes in then I would of had a tech look at it. It plays the same!!

I'm getting ready to buy one of these and go to that method. The one I am looking at plugs directly into my Fluke meter.

 

[allbutromeo]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

I have the one that eurotubes sells and I've been quite happy with it so far

 

[Darg1911]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Judging by the majority of responses, this isn't going to be popular but ... if I have to bring an amp to a tech to bias tubes, I'm not buying a tube amp. That doesn't mean that I think anyone and everyone should be pulling a chassis and opening themselves up to the potential of getting bit, or worse. Some people are truly incapable of thought and have no common sense, period. But I believe that the majority of people have enough common sense and smarts. I personally think that there is too much being made of the process in this thread. Absolutely, there is the risk of getting the **** shocked out of you, or worse. But IMO there is a sense of mystique being promoted in this thread. Biasing power tubes is not rocket science and avoiding getting shocked does not require a surgeons skill. If one has the desire and common sense and just lacks the knowledge, then I think they are a good candidate for studying up and learning how to do it themselves. If one is intimidated by the thought of an open chassis, or electricity in general and has no technical aptitude whatsoever, then leave it to a tech. Of course it's at your own risk if you decide to tackle it yourself but again, it's not rocket science.

All that said, I'm not a tech but I am capable of and competent in doing this myself. And, I fully understand those here who know what they're doing not wanting to share the information on a public forum and assume any risk or responsibility. I wouldn't give the details here either. I just think that some of the posts cross the line into fear mongering.

Flame away if you must.

 

[Shooter.556]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Judging by the majority of responses, this isn't going to be popular but ... if I have to bring an amp to a tech to bias tubes, I'm not buying a tube amp. That doesn't mean that I think anyone and everyone should be pulling a chassis and opening themselves up to the potential of getting bit, or worse. Some people are truly incapable of thought and have no common sense, period. But I believe that the majority of people have enough common sense and smarts. I personally think that there is too much being made of the process in this thread. Absolutely, there is the risk of getting the **** shocked out of you, or worse. But IMO there is a sense of mystique being promoted in this thread. Biasing power tubes is not rocket science and avoiding getting shocked does not require a surgeons skill. If one has the desire and common sense and just lacks the knowledge, then I think they are a good candidate for studying up and learning how to do it themselves. If one is intimidated by the thought of an open chassis, or electricity in general and has no technical aptitude whatsoever, then leave it to a tech. Of course it's at your own risk if you decide to tackle it yourself but again, it's not rocket science.

All that said, I'm not a tech but I am capable of and competent in doing this myself. And, I fully understand those here who know what they're doing not wanting to share the information on a public forum and assume any risk or responsibility. I wouldn't give the details here either. I just think that some of the posts cross the line into fear mongering.

Flame away if you must.

http://www.premierguitar.com/articles/17116-how-tube-amps-work?page=2

I agree with you biasing is not rocket science, I do way more complicated and dangerous stuff at work messing with DC buss voltages over 700 volts.
What makes tube amps dangerous is the rectifiers in play and the fact that you can have AC and DC voltages present on the same wire.
The link above goes into the theory of this pretty well. What I said above is what makes tube amps dangerous to work on. Even my $500 Fluke 87V with all of the extras I have purchased for it wont read AC and DC voltages at the same time. I will say this one more time.. IF YOU DON'T HAVE THE UNDERSTANDING AND WORKING KNOWLEDGE Of OHM'S LAW, BOTH TYPES OF ELECTRON FLOW OR HOW RECTIFIERS WORK THEN YOU DON'T NEED TO BE FOOLING AROUND WITH DEATH. I am not trying to act like a dick here and I fully encourage everyone who is into any type of hobby to learn how to work on their own ****.. It saves time and a lot of money. What I am saying is, don't post on the Seymour Duncan forum and ask us for help with something then get upset when we care enough as human beings not to say well just do this knowing damn good and well we might get someone killed with our advice. If you have to ask the question. How do I bias tubes in this DSL40 I am getting? You have zero business biasing the tubes in the DSL40 you are getting. I'm not trying to be mystic or act like I am smarter than anyone, I am acting like a man that deals with lethal voltages on a daily basis caring about what happens to another human being.

I am here for any questions he has, he can feel free to inbox many of us. I'll answer questions and give him links to things he needs to learn but I will not ever knowingly put another person or thing in harms way. The US Marine in me makes me a better person than that.. I have watched men draw their last breath, some I could help and some I couldn't. I always err to the side of caution, life is precious and everyone out there has someone who loves,cares and wants them around.

I assume everyone is stupid until they prove me otherwise. I had a Command Sgt Major tell me once time when I was a Boot. SON! ASSUMPTION IS THE MOTHER OF ALL ****UPS! REMEMBER THAT BOY! I did an eye sir and went on but I never forgot that..

Now I am off my high horse, carry on!

 

[Brandenburg]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Your's is a solid state amp right? That makes it even more important to drain any residual energy in the power supply before working on it-especially working on the output jack. With a tube amp its easy. Just locate the v1A plate terminal at the end of the line and jumper it to ground. This drains the power supply slowly through the plate resistor (no sparks, arcs, or mini lightning bolts). I can't tell you how to do it to your SS amp. But any short circuits or arcs will destroy solid state components, such as your output transistors. Do you you have a schematic for it?

Randall made a high gain all tube amp, RGT-100, that was a pretty good amp.

yeah.. i have a schematic.. used it to make a footswitch 6 years ago.. i also have a degree in electronics not to say that makes me competent..LOL.. i need to brush up on my electronics skills though as i havent used them in 5 years or so.. so ill scourer the net, and read. Been meaning to make me something to discharge a cap too.. the footswitch plug is easy.. its 26 years old and no longer makes good contact..and one of the speaker jack is busted.. one day i lifted up my amp w/o disconnecting the speaker cable and the stress broke the plug.. not sure on the switch.. i personally believe its the rocker switch and not the d5/d6 diode .. just the way it acts.. not to say the problem isnt something else as well

 

[Hank-]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

The problem or risk factor when troubleshooting or biasing a valve amp is the appliance needs to be plugged in and running. That puts one in close proxity to both live mains AC voltage & high DC voltages within the amp. So if anyone has proper understanding to deal with either, then that's a good starting point otherwise death can happen. That's why i guess most everyone here is suggesting not going inside an amp with no technical knowledge of safety & a typed out internet guide or vid. The proper safe approach would be to learn it from a human tech, that way someone experienced is around to guide you as well as protect your life just in case. For those that don't have nearby access to amp tech, there may be places that fix old tvs & stuff. You could take the amp along with the instructions found online regarding biasing to such a place & have them do the work, especially amps that require internal pcb trimmer adjustments or resistor swaps or other involved methods to adjust the bias.

 

[Brandenburg]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

The problem or risk factor when troubleshooting or biasing a valve amp is the appliance needs to be plugged in and running. That puts one in close proxity to both live mains AC voltage & high DC voltages within the amp. So if anyone has proper understanding to deal with either, then that's a good starting point otherwise death can happen. That's why i guess most everyone here is suggesting not going inside an amp with no technical knowledge of safety & a typed out internet guide or vid. The proper safe approach would be to learn it from a human tech, that way someone experienced is around to guide you as well as protect your life just in case. For those that don't have nearby access to amp tech, there may be places that fix old tvs & stuff. You could take the amp along with the instructions found online regarding biasing to such a place & have them do the work, especially amps that require internal pcb trimmer adjustments or resistor swaps or other involved methods to adjust the bias.

when i took my randall to get it fixed around 2003.. i took it to a tv repair shop.. seriously no amp techs in my area it would seem

 

[Darg1911]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

There are plenty of resources on the net that provide the information. That alleviates the forum or it's members from any risk or responsibility. If they are so inclined, they can seek the information out and apply it at their own risk, or don't apply it at all. I agree with shooter5.56 in that I don't personally want to enable or empower stupid. But, I'm not about discouraging people from expanding their knowledge and capabilities. It's up to the individual to know their own limitations and to understand the concept of personal responsibility (increasingly foreign concept that it may be).

Keep your booger hooks off the bang switch.

 

[misterwhizzy]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

ok yeah Ive been studying some vids on the subject and understand what not to touch.I did see they have trim pots in these amps that you turn with screw driver to get the current you need. And I am ordering a meter and bias tool. Im not saying I needed to do it right away Im just saying that if I do happen to have a problem with a power tube or want to change brands etc.. down the road I would like to learn how to do these things myself thats all. I am aware that amps store current even if not on in the capacitors etc...And I did hear that go in with one hand safety advice. I will study more and take my time and only do it if the problem occurs.thanks for all the concern I really do appreciate it thanks

You can't store current. Don't jump into this just yet, bro.

 

[ken361]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Theres a new vid on biasing the amp, looks pretty easy.

 

[ken361]

Re: HOW TO BIAS getting first tube amp!! Marshall DSL 40 EL34'S

Tman did you have it biased yet? was it off by much?