Marshall DSL 50 tube bias??

[Celik]

Have any of you bias DSL 50 your self? I bought my amp second hand, and it sounds nice, but the previous owner informed me that he never changed the tubes himself. My amp was build in 2004 i think.

 

I was thinking of buying a meter and trying to measure the bias on the amp and see if i can run it a little hot? I am hoping this way i will be able get more sweet tone out of tubes at lover volumes. I am playing in the house at vol 2, above that it gets insane. Maybe i have all this wrong what do you guys think?

 

Also what are these amps biased at by default, on how much can i push it?

 

Thanks for your help.

[zehn]

When I biased my brother's DSL100, all it took was a multimeter, nothing special. Marshall was actually smart enough to put bias test points and a pot on the back of the amp. I wish more makers did that.

 

Anways, I set it to around 88 mV on both sides, though I'm not too sure about the 50 watter.

 

Ask around the Marshall forum, they would know.

[ComingApart]

http://www.eurotubes.com/euro-Marshall-DSLTSLV.htm

 

Mine was biased a bit too hot from the factory, lowering it made a big difference for the better.

[zehn]

 

http://www.eurotubes.com/euro-Marshall-DSLTSLV.htm Mine was biased a bit too hot from the factory, lowering it made a big difference for the better.

 

 

Just read that really quickly.

 

To the OP: Halve the value I gave you, so put it somewhere around 40-45 mV

[Celik]

http://www.eurotubes.com/euro-Marshall-DSLTSLV.htm Mine was biased a bit too hot from the factory, lowering it made a big difference for the better.

 

nicee find bro.

 

I thought i needed a speacial probe for this but a simple multimeter will do the job, which i already have. They say for DSL 50 you want to run it somewhere between 40 and 45 milivolts. Ill measure my and lf i find it at 45 milivolts ill take it down to 40 just to see what kinda of difference it makes and viceversa.

 

Just out of curiosity what did you leave your amp at?

[Celik]

Just read that really quickly. To the OP: Halve the value I gave you, so put it somewhere around 40-45 mV

 

thanks zehn i just saw that.

[solarburn]

thanks zehn i just saw that.

 

45 is too high and will wear your tubes out faster and the tone it gives won't be worth it. Running your tubes at 70% is considered hot by most and at this percentage your Plate Voltage would be at 385 to meet that 45 bias. No where near my DSL's PV. Say 450 is the PV Marshall is measuring from then the tubes will be running at 80% which is unnecessary. Too hot IMO.

 

Depending on which brand El34 you use PV can vary some. Generally my PV runs at 450 to 470 depending on the tube. Quite a bit more than 385. This means that 45 turns into a lower 37 to 38 at 70%. I wouldn't go over 40 in general especially if you aren't taking PV and running the numbers to find your proper bias. 38 is a solid bias IMO. I've rolled alot of different power tubes and that bias is a safe bet.

[Celik]

 

45 is too high and will wear your tubes out faster and the tone it gives won't be worth it. Running your tubes at 70% is considered hot by most and at this percentage your Plate Voltage would be at 385 to meet that 45 bias. No where near my DSL's PV. Say 450 is the PV Marshall is measuring from then the tubes will be running at 80% which is unnecessary. Too hot IMO. Depending on which brand El34 you use PV can vary some. Generally my PV runs at 450 to 470 depending on the tube. Quite a bit more than 385. This means that 45 turns into a lower 37 to 38 at 70%. I wouldn't go over 40 in general especially if you aren't taking PV and running the numbers to find your proper bias. 38 is a solid bias IMO. I've rolled alot of different power tubes and that bias is a safe bet.

 

 

Ahh so to get the Plate Voltage what do i need to do? Is that the voltage of the tube sockets?

 

So if i understood you correctly the higher the PV the lover the bias gets am i right? This numbers are confusing, i guess i can just try to measure it and live it around 40 bias. My whole goal is to get more tube tone at lover volume. I dont really care for the tubes in the amp right now i was going to replace them anyways as i think i can get better ones then what Marshall puts in. I just dont want to damage the amp that is my biggest concern.

[solarburn]

 

Ahh so to get the Plate Voltage what do i need to do? Is that the voltage of the tube sockets? So if i understood you correctly the higher the PV the lover the bias gets am i right? This numbers are confusing, i guess i can just try to measure it and live it around 40 bias. My whole goal is to get more tube tone at lover volume. I dont really care for the tubes in the amp right now i was going to replace them anyways as i think i can get better ones then what Marshall puts in. I just dont want to damage the amp that is my biggest concern.

 

 

I use a Weber Bias right to get my PV number. It gives it to me with a flick of a switch. I have found that really the bias number doesn't go up or down much between PV's like say from 450 to 470. That is why I recommended 38 as a good solid number to be at. PV at 450 running at 70% is 38. 470pv running at 70% is 37. See what I mean. I have run mine at 75/80% and didn't notice anything to my ears that made me think it was better. Your power tubes will last longer at 70%.

 

Your amp needs to be at a certain volume to get your power tubes coming in other wise most of your tone is preamp. I think 2(on the volume knob)and above is when the power tubes start coming in. Definitely at 3 to 4 they're opened up good. If you are going lower in volume then you are going to be stuck with preamp tube tone. Get some Winged =C='s or some Ruby EL34 BSTR's and bias them at 38 with a Multimeter. Preamp tubes make a big difference too. You want high gain or classic rock tones or both? You can get much better tubes than the stock ones. Its worth it to change them.

[Celik]

I use a Weber Bias right to get my PV number. It gives it to me with a flick of a switch. I have found that really the bias number doesn't go up or down much between PV's like say from 450 to 470. That is why I recommended 38 as a good solid number to be at. PV at 450 running at 70% is 38. 470pv running at 70% is 37. See what I mean. I have run mine at 75/80% and didn't notice anything to my ears that made me think it was better. Your power tubes will last longer at 70%. Your amp needs to be at a certain volume to get your power tubes coming in other wise most of your tone is preamp. I think 2(on the volume knob)and above is when the power tubes start coming in. Definitely at 3 to 4 they're opened up good. If you are going lower in volume then you are going to be stuck with preamp tube tone. Get some Winged =C='s or some Ruby EL34 BSTR's and bias them at 38 with a Multimeter. Preamp tubes make a big difference too. You want high gain or classic rock tones or both? You can get much better tubes than the stock ones. Its worth it to change them.

 

Thanks solarburn,

 

Yah i have read so much about how new set of tubes can change the tone. So i think i will invest in a new set. I would opt for both high gain and classic rock if it can be done. I like high gain but its got to be usable, tight and defined gain i don't want it to sound to muddy. Which tubes are you running in your dsl?

[solarburn]

Thanks solarburn, Yah i have read so much about how new set of tubes can change the tone. So i think i will invest in a new set. I would opt for both high gain and classic rock if it can be done. I like high gain but its got to be usable, tight and defined gain i don't want it to sound to muddy. Which tubes are you running in your dsl?

 

Right now I'm running the Winged =C='s which I like for more of a blues/rock tone. I took my RFT's out to try them. So far I like em'. They will cover alot of ground. I think the Ruby BSTR's though are thick, well balanced and a bit tighter than the winged =C='s. You might give them a try first. They are cheaper in price too. Get your preamp tubes right and that will help a bunch too. I have NOS tubes in my preamp that are warm and dynamic.

 

I have to get to work now but I can discuss this more at length tomorrow. I work the graveyard shift hehe. A good tube change and that amp will be rock'n.

[Celik]

Right now I'm running the Winged =C='s which I like for more of a blues/rock tones. I took my RFT's out to try them. So far I like em'. They will cover alot of ground. I think the Ruby BSTR's though are thick, well balanced and a bit tighter than the winged =C='s. You might give them a try first. They are cheaper in price too. Get your preamp tubes right and that will help a bunch too. I have NOS tubes in my preamp that warm and dynamic. I have to get to work now but I can discuss this more at length tomorrow. I work the graveyard shift hehe. A good tube change and that amp will be rock'n.

 

Thanks bro, appreciate all the info, and ill keep you posted with how the bias goes.

[solarburn]

Thanks bro, appreciate all the info, and ill keep you posted with how the bias goes.

 

Yeah let me know. I've got some ideas on preamp tube arrangement if you are interested. Just some suggestions of what I have found after roll'n tubes in this amp for some time now. If not interested no worries man.

[colejustesen]

When I bias my DSL100 my tube are usually around the 32-34 mA (per tube) so I would set it anywhere from 65-70 mA per side. You don't worry about the sides, so I would say shoot for 70 mA. To me it sounded better backed off than to bias it hotter.........This is solely my opinion though.

 

I wouldn't go over 70% dissipation, but you might mess around with the value under that to see what you like. This is how I found I like mine around the 32-34 mA per tube setting.

 

Cole

[Celik]

Hey sup guys, just a quick update.

 

I got some time tonight to bias the amp, so i powered it up and let it sit there for the tubes to worm up. Once that was finished, i took the measurement and i was astonished to find that the right side was set at 50 milivolts and the left was set at 47 mV. Marshall recommends for dsl 50 to be between 40 and 45 mv. Anyways based on the suggestions above i backed of and set both sides to 38mV.

 

I was happy with this change. The difference in tone was very noticeable, the bottom was tighter and more defined when i kick the boost pedal. I noticed a little more fizzynes but when the boost was engaged it would be minimal but still there. I had the amp at 2.5 volume, gain was set to 6 on lead channel 1. It was definitly better sounding then how it was before.

 

Initially my whole goal was to increase the bias on my amp, not even realizing that it was already running hot past its threshold. Since i got this amp used, i assume the previous owner was tweaking it and didn't know how to bias it right. But this got me thinking now that i have been playing this tubes like this for a while it might be time to change.

 

So somebody doing a new set off JJ tubes mentioned that once he put the new tubes in DSL 100, the fizzy noise disappeared, he got more usable gain, tighter bass. This sounds good to me so i am leaning in the direction of putting a new set of JJ's, what do you guys think?

 

I will also mess a little more with bias, thinking of increasing it to 40mV and see what that does for the tone. Overall i am happy with the change so far.

[solarburn]

Hey sup guys, just a quick update. I got some time tonight to bias the amp, so i powered it up and let it sit there for the tubes to worm up. Once that was finished, i took the measurement and i was astonished to find that the right side was set at 50 milivolts and the left was set at 47 mV. Marshall recommends for dsl 50 to be between 40 and 45 mv. Anyways based on the suggestions above i backed of and set both sides to 38mV. I was happy with this change. The difference in tone was very noticeable, the bottom was tighter and more defined when i kick the boost pedal. I noticed a little more fizzynes but when the boost was engaged it would be minimal but still there. I had the amp at 2.5 volume, gain was set to 6 on lead channel 1. It was definitly better sounding then how it was before. Initially my whole goal was to increase the bias on my amp, not even realizing that it was already running hot past its threshold. Since i got this amp used, i assume the previous owner was tweaking it and didn't know how to bias it right. But this got me thinking now that i have been playing this tubes like this for a while it might be time to change. So somebody doing a new set off JJ tubes mentioned that once he put the new tubes in DSL 100, the fizzy noise disappeared, he got more usable gain, tighter bass. This sounds good to me so i am leaning in the direction of putting a new set of JJ's, what do you guys think? I will also mess a little more with bias, thinking of increasing it to 40mV and see what that does for the tone. Overall i am happy with the change so far.

 

Good job man! Go ahead and hit 40 to see what happens. Get to know your amp. Of course if you get new power tubes you will be doing it all over again to see how they respond to different bias but I think the sweet spot is from 36 to 40 depending on the tube.

 

The JJ's are a darker tube and usually do well with a brighter amp. DSL's are a bright amp. Unfortunately for me the idea didn't work out. I used a kit so I had all JJ's in the preamp. To me they sounded dull and lifeless. The gain was not defined at all. So I didn't like them.

 

For high gain I would use Ruby 12AX7AC5 HG+ and a Sovtec LPS in the PI slot. Don't use any other Sovtecs though. Sterile tubes but not the LPS.

 

For a mix of classic rock and hardrock I'd use a Mullard RI in V1, a Tung Sol in V2, a Ruby 12AX7AC5 Select HG(not the plus)and an LPS again in the PI.

 

Don't put a Tung Sol in V3 or a Mullard RI either due to them not being able to handle a cathode follower stage. Too much voltage there. Same with the LPS. It will die there.

 

I prefer NOS tubes in mine. YMMV

[colejustesen]

 

Good job man! Go ahead and hit 40 to see what happens. Get to know your amp. Of course if you get new power tubes you will be doing it all over again to see how they respond to different bias but I think the sweet spot is from 36 to 40 depending on the tube. The JJ's are a darker tube and usually do well with a brighter amp. DSL's are a bright amp. Unfortunately for me the idea didn't work out. I used a kit so I had all JJ's in the preamp. To me they sounded dull and lifeless. The gain was not defined at all. So I didn't like them. For high gain I would use Ruby 12AX7AC5 HG+ and a Sovtec LPS in the PI slot. Don't use any other Sovtecs though. Sterile tubes but not the LPS. For a mix of classic rock and hardrock I'd use a Mullard RI in V1, a Tung Sol in V2, a Ruby 12AX7AC5 Select HG(not the plus)and an LPS again in the PI. Don't put a Tung Sol in V3 or a Mullard RI either due to them not being able to handle a cathode follower stage. Too much voltage there. Same with the LPS. It will die there. I prefer NOS tubes in mine. YMMV

 

 

I agree about the JJ tubes, the only JJ I have liked was the KT77 power tube. I use the Ruby selects in V3 and V4, as well as the Tung-Sol in V2, but I use a Tung-Sol in V1. This to me yields really good results, and then use some power tubes like Ruby EL34BSTR or =C= EL34s and you will get a very awesome sounding amp!

 

Cole

[solarburn]

 

I agree about the JJ tubes, the only JJ I have liked was the KT77 power tube. I use the Ruby selects in V3 and V4, as well as the Tung-Sol in V2, but I use a Tung-Sol in V1. This to me yields really good results, and then use some power tubes like Ruby EL34BSTR or =C= EL34s and you will get a very awesome sounding amp! Cole

 

 

Yeah thats a good mix too. The reason I said a Mullard RI in V1 is because it is a lower gain 12AX7 and will add to that classic rock vibe as well give a good clean channel too. Having a higher gain tube in V2 will still give you a solid gain but won't effect the clean channel like V1 will.

 

There was a method to my madness on that mix. A good medium gain NOS 7025 in V1 and a high gainer in V2 covers a fair amount of ground I've found. V3 and the PI aren't as crucial as far as the gain factor of this amp so some well balanced(frequency)tubes will do well for them. To me the LPS has been as good as my NOS in the PI slot. Try an AT7 in V3. I was surprised that it didn't adversely effect the amps tone stack. It even sounds good and it will handle any voltage there.

[Celik]

Good job man! Go ahead and hit 40 to see what happens. Get to know your amp. Of course if you get new power tubes you will be doing it all over again to see how they respond to different bias but I think the sweet spot is from 36 to 40 depending on the tube. The JJ's are a darker tube and usually do well with a brighter amp. DSL's are a bright amp. Unfortunately for me the idea didn't work out. I used a kit so I had all JJ's in the preamp. To me they sounded dull and lifeless. The gain was not defined at all. So I didn't like them. For high gain I would use Ruby 12AX7AC5 HG+ and a Sovtec LPS in the PI slot. Don't use any other Sovtecs though. Sterile tubes but not the LPS. For a mix of classic rock and hardrock I'd use a Mullard RI in V1, a Tung Sol in V2, a Ruby 12AX7AC5 Select HG(not the plus)and an LPS again in the PI. Don't put a Tung Sol in V3 or a Mullard RI either due to them not being able to handle a cathode follower stage. Too much voltage there. Same with the LPS. It will die there. I prefer NOS tubes in mine. YMMV

 

Thanks solarburn, i am going to go look into the Ruby 12AX7AC5 HG+ and a Sovtec LPS for high gain. I am after the Alice in Chains tone of the Dirt album. I don't think Jerry Cantrell used Marshalls but i think with the right set of tubes i can get in the ball park.

 

I forgot to look when i was tweaking the bias, are the sockets labeled like you mentioned PI, V1, V2, V3 etc. I am trying to fallow your set up and just want to make sure when i get the tubes, that i know which type of tube goes in which socket?

 

As far as tweaking it again with new tubes, i really enjoy doing this kinda of work, like you said you learn how the amp works and i just like doing things my self vs a tech. I have done some moding on my fender amp so i enjoy this stuff.

 

I will do some bias tweaking again over the weekend and post my findings.

[solarburn]

Thanks solarburn, i am going to go look into the Ruby 12AX7AC5 HG+ and a Sovtec LPS for high gain. I am after the Alice in Chains tone of the Dirt album. I don't think Jerry Cantrell used Marshalls but i think with the right set of tubes i can get in the ball park. I forgot to look when i was tweaking the bias, are the sockets labeled like you mentioned PI, V1, V2, V3 etc. I am trying to fallow your set up and just want to make sure when i get the tubes, that i know which type of tube goes in which socket? As far as tweaking it again with new tubes, i really enjoy doing this kinda of work, like you said you learn how the amp works and i just like doing things my self vs a tech. I have done some moding on my fender amp so i enjoy this stuff. I will do some bias tweaking again over the weekend and post my findings.

 

The socket farthest away from your power tubes is V1 and the PI(V4)is the closest slot to your power tubes. V1 will have that metal shield on it. The rest follow it in numbered sequence. V1 and V2 are going to be your key gain sockets. The LPS is a high gain tube and sounds ok in V1 but is a much better tube in the driver slot(PI).

 

Have fun with it man I know I have and continue to roll tubes cause I have a bunch. I just make sure to write down my favorite tone packs so I don't forget.

[groovy13]

I am going to bias my 100 watt in a few days myself--amazing but I only found that some one video on line--looks fairly easy---crossing figures--hope it goes wel for all---

 

Rock on!!