DSLs ..run em' cool..

[Adrian R]

Just a quick reminder to the DSL100 group out there...

Keeping the amp biased on the cool side e.g. (mid<30s) keeps things tight...AND cool. My amp after 3 hours of practice just gets warm, 'almost' hot on the vent plate directly above the power tubes....

DSL100s were always observed running very hot due to the high voltages that Marshall recommended.

It doesn't run any hotter then any other properly biased 100w Marshall head...

 

[Rahlstin]

I biased mine at 83/side and used a 120mm silentish computer fan fastend to the inside of the rear grill. Ive used the fan for years. It certainly dosnt hurt to have very good airflow.

 

[Adrian R]

I biased mine at 83/side and used a 120mm silentish computer fan fastend to the inside of the rear grill. Ive used the fan for years. It certainly dosnt hurt to have very good airflow.

Man, I could be wrong, but that is WAY to hot! You should be running around 38-45mA per side...90mA max. both sides combined....

The amp will sound far tighter...and run far cooler...and your tubes will last for a LONG time....

I cannot believe how hot many folks on here run their DSLs!

btw...EVERY Marshall I have ever owned...including ALL 900s and three different 800s/JMP all were biased at approx. 30-42ma PER EL34 total for both 50 and 100watters... (depending AGAIN on plate voltage)

JUST DO THE MATH!! Get the PV, and determine what you should be running at within the 60-70% dissipation rate. let your ears be the final judge...In the end the cooler the amp can run (within spec) the better...

 

[Bloodrock]

I'm with you Adrian. Many people run the DSL's way too hot. Check your plate voltage to bias, don't rely on arbitrary settings from wherever. I run my 50 watter at 32-33ma (65%) and its tight, crunchy, and clear. No fizz, mud, or flub anymore.

 

[Adrian R]

I'm with you Adrian. Many people run the DSL's way too hot. Check your plate voltage to bias, don't rely on arbitrary settings from wherever. I run my 50 watter at 32-33ma (65%) and its tight, crunchy, and clear. No fizz, mud, or flub anymore.

PRECISELY BLOODROCK MAN.... This is why the DSL has been treated with such disdain by the pro 800 group...I too thought DSLs sucked until I really spent some quality time with them. In my band, I have mine sounding REALLY close to a vintage 2203...and if I use my Fulltone pedal...and set it for vintage mode (boosted mids)..it sounds nearly identical...PLUS I have the red channel in which the 2203 doesn't have..

I like DSLs more! BTW..you may also have noticed that the amp runs far cooler to the touch... I'm just as happy as a pig in shit when I reach over to my amp in the middle of practice and just feel 'warm'...I know she's chillin' and runnin' good..

 

[diesect20022000]

I liked mine ran at 42ma per side max. 40ma the best overall. i tried 38 per side and it sounded too brittle for my taste but i use a clean boost too so that wouldn't help i imagine. I agree though they should be cooler.

 

[Rozman62]

Mine is currently at 41/side and I can smell the hotness of the amp after 20 min. Toss a few ballpark franks on there and they will be done within the hour. Going down to 38/side and will evaluate. My amp sounds awesome right now but if I can equal or improve the tone by chilling it out a little that will give me additional tube life which is all good. Got to look into measuring the PV and applying the formula.

 

[MonstersOfTheMidway]

36mA each tube on my 410H (that's a combined 72mA for two tubes on each side).

 

[Sidebrowns]

30s per side?! I thought those were 50 watter values. I know the Marshall recommendation was high at 90 per side on a DSL100 but I thought the consensus here was high 70s - mid 80s?

 

[Adrian R]

30s per side?! I thought those were 50 watter values. I know the Marshall recommendation was high at 90 per side on a DSL100 but I thought the consensus here was high 70s - mid 80s?

This is where everyone is totally wrong...Marshall's instructions have been interpreted wrong...its 80-90mA (or mV if you measure from the pins) TOTAL of BOTH sides....for a DSL100

 

[Rozman62]

Oh fuck-Here we go again dude.

Refresher Course
DSL 100 = 90 total
DSL 50 = 45 total

Folks - Adrian is spot on with his commentary.

 

[SpiritOfTheAge]

Oh fuck-Here we go again dude.

Refresher Course
DSL 100 = 90 total
DSL 50 = 45 total

Folks - Adrian is spot on with his commentary.

No, its per side, not total,

go here Weber Bias Calculator

and enter your plate voltage (mine is 487 with valves in, 493 when out) and at 70% (which is hot hot hot) I have to run 35.9 per valve, so on my 50 watter I run at abrond 33 PER SIDE, not total so if you are running a 100 watter that would be around 66 PER SIDE, way below the 90 suggeted by marhsall (45 for 50 watter) but given my plate voltage I would be in trouble if i ran it around 45 I would exceed my maximum dissapation (is that the right term?)

According to you guys in the 'total camp' I would be running my 50 watter a close to double what is safe, but what is really happening is that you are running your super cold, like ice age baby thats why your amp isn't getting hot (like its desgined to do) its running like a fooking fridge. hope this helps.

 

[SpiritOfTheAge]

I'm with you Adrian. Many people run the DSL's way too hot. Check your plate voltage to bias, don't rely on arbitrary settings from wherever. I run my 50 watter at 32-33ma (65%) and its tight, crunchy, and clear. No fizz, mud, or flub anymore.

This man talks sense as he has a 50 watter and is running each valve at 33ma (as he says 65%) given his plate volatge, if you run you 100 watter at mid 30 per side then you are way starving your valves of the juice the so badly need. Tone Jucie!

 

[redscott131]

.....you are way starving your valves of the juice the so badly need. Tone Jucie!

so would that be diet tone juice?

 

[Adrian R]

This man talks sense as he has a 50 watter and is running each valve at 33ma (as he says 65%) given his plate volatge, if you run you 100 watter at mid 30 per side then you are way starving your valves of the juice the so badly need. Tone Jucie!

We are saying the same things...33mA TOTAL not per tube man...in a 50w amp...The bias calculator as illustrated does precisely what that simple calculation does. This still does not change anything. One hundred watter...the sum of BOTH sides together...as well as the 50w amp. btw...my 100w DSL biased at 38mA PER SIDE sounds kick ass, dynamic and loud as hell...right there with a healthy 2203...and is just 'almost' hot to the touch on the tube vents...

 

[RickyLee]

I set my DSL100 at 65mV/mA per side/two EL34's. Sounds no worse than when I go higher towards 80mV/mA per side. My plate voltage is aprox. 480V.

For a DSL50 you would go 30mV/mA to 40mV/mA per side. But it is wise to know your plate voltage as this will vary depending on your home/building MAINS Service voltage.

I have tried the hotter settings and never heard any MagiK V00d00 tone coming out of the amp. But the risk of tube failure at the higher settings is good betting odds for sure.

:Ohno:

 

[SWM510]

For the first few weeks I owned my DSL 100 I used Marshall's recommendations but biased it at 85 - 87 mA and when I got a bias probe and measured the plate voltage and did the math I found for 65% dissipation it should be biased around 68mA (34 per side), which is a big difference from what Marshall recommends.

Anyone who owns a DSL I recommend getting a bias probe and measuring the plate voltage and properly biasing it. As Adrian said it sounds much tighter and runs much cooler and overall the tone sounds much better when properly biased.

 

[SpiritOfTheAge]

We are saying the same things...33mA TOTAL not per tube man...in a 50w amp...The bias calculator as illustrated does precisely what that simple calculation does. This still does not change anything. One hundred watter...the sum of BOTH sides together...as well as the 50w amp. btw...my 100w DSL biased at 38mA PER SIDE sounds kick ass, dynamic and loud as hell...right there with a healthy 2203...and is just 'almost' hot to the touch on the tube vents...

Your 100 watt at 38 per side is way under spec, for a 50 watt it may be in the ballpark dependant on the readings from pin 3, but for the 100 watt head you NEED to be doubling that to get the power section working as it should, given that the 2 readings you get from the DSL 100 watt head are for the 2 valves on either side of the push pull circuit design.

(Of course the value that marshall gives per side for the 50/100 watt may also include the 5ma that the screen current or it may not so 45/90 respectivley may not be as hot as we imagine)

As it stands i know fuck all about amp design, building, trouble shooting etc, but real basic stuff like this really needs to be grasped if you are going to do this stuff yourself otherwise you are just pissing in the wind.

Im out of here now, can i suggest some reading on biasing, this is a good article.

Bias FAQ

 

[Adrian R]

Your 100 watt at 38 per side is way under spec, for a 50 watt it may be in the ballpark dependant on the readings from pin 3, but for the 100 watt head you NEED to be doubling that to get the power section working as it should, given that the 2 readings you get from the DSL 100 watt head are for the 2 valves on either side of the push pull circuit design.

(Of course the value that marshall gives per side for the 50/100 watt may also include the 5ma that the screen current or it may not so 45/90 respectivley may not be as hot as we imagine)

As it stands i know fuck all about amp design, building, trouble shooting etc, but real basic stuff like this really needs to be grasped if you are going to do this stuff yourself otherwise you are just pissing in the wind.

Im out of here now, can i suggest some reading on biasing, this is a good article.

Bias FAQ

I, shit man, I fucking give up man..The amp sounds fucking awesome the way I have it biased...I still think that everyone disagrees simply does not understand what is being portaryed. I don't know how I could be anymore clear...

DSL100: 38mA per SIDE...(two tubes)..my amps sound KICK ASS.... I'm done though..anyone who wants their DSLs to sound like proper Marshalls..that is tight, with great mids...warm with good, wall shaking power.. etc..do as I have done if not..then cool: enjoy the slop...

 

[SWM510]

I think some of the confusion about per side or total is because when you use a bias probe it shows each side individually and when you just use a DMM is shows a total for both sides.

For example in my experience when I use the bias probe (and for sake of this discussion) if I wanted to bias my DSL 100 at 90mA the bias probe would show 45mA per side but when I just use a DMM it would show 90mA per side.


I'm not a tech by any stretch of the imagination so if any of the tech's or any other of the knowledgeable people on here would like to chime in and set us all straight on this, please feel free.

So if I'm correct with this then Spirit both you and Adrian are basically saying the same thing just in a different way.