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Old 10-10-2008, 02:35 PM   #1 (permalink)
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Your bias number for your DSL...

I'm curious to see where you guys are biasing your DSL100's/50's. I've got Tung Sol EL34B's in my DSL50 and have been messing around with some cooler biases. Right now I've got it set at 33mv. Looks like I'm running mine in the 60% range according to a Jim Jones Bias table located on Weber's site.

Bias chart for EL34's
25 watts disipation.

EL34 - 25W Hot (70%) Avg (60%) Cool (50%)
300V 58mA 50mA 42mA
325V 54mA 46mA 38mA
350V 50mA 43mA 36mA
375V 47mA 40mA 33mA
400V 44mA 38mA 31mA
425V 41mA 35mA 29mA
450V 39mA 33mA 28mA
475V 37mA 32mA 26mA
500V 35mA 30mA 25mA
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Quote:
Originally Posted by steelhorse View Post
I couldn't handle it after a few minutes. I got whiplash during the cleans (from almost nodding off) and then thought the dog was howling during the first part of the distortion.

He pretty much lost me with the tongue thing right off the bat though to be honest.

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Old 10-10-2008, 03:59 PM   #2 (permalink)
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Re: Your bias number for your DSL...

86mV TSL100 w/KT77's
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Old 10-10-2008, 06:53 PM   #3 (permalink)
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Re: Your bias number for your DSL...

I am absolutely agree with the chart for hot tube EL 34 in 450V power supply-as mush as it is approximately in DSL-50.Bias should be arround 39 mA-my DSL-50 is 40mA.
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Old 10-10-2008, 07:08 PM   #4 (permalink)
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Re: Your bias number for your DSL...

Yah the reason I did this was to see if others found their amps sound better at lower bias than Marshall's 45mv which I think is too hot. Also curious just to see where you are at and how you like it. Keep em' coming.
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DSL50 - FJA modded
V1-7025
V2-Raytheon BP
V3-RCA 12AX7A
PI-Magnavox
Power tubes:Winged "C"/SED


Vox Night Train
V1-Russian EL84
V2-Russian EL84
V3-JP 12AX7WA
PI- RFT


Quote:
Originally Posted by steelhorse View Post
I couldn't handle it after a few minutes. I got whiplash during the cleans (from almost nodding off) and then thought the dog was howling during the first part of the distortion.

He pretty much lost me with the tongue thing right off the bat though to be honest.

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Old 10-11-2008, 09:34 AM   #5 (permalink)
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Re: Your bias number for your DSL...

Well that is very individuall and very discussed.Everyone is aming to find the most appropriate for himself sound.
When I bought my DSL-50-brand new from the music shop-bias was about 41,5mA(or mV in bias socket).If you set it's level too low you have a loss in the out power-but the sound is a little bit softer(accordnig to me).Some people like exactly that.
I have an amp with EL34 and power supply-450V which I have biased on 35mA-but it is not a Marshall.
Sometimes happens a misunderstandig e.g.-one JCM800 -50W which has a power supply about 380V - clearly needs a higher bias.
You can try to rebias it to about 40 mA and to bring it back to 33mA to hear the difference in the sound and to decide for yourself-what exactly do you want and how you like it.

Regards!
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Old 10-11-2008, 10:21 AM   #6 (permalink)
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Re: Your bias number for your DSL...

Right now I am running a 34mv bias at 470 plate voltage. I finally checked actual plate voltage. It sounds pretty good and I really don't hear it running thin. 70% which is considered hot my bias number works out to be 37mv. 60% my bias number is 31/32.

I hear mine get flabby and mushy at 45mv where Marshall recomends. Looks like Marshall is using 380 plate voltage to get that 45mv bias number. Nowhere near my actual plate voltage of 470v.

Are any of you guys checking where your plate voltage is or just using around the the zone of what these amps run at which is suppose to be 450v to 500v.
__________________
DSL50 - FJA modded
V1-7025
V2-Raytheon BP
V3-RCA 12AX7A
PI-Magnavox
Power tubes:Winged "C"/SED


Vox Night Train
V1-Russian EL84
V2-Russian EL84
V3-JP 12AX7WA
PI- RFT


Quote:
Originally Posted by steelhorse View Post
I couldn't handle it after a few minutes. I got whiplash during the cleans (from almost nodding off) and then thought the dog was howling during the first part of the distortion.

He pretty much lost me with the tongue thing right off the bat though to be honest.

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