Just watched your video and have the same amp. My amp works but it seems that volume is weak not as strong and have to crank up the master volume . I have never had to do that ever. You think maybe the power tubes are bad ? Mine is a 2004 model . Appreciate any advice, thanks .
Hey what is the best settings to get great Hendrix style tones? How can I get it to sound like a plexi? Do I need to change the speaker or what? If so, what is the best speaker to put in it for that type of tones?
Thanks so much for this, im still alive anyway. My bias reading is 1.2 volts and the Pot wont let me take it lower than 1.02v, is there anything I can do to make it lower?
There are a couple of options. You could select a different set of EL84's. The ones you are using appear to be a bit "hot". Or you could just set it to 1.02 volts and you would be at 9 watts plate dissipation at idle instead of 8 watts- hotter but should not present a problem except possibly shorten the tube life a bit. Still way better than the Marshall recommendation per service bulletin. The final option is more complicated. You could modify the bias circuitry surrounding the bias pot VR12 to give more negative bias voltage which would enable you to limit the plate current more. ( Also make sure all volume pots are turned down to "0" when taking measurements.
Hi James, thank you for your videos, I'm gonna pass this by you just in case... I have a JCM 2000, English 100w head, (2005 post bias drift), just purchased off the Internet, I just re-tubed it but it still sounds like it has a cool bias setting even though I have it set hot (88mV, Marshall recommends 90), I tried cleaning the effects loop, patching it but to no avail... Something I just noticed is, if I tap on the master volume knob it won't completely mute when I have it on 0, if I keep tapping it goes away (completely mute), and comes back so naturally I stop tapping when it's muted (normal), ever come across anything like this?
I would use contact cleaner on the volume potentiometer if you haven’t already. Even turning the knob to 10 and back to 0 multiple times will sometimes clear any buildup inside the pot.
0:32 OMFG! My heart was stopped. Do you know how to turn on/off the lamp amps? At first you must switch the POWER button and wait 1 minute, only after that you can switch the STANBY button. If you need to turn off the amp, you need to do the same but in reverse. Don't kill the lamps, pls.
Yes, I do know, do you? On power up of a tube amp, the "power on" switch is turned on first and after 20-30 seconds the amp is taken off standby. Turning on the power switch first allows the filaments to heat up the cathodes prior to the amp being taken off standby, which then applies high voltage to the plates of the tubes. Failure to do this may cause "electron stripping" of the cathodes and shorten the life of the tubes. However, there is no danger in turning the amp "off" without leaving on standby for awhile. When powered off at once, no electron stripping is possible. You may have heard otherwise from others or seen it on message boards, but if you don't believe me look at any of the Fender ( or other ) manuals for tube amps and you will see.
I love how your demonstrator plays Hendrix for testing.
Thanks so much for taking the time to record this. Very helpful indeed.
VERY helpful- make sure you hook the leads to your multi-meter correctly- it's pretty easy to do this!! Thanks James!!
After 5 years this is still valuable information
Jep :) Not too much stuff on this amp.
Have wanted to see a video on how to bias this amp for a long time. Many thanks!
May also be worth noting DSL 401's manufactured from 2003 onwards are recommended a lower bias setting of 550mv.
Just watched your video and have the same amp. My amp works but it seems that volume is weak not as strong and have to crank up the master volume . I have never had to do that ever. You think maybe the power tubes are bad ? Mine is a 2004 model . Appreciate any advice, thanks .
Hey what is the best settings to get great Hendrix style tones? How can I get it to sound like a plexi? Do I need to change the speaker or what? If so, what is the best speaker to put in it for that type of tones?
hi my 401 just went 'pop' and now there is static and cracking sounds... would that be a blown valve tub(s)e?
Thanks so much for this, im still alive anyway. My bias reading is 1.2 volts and the Pot wont let me take it lower than 1.02v, is there anything I can do to make it lower?
There are a couple of options. You could select a different set of EL84's. The ones you are using appear to be a bit "hot". Or you could just set it to 1.02 volts and you would be at 9 watts plate dissipation at idle instead of 8 watts- hotter but should not present a problem except possibly shorten the tube life a bit. Still way better than the Marshall recommendation per service bulletin. The final option is more complicated. You could modify the bias circuitry surrounding the bias pot VR12 to give more negative bias voltage which would enable you to limit the plate current more. ( Also make sure all volume pots are turned down to "0" when taking measurements.
1.02v is only 74% vs 70%. You should be fine.
Do you think these JCM2000 DSL combos are still worth it vs the newer made in Vietnam DSL40CR versions?
I've read the 40c are much better. 2 el34 vs the 401 4 el84s
Hi James, thank you for your videos, I'm gonna pass this by you just in case...
I have a JCM 2000, English 100w head, (2005 post bias drift), just purchased off the Internet, I just re-tubed it but it still sounds like it has a cool bias setting even though I have it set hot (88mV, Marshall recommends 90), I tried cleaning the effects loop, patching it but to no avail...
Something I just noticed is, if I tap on the master volume knob it won't completely mute when I have it on 0, if I keep tapping it goes away (completely mute), and comes back so naturally I stop tapping when it's muted (normal), ever come across anything like this?
I would use contact cleaner on the volume potentiometer if you haven’t already. Even turning the knob to 10 and back to 0 multiple times will sometimes clear any buildup inside the pot.
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Skull yeah hoss 1!1!-
0:32 OMFG! My heart was stopped. Do you know how to turn on/off the lamp amps? At first you must switch the POWER button and wait 1 minute, only after that you can switch the STANBY button. If you need to turn off the amp, you need to do the same but in reverse.
Don't kill the lamps, pls.
Yes, I do know, do you? On power up of a tube amp, the "power on" switch is turned on first and after 20-30 seconds the amp is taken off standby. Turning on the power switch first allows the filaments to heat up the cathodes prior to the amp being taken off standby, which then applies high voltage to the plates of the tubes. Failure to do this may cause "electron stripping" of the cathodes and shorten the life of the tubes. However, there is no danger in turning the amp "off" without leaving on standby for awhile. When powered off at once, no electron stripping is possible. You may have heard otherwise from others or seen it on message boards, but if you don't believe me look at any of the Fender ( or other ) manuals for tube amps and you will see.
@@jamelectronics ok, thnx😀