Just Got New Tubes For My DSL 100

[axl2]

Just replaced my Groove Tube stock pickups with 4 JJ ECC83's And 4 Svetlana EL34 EL34's. Which are the same "Tube Types" that were in the stock.

So question is can I simply just go ahead and screw them in and play or I have to do some kind of biasing??

 

[PaoloJM]

Just replaced my Groove Tube stock pickups with 4 JJ ECC83's And 4 Winged EL34's. Which are the same "Tube Types" that were in the stock.

So question is can I simply just go ahead and screw them in and play or I have to do some kind of biasing??

You need to bias the El34's which are the power tubes. The Eurotubes (euro-q)web-site gives an excellent video guide for doing this.

 

[steelhorse]

+1 what Paolo said

 

[spaceforlease]

how does he actually change the volts? i bought the multimeter, but the guy said that thing is only for MEASURING the volts... not changing it to 90 to 84.

 

[poeman33]

how does he actually change the volts? i bought the multimeter, but the guy said that thing is only for MEASURING the volts... not changing it to 90 to 84.

Thanks to the great info from other posts about the video available on Eurotubes...here is the link to the video on how to bias for the DSL100
euro-m

 

[axl2]

kk so I need to go out and get myself a Multi-Meter to do this. Other then that, it looks simple.

 

[spaceforlease]

he didnt quite show how to change WITH the multimeter. it just went up and down magically from what im seeing.

 

[axl2]

he didnt quite show how to change WITH the multimeter. it just went up and down magically from what im seeing.

That's true, He didn't have the camera on the right side where he was doing the "turning". I dunno lol

 

[steelhorse]

I think Bob realized that with the bias probes and the multimeter setup he used he probably confused a few folks but it's really simple with the DSL100.

All you need is a decent multimeter. I ordered mine form Euro Tubes.

Take the multimeter and set the dial to the 9:00 position which will be in the DCV 200m setting.

Take the black lead and plug that into the COM port at the bottom right side of the meter.

Take the red lead and plug it into the DC port

I have alligator clip adapters so I use one on the black lead which I clip on to the ground post on the amp bias adjustment.

You'll be using the red lead for the readings.

Be sure the amp has been on for a few minutes to get plenty hot on standby.

Take the amp OFF standby like you are going to play.

Take the red lead and touch each test point on the bias adjustment of the DSL to see where you're at.

We're looking for a reading of between 80 and 90 mV.

With an insulated or plastic small head Phillips screwdriver make MINUTE adjustments to 1 side at a time (you'll see what I mean when you adjust yours!). Remember when you make one side hotter it will cool the opposite side down some, so it will be a back and forth venture until the see-saw quits and you get near identical readings on both sides.

I set mine to 86mV. Played with it for a few days, and went back and checked it for drift but it was still very close so I left it.

The things that could make it easier is of course getting another multimeter, clipping both grounds to the ground post and the positive lead of each to one test point so all you need to do is watch the meters while making the adjustment but it's really simple to accomplish the same thing with only 1 meter, it just takes a little time and patience.

I recently read on the Euro site that the factory test points on the JSX heads are unreliable and they had steps to follow to bias it properly. With that head I switched the meter to the 4:00 position (DCA) moved my red lead to the mA port and used a bias probe on 1 of the tubes (it needs to be a matched set to do it this way). It took some time but with the JSX you just adjust the little dial to get the bias set.

Hope this helps!

 

[axl2]

I think Bob realized that with the bias probes and the multimeter setup he used he probably confused a few folks but it's really simple with the DSL100.

All you need is a decent multimeter. I ordered mine form Euro Tubes.

Take the multimeter and set the dial to the 9:00 position which will be in the DCV 200m setting.

Take the black lead and plug that into the COM port at the bottom right side of the meter.

Take the red lead and plug it into the DC port

I have alligator clip adapters so I use one on the black lead which I clip on to the ground post on the amp bias adjustment.

You'll be using the red lead for the readings.

Be sure the amp has been on for a few minutes to get plenty hot on standby.

Take the amp OFF standby like you are going to play.

Take the red lead and touch each test point on the bias adjustment of the DSL to see where you're at.

We're looking for a reading of between 80 and 90 mV.

With an insulated or plastic small head Phillips screwdriver make MINUTE adjustments to 1 side at a time (you'll see what I mean when you adjust yours!). Remember when you make one side hotter it will cool the opposite side down some, so it will be a back and forth venture until the see-saw quits and you get near identical readings on both sides.

I set mine to 86mV. Played with it for a few days, and went back and checked it for drift but it was still very close so I left it.

The things that could make it easier is of course getting another multimeter, clipping both grounds to the ground post and the positive lead of each to one test point so all you need to do is watch the meters while making the adjustment but it's really simple to accomplish the same thing with only 1 meter, it just takes a little time and patience.

I recently read on the Euro site that the factory test points on the JSX heads are unreliable and they had steps to follow to bias it properly. With that head I switched the meter to the 4:00 position (DCA) moved my red lead to the mA port and used a bias probe on 1 of the tubes (it needs to be a matched set to do it this way). It took some time but with the JSX you just adjust the little dial to get the bias set.

Hope this helps!

Thanks a TON! Yeah when he used the seperate instrument it confused me a bit. But I was on the right thought plane since I read yours. I didn't know what setting to set the knob on the meter at but you've covered that for me. Now I just need to buy myself a Multimeter and I'm set. I think I'll split the difference and go for 85-86 like you did.

 

[steelhorse]

Cool!

Yeah, either order one form Euro Tubes or get a decent one at Radio Shack. The really cheap ones there are crap fyi.

Let us know how it goes.

I just got a new complete re-tube kit for my new DSL100 but since I got the TSL100 I'm looking to sell it or trade it for a Vintage Modern so I haven't installed it.

 

[DevilsEve666]

Listen to STEELHORSE he knows what's up

 

[DevilsEve666]

DON'T buy this one if you get one at radio shack, i couldn't even get a dc voltage reading on a friggin' 9-volt, thought i was an idiot, but then I read the reviews and found that I wasn't alone...

 

[axl2]

I'm heading into Radio Shack tomorrow. I'll look for something in the 20 dollar range I guess? Not sure how much these things cost to be honest... I seen a few for 15 dollars off ebay.

 

[DevilsEve666]

with these things I guess price isn't always the best factor to consider...like that radio shack one that I bought was $29.99 and then i got the one from the eurotubes sight and it was 10.00 and it is excellent!! I had my amp biased in no time...

 

[steelhorse]

+1, get the one from Euro Tubes!

 

[axl2]

Wow, K guys thanks for the help. I just ordered the Multimeter on the Euro Tubes site.

 

[stock_hippie]

not getting the downloAd...is it me?

 

[solarburn]

Part of biasing your DSL is getting plate voltage too. You figure this number and you can get your correct bias number. DSL's run plate voltage from 450 to 500 with EL34's usually somewhere in between. Marshall recomends 40 to 45 bias. I set mine cooler at 36 with Tung Sol EL34B's.

Example formula - 25 watts disipation divided by lets say 450 plate volts = .055
Then multiply .055 times 60 or 70% depending how hot you want to run the tubes. .055 x .6 = .033 .055 x .7 = .038.

So at 60% your bias number is 33. At 70% your bias number is 38. Eurotubes didn't show how to check for voltage in the DSL vid. He just set the bias which is what you do after getting the plate voltage and crunching the numbers per the formula. He does show how with the JCM 800 vid though.

 

[steelhorse]

I spoke with Euro Tubes about this and this was their response:

"The plate voltage is a fixed amount of voltage supplied buy your transformer to the plates of the power tubes. It’s not variable and you really don’t need to worry about it.

Thanks,

Eddie"

fwiw