Bell 2420 tube amplifier. Bias question. 6v6 push pull - diyAudio
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Old 21st May 2008, 06:07 PM   #1
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Default Bell 2420 tube amplifier. Bias question. 6v6 push pull

Does anyone know how to bias a Bell 2420 properly. There are two tube balance pots on the unit. But it doesn't say what to adjust them for, or where to put your volt meter. Or how many volts, or no volts.

So, I'm hoping someone around here can make my day and point me in the right direction.


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Old 21st May 2008, 11:57 PM   #2
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Location: Monroe Township, NJ

Get a hold of the schematic. Without a "map", everything is just a WAG.

Those pots. may be for hum balance, not bias, setting. IIRC, I worked with somebody some time ago who had a Bell amp. That amp used the phono section heaters in the O/P stage bias circuitry, as a way to energize said heaters with DC. That's a "Cheap Charley" solution.
Eli D.
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Old 22nd May 2008, 12:43 AM   #3
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You need Sams Photofact folder 536-5 - sorry, not in my collection.
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Old 22nd May 2008, 02:36 AM   #4
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thanks for the replys fellas. I know it's the bias adjustments I'm talking about. There is a bum adjust pot as well. But these two trimmers are labeled tube balance. So, it's the bias.

tomorrow, I'm going to get slick willy on it and actually measure the bias current and then adjust everything until something makes sense or is even.
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Old 1st April 2013, 09:25 PM   #5
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Hi Adam,
I got the same amp.Pleased with it actually.But I know anything about caps and stuff...So the guy who sold it to me was a tech ,and told me the amp has been refubished....If you may have a glance to my album ,and tell me what's all aboutthere ,if I need to replace other things...It would be cool.You can see the photos by going on my profile ,clicking on megatchol(I don't know how to post them on a thread....!)
Many thanks
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Old 30th May 2013, 09:40 AM   #6
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Join Date: Mar 2013
Default the Bell sounds?....

Hi every body,
Here are 2 links if you want to listen to and see my little system(I focused on the sound ,not on the video itself -not enought light ,etc...! more light in the second one)
First link : recorded with the camera 's mic : singer Youn sun nah ,(korean jazz woman)
Second link :recorded with 2 vintage Beyer dynamic microphones . Nat king cole.
Very short videos on line already.No need to upload!
That gives an idea.
Feel free to answer!

Thorens TD 150 MK2 , Denon DL 103 with its little pre-preamp( with battery inside)Marcof PPA1 ,Integrated Bell 2420 ,JBL L Decade 36

1) My little system recorded at home . Listening to :Youn sun nah /vinyl. on Vimeo

2) my little system on Vimeo
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