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Re: I need a Bias Probe other than SwAmp

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4/14/2000 4:38 AM

Re: I need a Bias Probe other than SwAmp

Ryan:
Here's another option if you're willing to build your own:
http://www.vacuumtubes.com/
They have a kit listed for $6 to build your own socket. I've built several of these and they work well.
It's ideal to go along with R.G.'s layout/schematic and if you want the meter all electronics sells them for $10.
Course you could always scavange the base from a 6S*7 and a socket and put one together that way, but it's a pain and real time consuming.

Marc

4/14/2000 12:56 PM
Steve Slick	Mark, There is no bias kit listed there at that site. And, the site says it will be closed until then end of April or early May. Are you sure that's the right site??? Steve Slick

4/14/2000 2:52 PM

oops, left out the details

Steve:

Sorry about the incomplete info! I had also forgotten about his closing, moving to bigger dis.
The sockets I was thinking of, and have bought, are actually for adapting the 6BG6's that he sells. The adaptor has to have a hole plugged and a new one drilled by pin 8. It also comes with good instructions, wire, and a plate cap for the 6BG6's.
SO, it's not really a bias kit per say, but a set of the parts to make the bias sockets.
I Just finished a custom setup for a local shop owner who liked the one I built for my use. His has two separate meters with two sockets each to enable him to balance 2 pairs at a time.

Anyway SND's 'kit' is a convient way to get the parts at a time and $$ savings, if you're willing to do the assembly.

Marc

4/14/2000 5:43 PM
Ryan L.	It Arrived! Bias Probe arrived yesterday. Charles has new e-mail addresses that don't work. Use the one that ends in .bellsouth.

4/16/2000 7:47 AM
Chris	Hey Ryan, I've been using the .bellsouth email address all along with zero luck. 2 months and ....still.... waiting. But you already know the story. Chris Arteberry

4/16/2000 10:30 AM

Ryan:

Glad to hear that you received it! Charles doesn't post much over here anymore but he always seemed like a very ethical and honest person.

Does anybody have any tips for using these probes? To accurately set the bias you should know the B+ voltage going to the plates. To measure this without pulling the chassis (the whole point of getting the probe) would there be any problem in pulling all of the output tubes and just measuring the voltage at pin #3 for a 6L6-style tube?

--Thanks!

Steve Ahola

P.S. Can you post Charles' e-mail addresses so that I can update my records?

4/16/2000 2:50 PM

quote:
"Charles doesn't post much over here anymore but he always seemed like a very ethical and honest person."

Agree, I've done lots of business with him and hold in in very high regard. It's too bad he doesn't wander this way anymore. Charles was a valuable asset to this board.

quote:
"To accurately set the bias you should know the B+ voltage going to the plates. To measure this without pulling the chassis (the whole point of getting the probe) would there be any problem in pulling all of the output tubes and just measuring the voltage at pin #3 for a 6L6-style tube?"

I don't think you'd get a proper voltage reading without the load of the power tubes. Maybe in a 100w you could pull two of the tubes and get a reading that would be pretty close. But isn't the voltage in a amp without the tubes much higher than normal?

bw

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