Re: Modifying W Plugin to use 6DJ8 Tubes


Dave Wise
 

Because it represents +100V after (in some mainframe models) passing through two 12.6V 150mA tubes, pin 15 is 75V and must be loaded with exactly 150mA. Plugins that need more current use AC. I think one even contains a filament transformer. Since V124 operates at low level (current sink for 8056 input cathode follower), it probably needs that quiet DC heat. You could rewire for AC powered 6DJ8's but I think you'd have trouble with hum. <shrug> Try it and see. Be sure to keep the 8056 heater balancer.

Dave Wise

-----Original Message-----
From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Monday, August 18, 2014 12:07 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Modifying W Plugin to use 6DJ8 Tubes

http://w140.com/tekwiki/images/e/ea/Tek_w_differential_comparator.png


On Mon, Aug 18, 2014 at 3:04 PM, Cliff White cn.white@sunbelt-plb.com
[TekScopes] <TekScopes@yahoogroups.com> wrote:



Did you mean to say 8416? I can't seem to find a datasheet for an 8416.


Respectfully,
Cliff White, W5CNW
w5cnw@arrl.net <mailto:w5cnw@arrl.net>
On 08/18/2014 01:42 PM, Kurt Rosenfeld kurt.harlem@gmail.com [TekScopes]
wrote:


The filaments are in series, and a 6DJ8 has higher filament current
than an
8056. So the heater wiring topology will need to be altered. Furthermore,
how much current can be safely drawn from pin 15?

-Kurt

On Mon, Aug 18, 2014 at 1:51 PM, Cliff White cn.white@sunbelt-plb.com
[TekScopes] <TekScopes@yahoogroups.com> wrote:



The 6DJ8 is a 6-volt version of the very expensive 8416. I assume a mod
as simple as adding the appropriate resistor to the heaters. Has anyone
done this before?

--
Respectfully,
Cliff White, W5CNW
w5cnw@arrl.net <mailto:w5cnw@arrl.net>

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