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: []
Sent: Monday, August 18, 2014 12:07 PM
Subject: Re: [TekScopes] Modifying W Plugin to use 6DJ8 Tubes

On Mon, Aug 18, 2014 at 3:04 PM, Cliff White
[TekScopes] <> wrote:

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

Cliff White, W5CNW <>
On 08/18/2014 01:42 PM, Kurt Rosenfeld [TekScopes]

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?


On Mon, Aug 18, 2014 at 1:51 PM, Cliff White
[TekScopes] <> 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?

Cliff White, W5CNW <>

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