Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: deqqed on October 07, 2010, 02:45:59 pm

Title: 5E3/5G9 Hotswitch mod
Post by: deqqed on October 07, 2010, 02:45:59 pm

Howdy ya'll--I'm going to mod my upcoming 5G9 build to drop the mic channel and add Doug's hotswitch mod (http://www.el34world.com/projects/hotswitch.htm (http://www.el34world.com/projects/hotswitch.htm)), does this implementation look OK? 

I'm planning on experimenting a bit with the values for Rc and Rg.  Any thoughts?

(http://www.thewanderingbears.com/drop/5g9%20-%20schematic%20-%20mod%20-%20detail.gif)

thanks,
david earl

Title: Re: 5E3/5G9 Hotswitch mod
Post by: tubenit on October 07, 2010, 04:45:14 pm

That looks like it's drawn correctly to me.

With respect, Tubenit

Title: Re: 5E3/5G9 Hotswitch mod
Post by: tubeswell on October 07, 2010, 10:29:02 pm

I'd be inclined to make both Rks in V1 1k5 to begin with.

As for the grid load resistor after V1'b', that is in parallel with the V/TS - so if you may it smaller, everything will be more lossy.

Title: Re: 5E3/5G9 Hotswitch mod
Post by: deqqed on October 08, 2010, 12:40:20 pm

Thanks for the responses!

You know, I put that load resistor there because Doug's circuit had it--but it's not completely clear to me if it's necessary here.  What would be the effect of omitting the load resistor? 

thanks,
david

Title: Re: 5E3/5G9 Hotswitch mod
Post by: topbrent on October 08, 2010, 01:36:16 pm

You might take a look at Doug's Stout.  It is a simple amp with a similar architecture.
(http://www.el34world.com/projects/images/18WATT_VOLTAGES.gif)

(http://www.el34world.com/projects/images/18WattStout_8.gif)