Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: multmin on April 07, 2018, 09:55:37 am

Title: Tweed Mod for Vibro Champ (part 2)
Post by: multmin on April 07, 2018, 09:55:37 am

Hello All!

I am in the process of adding a tone stack mod to a Vibro Champ that I'm building. As per the old post regarding the tone stack mod:

http://el34world.com/Forum/index.php?topic=20012.0

SILVERGUN says to use .002 in place of .047 on the board. Then, have the switch engage the .047. I'm having trouble visualizing how to wire this up using a DPDT. Below is how I understand the usual 15k-lift as per the Ceriatone Champ Ultra:

(http://i597.photobucket.com/albums/tt57/VG16_Fodera_Auction_7-2-09/Ceriatone%20tone%20stack%20lift.png)

Below is how the turret board will be laid out. I will change the .047 to .002, but how do I wire the DPDT?

(http://i597.photobucket.com/albums/tt57/VG16_Fodera_Auction_7-2-09/Custom%20Board%204b.png)

Thank you in advance.

Title: Re: Tweed Mod for Vibro Champ (part 2)
Post by: shooter on April 07, 2018, 10:49:59 am

maybe like this?

I got lost on what value gets switched IN so I just made it .047. 

Title: Re: Tweed Mod for Vibro Champ (part 2)
Post by: multmin on April 07, 2018, 10:56:19 am

Hi Shooter,

Thank you for responding and for the picture! However, I'm still unclear on the wiring. To better answer your query on what gets switched in, I'll explain.

I'll put .002 on the board (in place of .047 in my picture). The switch is supposed to add back the old .047 (in parallel) to the .002 (creating .049). I hope this is a better explanation of what I'm trying to do.

Title: Re: Tweed Mod for Vibro Champ (part 2)
Post by: sluckey on April 07, 2018, 11:36:48 am

Wire it like this...

Title: Re: Tweed Mod for Vibro Champ (part 2)
Post by: multmin on April 07, 2018, 11:52:39 am

A million thank-yous to Shooter and Sluckey!