Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Rockranger on February 06, 2019, 04:35:30 pm

Title: V1 A and V1 B?
Post by: Rockranger on February 06, 2019, 04:35:30 pm

Hey guys I have a number of homemade 15 to 20 watt amps which I love, I play them with a 12ax7 in V1 when I play with other people and when I’m at home I play them with NOS 12 au7 or 12 at7 in V1 ( this is my favourite way to drop the volume and still have the amp sound great) , a friend really likes the way this sounds and wants me to build one for him (Hoffman 6v6 plexi), I was just wondering if there was an easy way to have 2 V1’s like mabey one input jack go through V1 A and another input jack through V1 B, instead of him taking tubes in and out of the amp? Any thoughts or suggestions would be greatly appreciated!
https://el34world.com/Hoffman/files/Hoffman_Plexi_6V6-V2.pdf

Title: Re: V1 A and V1 B?
Post by: sluckey on February 06, 2019, 04:45:01 pm

Very easy. Just use a 12DW7. One triode is like a 12AX7. The other triode is like a 12AU7. Use a separate input jack for each triode.

Title: Re: V1 A and V1 B?
Post by: Rockranger on February 06, 2019, 05:00:23 pm

Wow never heard of a 12dw7, that sounds easy enough, thanks sluckey! So other than a separate jack for each triode the rest of the V1 connections to the board stay the same?

Title: Re: V1 A and V1 B?
Post by: sluckey on February 06, 2019, 05:43:16 pm

Yep. It's that easy. Shop around. The JJ 12DW7 is much more affordable than other brands. I have some JJs and they sound fine to me.

However... Please note that on the Plexi6V6 one triode uses components to give a normal sound and the other triode uses components that give a bright sound. So, while the 12DW7 would give the results you're looking for if both channels were identical, it will become more complicated if the channels are different as in the Plexi6V6. It could be the latest golden mojo sound of the year. Might be a disaster too!  :icon_biggrin:

Title: Re: V1 A and V1 B?
Post by: Rockranger on February 06, 2019, 07:21:49 pm

Sounds good I Will give it a shot! Thanks

Title: Re: V1 A and V1 B?
Post by: Rockranger on February 09, 2019, 01:59:43 pm

Sticking with the same idea using a 12dw7 in V1 what could you do in the case of a deluxe reverb style where you have the input going in one side and the volume in the other?
https://el34world.com/Hoffman/files/Hoffman_AB763_2.pdf

Title: Re: V1 A and V1 B?
Post by: sluckey on February 09, 2019, 02:39:55 pm

Nothing. The Hoffman AB763 amp is not a candidate for the 12DW7.

Title: Re: V1 A and V1 B?
Post by: Rockranger on February 09, 2019, 03:53:36 pm

Thought so, thanks again