Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: uki on January 07, 2026, 12:25:06 pm

Title: Changing tone stack sanity check
Post by: uki on January 07, 2026, 12:25:06 pm

Hey guys !

This amp (https://el34world.com/Forum/index.php?topic=31488.msg346903#msg346903) is getting new chassis and cab, the new chassis come with holes for a TMB tone stack !

Here the original(lil moded) schematic and the one with TMB,

 is this TMB implementation correct ?

Thanks in advance !

Title: Re: Changing tone stack sanity check
Post by: uki on January 10, 2026, 09:04:17 am

The power supply and nodes for each tubes are in place, still have to install the tremolo and tone stack,

I am unsure thou if the tone stack is correct,  anyone? Thanks !

Some more pictures.

Title: Re: Changing tone stack sanity check
Post by: SEL49 on January 10, 2026, 09:40:11 am

Your TMB tonestack is the same as a typical Fender AB763. Should work just fine. However, that tonestack is very lossy and may not give enough signal to drive the 6AQ5 to it's full glory without adding another gain stage. Just try it and then you'll know for sure.

If you find you need more gain, one option would be to replace V2 with a 5654/6AK5 higher gain tube. Look at lil Smoky (https://sluckeyamps.com/smoky/smoky.pdf) for a known working 6AK5 circuit.

Title: Re: Changing tone stack sanity check
Post by: uki on January 10, 2026, 01:27:53 pm

Quote from: SEL49 on January 10, 2026, 09:40:11 am

Your TMB tonestack is the same as a typical Fender AB763. Should work just fine. However, that tonestack is very lossy.....

Any suggestions for a different tone stack , that isn't so lossy ?! Thanks

Title: Re: Changing tone stack sanity check
Post by: SEL49 on January 10, 2026, 01:55:09 pm

My favorite is the V1 tonestack in my Dual Lite (https://sluckeyamps.com/dual_lite/dual_lite.pdf) amp.

Title: Re: Changing tone stack sanity check
Post by: uki on August 13, 2026, 02:53:58 pm

Hey guys !!

Took some time to get back to this but it is done now !!

Title: Re: Changing tone stack sanity check
Post by: acheld on August 14, 2026, 09:39:24 am

Looks great!  What did you decide regarding your tone stack and what were the results?

Title: Re: Changing tone stack sanity check
Post by: uki on August 14, 2026, 11:49:04 pm

Quote from: acheld on August 14, 2026, 09:39:24 am

Looks great!  What did you decide regarding your tone stack and what were the results?

I went with the TMB , the mid pot is 250k, the mid works as mid until mid, then it lift the TS and add some hair, got it from one of Sluckey's schematics. Also i did remove the NFB.

The amp sound really good !!

Title: Re: Changing tone stack sanity check
Post by: ac427v on August 15, 2026, 08:40:51 am

That is a rockin amp! Love the trem too.