Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on July 14, 2022, 10:03:08 am

Title: Simplify or remove tonestack?
Post by: joesatch on July 14, 2022, 10:03:08 am
i blast you folks with questions . I have multiple projects going.  I would like to simplify this tonestack to just a Tone pot or remove it all together. I still would like to keep the master vol in place.
Title: Re: Simplify or remove tonestack?
Post by: sluckey on July 14, 2022, 10:33:04 am
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Title: Re: Simplify or remove tonestack?
Post by: joesatch on July 14, 2022, 10:56:04 am
Outstanding. i see. come off v1a pin 1 with a 22nf cap into the master with a 220pf cap over the master in/out lugs
Title: Re: Simplify or remove tonestack?
Post by: SILVERGUN on July 14, 2022, 11:45:36 am
I did something similar and had these results:
The "tame" mid-scooped clean channel turned into a mid-heavy crunch channel. The only clean-cleans existed at the very low end of the volume pot.
That tone stack is pretty lossy so if you completely remove it there will be much more gain available at the volume pot to feed the next stage.
Positive or negative is up to your taste.
Title: Re: Simplify or remove tonestack?
Post by: joesatch on July 14, 2022, 01:45:06 pm
I did something similar and had these results:
The "tame" mid-scooped clean channel turned into a mid-heavy crunch channel. The only clean-cleans existed at the very low end of the volume pot.
That tone stack is pretty lossy so if you completely remove it there will be much more gain available at the volume pot to feed the next stage.
Positive or negative is up to your taste.

Thanks for the heads up, i will retain the TS in the schematic
Title: Re: Simplify or remove tonestack?
Post by: kagliostro on July 18, 2022, 05:55:42 am
Quote
i blast you folks with questions . I have multiple projects going.  I would like to simplify this tonestack to just a Tone pot or remove it all together. I still would like to keep the master vol in place.

You don't specify the reason by which you want to semplify or remove the TS

as your decision wast to retain it, may be you can be interested in a RAW control

Connect a pot as rehostat and put it between the TS and ground, this has the effect to control the effect of the TS on the circuit

(https://i.imgur.com/7RACxCP.jpg)

Franco
Title: Re: Simplify or remove tonestack?
Post by: jordan86 on July 22, 2022, 09:22:11 am
A raw control is great on a blackface type TS. I have one on my Princeton. What you are essentially doing is adding to the value of that mid resistor, which minimizes the effect of the tonestack. Most blackface amps have something under 10K for the mid resistor value. As you get that closer to 25K-50k things feel much more tweedy. Over about 100k the tonestack is not much more responsive, mostly defeated. After that, it’s just more gain.

If you go here and adjust the value of RM (mid residtor), you can see what it does to gain and frequencies. I made a graph of this once at several snapshots but can’t find it.

https://www.guitarscience.net/tsc/fender.htm#RIN=38k&R1=100k&RT=250k&RB=250k&RM=10k&RL=1M&C1=250p&C2=100n&C3=47n&RB_pot=LogA&RM_pot=Linear&RT_pot=LogA
Title: Re: Simplify or remove tonestack?
Post by: jordan86 on July 22, 2022, 09:26:41 am
Here is my graph.  Also an image of how guys usually implement it. The normal mid resistor (6.8K or 10K) comes off the raw pot to ground.