TSTT (tone stack think tank)

[Reeltarded]

First off, what happens if I simply rewire a Marshall TS with the mid contol in parallel to the bass control?

My ears tell me I's like to bring the treble range down to a sweeter place that doesn't include so much finger noise.

Here is what I have now. Marshall .022/470p B-1M M-25k T-150k slope is variable 33k to 83k and I have a preamp Cut 3300p over a 250k pot with 5k/.1u pres and 56k NFB to the 8R. Fixed resonance 1500p over 82k.

It will rip your face off and it's has a very short range of sweetness with mids that come on too quick and short.. as expected..

Maybe I have been approaching this wrong. If I remove the bypass of the stage driving the CF I might be halfway there..

I kind of like Skyliner, but it has something of the opposite problem where the treble doesn't do much of anything at all by comparison.. right.. that TS makes it hard to get into trouble. I like to get into some trouble.

Just thinking.. Anyone have any weird ideas? Maybe throw 1kp or larger over the CF.. maybe all of this.

Or maybe you have another idea. Hit me. I'm going to heat up the iron after I go to the coffee squeezer once more.

[Reeltarded]

Look at the curve in TSC

Tilt it 15° down with 500Hz as the axis..nthat would be better.

[roberto]

Can you please implement a schematic to let everyone clearly understand?

[Reeltarded]

It's just a Marshall with a limited treble range. The amp has resonance, early style NFB/Pres circuit and a preamp cut control.

I am not happy with the separated action of the ranges like I had been for a very long time. I recently made a blonde Bandmaster into most of a #183 and although I only kind of like that tone setup, I like it better than the Marshall setup.

I installed a James setup a few years ago and never found any magic there. I had not considered a parallel mid control.

Tone stacks are black magic.

[Tony Bones]

Tone stacks are black magic.

Yeah, and calculating their frequency response requires millions of calculations. There just isn't room on a single napkin.

OTOH, computers enjoy that sort of thing, and special software exists to make it easy to setup the calculations without having to understand them at all. There is always Duncan's Tone Stack Calculator. If what you're thinking of isn't supported by that software, then LTSpice is very flexible. Harder to use than TSC, but not beyond the realm of a tube amp hack like me. If you provide a schematic, or at least make it more clear what you're talking about, then I can put it into LTSpice and see what we can learn.

[roberto]

TSC is a fantastic tool to let you explore infinite scenarios within a restricted range of possibilities.

[Reeltarded]

Limited.. the whole topic is hard to approach. It's the toughest part of amps to know.

I need to mess with spice but I am aware it's also very limited. I wish a new tone stack culture would develop with as many new ideas or remembered old ones as mobile phones brought on us, except for instagram, facebook, and snapchat. Those are all subversion.

[ER]

My dumblesque amp is basically a 70's pre into a 183 OD and power section, except there's a hiwatt tone stack at the entrance of the OD section fed off the plate of V1B and the OD relay, and the treble wiper goes to a 250k OD trim pot (same place as the Master vol on the Hiwatt schem).

Both tone stacks are on the front panel and have lifts on relays, and a secondary manual lift on 100KL switching midpots. So it can be kinda sorta a 70's Dumble, or a Hiwatt, or, if too much is never enough, 4 gain stages with no tone stacks.

Here's a Hiwatt scheme, imagine if there were another fender/dumble tonestack between V1 and V2 and you could lift either one...pretty usable frequency ranges.

[Lynxtrap]

How would you describe the difference between the Hiwatt and a Fender tone stack, as to sound and function?
I guess my version of the TSC must have a bug? As soon as I touch any of the controls on the Hiwatt, this happens:

[Davidg]

I'm sure u have tried some version of the 6 way rotary mid sweep control used by Matchless and others. I thi k Cameron used this on some of his amp mods (His amps are the ultimate modded marshall sound to my ears). Maybe try this if you haven't? Or in a different variation alternating mid caps in TS? Perhaps using a 3 way for treble or high pass cap?

Also it is more of a subtle flavor thing but have u tried polystyrene caps for high pass and treble cap applications. To me they really smooth out the high end and accentuate upper mids more but may just be my ears lying to me. They may not be enough "trouble" for your taste though.I think I remember reading they exhibit less ringing than silver mica or ceramic and I know they are used mainly when precise values are needed for stability or reliability as they rarely drift over time and are usually within 1-2% tolerance. Just a thought? I know I rarely use silver micas anymore for any tone shaping and a .0001 polystyrene for treble cap can really help tame an amp that is too bright or harsh sounding (think Express) especially in high gain amps. 250pf polystyrene is great at smoothing a Fender circuit too to my ears too. But my ears may be lying to me?

[Reeltarded]

TSC also crashes for me with the HW TS.

I spent he last few hours of amp things reimagning what I had in there already. All changes based around stages and how a Marshall develops enough treble if it's unplugged and in a road case. Recently having turned my Bandmaster into a 183 really changed my ears. I stll have a couple ideas to go, but generally I approached it from the beggining, again. I played 4 holers for a couple decades by hammering them with something fatter and rolled off in front. Maybe that works. I set the amp up as a 72 50 with a pre circuit driver stage. 100k 1k5//22u-1500p-1M up front driving two 2k7 stages into the CF. The driver stage has the bright selections, s it works pretty much like an onboard pedal I would have used previously. This was a good direction.

I think I could go .1u on the bass cap and lower the treble cap from 470p to 270-330 but I still need an epiphany about frequency ranges in the tone stack. I might need a stepped filter setup to shape the highs. I have room for controls.. heh

I need the mid control to eat half the range the treble control has. I have burned enough solder on this thing to make 50 other amps trying to make some magic. It's driven me insane.

(ok.. it drove me to another block of insanity.. I know, I know..)

[Reeltarded]

I'm sure u have tried some version of the 6 way rotary mid sweep control used by Matchless and others. I thi k Cameron used this on some of his amp mods (His amps are the ultimate modded marshall sound to my ears). Maybe try this if you haven't? Or in a different variation alternating mid caps in TS? Perhaps using a 3 way for treble or high pass cap?

I changed the slope from continuously variable to a 6 position switch, 33-150k. I removed bright peaker 6 position and put it over my pre-circuit driver stage I described above. It's very close to what I really like at high slope settings (82-150k) but the treble is still a sting and the range of that control goes way too far into the mids. This amp will knock you down with punch though. Fer shur. lol

I really need a fourth control in the TMB that splits M and T.. something like that.

[TUBEDUDE]

Have you considered seperating the M and T controls with a gain stage to isolate them so their not interactive? Or is it just the circuit values need modification to change the center frequencies?

[Reeltarded]

Have you considered seperating the M and T controls with a gain stage to isolate them so their not interactive? Or is it just the circuit values need modification to change the center frequencies?

I have considered everything I know. I have it so very close with a much smaller treble cap, but it still needs the bands moved around a little and the treble just needs to be a little sting below the presence.

[TUBEDUDE]

I have considered everything I know. I have it so very close with a much smaller treble cap, but it still needs the bands moved around a little and the treble just needs to be a little sting below the presence.
[/quote]

I hear ya. Slotting the center freqs is one thing, the interaction is due to low Q of the TS and might require more components to increase the Q of the treble circuit to keep it out of the mid band and under the presence.