Tube Screamer Tone Control

[audioguy]

Hey all... I just built a Tube Screamer and used a bunch of the 'Boutique' mods at GGG. I didn't do the 3 way toggle, just a 2 way for 2 diodes to 3 diodes... nice tone change. Anyway... the tone control was horrid! I was using a B25k. Only the first and last 5% had any affect. I pulled it and dropped in a B5k and it works really well. Tone changes along the full sweep ending in a nice open top end.

I just wanted to pass that along as I did not see anyone mention it while I was searching... it doesn't mean that no-one did, just that I didn't find it.

All the best!

Audioguy

[96ecss]

Hi, I used this one and I'm very happy with it. http://www.smallbearelec.com/Detail.bok?no=463

Dave

[rogeryu_ph]

96ecss,
Hi, what is the value of the tone pot you bought from smallbear? Is it "W" tapered or something else?

Audioguy,
Does the low end (bass)or the high end (Treble) not much affected or degraded?

Thanks
Roger

[audioguy]

The B5k gives a pretty good full sweep, for me at least. I'll play with it a little more, but from the 15-30 minutes last night I couldnt find any complaints with it. I'm sure that there is plenty of science behind why it works, and how I might be missing something, and I would be interested in hearing it, but at this point I think I'll stick with what I've got.
I went with the 5k because I didnt want to order the W from Small Bear. I had everything else on hand, and wanted to build something with what was available... Im sure that pot is great, and had my experiments with other pot values not turned out so well, I might have ordered one... but Im happy with using the B5k.

[JHS]

You can use the 25k pot. Wire a 100 -150k R between pin 2 and 3, this will give a more useful sweep.
The tone pot in the Blue Collar is wired that way (25klin +100k R).

JHS

[audioguy]

Hmm I'll give that a shot... has anyone here tried it?

[Plinky]

Hi, I used this one and I'm very happy with it. http://www.smallbearelec.com/Detail.bok?no=463

Dave

Same here. Nice full sweep in the tone circuit instead of the quick build up of highs you get with a 25k linear pot. Wish it could be a bit cheaper though.

[audioguy]

The 5k gives good sweep... without the price tag!

[96ecss]

96ecss,
Hi, what is the value of the tone pot you bought from smallbear? Is it "W" tapered or something else?

Audioguy,
Does the low end (bass)or the high end (Treble) not much affected or degraded?

Thanks
Roger

Hi Roger,

It's a 20K "G" Taper. It gives a nice overall range. I did a bunch of other mods to mine so I don't really know how much better it would work in the stock TS-808.

Dave

[johngreene]

Hey all... I just built a Tube Screamer and used a bunch of the 'Boutique' mods at GGG. I didn't do the 3 way toggle, just a 2 way for 2 diodes to 3 diodes... nice tone change. Anyway... the tone control was horrid! I was using a B25k. Only the first and last 5% had any affect. I pulled it and dropped in a B5k and it works really well. Tone changes along the full sweep ending in a nice open top end.

I just wanted to pass that along as I did not see anyone mention it while I was searching... it doesn't mean that no-one did, just that I didn't find it.

All the best!

Audioguy

http://www.diystompboxes.com/smfforum/index.php?topic=37882.msg270809#msg270809

[stopstopsmile]

You can use the 25k pot. Wire a 100 -150k R between pin 2 and 3, this will give a more useful sweep.
The tone pot in the Blue Collar is wired that way (25klin +100k R).

JHS

how does this compare to just a stock 5k, ala lovepedal? 

[tube]

Hey all... I just built a Tube Screamer and used a bunch of the 'Boutique' mods at GGG. I didn't do the 3 way toggle, just a 2 way for 2 diodes to 3 diodes... nice tone change. Anyway... the tone control was horrid! I was using a B25k. Only the first and last 5% had any affect. I pulled it and dropped in a B5k and it works really well. Tone changes along the full sweep ending in a nice open top end.

I just wanted to pass that along as I did not see anyone mention it while I was searching... it doesn't mean that no-one did, just that I didn't find it.

All the best!

Audioguy

[JHS]

A 5k tone pot alters the corner frequencies of the tone control a lot. The low pass filter in front of the tone control and the R/C combination connected to the middle pin of the control is different on the Eternity too, so all in all it's a complete different tone control compared to the one found in a TS with different corner frequencies. All in all, the Eternity is Jack's SoS with less gain and a different voicing, nothing more.

IMHO the classic tone control with 20k G taper in the TS is not that good, to muddy on zero and to trebly and noisy when fully open.
I prefer at least a 1k limiting R in series with the 20k pot on the bass side to limit the sweep and other mods on the other end to limit the treble sweep in a TS-style circuit with this kind of tone concrol.

The Barber LTD has a muff-style tone control between the stages and the DD a RAT-style tone control, for me way better solutions and more useful than the TS-style tone control.

JHS

[stopstopsmile]

I agree the TS tone control is shit.  The blue collar trick sounds interesting, I might have to try it out.  I am curious if it sounds good. 

[JHS]

The 25kB pot with the R is a subtitute for a 20k G tapered pot, it can't fix any drawbacks of the tone control circuit.

JHS

[stopstopsmile]

ok gotcha

I never built a screamer.  I might make a go at something more simple like the sos.   what kind of tone stack is in the sos? 
which do you like better the rat or the muff tone control in a ts?

[Krinor]

I just got a Tube Screamer kit from GGG today. It includes a W25K pot for the tone control. Is this the same as the one Smallbear sells? And what does the "W" stand for?

[bipedal]

Revisiting this recent thread because I'm having trouble with the calculations...

My plan:
-- Use a modified Big Muff style tone control between a Son of Screamer's op-amp stages, as per JHS' suggestion in this thread.   (Actually, I'm looking at version 2 of the AMZ tone/presence control as shown on http://www.muzique.com/lab/tone3.htm.)
-- In place of the 20K tone pot in the "stock" TS tone control feedback loop, I'd use a pair of 10K resistors in series, with the .22 uF cap -> 220 ohm resistor -> ground placed between the two 10Ks.

I'm wondering if inserting this tone stack arrangement prior to the second op-amp stage is likely to result in too great of a reduction on the pedal's gain potential.  I see that max output ought to be less than the normal TS circuit, but would it still be able to exceed unity by a noticeable margin?

Since gain is multiplicative, perhaps building that tone/presence stack after the op-amp's second stage would better preserve output potential?

Cheers,

- Jay

[Mark Hammer]

The earliest Maxon incarnations of what became the Tube Screamer had the Tone control/stage before the clipping stage.  Same circuit and values, just a different order.  I wonder if the Tone pot value selected was because it worked well in the "before" position than in the "after" position.

[shredgd]

I am happy with a 25k log pot wired backwards. I have to turn it counterclockwise instead of clockwise to increase treble, but who cares? 

Giulio