TS clone tone pot issues. Am I missing something?

[skiraly017]

So I got the correct value/taper pot for my TS clone and maybe it's just me, but I don't hear that much of an improvement over the 25k tone pot that was supplied with the kit. To my ear, it still seems that the treble comes in at the last 10% of the travel. To me, it would seem that there should be some some sort of "halfway" point where bass and treble are equally present. Am I asking for too much? Is this just inherent in the design? I read a post a few weeks back about taking a linear pot and using a resistor to create a smoother sounding taper. I'd like to get all I can out of the sound from this TS clone. I'm not looking to add/subtract any bass/treble. I just want a smoother transistion. Any help would be greatly appreciated. 

[formerMember1]

i was wondering if the stock ts9DX reissues(well not exactly a reissue) had the smoother taper pot like smallbears or not?

[MartyB]

Hey Skiraly,  Not a reply, but my buddy occasionally gives me his olderGP magazine and I saw your name in there for the tsunami pedal fundraiser, along with several other forumites.  I know its old news but I thought it was very cool.  Way to go dude.

[johngreene]

The TS tone control is really just a treble control. It either boosts or cuts the treble.

But this response is altered severely by the 1K/.22uF lowpass before it so you end up with just a little wiggle room in the treble area.

So, you would never hit this 'half-way' point because of this lowpass. Removing the .22uF to ground would give you full boost/cut control of the treble with the series RC on the wiper of the pot setting the corner frequency.

--john

[waldo041]

have you tried smallbears version of the original?

http://www.smallbearelec.com/Detail.bok?no=463

peace,
waldo

[skiraly017]

I think I understand what you're saying, but truly technical info is lost on me. The pictures were pretty though!   

[skiraly017]

have you tried smallbears version of the original?

http://www.smallbearelec.com/Detail.bok?no=463

peace,
waldo

Yep, that's the one I used.

[waldo041]

have you tried smallbears version of the original?

http://www.smallbearelec.com/Detail.bok?no=463

peace,
waldo

Yep, that's the one I used.

i had the 25k pot in my ts808 clone and it had the treble bunched up at the end of the rotation. it wasn't until i got smallbears 20k G pot that there was sort of a middle to the whole thing. now there is clearly a bassier side and once it gets past halfway it definately gets more treble. that's why i had asked.

peace,
waldo

[johngreene]

I guess the point is that if you want to hear how the tone control itself is actually working, lift the .22uF to ground before it. Then when you turn the knob you will hear what difference it is actually making and what the resonse is. From the graphs I posted, you can (sorta) see that when the pot gets near one stop or the other you get a lot more change than you do in the middle. (The lines in the graph indicate a uniform change in the wiper position, I think I did 10% steps). But it's symmetrical.

--john

[Fp-www.Tonepad.com]

I really enjoy seeing those simulator graphics.

IMHO the linear 25k pot works nice enough for me 

Fp

[sovtek50]

A reverse log pot would be needed here. Since these are hard to find in 25K, You might wanna use a normal 25K log taper and wire it backwards... The Rat solution .
Now the tone control works backwards, i.e. Treble is on the left, but it also works more smoothly.

[skiraly017]

Just curious. From what John Greene says, what I'm looking for really can't be done. 

[johngreene]

I think I may have found your answer. Here is a plot of the tone control with a 25k pot:



Notice how the outer curves are so far separated from the inside curves. This means not much action going on for most of the rotation of the pot, it's all in the extremes, in this case the increment value is .1 of 25k so the blue line is 25K, the next curve up is 22.5K.

Now look at the curves when I change the value of the pot to 2K:



The max gain/attenuation didn't change, the corner frequency didn't change(much), but the curves are now almost perfectly distributed over the range of the pot!

So now it should have a much more even adjustment.

Just for completeness, here is a plot of the circuit with the 2K pot and the 1k/.22uF network in place:



--john

[SteveB]

I am trying to understand your plot. What exactly do the colors & symbols represent? Frequencies?

Thanks,
Steve

[johngreene]

The symbols are so if you don't have a color printer. You can tell the traces apart. Each trace is a frequency sweep with the tone pot in a specific orientation. With Pspice you can tell the program to start with the POT set at '0' and increment it a percentage at a time until it reaches the final value. I have it setup to start at '0' (0*2K) and end at '1' (1*2K) with increments of .1 (.1*2K, .2*2K, etc) inbetween. So there should be a total of 11 lines.

Hope that helps,

--john

[SteveB]

The symbols are so if you don't have a color printer. You can tell the traces apart. Each trace is a frequency sweep with the tone pot in a specific orientation. With Pspice you can tell the program to start with the POT set at '0' and increment it a percentage at a time until it reaches the final value. I have it setup to start at '0' (0*2K) and end at '1' (1*2K) with increments of .1 (.1*2K, .2*2K, etc) inbetween. So there should be a total of 11 lines.

Hope that helps,

--john

Perfect! That's what I needed to know.

Thanks,
Steve

[rogeryu_ph]

Hey Guys, I read your topic is nice.  John, I made a TS clone project also from Tonepad, It's kind of noisy and treble response is on on the full right setting only. Based now on your explaination is it better to change the tone pot into 2 k? I have trouble looking for this pot value here in the Philippines also is it a linear or audio pot? Some say you could convert a linear into audio pot, can guide us?
I also read the Aron mod saying remove the .22uf tant on ground and just use jumper to brighten the circuit? Does this mean the noise will be minimized. Thsnks guys in advance hope you could give some advise.

[MartyMart]

You could try making the .22 to ground much smaller, I have a .047 in my "real" TS-9
and I like the brighter sound a lot more. ( 0.1 may be enough )
With this in place, my tone pot stays between 11/12 o'clock and is bright enough, there's
plenty more top after 12 o'clock.
I allways thought that original 1k/ .22 lowpass network was a bit severe !!!

MM

[amz-fx]

The correct pot for this application is an S-taper, also called a W-taper by Alpha...   not linear, not audio, not reverse....    The W-taper bends the response at both ends to make the  tone control have a more gentle effect as it is adjusted to each side.

Small Bear carries the part. It is shown here: 20k W-taper Tube Screamer 16mm pot

(Steve, you need to update the description on that page to show "20k W-taper")

Best regards, Jack