Smoother gain from a TS clone?

Started by skiraly017, September 27, 2005, 02:26:17 PM

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skiraly017

I've built a TS clone that I'm very happy with. The last thing I'd like to do is make the gain a little smoother, less grainy. I've read RG Keen's TS article, tried different op-amps, diodes and symmetrical/asymmetrical clipping. Am I overlooking something obvious? Any suggestions? Thanks.
"Why do things that happen to stupid people keep happening to me?" - Homer Simpson

Bernardduur

Try running it at 18V. Check all the caps before doing this BTW. More headroom ;)

I also like the fat mod and the bassdrive mods. Give the pedal more low end.
Am learning something new every day here

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skiraly017

I'm happy with the low end, just want to smooth out the gain.
"Why do things that happen to stupid people keep happening to me?" - Homer Simpson

SteveB

At the risk of losing some high end, you could up the value of the 51 pf capacitor in the clipping circuit. Did you try red LED's in the clipping circuit?

Steve

TheBigMan

Try socketing the clipping diodes and experiment with a few different types.  I like 1N914/1N4001 personally, and LEDs also sound pretty good.  You can also try germanium diodes or MOSFETs like the new version of the Fulltone Fulldrive.  SteveB's suggestion is also a good one, but I'd personally try the diodes first.

skiraly017

I'm running the 1N914/1N4001 combo already. Best sounding to my ears. Maybe I need to tinker a little more.
"Why do things that happen to stupid people keep happening to me?" - Homer Simpson

mojotron

#6
Quote from: skiraly017 on September 27, 2005, 05:54:38 PM
I'm running the 1N914/1N4001 combo already. Best sounding to my ears. Maybe I need to tinker a little more.
That's my favorite combo too (the 914/4001 combo) - the best IMO and I tried every combo I could think of.

In this thread http://www.diystompboxes.com/smfforum/index.php?topic=17942.0 I found a lot of interesting findings with different opamps. I used this as a list of opamps to try in TS clones. I'm really sold on the CA3260E - it really makes the overdrive smoother.

bwanasonic

The other factors to consider are the signal chain after the TS, and what you are driving the TS with (clean/ dirty amp? SS / tube amp? Active/ passive pickups? ). If I want a TS to sound really smooth, I run it into a darker, somewhat dirty tube amp. A compressor before the TS, and some EQ after the TS can smooth things out as well.

Kerry M

SteveB

Quote from: bwanasonic on September 28, 2005, 11:40:44 AM
The other factors to consider are the signal chain after the TS, and what you are driving the TS with (clean/ dirty amp? SS / tube amp? Active/ passive pickups? ). If I want a TS to sound really smooth, I run it into a darker, somewhat dirty tube amp. A compressor before the TS, and some EQ after the TS can smooth things out as well.

Kerry M

Boy, you hit on something there. I agree. Put a compressor (like a Dynacomp) in front of the TS, keep the sustain around 12 o'clock, & the output anywhere from 12-2 o'clock. You'll get a milder smoother overdrive with this setup.

Steve

johngreene

I think you are actually looking for smoother distortion rather than gain. Adding a bit of an octave can really smooth things tremendously as well. Typically we filter the higher order odd harmonics to make distortion sound 'less grainy' but it is also removing most of the distortion in the process. By adding even harmonics, even a little, you get a smoother, fuller sounding distortion. I've noticed that if you drive the input of a JRC4558 hard enough that the signal goes below ground at the input of the opamp, it will cause a positive going bump where the negative peak of the signal should be. This results in a bit of octave being added. However, it's also bad for the IC and if done hard/long enough will blow the input. But for a while it sounds really cool! Also, the level at which the input no longer goes below ground is very noticable when it crosses.

--john
I started out with nothing... I still have most of it.

synd7

I found this on arons page:

Quote"Refine" your pedal and smooth the tone out

A Jake Nagy special! Put a smallish value capacitor on the output lugs of your volume pot (from signal to ground) to clear up the high end "buzz and hash" from your pedal and give it instant smoothness!

Try different values from 220pf to .0015uF or even larger values depending on the amount of high frequency content you want to remove.


I'm thinking about trying this on my TS clone
<<Insert Witty Remark Here>>

petemoore

  Caps like that [signal path to ground] can be placed basically anywhere in the circuit...I haven't figured out where I like to rolloff on a TS type...smallie cap at the input to Gnd. can be cool too.
  All of those caps can be messed with, changing them all to metal film types you may hear 'clearer'...I never tried it on a TS, some have I'm sure, they can also be changed in value...
  Adding a small cap across electrolytics helps the high end through that part of the circuit, where/whether that makes I diff I don't know.
  That's why there are lots of TS mods, which one[s you want is what's the hard one to find.
  Just playing around with the circuit increases 'tuition about what might influence what...
  If you think you'd like a TS 'if' ... then building one with sockets, mods, or using a breadboard might be a good idea.
  Also simply going to a different circuit altogether may have merits.
Convention creates following, following creates convention.

MartyMart

That cap across the vol pot works quite well, I also use way too many small
caps in circuits to roll out the "harsh hi end", between stages and at the front/back
end to ground !!!
470pf -to-2n2 seem to deal with that and can smooth things out some.
Have you tried increasing the 4k7 resistor to "lower" the drive a little ?
Perhaps 6k8 or 8k2 would help.
Also OPA2134 sounds great in my TS's with the 1n4001/1n4148 combo.

Marty.
"Success is the ability to go from one failure to another with no loss of enthusiasm"
My Website www.martinlister.com

SteveB

Quote from: synd7 on September 28, 2005, 10:54:01 PM
I found this on arons page:

Quote"Refine" your pedal and smooth the tone out

A Jake Nagy special! Put a smallish value capacitor on the output lugs of your volume pot (from signal to ground) to clear up the high end "buzz and hash" from your pedal and give it instant smoothness!

Try different values from 220pf to .0015uF or even larger values depending on the amount of high frequency content you want to remove.

I did that very thing to tame some of the highs on my Octavia clone.

Steve

GBlekas

#14
Most of the ideas have been beat to death where the TS is concerned.
I have done LEDs, 914s,914&4001s assymetrical/symetrical and pretty much the whole 9 yards with this TS circuit.

My two favorites, after all the experimenting, are replacing the diodes with Mosfet & resistors in the feedback loop or keeping the diodes as they are and trying the following.

If you look at the second feedback loop, pins 6 & 7,  there is a 1k resistor there.
With the 1k going from pin 1 to pin 5 of the opamp we have a gain of one in the second feedback loop.
Try cascading  a 20k pot with the 1 k resistor between pins 6 and 7.
This will open up the pedal a lot! The way it changes the tone pot is pretty cool. You have to be careful not to get into oscillation but you will notice less of a difference between diode types in the first feedback loop and a more effective tone control. If you go too high you will have to add a small value cap but try it out.

I had built a TS with a pot that swept between a  .1/2k2, 662hz rolloff, and the standard .047/4k7, 722hz,  and think the original very well could be the proper setting regardless of who is moding what in order to make the thing fatter or what have you. The idea is you have to try this stuff live and testing for clarity in the lab really only goes so far, imho. This pedal also has a toggle for diode swapping and a 20k pot as described above. I  thought the toggle idea was pretty hip when I started doing it but the pot idea kind of opens up the pedal almost like switching from 914s to LEDs and almost making the diode switching toggle redundant.

Anyway, give it a test and let me know what you think of the idea.

Regards,
George


mojotron

Quote from: petemoore on September 28, 2005, 11:33:51 PM
  Caps like that [signal path to ground] can be placed basically anywhere in the circuit...I haven't figured out where I like to rolloff on a TS type...smallie cap at the input to Gnd. can be cool too.
  All of those caps can be messed with, changing them all to metal film types you may hear 'clearer'...I never tried it on a TS, some have I'm sure, they can also be changed in value...
...

I add a 30pF to 50pF right on the front end of the circuit - right across R22 in http://www.generalguitargadgets.com/diagrams/ts-808_sc.gif
Some opamps (or circuits that use opamps) are pretty good at demodulating radio signals - so I dump the VHF+ frequencies (as well as a little bit of the extreme high of the audio range).

GBlekas - Thanks for the tip about the feedback resistor in the 2nd feedback loop; I had played with fixed value resostor changes in the tone and 2nd feedback circuits and liked some of the results - no results that I wanted to keep there - but it seems like the perfect place for a pot for experimenting.  :)