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DIY Stompboxes => Building your own stompbox => Topic started by: nooneknows on March 05, 2021, 08:39:45 AM

Title: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: nooneknows on March 05, 2021, 08:39:45 AM
hi

I posted this question in other forums but I haven't received many feedbacks yet.

there are billions of mods around for the TS, what I look for is some minimal NO Mojo mod to:

- mantain the gain characteristics
- get a more transparent sound
- flatten a bit the mid hump without loosing the TS overall characteristics.

looking at the schem what comes to my mind is:

- replace the 2 NP 1uF electro with 2 1uF Film (better quality)
- replace the 47nF in the feedback loop with a 100 nF (a bit more bass)
- replace the tant. 220nF at the 1st opamp output with a 100nf film (to get a higher low pass corner)
- replace the tant. 220nF of the tone with a 220nf film (better quality)

(I don't believe the opamp sub can get a more transparent sound, I did it few times with my SD! with 0 results)

any idea about it?
much appreciate
thx
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: ElectricDruid on March 05, 2021, 09:10:48 AM
I'd have to play with a Sim to be sure (or build one, equivalently) but I think your ideas are definitely along the right lines. Certainly playing with the tone response (which is heavily shaped at every stage in the TS) is the way to go. Changing op-amps is ok for magic-mojo cork sniffers, but they're missing a much bigger picture!
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: Fancy Lime on March 05, 2021, 10:07:13 AM
The problem may be that you want to (1) maintain the Tube Screamer Character and (2) make it more transparent. In my, and I think most people's understanding, those are incompatible opposites. If you can describe in a little more details what you consider the TS characteristics that you'd like to keep and what you think of when you say "transparent", we should be able to help you. Putting sound in words is hard though. So the solution will likely involve some experimentation on your part. Do you have a breadboard?

Also, I second Tom in that changing opamps will not really make an audible difference (unless you use something really unsuitable for audio). Changing cap types to film will make a bit more difference but I don't have the golden ears to hear it. I'd use film caps in a from scratch build but I wouldn't change existing ones.

Andy
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: r080 on March 05, 2021, 11:35:24 AM
Clear acrylic case?

Take a look at Fulldrive 2 MOSFET schematics. The "Flat Mid" mode is a switchable feedback loop, which will flatten the frequency response some.

http://fuzzypedals.blogspot.com/2015/06/fulldrive-deadringer-mosfet-overdrive.html
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: choklitlove on March 05, 2021, 11:52:42 AM
Transparent is actually one of the first things I think when it comes to TS's.  Maybe all you're looking for is more range of the Drive pot when turned down?
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: Halkbi on March 05, 2021, 12:06:47 PM
Like stated, the sound of a Tubescreamer is much about the mid hump. I never really got along with it and I imagine you'll be looking to extend it's frequency response without altering it's distortion characteristics too much. Sounds good to me, but it shouldn't really be considered a tubescreamer as such.

I'd suggest you raise the cap to ground in the feedback loop all the way to 470n. Haven't tried it in a tube screamer but I always do it in Distortion+/DOD 250 type circuits (which stock and with their gain maxed out out will give a similar low end response to a Tubescreamer) and anything less might not give you what you want. Cutting less bass will alter how the pedal distorts which may or may not be a good thing.

Lowering the 220n after the clipping stage may make it might end up more harsh sounding since it's post-distortion, but you could try and compensate by raising the 51p feedback cap in the clipping stage. If I'm not mistaken, raising the feedback cap in the clipping section is going to cut some highs before the clipping occurs and will therefore alter the characteristics of the pedal (again, for better or for worse). I also gather that with a TS type of gain control, a bigger feedback cap will also diminish highs as gain is increased. But you never know for sure what your results will be before actually trying it out. Use sockets and see what you like.

If more transparency is all about raising the distortion headroom, try and swap those silicion clipping diodes for red LEDs. I wouldn't bother about swapping other component types. Looking forward to hearing your results!
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: Mark Hammer on March 05, 2021, 01:58:26 PM
Tubescreamer transparent?  What?  Exactly what do you consider transparent about it?  The basic design of the TS is intended to provide relatively consistent clipping across the entire fingerboard.  So what is supposed to be changed or changeable to make that more "transparent"?
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: kaycee on March 05, 2021, 03:24:03 PM
Two suggestions:

1. Turn the gain down and the volume right up.

2.Add a clean blend circuit with the ability to boost the clean/input signal if needed.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: slashandburn on March 05, 2021, 04:26:14 PM
The clean blend part of the Voodoo Labs Sparkle Drive might be worth looking at. No doubt its borrowed from elsewhere but its really handy.

That aside, I'm with everyone else wondering what you mean by transparent. If you want to flatten the mid hump I'd say it's no longer really a tubescreamer. Something like a Timmy might be a better option.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: 11-90-an on March 05, 2021, 10:52:39 PM
Have you tried looking at the EQD Westwood?

seems “transparent” to me...
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: nooneknows on March 06, 2021, 02:39:03 AM
Thank you,

ok, maybe 'transparent' it's not the right word (btw my language is not english, so please excuse me if I can't be more precise) .

My main OD is the Timmy, I have a v2, if you compare TS and Timmy the difference is huge in terms of 'details', apart from the evident hump characteristics, the TS, at comparable gain, seems having a blanket on the amp cone, that's where my concept of transparency comes from. Timmy is definitely more hi-fi, but, as you know, it doesn't have really any mojo features, it's just a wonderful good design.

That said, the TS mid hump is really useful sometimes and its distinctive compression is so friendly in a band mix that I'd like to find something of a compromise between the two, to maintain both in my board, eventually using one to boost the other.

So ok the TS mid hump, a bit flatter and wider would be better, also, a bit more detailed sound would be welcomed, all that with the minimum no-mojo mods possible.

I built many pedals, I certainly could breadboard a circuit but what I was looking for was your opinions on the matter.

thank you all.


Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: kaycee on March 06, 2021, 04:37:29 AM
Your English is very good indeed.

I'd certainly look into the pedals suggested above, but would once again make the case for trying a clean blend on the pedal you have.

I had a TS9 in the late 70's and never really liked it then, and my opinion didn't change much when I returned to guitar playing and took up effects building.

Having a crush on SRV at the time I built J.C's SRV special and added a simple jfet blend, and that I did like. Having the original guitar tone in the mix with the TS sound was really nice, it added clarity and detail to my ears. But, it only sounded good on low gain settings, at higher gain it was like a tinny buzzing in the background of the clean tone, horrible!

Much as I liked that, I eventually settled on a Klon clone (Harald Sabro's Workhorse) for that kind of tone, which does a similar thing in a more elegant way.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: anotherjim on March 06, 2021, 05:35:01 AM
Maybe you'd be happier with the Marshall Blues Breaker type.
The operation of TS distortion is coloured by the diode switching response. The diodes switch at a particular speed and I think that is responsible for an upper halo of "fizz" distortion that has nothing to do with the pitches or harmonics of the notes you play. The Blues Breaker still switches the diodes but is softened due to having resistance in series with them.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: 11-90-an on March 06, 2021, 09:30:51 AM
Maybe you'd be happier with the Marshall Blues Breaker type.
The operation of TS distortion is coloured by the diode switching response. The diodes switch at a particular speed and I think that is responsible for an upper halo of "fizz" distortion that has nothing to do with the pitches or harmonics of the notes you play. The Blues Breaker still switches the diodes but is softened due to having resistance in series with them.

And if you go with a blues-breaker type, a perfect breadboard-able (and great sounding!) example would be Mark Hammer’s Wattbreaker  ;)

https://www.diystompboxes.com/smfforum/index.php?topic=126135.0

I don’t think i would describe it as “transparent”, though, probably as “tight”...

Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: nooneknows on March 06, 2021, 09:56:12 AM
And if you go with a blues-breaker type, a perfect breadboard-able (and great sounding!) example would be Mark Hammer’s Wattbreaker  ;)

https://www.diystompboxes.com/smfforum/index.php?topic=126135.0


I had some trouble finding the schematics in the thread, finally I got it, very interesting, minimal and clever, I have to try it (although actually my aim was obtaining something with the TS9 pedal I already have)
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: Mark Hammer on March 06, 2021, 12:44:46 PM
As noted earlier, the intent of the TS design was to provide consistent clipping across all strings and frets.  It doesn't quite achieve that, but aims reasonably close by providing more gain for content above 720hz and correspondingly shaving off top-end as more gain is applied.  One of the results of the combined highpass and lowpass filtering IS the dreaded "mid-hump" - that point where highpass and lowpass filtering is negligible but gain is still applied to what lies in between.

Flattening out the frequency response, to avoid excessive midrange, or rather too-prominent midrange, can be achieved in a variety of ways.  One way is to increase bass response a bit and move the lowpass filtering over a smidgen.  So, that would imply increase the value of the .047 cap to .1 or similar, and decreasing the .22uf cap on the output of the clipping stage to something like .15 or .12uf.  Doing both of these expands the passband both upwards and downwards.

A strategy I've become fond of is that employed in both the Rat and the Bluesbreaker, which is to use TWO ground legs in a gain stage to provide a basic gain to the entire spectrum, and additional gain for content over some point of interest in the spectrum.  The TS uses a single ground leg and choice of rolloff such that less and less gain is applied to frequencies below some corner frequency.  The "two-leg" strategy provides constant gain for everything below the point of interest, just less of it.  You get to keep your bass, but goose the mids and highs a little more to bring them closer to the clipping threshold.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: nooneknows on March 06, 2021, 01:33:01 PM

A strategy I've become fond of is that employed in both the Rat and the Bluesbreaker, which is to use TWO ground legs in a gain stage to provide a basic gain to the entire spectrum, and additional gain for content over some point of interest in the spectrum.

this sounds interesting: if I understand correctly what you're saying, in the blues breaker schematics I see a 4K7+10nF with a corner at 3386Hz, and another combo with 3K3+10nF ,but I think the other 10nF cap in series affects the value, so it could be a 3K3+5nF that means 9645Hz (is it correct?).

what values would you suggest for the TS?

thank you
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: POTL on March 06, 2021, 02:24:42 PM
Hello Earthquaker Devices already did it for you. find schemes Dunes and Plumes, they have these very mods. It's hard to think of something new for TS mods in 2021.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: ElectricDruid on March 06, 2021, 03:25:36 PM
It's hard to think of something new for TS mods in 2021.

Lol, Amen to that! ;)
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: iainpunk on March 06, 2021, 03:47:33 PM
It's hard to think of something new for TS mods in 2021.

Lol, Amen to that! ;)
that sounds like a challenge, where can i buy a cheap ibanez TS? i need to mod it in a way no one has ever done before! [[chainsaw mod???]]

cheers
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: Mark Hammer on March 06, 2021, 04:17:05 PM

A strategy I've become fond of is that employed in both the Rat and the Bluesbreaker, which is to use TWO ground legs in a gain stage to provide a basic gain to the entire spectrum, and additional gain for content over some point of interest in the spectrum.

this sounds interesting: if I understand correctly what you're saying, in the blues breaker schematics I see a 4K7+10nF with a corner at 3386Hz, and another combo with 3K3+10nF ,but I think the other 10nF cap in series affects the value, so it could be a 3K3+5nF that means 9645Hz (is it correct?).

what values would you suggest for the TS?

thank you

Gotta say, I do not understand the math of that one.  What advantage could there be in increased gain for content outside the range of most guitar speakers?  Hopefully one of our more technically-inclined EE types can explain how to do the calculations for that sort of arrangement.

That said, sticking with a simpler arrangement, try putting a 10k/470nf pair in parallel with the 4K7/47nf pair.  That will provide fairly even gain for content down to just over 200hz, before rolling off below that, just less gain for the sub-720hz stuff as you turn up the drive.  If my calculations are right, that should provide a "relaxed" lower end - not so much bass that it clips too seriously - to take some of the spotlight off the mids.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: ElectricDruid on March 06, 2021, 05:25:04 PM
It's hard to think of something new for TS mods in 2021.

Lol, Amen to that! ;)
that sounds like a challenge, where can i buy a cheap ibanez TS? i need to mod it in a way no one has ever done before! [[chainsaw mod???]]

Of course, there's stuff you can do to it that hasn't been done before, but the tricky bit is that the end it still has to be recognisably a Tubescreamer. Otherwise I could just change every component value, add a few bits, take few others away, and say I'd done a new mod, whereas actually it's a totally different circuit. What counts? What doesn't count? There *are* no defined rules. This is science in pursuit of an art.

Still, I think the "Chainsaw TS" is definitely an option worth pursuing, just for grins and brag-points!

Wha ck the gain up. Start with some coring diodes for that crossover distortion/noise gating sound. Can we change the single midrange peak into a double-humped mid-scooped sound easily? I reckon we're nearly there already?!?
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: PRR on March 06, 2021, 06:02:53 PM
......so it could be a 3K3+5nF that means 9645Hz (is it correct?). ...........
Gotta say, I do not understand the math of that one.  What advantage could there be in increased gain for content outside the range of most guitar speakers?...

If a string has one end, it may have another.

If a slope has a pole at 10kHz, it *may* have a zero at some lower point. Here, where a ~~500k resistor/pot works against this 5nFd cap. Or observing that 500k/3k is max gain of 167, then 10k/167 is 60Hz. Which is interestingly near the _low_ note of guitar. We have set the whole guitar spectrum slanty.

The "dreaded mid hump" may just be the true raw sound of a naked steel string and velocity pickup. Note that the position of guitar in the band was narrow until guitar amps developed deep 700Hz dips; then it could play anything/anywhere. But if you are going to compare guitar spectrum to a 'flat' clipper, getting a good anti-hump fit may be very difficult.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: Rob Strand on March 06, 2021, 06:23:24 PM
You never get to win the transparency game you just move the pieces around.    That's why you have TS-9's and Timmy's.

To be honest just try decreasing the 220nF cap to ground.  Try 100nF, 47nF and 22n.  However don't *just* do do that see if you can use the tone control to push the sound where you want.    Once you pick a cap to ground value and the tone pot position it's possible to get the same tone with the tone control centered by replacing the 220nF cap to ground with an RC network with appropriate values.

If you look at the Xotic stuff they use a 100nF cap followed by a Baxandall.

Playing with the 47nF bass cap and blending is up to you but I'd say if you can't get the general tone with the above plan you are probably not going get to what you want.

Some people like adding another diode to one side can help, like the old Fulltone,  (the lower diode is two in series - see note)

http://generalguitargadgets.com/wp-content/uploads/fulldrive_2.jpg

Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: iainpunk on March 06, 2021, 07:11:06 PM
It's hard to think of something new for TS mods in 2021.

Lol, Amen to that! ;)
that sounds like a challenge, where can i buy a cheap ibanez TS? i need to mod it in a way no one has ever done before! [[chainsaw mod???]]

Of course, there's stuff you can do to it that hasn't been done before, but the tricky bit is that the end it still has to be recognisably a Tubescreamer. Otherwise I could just change every component value, add a few bits, take few others away, and say I'd done a new mod, whereas actually it's a totally different circuit. What counts? What doesn't count? There *are* no defined rules. This is science in pursuit of an art.

Still, I think the "Chainsaw TS" is definitely an option worth pursuing, just for grins and brag-points!

Wha ck the gain up. Start with some coring diodes for that crossover distortion/noise gating sound. Can we change the single midrange peak into a double-humped mid-scooped sound easily? I reckon we're nearly there already?!?
a few ideas:
we keep the gain-stage original!!!
1) i have been doing a simple gyrator ''mod-board'' with a single gyrator band-pass filter at 1.2kHz, originally to make my superfuzz in to a chainsaw but if you replace the capacitor and resistor to ground in the tone control of the tube screamer with the band-pass 'input' of the mod-board, you can have the chainsaw mid-range (ignoring the little dimple), and an aggressively thicc mid scoop as well on the other side of the sweep.

2) we replace the original clipping diodes with green LED's
3) we lift up one leg of the R7 1k and put Ge clipping diodes in series to create that crossover distortion,
4) replace C5 220nf with 22n, to bring out more top end, since the filter isn't going to be able to boost it back up again.

and obviously use it like a boost, not a stand alone distortion/drive

cheers, Iain

for reference:
(https://www.electrosmash.com/images/tech/tube-screamer/tube-screamer-block-diagram.png)

Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: 11-90-an on March 06, 2021, 10:02:51 PM
[ot]

1) i have been doing a simple gyrator ''mod-board'' with a single gyrator band-pass filter at 1.2kHz, originally to make my superfuzz in to a chainsaw but if you replace the capacitor and resistor to ground in the tone control of the tube screamer with the band-pass 'input' of the mod-board, you can have the chainsaw mid-range (ignoring the little dimple), and an aggressively thicc mid scoop as well on the other side of the sweep.

Iain, do you happen to have a schematic of this? Or at least the Q value, i can probably calculate it myself after knowing that... Im working on a fuzz, and im testing out many possible tone-shaping controls, and I’m quite curious on some sounds... :icon_biggrin:

[/ot]
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: iainpunk on March 07, 2021, 07:49:17 AM
i don't know the actual Q, i just ''stole'' the HM2 lower of the two filters, but replaced the opamp with an transistor. it doesnt give the exact same eq curve, but it does give a chainsaw on the Behrnger SF300 / BOSS FZ-2 (especially nice in BOOST mode!)

its nice since its basically a 3 wire daughterboard that can easily be placed in most enclosures.
the transistor i use is the BC547 and/or BC557 since i have dozens of them!

cheers
(https://i.postimg.cc/bGYR36Nn/gyrator-mod-board.jpg) (https://postimg.cc/bGYR36Nn)


EDIT!!!!!! i replaced the 6.8 in the chematic with a 4.7 for a more accurate sound.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: duck_arse on March 07, 2021, 08:28:31 AM
It's hard to think of something new for TS mods in 2021.

Lol, Amen to that! ;)
that sounds like a challenge, where can i buy a cheap ibanez TS? i need to mod it in a way no one has ever done before! [[chainsaw mod???]]

cheers

has anyone added a big muff tone control to a TS?
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: niektb on March 08, 2021, 06:46:05 AM
Maybe make a separate topic for the chainsaw mod as it's rather 'anti-transparent'  ;)

On topic: maybe you could take a look at the Zendrive (or the Golden Pearl)! They have a 'VOICE' control in the clipping stage, which lets you choose a HPF frequency on the fly :)
The Zendrive also has a passive RC-filter as tone control, which might make it more transparent (but you lose some of that Tubescreamer characteristic)
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: garcho on March 08, 2021, 09:05:06 AM
I have an EQ with presets, it works well for cases like this. Sometimes all you need is a little notch or bump. I usually have it about halfway through the chain; after overdrives, before mod/time stuff.
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: iainpunk on March 08, 2021, 06:00:10 PM
Maybe make a separate topic for the chainsaw mod as it's rather 'anti-transparent'  ;)
not fully accurate, since the tone control can also scoop mids, flattening out the response thus making it more transparent.

but none the less, sorry for slight derailment.

an extremely simple mod to add some low end and high mids, swap out C3 and C5. it doesn't make it fully transparent, but it evens out the response a lot, but it can also be a bit muddy.

cheers
Title: Re: Looking for minimal Tube Screamer mods for a more transparent tone
Post by: nooneknows on March 13, 2021, 10:43:47 AM
That said, sticking with a simpler arrangement, try putting a 10k/470nf pair in parallel with the 4K7/47nf pair.  That will provide fairly even gain for content down to just over 200hz, before rolling off below that, just less gain for the sub-720hz stuff as you turn up the drive.  If my calculations are right, that should provide a "relaxed" lower end - not so much bass that it clips too seriously - to take some of the spotlight off the mids.

Mark, this worked like a charm, combined with a 120nF in place of the 220nF C5 I quite obtained what I was looking for, thank you for the hint.

BTW, I also replaced the two electro NP 1uF caps with two polys 1uF but, as I expected, I haven't heard much difference, maybe a very little more crispness, but it could be just psychoacoustics.