Looking for minimal Tube Screamer mods for a more transparent tone

Started by nooneknows, March 05, 2021, 08:39:45 AM

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Mark Hammer

Quote from: nooneknows on March 06, 2021, 01:33:01 PM
Quote from: Mark Hammer on March 06, 2021, 12:44:46 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.

ElectricDruid

Quote from: iainpunk on March 06, 2021, 03:47:33 PM
Quote from: ElectricDruid on March 06, 2021, 03:25:36 PM
Quote from: POTL on March 06, 2021, 02:24:42 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?!?

PRR

Quote from: Mark Hammer on March 06, 2021, 04:17:05 PM
Quote from: nooneknows on March 06, 2021, 01:33:01 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.
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Rob Strand

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

Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

iainpunk

Quote from: ElectricDruid on March 06, 2021, 05:25:04 PM
Quote from: iainpunk on March 06, 2021, 03:47:33 PM
Quote from: ElectricDruid on March 06, 2021, 03:25:36 PM
Quote from: POTL on March 06, 2021, 02:24:42 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:


friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers

11-90-an

[ot]

Quote from: iainpunk on March 06, 2021, 07:11:06 PM
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]
flip flop flip flop flip

iainpunk

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



EDIT!!!!!! i replaced the 6.8 in the chematic with a 4.7 for a more accurate sound.
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers

duck_arse

Quote from: iainpunk on March 06, 2021, 03:47:33 PM
Quote from: ElectricDruid on March 06, 2021, 03:25:36 PM
Quote from: POTL on March 06, 2021, 02:24:42 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

has anyone added a big muff tone control to a TS?
You hold the small basket while I strain the gnat.

niektb

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)

garcho

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.
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"...and weird on top!"

iainpunk

Quote from: niektb on March 08, 2021, 06:46:05 AM
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
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers

nooneknows

Quote from: Mark Hammer on March 06, 2021, 04:17:05 PM
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.