What are your favourite tube screamer mods?

[Brett]

You should be fine with the switching you have if you’re using off board bypass switches for each circuit. It may be a good idea to adjust your net labels so your CAD software shows the correct connections when you start your layout.

 

[neiltheseal]

Hello again.
I finally got around to putting this together and (as I had suspected) it doesn't work properly.

Would anyone be able to have a look at the schematic for me and give me some tips re why why it's not working? The most recent schematic is attached.

It passes signal so that's a win, however there is no gain. With an audio probe I have tracked the problem to IC1.1. The signal enters strong on pin 3 but comes out extremely weak from pin 1 and therafter.

I measured the voltages and they are as follows:

1. 7.8
2. 7.8
3. 0.2
4. 0
5. 7.6
6. 7.6
7. 7.6
8. 8.6

This seems to confirm the problem is here as I assume that pins 1,2,3,5,6 and 7 should be about 4.5v. I suspect this means that I need to bias the op amp but I have no idea how to do this.

Thanks!

 

[Blackboarcult]

Leg 2 of LoCut should go to VREF and not to ground. Although I suspect that this is only part of the issue, your Vref voltage is too high to be caused by this accidental ground connection. Double check that you have 1/2 V+ between R16 and R17, and track from there.

 

[nooneknows]

you are too much rude on the TS, it is a good pedal with a particular purpose, almost completely forgotten these days (driving a non master volume tube amp in a much more comfort zone) , I can't say any other use is wrong but just put it in the right context and it works pretty well.

Anyway, if you don't want to use it that way, the only mods I really like are:

1) getting rid of the input and output buffer (useless if you run with a mechanical true bypass switch)
2) a variable bass control or, at least, moving the bass cut corner lower, doubling the infamous 47nF cap to ground for example
3) adding a germanium diode or a schottky diode (same voltage more or less) on one side of the clipping stage to enhance harmonics

that's it.

 

[rosssurf]

you are too much rude on the TS, it is a good pedal with a particular purpose, almost completely forgotten these days (driving a non master volume tube amp in a much more comfort zone) , I can't say any other use is wrong but just put it in the right context and it works pretty well.

Anyway, if you don't want to use it that way, the only mods I really like are:

1) getting rid of the input and output buffer (useless if you run with a mechanical true bypass switch)
2) a variable bass control or, at least, moving the bass cut corner lower, doubling the infamous 47nF cap to ground for example
3) adding a germanium diode or a schottky diode (same voltage more or less) on one side of the clipping stage to enhance harmonics

that's it.

Kinda new at this but, I am building the pedalpcb "Little green scream machine" I will probably add a toggle switch to offer the .047 (720hz) high pass filter as well as a .1 (338hz) option for more bass.

Might the 51pf be raised considerably to add more clarity? If I understand correctly that small cap has less effect when running the "DRIVE" at lower settings. I plan to use it in this manner with only the level turned up for more boost into an already dirty JCM 800. Might a toggle for the 51p be a good way to mod the high frequencies to taste?

I plan to build it per the schematic which includes the buffer. I also am using a 3pdt blue stomp switch. Does your suggestion 1, regarding the buffer mean that my pedals buffer will not work because I will be using this 3pdt footswitch? Or does it mean it will only buffer when the pedal is "on"?

 

[nooneknows]

The 51p it's there to tame a bit the higher umpleasant freqs, if you raise it more higher frequencies will be cut, matter of taste.

The buffers are functional in the original scheme because there are fets used as switches for the electronic bypass, you must decouple them from input and output, if you use a true bypass with a mechanical switch you don't need buffers, unless you use some exotic opamp which could cause some driving problem. With a TL0x2 or even the 4558 you have enough input impedance and output driving capability to manage the effect without the need for buffers, which could introduce some unnecessary coloration. There are a number of ts derivative circuit examples without buffers

 

[HamishR]

Probably my all time favourite TS mods are as follows: I take great care to follow the TS-808 narrow box schematic. The TS-9 just isn't the same. I also prefer 1N4148 diodes over 1N914s as the 914s don't "bloom" in the same way. I like to use just a bit more diode: 2 1/2 usually. Metal film resistors are a necessity except for R5 - I like carbon comp there for a hint of '50s south-side Chicago. If you intend to use this for metal then disregard. Standing the resistors up is a killer mod for that authentic vibe. There is no actual sonic benefit but damn the vibe is cool.

A JRC4558 that was originally used in a Sony clock radio is essential. No other IC will do. Not as difficult to get as you might imagine. As far as the yeast is concerned I prefer brewer's yeast over baker's yeast but if you can't find it use a good sour-dough starter. San Francisco residents often have the very best sounding Tubescreamers. For a more original Japanese sound panko crumb yeast is amazing.

It goes without saying that altering the green of the enclosure will affect the tone. I generally prefer a tad bluer than Ibanez used originally - for obvious reasons. And fitting the entire finished assembly into enclosure I like to loosely fit the nuts. It makes it easier to just remove the whole thing, chuck it out and put a different circuit in there.