Son Of Screamer and Tube Screamer

[shredgd]

Hi,
A few years ago, when I didn't know much about the Tube Screamer I built a Son Of Screamer. I like its tone, but it doesn't have any sustain so I can't play solos with it. Can anyone tell me how the added input and output buffers in the TS affect the tone and wether the lack of "solo capability" of my SOS depends on those or not?
Thank you in advance,

Giulio

[Ansil]

input and output buffers are set to provide a gain of 1 or unity. and the according to the article on the tube screamer if you mod the thing to a ts808 it supposedly drives your amp harder.

but the thing wasn't built for solos buy itself.  are you using it to create distortion alone or as a booster.   if as a booster then i don't see why it isn't screaming.. (pardon the pun)  if you are using it as a standalone distortion pedal then you will probally be sad.  but you can change out the 4.7k and drop it to 1.5k and the 0.047uF cap is raised to 0.22uF to give you the same freq response but to increase the gain from       117.23404255319148       to       367.3333333333333

should be enough for solos

[brett]

Are you sure that your SOS is working properly?  It should give enough gain and sustain for a fine solo.  Mear max gain it turns even a small signal (like a finger-picked artificial harmonic over a single coil pickup) into a full-volume sound.  Sustain-wise, you should be getting 3 or 4 times the length of note with the SOS as you do without it. (at least that's my impression - I haven't measured it or anything).

Do any of your friends (or a music shop) have a TS that you can compare your SOS with?  They should be quite similar.

[shredgd]

I did some experiments today. I decided to replace the ceramic and electrolytic caps with better ones, even if I only found polyester caps a the local store. Anyway I read they're better than ceramic and electrolytic, aren't they?

For Ansil: I put a 3.3k resistor and a 0.1u cap in the clipping stage instead of the 4.7k/0.047u combo (the same as the Greene Screamer+). I thought 1.5k may be too much because I already have a 1 Meg drive pot. However I'll use another resistor in parallel to lower the total resistance tomorrow and see what happens...!

I could only try the pedal with headphones (through my amp of course) tonight, so it's the same as if I didn't test it.
Maybe I simply ask too much from this kind of circuit, that's why I perceive this lack of "solo capability". I usually play with high gain so probably I'm also not used to overdrive pedals. Though, I realize a nice application of this circuit is as a booster. I'm looking forward to hearing it at full volume!

Giulio

[shredgd]

I forgot to say I also rearranged the diodes in the clipping stage, again applying Greene's Screamer+ design (i.e. one 1N4148 in one direction and a germanium diode and a 1N4001 in the other). I did all the changes at the same time, but I suppose (for what I read) it's thanks to this last mod I now don't experience the uneven clipping when picking softly I experienced before.

Giulio

[Ansil]

I did some experiments today. I decided to replace the ceramic and electrolytic caps with better ones, even if I only found polyester caps a the local store. Anyway I read they're better than ceramic and electrolytic, aren't they?

For Ansil: I put a 3.3k resistor and a 0.1u cap in the clipping stage instead of the 4.7k/0.047u combo (the same as the Greene Screamer+). I thought 1.5k may be too much because I already have a 1 Meg drive pot. However I'll use another resistor in parallel to lower the total resistance tomorrow and see what happens...!

I could only try the pedal with headphones (through my amp of course) tonight, so it's the same as if I didn't test it.
Maybe I simply ask too much from this kind of circuit, that's why I perceive this lack of "solo capability". I usually play with high gain so probably I'm also not used to overdrive pedals. Though, I realize a nice application of this circuit is as a booster. I'm looking forward to hearing it at full volume!

Giulio

when you have a 1 meg drive pot you are cutting your high response in half of what the original specs are unless you halve the high cut capacitor.if you are still running a 51pf like the schematics say. then you are only geting around 3.3k  of highs,  where the original would give you 6.6k   if you want to put it back to spec then you need a 25pf cap to get you there.

as far as the lows go
the usual freq cut off is 720hz on the stock circuit.   the one you have is around 483hz.  more bottom.   and the gain is  303 ~ aprox.  thats about a hundred more than an mxr.  should be screaming fine

[shredgd]

when you have a 1 meg drive pot you are cutting your high response in half of what the original specs are unless you halve the high cut capacitor.if you are still running a 51pf like the schematics say. then you are only geting around 3.3k  of highs,  where the original would give you 6.6k   if you want to put it back to spec then you need a 25pf cap to get you there.

What about if I decide not to go past half-way with the drive pot? Being it a variable resistor I should keep the frequencies in spec, am I wrong?
By the way, can you write the formulas you're using to give me those numbers?
I only know the one for the gain, which I read is given by: 1 + resistance in parallel with the diodes/resistance in series with the one above (is it right?). I would like to know the one(s) for the frequency.
Also, when upgrading the caps I got wrong and bought a 0.1u instead of 0.05u as C1. This should give me more bass, isn't it? But what about the interaction with the following 470k resistance (R1) to ground? (In the Son of Screamer article I read there's a relation between these two components and frequency response).
Lastly, would it be a useful improvement to raise R1 to increase input impedance? Or should I keep things like they are?

I finally plugged the now modded SOS with my cabinet working and I must say the pedal sound has improved a lot!
Yes, now I can play solos!