TS Boost

[drewl]

So, I've built a couple tubescreamer variants with the switchable 1M "boost" pot which adds a nice push to the pedal, except I have a friend who thinks it should add more gain.
Any other ways to increase the boost without making it sound crappy?
And what is this "grandlaff" mod I've seen pop up here?
Just changing the voltage to the feedback loop?

[frankclarke]

Going  over 1M would sound crappy to me. If you want more volume you could add a transistor gain stage, or put more clipping diodes in series (The BYOC Grandlaff thing).
A lot of people are using 1-transistor boosters as a boost alongside overdrive pedals.

[Jobet]

Here also, changing the clipping diodes to LED's will increase the volume, albeit it decreases the grit.

If you want to increase the volume without changing the tone of your ped, look for that 1k resistor in series with the level knob and decrease that, say, to 500 ohms. Maybe you can even short it out altogether. I dunno, I've never found the need, but if you ever do need to, that's one more place to look. And oh...doing that TS808 mod will also increase the volume as you replace the 470 ohm resistor in the output buffer to 100 ohms.

[R.G.]

If you want to make a real difference in the TS, run the signal from the input buffer through a capacitor/resistor to the inverting input, not the non-inverting input as stock.

[slideman82]

Well, that's interesting, RG! Mine is simpler: just replace the 100K vol pot for something bigger, I mean, 1M. I think it boost the avaible volume, and the sound stills the same.

[drewl]

The boost is like that of a Fulltone Fulldrive II, sounds good and adds a bit more oomph, but my friend is real
critical about knobs!
They have to do alot when turned.....

[d95err]

Well, that's interesting, RG! Mine is simpler: just replace the 100K vol pot for something bigger, I mean, 1M. I think it boost the avaible volume, and the sound stills the same.

Have you tried this? The output of the TS is buffered, so I can't see that a 100k pot at max would reduce volume at all. To me, it seems that a 1M pot would just add noise.

EDIT: Hmm... I got that slightly wrong. The volume pot is before the output buffer. Anyway, the output of the second opamp stage should be very low, so I don't think the 100k would load down the signal at all. Using an 1M pot should not change the output level at all, unless I've missed something significant.

[Jobet]

I don't think replacing the level pot with a higher value will result in a higher signal because at the top, you'll still have the signal voltage at the same level, and ground at the other. And since there is an output buffer after the volume control...oh well. Maybe it will result in a more "loose" sound, but not one with higher levels.

Let's just say, look for those series resistances after the two op amp stages and reduce those. You'll be reducing the resistance that burns away the signal.

[slideman82]

Well, that's interesting, RG! Mine is simpler: just replace the 100K vol pot for something bigger, I mean, 1M. I think it boost the avaible volume, and the sound stills the same.

Have you tried this? The output of the TS is buffered, so I can't see that a 100k pot at max would reduce volume at all. To me, it seems that a 1M pot would just add noise.

EDIT: Hmm... I got that slightly wrong. The volume pot is before the output buffer. Anyway, the output of the second opamp stage should be very low, so I don't think the 100k would load down the signal at all. Using an 1M pot should not change the output level at all, unless I've missed something significant.

Maybe you've missed experimentation... try it, then you tell me. Well, I haven't tried it in a stock TS, just in something similar and it did work!

[drewl]

I'm not trying to turn this into an all out screaming distortion pedal, or pump up the output so that it slams the input
of an amp!
Just trying to get the switchable "boost" or gain of the 1st opamp stage a little hotter.
I found several ways and most sounded pretty good.
I opted for bypassing the 51k resistor before the gain pot, which actually lowers the gain but when the 1M boost pot is switched in the change is now more noticeable and the overall gain of the pedal is higher.

as a side note: I lowered the value of the .22uf to gnd after the output of the first stage to a .022,  which made the pedal a little brighter, which sounded better to me. The problem is it wants to oscillate with the tone cranked up and the sound is a little thin....I settled on a .1 as a compromise.
Any other easy ways to brighten these up a tad.

Sure, I can dick around with different values, but it's alot easier to just ask as I'm sure many have done it before!

[d95err]

Well, that's interesting, RG! Mine is simpler: just replace the 100K vol pot for something bigger, I mean, 1M. I think it boost the avaible volume, and the sound stills the same.

Have you tried this? The output of the TS is buffered, so I can't see that a 100k pot at max would reduce volume at all. To me, it seems that a 1M pot would just add noise.

EDIT: Hmm... I got that slightly wrong. The volume pot is before the output buffer. Anyway, the output of the second opamp stage should be very low, so I don't think the 100k would load down the signal at all. Using an 1M pot should not change the output level at all, unless I've missed something significant.

Maybe you've missed experimentation... try it, then you tell me. Well, I haven't tried it in a stock TS, just in something similar and it did work!

I've experimented allright. For instance, in my BSIAB2, using a bigger (1M) volume pot made for a slight increase in output level. But that's a very different circuit with much higher output impedance than the second opamp stage of a TS. What circuit did you try it with?

(I'm not saying it won't work in the TS, just that from what I've learnt of audio electronics (not very much) it seems unlikely to make a significant difference.)

[drewl]

Just to report my findings, with around 100mv signal into the pedal, removing the output pot load only increased the output level around a few mv.
YMMV.

[Jobet]

If you want something hotter, look at the TS7 which has a "hot" mode and examine the schematic on the switching. You'll notice it switches RC circuits in andout of the feeback portion of the first OP-Amp.

You can also search the net for the Keeley "Baked" mod which is practically the "hot" mode of the TS7 implemented on a TS9.

[slideman82]

Well, that's interesting, RG! Mine is simpler: just replace the 100K vol pot for something bigger, I mean, 1M. I think it boost the avaible volume, and the sound stills the same.

Have you tried this? The output of the TS is buffered, so I can't see that a 100k pot at max would reduce volume at all. To me, it seems that a 1M pot would just add noise.

EDIT: Hmm... I got that slightly wrong. The volume pot is before the output buffer. Anyway, the output of the second opamp stage should be very low, so I don't think the 100k would load down the signal at all. Using an 1M pot should not change the output level at all, unless I've missed something significant.

If you don't want to change that pot, just add a switch with a 1M resistor to lug 1.

Maybe you've missed experimentation... try it, then you tell me. Well, I haven't tried it in a stock TS, just in something similar and it did work!

I've experimented allright. For instance, in my BSIAB2, using a bigger (1M) volume pot made for a slight increase in output level. But that's a very different circuit with much higher output impedance than the second opamp stage of a TS. What circuit did you try it with?

(I'm not saying it won't work in the TS, just that from what I've learnt of audio electronics (not very much) it seems unlikely to make a significant difference.)

Ok, my experience says theory sometimes got nothing to do with practice, with what you solder and what youi listen after doing that... I experimented with differenet EQ in the TS, good results I obtained, Master Yoda with.