ibanez tubescreamer ts9 volume increase mod?

[Renegadrian]

Did a quick search before posting this, didn't find that much that answers my question and need.

Question is - on a TS9 schematic, which some people find not having sufficient output volume, what can be done to adjust it?! would removing the resistor just before the pot help somehow?! suggestions?!

[antonis]

If you like to talk about without a schematic, it's OK with me...

You shouldn't remove that resistor because it sets OpAmp's maximum Output current when Vol pot is set at max..

You could raise the NFB loop resistor value at the tone circuit but this should have significant result only at high treble settings..

IMHO, "Sufficient" output volume is something that is related with whatever the pedal is connected to and maybe you'll have to tweak output buffer's resistor values...
(which is the only difference between TS versions - together with OpAmp types..)

P.S.
The technology of the Tube Screamer by R.G. Keen / Tube Screamer Anatomy by Electrosmash are far away from just been excellent references...

[Renegadrian]

yep I did read about that feedback 1k resistor, but it may change the tone somehow. so I guess there's no way to improve it...
I built a couple of ts808 without buffers in the past, both were having the same issue, so I think it's not something you can change that much with buffers...unless you rewire one (which one?! input or output?!) to a regular common emitter stage.

[ashcat_lt]

yep I did read about that feedback 1k resistor, but it may change the tone somehow. so I guess there's no way to improve it...
I built a couple of ts808 without buffers in the past, both were having the same issue, so I think it's not something you can change that much with buffers...unless you rewire one (which one?! input or output?!) to a regular common emitter stage.

That's gonna be your answer.  It has to be the output buffer, though.  More gain into the thing just clips harder but doesn't get much louder.  You'll probably end up trying to compensate at the gain knob, which will change the overall tone...

Both opamp stages are complex networks of Rs and Cs and Ds and changing any one of those components always changes two or more parameters - gain and "cutoff" of one or more filters - at the same time.

How loud do you want it?

[J0K3RX]

This may not be the route you wanted to go but it has plenty of volume and leaves all other straight up tube screamers in the dust... It's a tube screamer into a MXR microamp combo. So many variations and options are possible...

[Renegadrian]

thx guys, it is about a specific ts5 I rehoused some time ago, the new owner wants to keep its tone (so a lot of mods would be bad, as ashcat_lt wrote) but have a tad more volume. I guess rewiring the output buffer to a common emitter wouldn't change the overall characteristics of the TS but boost it just a little.
BTW, as we're all here, I'm no TS fanatic, so I didn't experience myself, but really a change in buffers (ts9/ts808) is so dramatic!? if so, bufferless TSs (son of screamer, which I like, ecc) should be supposed to sound so much different! don't they give you the same sound?! do you hear the differences?!

[Mark Hammer]

How easy is it to transform the transistor buffer on the TS-9 output into a gain stage?

[ashcat_lt]

How easy is it to transform the transistor buffer on the TS-9 output into a gain stage?

Add an emitter resistor, move the outut resistor up to the emitter.  Play with the E and C R values until it does what you want.  If you can't get it with reasonable values, change transistor.   Or I suppose measure the tranny and do some math. 

This does invert the output.  If that's a problem for some reason, you're going to need more parts.

[PRR]

> on a TS9 schematic

*Which* TS9 schematic?

The one I found, you diddle the output buffer, it also diddles the bypass gain. So no net improvement.

> which some people find not having sufficient output volume

The output is 0.6V peak (or less).

When it was new, guitars were generally more like 0.3V peak, so this was louder.

I think now with massive pedalboards and hot guitars, some players' cord levels are upward of 0.6V. So the old toy seems weak.

1) Double-up the diodes for 1.2V peak output. But this has subtle side-effects on overload. (Cheap to try though.)

The 1K around the last opamp. (Not the 1K to the 100K pot; that's only 1% difference.) It has to look like 1K to the tone-network or tone will be different. However it does not have to be unity gain. Try 1.5K in that place, opamp out to tone pot, and add 3K (3.3K) that end of tone pot to ground. That gives gain of 1.5 with same tone impedance.

[PBE6]

PRR the output volume of the Tubescreamer shouldn't be limited by the diode voltage, the non-inverting clipper output magnitude is Vout = Vin + Vd. It should routinely crest the 1V level at max volume and even moderate gain levels. That has me scratching my head a bit, how loud does Renegadrian need his TS9 to be?



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[Mark Hammer]

Paul, good point about the output buffer's impact on BOTH effect and bypass level.  When one gets used to looking at the effect circuit without the switching accoutrements, you tend to forget that the bypassed signal also passes through that same output buffer! 

PBE6, one of the things that people like about the Timmy and similar pedals is that the use of multi-diode combinations provides a higher clipping threshold, which affords not only more dynamics, but also a hotter output level, even when not set for max gain.  So, if a person does not typically set their TS-9 for max gain, then perhaps one way of goosing the output level is to simply stick a back-to-back pair of Schottky diodes in series with the existing diode pair in the feedback loop.  That will up the clipping threshold by 20-30%, without changing very much else.

[Renegadrian]

This particular one I have to push its volume it's a ts5 I rehoused some time ago, it also got a new regular dpdt switch with millenium 2 and true bypass. no problem on the buffer then!!!

[PBE6]

The simplest version of a non-inverting opamp clipper does indeed give you Vout = Vin + Vd, which means it's always louder than the input signal. I did however forget that the Tubescreamer is not just a simple clipper, it's a clipper with an enormous amount of filtering!

The clipping stage itself adds a shelving high pass filter that cuts frequencies below 720 Hz, while the static filter before the tone control cuts high frequencies above 720 Hz - that leaves you about 6dB down at 720 Hz and lower everywhere else. Turn the tone control down and you're losing even more signal. Turning up the tone control gets you a substantial boost (~14dB) but only above 3.3kHz. No wonder it loses so much volume!

If it's easy to convert the output buffer to a gain stage on your rehoused TS5, that's probably your best bet. It shouldn't colour the sound much at all if the gain is within reason (2x or 3x). I note that the Timmy boosts the output with an opamp gain stage, and also avoids the heavy filtering of the TS tone stage, so I'm not surprised it has such a high output.

Mark and PRR are both of course correct about changing the clipping diodes to LEDs or multiple series diodes to get more volume and playing dynamics. That is an even easier fix, although I've found that LEDs do audibly change the clipping character in these circuits so I'd recommend using "more of the same" if it's already got silicon.




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[Mark Hammer]

That's why I suggested supplementing with a pair of Schottkys, rather than radically changing the forward voltage with LEDs, or even a second pair of SI diodes.  They will nudge the clipping threshold up roughly another 200mv in each direction, rather than a more radical jump of another +/-500-600mv like you would get from a second pair of 1N4148/914s.  The idea is that one retains most of the clipping character of the original, but gets a bit more output.