YATS overdrive. No buffer. What is the disadvantage?

[nguitar12]

Hi I am going to start my another project. Which is YATS overdrive



However I noticed that there are no buffer in this circuit. So what is the disadvantage of this?

[Kipper4]

I guess the disadvantage bieng that the input buffer would preserve some of the high end. However the buffer really wants to be on a really really short cable to do its job best. So not much disadvantage.
I notice theres no reverse polarity protection diode on the layout or schematic. Something I just do to all my builds now as a matter of course.

Have fun

[R.G.]

None if you're using external switching. The buffer in the original was to enable the JFET switching.

And by the way, true bypass switching is a solution to a problem we no longer have.  

@kipper4: the input impedance of the opamp there is high enough not to lose treble.

[Brisance]

An ideal op-amp has infinite input impedance, in reality it's just really high, what you have there is that the op-amp is doing the same function as a buffer normally would.

[Kipper4]

Thanks guys

[nguitar12]

None if you're using external switching. The buffer in the original was to enable the JFET switching.

And by the way, true bypass switching is a solution to a problem we no longer have.  

@kipper4: the input impedance of the opamp there is high enough not to lose treble.

Sorry for the noob question but what do you mean by external switching / internal switching?

[bluebunny]

None if you're using external switching. The buffer in the original was to enable the JFET switching.

And by the way, true bypass switching is a solution to a problem we no longer have.  

Sorry for the noob question but what do you mean by external switching / internal switching?

R.G. is referring to bypass switching.  By "external", he means external to the circuit - so mechanically by means of a 3PDT (or DPDT) footswitch.  R.G. didn't say "internal", he said "JFET".  The original TS circuit uses JFETs to turn the effect on and off.  Check out R.G.'s excellent Technology of the Tube Screamer article (and this schematic).  All will be revealed!   

[Gus]

The posted schematic has a lower input resistance. 
You can increase R1 and R2 and adjust C1.

The output resistance is higher than the buffer output of a TS except at full and close to full volume.  This can matter with what is after the circuit.

[Ice-9]

The input and output buffers are only really there for the fet bypass switching, when using true bypass switching the buffers can be ignored. By the way True bypass is not the best way to do bypass these days. In my opinion the only benefit of true bypass are - simplified builds.