Need a very good, clean and transparent buffer circuit to finish off a build!

[alex_spaceman]

Hi everyone,

as the title say, I'm looking for a very clean and transparent buffer to finish off a true bypass/blend kind of box. I've looked at the AMZ circuits which look good, but are there other options? which one would, in your opinion, be my best bet?

I designed the box to implement an old yamaha reverb in my setup and be able to both use it added to my straight signal and at 100% wet settings. The circuit is this one:



Any input would be much appreciated, thanks in advance!

Alex

[petey twofinger]

klon buffer seems to be VERY popular , i havent got around to trying it yet , but i heard its all the rage . , i have used tillmans , those are nice and easy , also to me sound very "good clean and transparent" ...

http://tagboardeffects.blogspot.com/2011/04/klon-buffer.html

http://revolutiondeux.blogspot.com/2012/02/klon-buffer.html

http://www.till.com/articles/GuitarPreamp/index.html

[R.G.]

It is really very difficult to beat a TL07x opamp set up for gain-of-one for a simple, effective and clean buffer.

The incremental value-per-effort-expended for other things is a strongly diminishing return. A simple transistor buffer is lower performance and can only buffer smaller signals cleanly. A multi-transistor buffer can have better performance, but is much more complex and more parts than a simple opamp buffer. A fancy la-de-da opamp may give increased performance as measured by audio instruments, but there's little real audible difference in a guitar pedal setup. Multi-opamp fancy circuits largely improve things that may not need improving, or offer only theoretical or placebo advantages.

It is really very difficult to beat a TL07x opamp set up for gain-of-one for a simple, effective and clean buffer.

[alex_spaceman]

Thanks to you both.

RG, I take it you subscribe to the point Petey made by throwing the TL based Klon buffers? I have some 072's lying around, might have to give those a go!

Anything else anyone wants to throw in the bunch?

Thanks,
Alex

[petey twofinger]

isnt on the tillman site where the op amps get bashed a bit ?

i mean , i am not trying to make a point either way , i actually will end up trying a clon buffer next time i need one , at the time i only had jfets .

BUT i do seem to remember someone HATING on opamp buffers , something about tone ... heh .

i would ideally have a tillman boxed up (which i do) AND a clon or other chip buffer that is in a box . that way , i spose i could implement them easily when breadboarding ... i would THINK the clon would have more output , but i am pretty sure i am wrong .

[oliphaunt]

I have no issues with the tone of an opamp buffer, they sound pretty dang transparent, but I don't like the "feel".  I have built several and they have all felt a bit stiff and lifeless to me.  I have not tried the Klon buffer.  The best buffer I have used so far is a tube buffer, a close second is the Cornish buffer, a bootstrapped single transistor buffer.  It has a great "feel" to it.  It seems to have a fairly low input impedance and I have heard a tiny bit of high end loss into some (but not all) amps, but it will drive a lot of cable without additional loss. 

[R.G.]

It is very stylish to bash opamp circuits of all kinds. People who think they are golden ears will claim they hear subtle differences, and if you don't hear them, YOUR ears are not as good. Shrug. Maybe. Maybe not. Could be real, could be the Emperor's new ears.

Tubes are pursued for their inherent, slight sweetening of sounds. It's measurable. Is it transparent? Shrug. If you like lots of sugar in your coffee, does that make you less able to enjoy coffee? Is coffee without sugar sterile and lifeless? Or accurate and transparent?

I think a tube buffer is more work. It's well over into the diminishing returns on investment side of things. You ought to use it if you like the taste, and are willing to pay the freight.

Music is after all, all about artistic taste.

[Ronan]

http://sound.westhost.com/dwopa.htm#buffers

[chromesphere]

I recently built the amz germanium buffer, except i used a 2n3906 in place of the germanium pnp and a few other changes. 

Sounds pretty good (in the right situation), seems to be doing what a buffer is meant to do:

Good luck!
Paul

[Cliff Schecht]

I'm with R.G. 100% on this one. For a "very good, clean and transparent buffer" a simple op amp buffer can't be beat. You can build the circuit with a thimble-full of parts and the op amp will sport the lowest distortion numbers and most transparency of any circuit you can build. A good op amp is as close as you can get (currently) to an ideal amplifier, especially if you choose the right part for the job, and should give you no fuss whatsoever regardless of what you put into it (assuming you aren't clipping it or something).


With that said, most guitarists don't like clean and transparent. Most boost pedals that I've seen also do some sort of toneshaping, this is what differentiates one circuit from the next and in many cases is how manufacturers differentiate "their sound" from someone elses. For what you are trying to do though, I would go for exactly what you described in the thread title. Build a little op amp circuit and be done with it!

I think the reason we don't see more op amp circuits employed is because 8-pin DIP packages are relatively large compared to a single transistor buffer circuit. While there are alternative op amp packages available (ignoring SMD for a second), I don't have any of them on my bench readily available. Now if I include the op amps on my bench that are SMD then I can fit an op amp buffer with whatever passives I need on a board smaller than a quarter and mount it wherever with some double sided sticky tape. This is the route I'd take but it seems DIY'ers (at least beginner ones, not sure where the OP fits in this scheme) tend to shy away from SMD's.