Second eyes, buffer help

[selfdestroyer]

I am attempting to make a etchable klon buffer with 2 buffered outputs. I used Jimmybjj's klon buffer layout and added the 2nd output. I just wanted to see if I am totally wrong with this aproch.

My application was to use this in my Ernie Ball VP Jr for an input buffer and a buffered tuner out. I also have a few other A/B stuff I want to use it for also.

Here is the schematic I drew up in Diptrace:


Thoughts?

Cody

[jubal81]

Looks good to me. I usually use 10K for R1 & R2. I'm not familiar with Diptrace, but don't forget to power your opamp - I've made that mistake before.

[muddyfox]

it is powered, the little u1 box on the top.
and yeah, what's the logic behind the 100k divider?

[rullywowr]

it is powered, the little u1 box on the top.
and yeah, what's the logic behind the 100k divider?

The 100k divider provides a reference voltage around 4.5v to the opamp.  This is injected into the incoming AC signal.  You can see from the actual K.L.O.N schematic how this works.  In K.L.O.N schematics, this is done in the power section then added to NET "VB".  "VB" is then injected into the incoming signal.

In this schematic you are using, you are basically combining the signal with the power section from the get go....starting with the power section.

[muddyfox]

Well I do know how a voltage divider works (surprisingly enough  and apparently I need to re-read what I write because I haven't been getting my point across lately), what I was actually wondering is whether there's a reason they are 100k in this circuit instead of 10k that I usually see used?

[selfdestroyer]

Thanks everyone for taking a look at the schematic and to make sure my second output "should" work. I wish I know the answers to the question with R1 & R2 but I have no idea how a buffer work and I just read up on how to add a second output from a TL072 and altered Jimmybjj's layout.

Here is the prototype from this morning all populated.


Here is a dumb question, How can I tell if this thing is working since its so subtle of a change to the chain? Is there a way to check it on a scope or DMM? Or do I have to just believe in magic?

Cody

[blearyeyes]

That is a great question! I don't have a clue either..There are some interesting books on VooDoo based Mojo on Amazon... har har.
This is a great idea and I hope it works. I have an unused EB VP jr sitting there yelling at me to do something to it.
Maybe this and a bit of adjustable gain?  Wish I could be of some help. 8-(   

I just want to be a useful engine..(Thomas)

[rullywowr]

Thanks everyone for taking a look at the schematic and to make sure my second output "should" work. I wish I know the answers to the question with R1 & R2 but I have no idea how a buffer work and I just read up on how to add a second output from a TL072 and altered Jimmybjj's layout.

Here is the prototype from this morning all populated.


Here is a dumb question, How can I tell if this thing is working since its so subtle of a change to the chain? Is there a way to check it on a scope or DMM? Or do I have to just believe in magic?

Cody

The best thing is to put it on your testing rig and activate it/bypass it. In lieu of that use a looper or a/b switch. I notice a definite change to  the signal (more articulate highs) when engaged.

[selfdestroyer]

That is a great question! I don't have a clue either..There are some interesting books on VooDoo based Mojo on Amazon... har har.
This is a great idea and I hope it works. I have an unused EB VP jr sitting there yelling at me to do something to it.
Maybe this and a bit of adjustable gain?  Wish I could be of some help. 8-(   

I just want to be a useful engine..(Thomas)

Thanks, I have a bit to do in Diptrace to make the pads of the TL072 a little larger then I will post the etch mask in the Member Projects & Tutorial section and see if I can get some help verifying it.

Cody

[selfdestroyer]

The best thing is to put it on your testing rig and activate it/bypass it. In lieu of that use a looper or a/b switch. I notice a definite change to  the signal (more articulate highs) when engaged.

Thanks Ben I will do that. I think I may even have a 25-30' mono cable I can test with. lol

Cody

[blearyeyes]

actually I was going to say that as a goof but if you can drive a long unbalanced run you be able to tell...