# Keeley Oxblood



## Chuck D. Bones (Nov 11, 2021)

Anyone ever build one of these?  An interesting take on the whole Klon thing...


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## cooder (Nov 11, 2021)

Is there a schematic around?!? Are you tempting me...?


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## Flying (Nov 11, 2021)

Mr Keeley posted the schematic on his blog years ago, very kind of him.



			https://robertkeeley.com/woo/wp-content/uploads/2015/07/Keeley-Oxblood.png


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## Mcknib (Nov 11, 2021)

I've repaired one to me it's got much more gain than other klons I've built

I also helped develop a pcb for it which sounded exactly like the original but had oscillation problems

I'll maybe dig that out the drawer and see if I can sort it

The schematic differs slightly the real one has a W20K tone pot and A100K volume apart from that as far as I remember it's the same


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## cooder (Nov 11, 2021)

Awesome, thanks Gents. I'm tempted...


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## Chuck D. Bones (Nov 11, 2021)

Another one goes in the breadboard queue.  Lotta mod potential.  split the DRIVE pot.  Add a BASS pot.  Different diode options.


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## Mcknib (Nov 11, 2021)

@Chuck D. Bones I don't know if I've got any spare pcbs or not I'll have a search see if I've got any


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## Darrencp (Nov 11, 2021)

Chuck D. Bones said:


> Anyone ever build one of these?  An interesting take on the whole Klon thing...


Hi mate!

It's my board McKnib has been helping with - happy to send you one and my kicad files if you want to have a look? 

Cheers
Darren


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## Chuck D. Bones (Nov 11, 2021)

That would be great.  Hadn't heard of KiCAD before, but I'm willing to give it a look.


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## fig (Nov 11, 2021)

Everyone seems to have dozens of plates spinning. Isn't it wonderful? 🙂


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## Chuck D. Bones (Nov 11, 2021)

One more plate for me.

FET - Germanium Booster


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## Darrencp (Nov 12, 2021)

Chuck D. Bones said:


> That would be great.  Hadn't heard of KiCAD before, but I'm willing to give it a look.


No worries! 
Drop me a PM and I'll get a board out to you


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## jimilee (Nov 12, 2021)

That is an interesting looking drive. Definitely gonna throw it into eagle and see how it looks.


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## bowanderror (Nov 12, 2021)

Chuck D. Bones said:


> Anyone ever build one of these?  An interesting take on the whole Klon thing...


Haven't built one, but I did play the Oxblood Germanium at a guitar shop a few years back and REALLY liked it. It had a nice saggy, zippery sound that was good at a variety of gain levels.

From the ones I've built, I'm not usually a fan of Klon circuits, but I didn't know the Oxblood was based on that until now. The Keeley product page says the difference in the Germanium version is "We’ve taken out the compression and added a germanium transistor to the output." I wonder if it's as easy as popping a Ge NPN in for the Si NPN and leaving out the clipping diodes - which I assume is what they're referring to when they say "We’ve taken out the compression"?


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## Chuck D. Bones (Nov 13, 2021)

There's probably more to it than that.  That last transistor is an emitter follower, so swapping Ge for Si isn't going to make much, if any, difference. Maybe someone can find a trace.  

Since the Clipping switch is still there, it appears that the clipping diodes are present. Maybe the dirty channel's gain range is altered.  Or there's a resistor in series with the clipping diodes.


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## giovanni (Aug 10, 2022)

I want to revive this old thread and pick your brains on the oxblood. Is it worth it? Should I put it on the wishlist? The demos I heard sounded good but who knows!


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## Chuck D. Bones (Aug 10, 2022)

Someone should breadboard it.  I never got around to it, too many other irons in the fire.  Teaser: there is another compressor circuit coming up.

I really like the Klon design and its variants.  The Keeley OB is enough different from the Klon that I would not expect it to sound or feel the same.  Balancing the blend on the DRIVE control is not an easy task.  Getting the note decay to sound natural when there is a clean bleed is tricky.  Keeley is a smart guy, maybe he nailed it.


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