B. Blender TLO74 pcb Questions

[goldstache]

Hey I was building this on the breadboard Based on Mr. Maclennan's schematic and it worked exceptionally well.  Then I decided to make a PCB for it using the PDF version on the same page.  Looking it over I am confused about how the layout is identical to the schematic.  Are the amps switched or something.  It just seems that all the pads for the controls are labeled in the wrong spots or something??!!!!!!  Anyone ever built this bad boy???
I used the Jari Oinonen PDF, the one with the TLO74:

http://seanm.ca/stomp/bblender.html

Just want some understanding before I build ya' know!  Thank you all!!

[Mark Hammer]

I actually built one of those recently for a friend, but with a bypass switch, a little gain on the output stage, and a volume pot.  I had to perf it to make it fit inside a pre-existing chassis with the jacks already installed, so I can't offer any insight into the PCB layout.

It worked great.  Nice and quiet.  The design does not stipulate a particular op-amp.  Could be singles, duals (as in the gaussmarkov layout) or a quad.  The quad could be a 324/TL074 type pinout, but could also be a 4136 pinout.  Naturally, if you change chips, you need to be cogniscent of the pinout and especially the power connections.  A 324/TL074 pinout works quite well, because the output pins are all essentially at the "corners" of the chip.

It's really simple to perf, so if you are confused about the PCB, I suggest just perfing one.

Sean McLennan WAS a student at the community college 5 minutes from me, in addition to being a member here.  I'm not sure where he's at now.  If you're out there Sean, pop me a note and let me know what you're up to.

[goldstache]

Thanks!  I think Im just confused because he used a different amp order on The TLO74.  It does not correspond with original schematic amp order of 1,2,3,4.  He used different amps around the chip to make his layout smaller and it through me for a loooooop!!!!!!

[karter2000]

I've actually had that layout etched for me, and it works great.  Any questions feel free to ask!

[PRR]

I think one uses a single TL074, the other uses two TL072.

[goldstache]

@Karter2000:  Thanks.  I built it and modded the layout for the volume boost described in Sean M.'s notes. I added pads on pins 6 and 7, and redesigned the trace from pin 6 > blend knob lug1 to, pin 7 > blend knob lug 1.  Should of went fine.  Instead I'm getting some strange oscillations, dry guitar and no boost!!!!!!  On top of that, not a peep out of the loop section.  Hahahaha  Hmmmmnn..........   Guess I should just etch another and try it stock. 

In the PCB layout of the quad amp version it looks like the blend controls from left to right should be lugs 1, 2, then 3.  Is that correct are am I missing something.
Thanks for the help everybody!!!!