Tube Reamer debug No Drive

[brefmint]

Hey all,
I'm looking for some ideas because after trying to figure this one out all night I've run out of them. 
I just built a Minibooster and a Tube Reamer V2 inside the same enclosure using two separate 3pdt switches, 1 shared 9v jack, and shared input/output jacks. The Minibooster is working fine but I'm having problems with the Reamer. First off I used this V2 vero layout from the gallery: http://www.aronnelson.com/gallery/main.php/v/Toneys-Album/tube_reamerv2_333.png.html

Here's what's happening:

The Tube Reamer powers on. Signal passes through. The tone of the effected signal is very odd. There is no drive. It is getting boosted but it is very clean and bassy. Very boomy. The drive knob has no effect at all. The volume knob works. I followed the vero layout exactly. I have triple checked it twice. All of my traces are in the right spots. All of my diodes are facing the right way. My IC is in correctly (I already fried one when I tried it backwards), My electro caps are facing the right way. My pots are wired correctly according to the layout.  I checked my ground points and they all seem correct. The only difference I can see is that I did not ground the volume pot to the Reamer board. Since I'm powering two pedals I grounded all of my points to a small piece of vero with 2 strips. One strip for all of my - points and one strip for +.

Side note: Also my guitar's volume knob is scratchy when the Reamer is on only. This only happens when the Reamer is on. If I turn the guitar's volume knob even slightly, a scratchy signal comes through very loud. It sound like a dirty pot but only happens when the Reamer is on. It doesn't happen when the Miniboost or any other effect for that matter is engaged.   

Thanks for any help!

[JDoyle]

Does the scratching go away if you put another effect in front of the Reamer? Even if it is just a buffer from a commercial non-TB pedal like the Boss...

If if does go away, there is either a short around the input cap allowing DC to enter/exit, or the cap itself is defective leading to the same result...

My first thoughts at least,

Jay Doyle

[GibsonGM]

Measure for DC across the pot, too.  And at the output.  I always do this before trying out a new effect, searching for shorts.  DC isn't great for an amp, sounds like crap ;o)

[brefmint]

Hey guys,
I turned another boost pedal on in front of the Reamer and the scratching went away! I guess I'll check out the input cap. Would the short be causing the circuit not to clip as well?

Thanks for the help. This forum rules!

[brefmint]

OK the crazy short is gone now. I cleaned up the solder joints and the cut traces by the input cap. Still no drive though. I'm thinking about replacing the diodes. It bothers me that the drive knob does absolutely nothing. If the diodes were shot I should still be hearing some sort of difference when I turn the knob....right?

[brefmint]

I just replaced the 4148 diodes and there is still no drive.

[sed]

Are you sure there isn't anything wrong with the drive pot? When you turn it the resistance int feedback loop of the op amp increases and the gain goes up which get the diodes to clip the signal.

[brefmint]

I am not "sure" about anything at this point. 

It is a brand new Alpha pot from Mouser so I hope it's good.

[brefmint]

Any other thoughts as to why this thing isn't Reaming?

[burnt fingers]

I don't do vero/stripboard myself but my guess is a connection,trace, or solder joint around the gain pot is faulty. 

re check each connection of the gain stage from opamp to diodes to wire to pot to wire to resistor...

Also....probably the first question should be, is this layout verified.  Has anyone else built it successfully

Scott

[brefmint]

Yeah, I searched the forum and found a few completed builds with this layout before I started.

http://www.diystompboxes.com/smfforum/index.php?topic=57356.0
http://www.diystompboxes.com/smfforum/index.php?topic=64505.0

I will try touching up all of the solder joints and cut traces and let you guys know the outcome. Thanks for all of the help.

[brefmint]

OK...
I touched up my traces with a razor blade and now it is reaming with tons of gain! I think 2 traces were being joined together by solder before.

My next issue is my drive pot seems to be working backwards. When I turn it up I get less gain and vice versa. I have a question about the wire that goes to Lug 1,2 of the gain knob....Does it matter which point the wire goes to first? I have it going to lug 2 first and then connecting to lug 1 as well.

This is how I am viewing the lugs. Is this correct?

back of pot
u u u
3 2 1

Thanks for all the help people!

[AceLuby]

Edit, sorry... I think you want the input going to lug 3 and the output connected to 2 & 1

[burnt fingers]

Congratulations.

The tube reamer was my third build I think.  Cool pedal.  Lots of opportunity for tweaking.

Scott

[brefmint]

Thanks for the congrats! I'm still working on getting this thing right though. Here's a pic of the layout I used:


The layout doesn't have the input and out put labeled for the drive knob. It just has the lug numbers. Is it correct?