Paralooper Debugging... Help please

[Ozymandias]

Hello,

I've been trying to build the paralooper as my first "real" (= non-kit) build. And it's kicking my behind

I've used Torchy's vero-layout (http://www.aronnelson.com/gallery/v/bcreekmur/paralooper.jpg.html). First try: Nothing.
On this forum, I read that caps C1, C6 and C9 have to be reversed, so I did that. But now I'm not really sure that was actually needed  , so could somebody check that, please ?

I've also read somewhere R9 should connect to pin 7 of U1 in stead of U2... This is very confusing... Let's stick with the labeling on the vero-layout, and call the bottom IC U1. Should R9 connect to this IC's 7?

Now trying it, I get a reaaally silent and clean effect. Not at all mixed with the fuzz I've put in the send&return... So here come the pinouts with a PSU that delivers 9,40V:

U1 (bottom IC):
-pin 1: 1,46V
-pin 2: 1,46V
-pin 3: 1,43V
-pin 4: 0,00V

-pin 5: 0,85V
-pin 6: 0,82V
-pin 7: 8,58V
-pin 8: 9,40V


U2 (top IC):
-pin 1: 1,40V
-pin 2: 1,40V
-pin 3: 0,93V
-pin 4: 0,0V

-pin 5: 1,45V
-pin 6: 1,45V
-pin 7: 1,45V
-pin 8: 9,40V


Pins are like this:
1     8
2     7
3     6
4     5

Any ideas ? Any help would be greatly appreciated..



EDIT: I've poked around with an audioprobe, and I've uncovered that I'm a dumbass. I connected the ring of the effect out with the return of the board.
Anyways, the problem remains as follows: The clean signal is so weak, the blend-knob acts as a volume-knob...

[tommy.genes]

First off, that's not Torchy's layout you linked to above, so any corrections to Torchy's layout you've read about wouldn't necessarily apply to that one (obviously). Second, Torchy did release a second corrected version, but I'm not sure if or where Torchy's layouts are posted at the moment. I'll check my office computer tomorrow to see if I have it there.

-- T. G. --

[tommy.genes]

I only have the original uncorrected version. PM me if you want that.
-- T. G. --

[Ozymandias]

Thanks, but I don't thinkt those layouts will be necessary. After you've indicated I haven't been using Torchy's layout, I've started looking for his layout and found it...

Yet I would like to finish this one off. If it turns out it's unfixable, I'll redo everything.

[Ozymandias]

Okay, I'm one step further already. In fact, quite a few steps: It works! Thanks to a certain forumite over here

However, I've got some more questions which might be easy to answer, but I couldn't find anything with the search...
1. By lowering the 100K resistor that connects pin 6&7 of U1 to 10K, I get less breakup, correct ?
2. By lowering the 10uF caps C1, C6 en C9 to filmcaps of 0,047uF, as the original BassThru schem suggests, do I then cut more bass, or more highs ? Pretty crucial question for a basspedal...

[tommy.genes]

1. The gain of the non-inverting op amp output stage equals (R₁₂/R₁₁) + 1. With R₁₂ = 100k, gain equals 11; with With R₁₂ = 10k, gain equals 2. The output stage is far less likely to clip (break up) at a gain of 2 rather than 11. Short answer: yes.

2. Generally, for caps like C1, C6 and C9 that are in-line with the audio path, increasing the cap value lowers the high-pass cutoff frequency, allowing more bass through. However, eventually the cutoff falls below the range of your instrument and making the cap even bigger doesn't really make a difference. The .047u from the original BassThru schem were already big enough, but yours are bigger!   So, if you already have the 10u caps installed at C1, C6 and C9, there is really no reason to change them - bigger or smaller - at this point.

-- T. G. --

[Ozymandias]

Okay, thank you very much for your replies and patience! Your karmapoints just went up a bit
I'll see how I like the new resistors, also in terms of volume (which won't be a problem, I suspect), and maybe post some pictures in the picturethread once it's finished...