feedback looper success!

Paul_C

You can ignore the first bit and jump to B if you wish

A) I made myself a loop pedal a while ago (to take my Weeping Demon wah out of line when not in use as by-passed it messed with my preamp tone) and then it mutated
Then I added a vol pot to try and reduce some of the huge difference in volume when my Bone Collector was turned on, and finally a blend kit from Fuzzdog was added and the whole thing put into another enclosure

Today I decided I could use the old enclosure, add a pot and a switch and make it a feedback looper, using this schematic:



except I left out the LED and resistor and just used a DPDT foot switch.

Now I can usually follow a schematic, and without starting again from fresh I'm sure that everything is as it should be, but it doesn't work  
Switched on it engages the pedal in the loop, but nothing seems to change when the toggle switch is switched on, nor does the pot do anything.
I found another schematic where it didn't have the jump between lugs 2 and 3 on the pot and tried that, but still nothing.

*sigh*

I'm sure I'll track down my mistake in the end (assuming it's not a faulty switch), but it's always frustrating to spend ages putting it all together and not get the result you want

Paul_C

I managed to get it "working" - having never experienced a commercially available pedal I can only assume it's doing what it should

The control seems to work in reverse but even then I was only really noticing the effect towards the last 1/4 of the sweep.

I swapped the connections round and exchanged the 500k log pot for a 500k lin, which seems to have given me a little more useable range, but still by and large in the last 1/4 of the sweep.

Any suggestions ? Maybe a different pot ?

Or is this everything anyone's been able to eke out of such things?

It's quite amusing, especially the bird noises

steamabacus

I would have thought, seeing as you are working with a buffered low impedence signal (the fx signal output), something like a 25k log might work better?

There's an interesting article on pots here that includes details of how to modify the sweep of a pot using a couple of resistors. Might prove useful in fine tuning it?

Paul_C

I've got loads of 25k log pots so I'll try that later, if it makes things worse then I'll have learnt something at least

Paul_C

25k was too much, it started oscillating as soon as I switched it on.

I was going to try 250k but I couldn't find a mini pot so I stuck a 100k one in and it's pretty much spot on for what I want

I've only tried it with battery-powered pedals so far, so I haven't exhausted what it can do, but a Line 6 Liqua Flange is fun (and the noises are fairly musical), a Joyo Tremolo just beeps and a Line 6 Otto Filter mostly squeals uncontrollably.

I'm not sure I dare plug my Bone Collector in, but I shall try some others at some point