Klein Bottle problem :(

[EBK]

I can't seem to reproduce the bleedthrough problem.  I'm not sure what the magical combination of settings is.  Any ideas?

[benny_profane]

I can't seem to reproduce the bleedthrough problem.  I'm not sure what the magical combination of settings is.  Any ideas?

Are you in sends or all mode? What's the dry signal level set to?

I think the bleed is most prominent in ALL mode and also with the dry signal turned all the way down.

[Masochist]

I can't seem to reproduce the bleedthrough problem.  I'm not sure what the magical combination of settings is.  Any ideas?

Did you have any luck mate?

[EBK]

Haven't been able to try again yet.  Been juggling a few family and work things.  Sorry to keep you hanging. 

[Masochist]

Haven't been able to try again yet.  Been juggling a few family and work things.  Sorry to keep you hanging.

No that's fine man, you have a life! Looking forward to hearing from you though

[Masochist]

Hey did anyone end up emailing Peter about this? If not, let me know and I'm happy to attempt to see what he thinks?

[EBK]

Hey did anyone end up emailing Peter about this? If not, let me know and I'm happy to attempt to see what he thinks?

Go for it.

[Masochist]

Ok, email sent. Will let you know what transpires. Any chance you might have some time this weekend to attempt the testing phase again? Hope all's well with you.

[EBK]

I might try testing today.  Will let you know.

I'm trying to find the original description of the bleedthrough problem.  I can't remember if it was in one of the videos or on the website, or in one of the docs.  I want to understand what I'm trying to hear.

[benny_profane]

I'm trying to find the original description of the bleedthrough problem.  I can't remember if it was in one of the videos or on the website, or in one of the docs.  I want to understand what I'm trying to hear.

I think he mentions it in the build video as well as the kickstarter video. This is taken from the KB page on the VFE site:

"Due to design constraints when building a low noise circuit that ran on an industry standard 9-18V power supply, the signal to each effect loop has some bleed in ALL mode. This is one aspect of the Klein Bottle that I continue to research, and if I find a simple solution, I will share it openly."

The DRY knob is never really out of the circuit. That particular bleed issue isn't what's addressed with the big honkin' capacitor (BHC) fix, though. Here's the information about that:

Due to design constraints when building a complex & compact circuit, the dry knob is technically still active when all 3 loops are in bypass. However, it has been shunted to ground with an optocoupler. Because an optocoupler can't reach zero ohms of resistance, a tiny amount of bleed comes from the dry path. You can hear it in bypass if you crank up the dry signal, but even then it just makes the bypass signal a bit louder.

EDIT: I finally got my BHC. I'm holding off until hearing more about this daughterboard strategy. It reminds me of an M80.

[EBK]

So, when in ALL mode, with a loudish effect hooked up to one channel loop, I should hear it a tiny bit when bypassed, right? It's not dependent on any of the feedback stuff then.  I will give it a go.

[benny_profane]

So, when in ALL mode, with a loudish effect hooked up to one channel loop, I should hear it a tiny bit when bypassed, right? It's not dependent on any of the feedback stuff then.  I will give it a go.

I don't think that the feedback controls are crucial here. The PRE and MIX knobs are the main ones (although the makeup gain trim would also have a role). The feedback controls will have an influence as well, though; since there's signal bleed to each effect loop, there will be bleed to other channels if you're routing from it. The most prominent occurrence (I think) would be with the effects loops themselves.

[EBK]

So, in ALL mode, I sent loop 1 through my theremin fuzz.  I had the mix knob maxed and the pre knob at noon.  Nothing connected to loops 2 and 3.

When I clicked off loop 1, I heard the normal trail, then silence. 

With loop 1 on, I dialed the Mix knob to zero.  Silence. 

Maybe I need to try plugging my guitar into the return jack of loop 1 instead of using a pedal....  The theremin fuzz is a gated effect and although it sometimes will oscillate slowly when in idle, maybe it was just dead silent this time.

Some of my pots seem loose, electrically.  I get some oscillation in parts of their sweep (dry knob and Ch 1 Mix are two I've notice this with).  Maybe I need to reflow those joints.

[EBK]

I think I've got all sorts of wrong things happening.  If I crank the 1-to-3 knob to max, loop 1 is muted. Multiple pots doing weird things.  I'm stopping my testing until I get this back to working order.  Once I fix it up, I will try it again.  I haven't changed anything since my initial testing (when I verified that every control worked), and I haven't dropped the pedal or anything like that.  Must be cold solder joints (from not heating the heavy copper board enough).  I hope it is just that, anyway.

[benny_profane]

I think I've got all sorts of wrong things happening.  If I crank the 1-to-3 knob to max, loop 1 is muted. Multiple pots doing weird things.  I'm stopping my testing until I get this back to working order.  Once I fix it up, I will try it again.  I haven't changed anything since my initial testing (when I verified that every control worked), and I haven't dropped the pedal or anything like that.  Must be cold solder joints (from not heating the heavy copper board enough).  I hope it is just that, anyway.

Huh, I wonder what's going on. Is this happening with different pedals in the loops? And this is just now happening? Nothing in the time since initial testing till now?