Harmonic Percolator vs Barge Concepts BP1

[rocket]

On the website of Barge Concepts (http://www.bargeconcepts.com/bp/bphistory.html) I have found the statement that all schematics of the Interfax Harmonic Percolator are wrong in a central point: they claim that both transistor have to NPN for the circuit to work and there is also a coresponding schematic (http://www.bargeconcepts.com/bp/largeschem.bmp).

I am now somewhat confused because it seems that the PNP+NPN version was build many times with good success including Tim E.'s all silicon version. I also remeber breadboarding it some years ago and it worked apart from uncureable oscillations at some settings.

Please give your opinions.

[Doug_H]

Quick answer: They either weren't using the same schematics as we were or they are full of crap. Equal probability for either possibility.

[analogmike]

Use your ears

http://www.gearwire.com/bp1-albini-comparison.html

http://www.gearwire.com/bp1-albini-comparison.html

[Skreddy]

Yes; it would appear that the correct HP schematic should use the mix of NPN and PNP.   Not to indulge in Schadenfreude or anything, but... calling something a "clone" kind of implies that...  uh... one had done everything... to, uh... make it sound at least... VERY close to the original? 

Now, lots of people do love the Barge Concepts pedal for exactly what it does and what it is.  Really.  It has an enthusiastic following.

[Doug_H]

Interesting. According to the video, the bp-1 didn't seem very stable. I'll have to try the "whistling" trick with my Brick.

[slacker]

Just to show that you shouldn't believe anything on the internet, especially if someone's trying to sell you something here's another website that claims their's is the real Harmonic Percolator and it uses a PNP/NPN combo.
http://pages.prodigy.net/chuckcollins/percolator.html

[Doug_H]

Yeah, good ol' Chuck. He came in here and dropped a few hints when we were building perc clones a few years ago.

[Doug_H]

BTW that Perc sounded good in that vid, as well as the p*ssy fuzz in the other vid. I don't usually run my Brick with both controls dimed. I'm gonna try that tonight and have some fun...

[Bernardduur]

Awesome vids!

[mac]

This is my HP test:

http://www.diystompboxes.com/smfforum/index.php?topic=49035.0

I used A. Hermida's schem for my test and it really had a lot of even order harmonics on it.  Going to try the NPN-NPN anyway.

mac

[Dan N]

We played around with that same pcb that Barge concepts reversed:

http://www.diystompboxes.com/smfforum/index.php?topic=36110.0

Guess I'll have to try it with 2 NPNs.

I don't have the internet speed to watch the Albini video. How did the face off work out?

[Harry]

I don't have the internet speed to watch the Albini video. How did the face off work out?

It was hilarious. You could tell he didn't wan't to out and out say it was a total piece of crap (which it sounded like), but the word horrible did come from his mouth more than once.

[Dan N]

Ha! So, nix on the 2 NPNs.

Thanks!

[Doug_H]

I just finished playing my Brick with my Firefly amp and I think Albini would approve. My Brick is a Perc with the proper Si/Ge transistor types but 1n46 diodes instead of the 1n34a's. It did all the whistling stuff he was doing. Turn up the amp, hit the switch and it started instantly, and would change pitch based on guitar position. I had the Brick controls completely dimed like he did. It's been a while since I've tried this one, esp opened up like this. The harmonics are really insane in a good way. Don't need to pick, just use your left hand if you want. It's great with an amp that responds like this too. Very nice tone.

That BP1 in the vid was unstable and was oscillating like crazy. He didn't really understand that, but it wasn't a microphonic feedback from the pickups. It's funny to watch a musician try to explain electronics. They almost get there, but not quite...

[Sindran]

What about Barge Concepts Bee Baa, has anybody tried that?
Or has anybody build one of those???
I have no idea how it sounds, or should sound, but it looks reallly interesting!

[Gus]

If you search you can find the bee baa.  Hint,top left has  a link

[herr.satz]

That video has made me really want to build one of these for my guitarists birthday. Can anyone offer help with a few questions?

How good is the RLBJR65's Harmonic Speculator layout from the gallery with the 1n60 diodes compared to the Brick or even the speculator if the original values are used? Has anyone built one and can anyone point me in the directioin of schematic/layout?

Thanks!

[ethanw]

Entertaining video. That Barge sounded like poop. His pedals look to by made well, maybe that one missed the mark.

[mattpocket]

That video has made me really want to build one of these for my guitarists birthday. Can anyone offer help with a few questions?

How good is the RLBJR65's Harmonic Speculator layout from the gallery with the 1n60 diodes compared to the Brick or even the speculator if the original values are used? Has anyone built one and can anyone point me in the directioin of schematic/layout?

Thanks!

Original hermida values and layout (unverifed) http://www.diystompboxes.com/smfforum/index.php?topic=56221.0

update on my build http://www.diystompboxes.com/smfforum/index.php?topic=56796.0

I need a few questions answering if possible regarding biasing in that second thread link, thanks guys!

Matt

[Gus]

If i was to make a two NPN I would build it different

Q2 the same as the HP build the fragment and adjust the C to B resistor using a 5.5VDC supply

Q1 part build it as a fragment first

Ground Q1 emitter
use a collector resistor of  20K
Adjust the C to B for 2.5 V at the collector using a 3.5VDC supply at the top of the 20K collector resistor

Connect the 'top" of Q1's collector resistor to Q2's emitter and connect a 47uf cap + side to that node  and - side to ground.

Using a .1uf cap from Q1s collector to Q2 base.

Gus