Been a while since we had a HARMONIC PERCOLATOR thread, no?

[Chankgeez]

It's just a noisy circuit.

[BetterOffShred]

I'm going to try and use a fairly low leakage Ge as they produce a ton of noise typically, and then I may use a huminator power filter and maybe a small load in series with the power source like 33r or something. Also I've read using shielded cable can keep noise down too.

[D Rock]

Percs have been my dirt/fuzz of choice lately. Spent quite a bit of time with the circuit on the breadboard so if anyone needs any help please PM me.

Also, did I mention Russian Germanium PNP transistors. Fuck yes.

This guy! My Man!!
Thanks for the pics dude, and thanks for your input!
What gain range sounds the best on these? I'm sure that's subjective but you seem to have a handle on what it should sound like. I have recently bought huge piles of Russian PNP'sand I certainly have a few favorites .. does this circuit handle leaky (say .4ma or above) trannys at all? Maybe I should have PM you ..

The low gain (30-50)HFE Germanium trannys sound best to my ears, I'm still not convinced anyone knows exactly what is happening inside this circuit so I had to do a lot of listening. Leaky transistors seem to work better as well. Complete opposite of most things you are looking for in trannys, but yes, low gain and high leakage is what you want in this circuit. Now I just keep a perc on the breadboard so I can test any transistors before I solder them to PCBs because each one sounds a little different. Some are just magical dare I say. I have tried power filtering on the circuit as well and it just tends to introduce more noise or change the frequency of the noise, it's a touchy circuit for sure.

[D Rock]

So does it cut and boost or just cut?

It is just an input cap blend on a pot. I have the smaller cap hardwired so it is always going into the circuit and then more bass can be introduced by turning the pot clockwise. A 1uf input cap will let in much more bass than the stock circuit and this does cause the circuit to break up a little sooner when riding the volume knob on the guitar. With that said the bigger the input cap the better the perc sounds as it cleans up. Just a little fuller sounding circuit. Clean Perc sounds are just so sick in a band context as you can actually hear the guitar. I turn off the perc sometimes and just totally drop out of the mix.

Also I should note that I put diode options on my first few percs and really don't see the need. It is such a unique sounding circuit and you are getting all of that from the transistor arrangement. With diodes clipping the top or bottom of the waveform you are losing some of that bite and harmonics. I'm sure you will get a little more compressed sounding output with the diodes, but IMO they are not needed and actually dull the circuit a bit.

[BetterOffShred]

I used a mpsa13 and a mp42b that's around 60 hFe.. and yeah I prefer it with no diodes for sure. It sounds pretty good, the volume is a little underwhelming, but I was fixing to run a boost with it anyways, probably after the perc.

I had some D9E's.. they compress and make it sound pretty awesome, but of course the volume takes a shit. I may see how much boost I can give it haha! More to come

[ck3]

Well I've researched this device to death and listened to like 50 clones, and that land devices definitely sounds fantastic. It looks like it also has 3 diode modes (Si, lift, Ge). Curious what pre and post values he's got in there.

I just noticed this info in the ad copy for the HP-2 that I purchased:

Parts / Components:
- 2N404, 2N3565, 1N695 x2
- standard 9V (-), no battery clip
- Switchcraft jacks

Hope it helps.

[codetocontra]

Looks real nice, D Rock.

[BetterOffShred]

I have a 2N404, legit one I bought for another circuit, but it's like 115 hFe and it just didn't sound great with any of the si npns I tried. I am becoming convinced of this particular circuit being very centered on having a good pair of transistors. Thanks for the information man.

I tried literally 15 npns with each Ge PNP.. the mpsa13 and that mp42b sounded the best to my ears... somehow. It's a darlington... but either way it sounds good.

In hindsight I wish I had socketed my Ge diodes, I think the D9E had too much forward loss, I have a bunch I could try. I'll probably pull them out and put in a couple sockets. The 914's sound dope though and don't really cut volume much. I tend to agree this circuit isn't really about diode clipping after messing with it for a few hours/beers.

I also think I'm definitely going to whip up an Escabedo jercolator just to see what the comparison is like now that I've got this going.

Plan is still to box it with a green ringer and the venom boost and an order switch, and on/off toggles for everything. I think I'm going to have to stick the boost after the percolator and have it switch as if it's part of that circuit.

I just want more volume.
I should point out that I use a crappy little peavey rage I got for free as my workshop test bench amp, and when I get this plugged into the Bassman it may totally have mustard for days
. But the volume isn't blowing my skirt up so far.

Edit: in light of the suggestion to use low hFe leaky trannys.. I may try out a couple of junk drawer AC128's I have that are somewhat unusable in other shit I've tried them in.

I also built a D*A*M red rooster clone today with an AC176.. balls it sounds good. My new favorite dirty boost.

[BetterOffShred]

Sorry
That was really wordy.. nobody cares about clones hah!

[actual]

So does it cut and boost or just cut?

It is just an input cap blend on a pot. I have the smaller cap hardwired so it is always going into the circuit and then more bass can be introduced by turning the pot clockwise. A 1uf input cap will let in much more bass than the stock circuit and this does cause the circuit to break up a little sooner when riding the volume knob on the guitar. With that said the bigger the input cap the better the perc sounds as it cleans up. Just a little fuller sounding circuit. Clean Perc sounds are just so sick in a band context as you can actually hear the guitar. I turn off the perc sometimes and just totally drop out of the mix.

Also I should note that I put diode options on my first few percs and really don't see the need. It is such a unique sounding circuit and you are getting all of that from the transistor arrangement. With diodes clipping the top or bottom of the waveform you are losing some of that bite and harmonics. I'm sure you will get a little more compressed sounding output with the diodes, but IMO they are not needed and actually dull the circuit a bit.

Thanks for the info
Please keep us posted if you decide to make a few!

[actual]

Also where the fuck are all the Perc bass demos at?

[BetterOffShred]

Also where the fuck are all the Perc bass demos at?

I just got an 8-string guitar and I drop E it, my perc clone sounds pretty good on the low E so far. I have yet to boost it but I'm seriously wanting to wire it up tomorrow with the boost .

[D Rock]

I have a 2N404, legit one I bought for another circuit, but it's like 115 hFe and it just didn't sound great with any of the si npns I tried. I am becoming convinced of this particular circuit being very centered on having a good pair of transistors. Thanks for the information man.

I tried literally 15 npns with each Ge PNP.. the mpsa13 and that mp42b sounded the best to my ears... somehow. It's a darlington... but either way it sounds good.

In hindsight I wish I had socketed my Ge diodes, I think the D9E had too much forward loss, I have a bunch I could try. I'll probably pull them out and put in a couple sockets. The 914's sound dope though and don't really cut volume much. I tend to agree this circuit isn't really about diode clipping after messing with it for a few hours/beers.

I also think I'm definitely going to whip up an Escabedo jercolator just to see what the comparison is like now that I've got this going.

Plan is still to box it with a green ringer and the venom boost and an order switch, and on/off toggles for everything. I think I'm going to have to stick the boost after the percolator and have it switch as if it's part of that circuit.

I just want more volume.
I should point out that I use a crappy little peavey rage I got for free as my workshop test bench amp, and when I get this plugged into the Bassman it may totally have mustard for days
. But the volume isn't blowing my skirt up so far.

Edit: in light of the suggestion to use low hFe leaky trannys.. I may try out a couple of junk drawer AC128's I have that are somewhat unusable in other shit I've tried them in.

I also built a D*A*M red rooster clone today with an AC176.. balls it sounds good. My new favorite dirty boost.

That is weird that you need more volume, the circuit should have plenty, especially without diodes. I use a 2N3904 for my silicon transistor which is much lower gain than the mpsa13 and have plenty of volume on tap. Feel free to shoot me a PM with resistor values, maybe there is one off somewhere that is causing that. Also I would highly suggest using those junk ac128s, they may be just perfect.

[BetterOffShred]

Box is drilled. I'm going to have to "stack" my boards to get all 3 in here. And then there are toggles for order switching, though the boost will always follow the percolator, then a toggle to turn the boost on or off, and then 2 stomps for the ringer and percolator on/off. LEDs for order, blue perc first, green.. ringer first. And then engage indication for all 3. There's only 3 pots and it has top jacks. This is going to be a lot of wiring.

More to come

[BetterOffShred]

Box is drilled. I'm going to have to "stack" my boards to get all 3 in here. And then there are toggles for order switching, though the boost will always follow the percolator, then a toggle to turn the boost on or off, and then 2 stomps for the ringer and percolator on/off. LEDs for order, blue perc first, green.. ringer first. And then engage indication for all 3. There's only 3 pots and it has top jacks. This is going to be a lot of wiring.

More to come

Oh, it also has an input cap selector for the percolator. Kind of like what D was talking about, I'll test a couple values but I'll probably go with the 47n stock value and a bigger value to make it nasty and break up earlier. I originally wanted to have a 4 way selector, but it would definitely not fit in this BB .. haha