Please verify/check my layout? Harmonic Perculator

[mattpocket]

I used this schem here, sorry if its too big:



and this is the layout I came up with. the only bit I am unsure of is whether the connection between C2 and Q1base intersects the connection from C3 and R2, i took it as a yes and thats why the little blue jumper is there, otherwise I will remove the jumper and move the bottom lead of C3 down to the same track as the bottom lead of R2. I am also aware that C4 should be a tantalum/electrolytic cap and the the positive lead should be nearest the top of the board.



Also, if you plan to build this, you will want to have a read of this thread. Some of the guys have been experimenting a lot with this circuit, since it seems there has been no distinct "clone" for some time, with several varying schematics and layouts flying around, these guys are giving the harmonic perculator a revamp! Check it out: http://www.diystompboxes.com/smfforum/index.php?topic=55987.60

Thanks

Matt

[spudulike]

1. Pots are log not lin (A suffix)
2. Blue link is shorting out R2 and is not needed (no connection on schematic).
3. Move lower leg of C3 down one trace to connect to R2/Q1c.
4. +9V goes to first trace (top) - not labelled.

[mattpocket]

1. Pots are log not lin (A suffix)
Seriously? I thought that A meant Lin and B was Log and C was reverse log

2. Blue link is shorting out R2 and is not needed (no connection on schematic).
I didnt know whether there was a connection on the schem where the "wires" crossed. Thanks for clearing that up.

3. Move lower leg of C3 down one trace to connect to R2/Q1c.
Yeah, as a result of the above.

4. +9V goes to first trace (top) - not labelled.
Crap, forgot to put the power in! haha

[spudulike]

The standard in Europe is/used to be A = lin B= log.
Almost everywhere now uses the US nomenclature A = Log.
99.9% of schematics you see will follow it.

[mattpocket]

Oh cool, thats a useful fact!

Here is revision 2, is this one ok?



Thanks!

[spudulike]

Looks good to go

[mattpocket]

I could do with a second pari of eyes to have scan over this, see if you can spot any mistakes...

Thanks

Matt

[Sir H C]

I would look at making R2 a trimpot or adding one to set the bias on this guy right.  The NPN being silicon should be more stable and tweakable only once, but the Ge PNP might need more.

[markm]

I could do with a second pari of eyes to have scan over this, see if you can spot any mistakes...

Thanks

Matt

Just thought a BIG thanks is in order for the kind gentlemen of the BB looking over your work the past few days.
Their input is very valuable. 

[mattpocket]

Definately!

THANKS!

[solarplexus]

is this has been verified ??


I tried to build it yesterday but it's not working.  Before I try to debug it I was wondering if anyone else had built it and if it worked??

I also used a 680K instead of a 750K and two 100K-B for the pots    that's all I had in hands 

[enigmur]

Ill give this a go in the weekend Matt if I have the parts and get back to you

[solarplexus]

thanks enigmur, really appreciate it... and we'll be able to tell if it's good to go for future reference...

Matt

[QSQCaito]

I may be blind maybe.. but I havent seen ground, negative terminal of the battery. Where should it go?

[enigmur]

Looks to me ground is the bottom strip. Neg from the battery will go to the ring of the input jack I believe (for power when plugged)

[mattpocket]

Yeah thats right about the ground and power...

I have not built this vero layout yet, but I am breadboarding the circuit as we speak and it should be finished this afternoon?

Did you check/get the correct gain for the 2n404a? You need a gain of about 50...

I am breadboarding the whole thing with trimpots so I can tweak it as I go... I have never done any biasing before though... Where should I be measuring to bias the transistors? I am guessing I put my negative lead on ground and measure the DC voltage at the transistor? But which leg, and do I measure it before it gets to the transistor or after?

Matt

[mattpocket]

Hey guys,

I breadboarded this today and got it working, sounds pretty good... a really good distortion actually, the best I've built so far... I am going to play around with the clipping and a few different amp/guitar setups, I will probably add a tone stack of some description too... I am currently playing it with my PRS Singlecut with humbucking P90, and my Marshall MG100DFX (no jokes  ) and it sounds good even through that amp! I will give it a go through my valve head and cab tomorrow when I can be arsed to lug the cab upstairs...

Has anyone else had a go yet? I used the schem from above to do my breadboarding, rather than using the layout, so I cant verify it yet... and I dont want to re-breadboard until I have tweaked some more...

Can anyone give me any info on the biasing... I currently have all the resistors apart from the one in the clipping diodes wired up as trimpots... which trimpots should I alter to change the bias, and where do I put my multimeter?

Thanks for the help with this circuit guys...

Matt