harmonizer posted

[RickL]

I've been using graph paper to do perf layouts before I build them. I use the line crossings as hole locations, draw the components in putting a dot where the lead goes into the hole and a different coloured pencil (or more often a wiggly line) to show the "trace side" connections. As you say it makes it almost as easy as populating a PCB.

I've been able to make nice compact perf layouts, rarely have to use flying leads to join parts and having a layout to reference makes it way easier to continue a build a couple of days later and to do the (not as) inevitable debugging. I'd much sooner catch a layout error on paper where I can fix it with an eraser than after I've soldered.

[Paul Marossy]

Yeah, it's easier to fix a mistake on graph paper than it is to fix it when it's on the perfboard. I'll hand you that. Fortunately, I usually catch any errors before I actually start soldering.

[Joe Davisson]

Well, I did some work on getting different intervals, but it's not happening. The thing wants to divide in two, and does the best job when the cap values are right. I updated the schem and dubbed it an "octave-down".

I found that if you want to mix in a clean signal, you need to use an inverting buffer (like a JFET gain stage). That will make the overall sound a lot cleaner, without affecting the performance of the trigger.

The math for obtaining new frequencies isn't rocket science:
next_note = old_note / 0.94387431268169349664191315666784;

So dividing by that number N times, you get the intervals:

Code Select Expand


A  440.0
A# 466.2
B  493.9
C  523.3
C# 554.4
D  587.3
D# 622.3
E  659.3
F  698.5
F# 740.0
G  784.0
G# 830.6
A  880.0


Guess I'll work on that divider some more =)

-Joe

[RDV]

I perfed one up this afternoon, and I seem to be getting the same thing as Paul M. It sounds like a ring modulator w/out much of the octave thing happening. I did not substitute anything. The blackfire section works fine, but when you dial in the effect you lose a lot of volume and get a gated, sort of ring mod effect. Gives a pretty cool sitar-ish thing especially with some finger vibrato.

Regards

RDV

[Paul Marossy]

RDV,

Did you check your transistor Hfe's? I'm still wondering if that has anything to do with it. Or if the oscillator section needs to have matched transistors or not...

I have the octave down effect, but it doesn't seem to be as strong as in the sound clip.

[RDV]

It almost seems to be phasing, if there is an octave, it's the upper one strangely enough. A very synthy sound if you will, almost un-guitar-like. The blackfire section sounds great though. I'd never tried a single stage before, it makes a nice overstortion/distdrive. Even if I don't get it right, I may box it as it's a unique sound, and it will double as a boostortion.

I don't have a Hfe checker, just a cheap RS digital MM, so I don't know about whether the BJTs are matched or not.

I did add a 100ohm resistor in line with the power supply, & a 100uF to ground for filtering, so I don't know whether that would have some effect or not.

RDV

[Paul Marossy]

Hmmm... I also did add a 100uF cap across the power supply. I wonder if this is not a good thing on this circuit? If that is why it sounds a little different, then maybe we just stumbled upon a mod for it...
One of us should disconnect that cap and see what happens, don't you think? The more I think about it, the more I think that might just be it. It appears that could apparently affect the charge rate of that 1uF cap in the frequency sensor section...

In any case, I like mine, and I have it boxed up. Here's a pic:
http://www.diyguitarist.com/Images/Shocktave.jpg
Of course, I changed the name a little bit, as usual.  :wink:

[RDV]

Paul, you're an amazing man. Mine's still a bunch of wires and a piece of perf. I'm really getting no octave whatsoever, and I did unhook the ground of the 100uF cap and it had no effect whatsoever one way or the other. The term "too good to be true" seems to apply here. Unless it's the matching thing, I don't know what it is. I guess sometime this week I'll try to install a couple of sockets, but I made the layout so tight it's going to be tough to do.

I also used a film cap for the 1uF, Joe said it wouldn't matter, but I may try an electro there. I've just got so many of those 1uF films(Phillips) I've been sticking them in everything.

Regards

RDV

[Paul Marossy]

Not so amazing really. I've just got putting these things together down. I can really whip 'em out pretty fast with my systematic approach for building stuff.  :wink:

I probably spent about 5-6 hours or so building it over the course of two days. It's amazing how much you can get done when everyone else is asleep.

[Arn C.]

I am building this Harmonizer.   I have 5 2n5089's in front of me with different Hfe's:

625, 634, 647, 679 and 700

Is there any particular order i should put these in the circuit ?
Highest value towards input lowest towards output or the other way around or does it even matter?

Thanks!
Arn C.

[Paul Marossy]

I put the highest ones at the input for the most drive. I used the lowest ones for the oscillator and matched them as close as possible.

[Arn C.]

Thanks Paul for your response!
I actually already put the 625 first, then 634, 647,  but I matched up the last two at 700hfe each for the oscillator.

I will finish it tomorrow, time to go home and try it tomorrow night.
Peace and Thanks again!
Arn C.

[Paul Marossy]

Interested to see how yours works.

[Hal]

argh wanna build!!

I actually have 2n5089's in the mail...anyone know if it'll work with  2n3904's?

I guess ill probably try it soon...

[Paul Marossy]

It would probably work fine with 2N3904s, but I'm sure they would be very noisy compared to 2N5089s. But, for testing purposes...

[Hal]

cool...thanks :-D

I just went to build it, and took a look at the floor of my room, and decited it was time to clean off my old computer desk and put my efx stuff on it, instead of on my floor!  

So I spent the last hour or so getting my desk clean...then my mom walked in and i got pissed at her (what else is new)  SO im back here!  HAHA

Maybe later...

[RDV]

HAH!!

Mine finally works!

I made a big fat wiring mistake where the oscilator hooks to Q3!

Imagine that!

Mine sounds just like Joe's samples now.

I'm stoked. Joe's a freaking genius. Who knew you could do this with so few components. It's like a much more ruly MXR Blue Box. I can't get over it. Sounds like the guitar at the beginning of "When Doves Cry"(sorry, Prince haters).

Build this now, but watch that wiring.

RDV

[Joe Davisson]

Wiring is usually the problem, glad it works now. I don't think the Hfe matters much, you're in the zone. Mine are around 500.

-Joe

[RDV]

I did socket Q4, and tried a whole bunch of different 2N5089s in there, but there was only one that really gave it 'the' sound. With the one tranny it did less searching for the note, and had a real strong octave. I don't know why, it just seemed that way. I got the whole mess in a 1590B with a nice green LED. I'll be making me some serious octave noise this weekend! Maybe I can get us fired(the joint blows chunks) if I'm lucky!

With my Les Paul's front PU it just sounds awesome.

Regards

RDV

[Joe Davisson]

It does pretty good before a distortion, but you may have to reduce the distortion level since the preamp in the octave pedal adds it's own. Something to try...

-Joe