Buzzaround build....

[PorkyPrimeCut]

Hi folks,

I'm at a stage where virtually all the parts I need have arrived (except a bag of 10 WIMA caps which are in the post) so I thought I'd share what I've done so far & ask a couple of questions, in case anyone felt like helping.

The enclosure is based on the Hammond 1456FE1 but slightly smaller, with nicer Vox-style feet & no vents. It's also already painted black. I think it's perfect & actually trumps the Hammond, at least for my needs. My original worry about it being flimsier was unnecessary. It's very solid.

I love interesting shaped boxes, particularly on the larger side, harking back to the old fuzz boxes of the 60s & 70s, & this pedal will actually go to a guitarist who feels the same way. He's a touring musician who'll hopefully do the pedal way more justice than I can.

I'm using turretboard rather than veroboard & am going down the "mojo parts" route with this one...



That Phillips cap is massive!!! Kinda got my measurements wrong with that one but I made it fit & so far everything's working out.

Pretty soon though, I'll be sorting out the transistors. I snagged 3 tested NKT213s a few years back that were originally meant for this build (which then got shelved). I also got a set of 2N404As from a guy in the know who reckoned they'd make perfect substitutes.

QUESTION - I've read that having a leaky transistor (in Q3, I think) is what can make all the difference. As these don't leak I was wondering, will the pedal still do the job or will it be lacking somehow? He sent me a set that have 2 closely matched - 65 & 60hfe - and another for Q3 that's 109hfe.

I need to measure the HFE of the 3 other NKTs aswell, then decide which ones I put in this build & which I save for one I'm building for myself. Measuring the leakage myself will be a real test. I'll fully admit to being useless at understanding electronics. I'm an illustrator by trade, occasionally dabbling in graphic design, and very much a "painting by numbers" builder. I try to read up on what I'm doing, to get a better understanding of what I'm dealing with, but the maths is hard to soak up & remember!

Anyway, there'll be more in the next few days. I'm hopefully drilling the enclosure tomorrow.

[digi2t]

This is the work I did on the Buzzaround. Lucifer's Trip provides all the pertinent info.

http://www.diystompboxes.com/smfforum/index.php?topic=96991.0

My last post in that thread lists the gains and leakages that I settled on.

[PorkyPrimeCut]

Thanks for that! I'll do my best to read through it & hopefully get a grasp of the numbers.

One thing someone else has recommended is using a trimpot in place of the 24k resistor to help with biasing. As I won't be breadboarding this I'm hoping that'll help a lot.

[digi2t]

If you want to preserve the "old mojo" look of your build, I wouldn't go with a trimmer, except if it's to figure out just the right resistor to settle on. Then again, with the carbon comps, I don't think you're going to find a great selection of exotic values.

I did a lot of transistor rolling with this circuit to find my perfect set. Breadoarding is really going to be your friend in this case.

I also noticed that you used a silicon diode for the clipping. You may want to test it with a germanium as well. Deciding which way to go here will also depend on your transistor set. The knee bone is connected to the leg bone sorta thing. I found that a germanium diode sounded much better in my unit, it already had quite a bit of top end, and the germanium diode helped take a bit of the edge off. Besides, if you're going for the old look, that 1N4148 looks a bit outta place there.

[Fast Pistoleros]

looks fantastic but I agree with Digi, going old school you need an NOS GE in the diode spot

[PorkyPrimeCut]

looks fantastic but I agree with Digi, going old school you need an NOS GE in the diode spot

You mean the diode that's top left in the photo (the only diode that's in the circuit, I think). That's, supposedly, a "1N34 Germanium Diode", at least that's what it was sold to me as. If its not I'd love to know of a better outlet for that particular part. It's actually the easiest one to remove, compared to the rest of the board!!!! Heheheh!

[Cozybuilder]

Your diode looks a lot more like this:


Than this:


But then again:


Might be a good idea to measure the forward voltage drop, and see if you have Ge or Si diodes in that purchase.

[digi2t]

+1 on measuring the forward voltage. It sure looks like a silicon diode to me. 

[Fast Pistoleros]

its probably GE , I was thinking along the lines of all NOS meaning aesthetics, an old oversized Diode that looks the part if you know what I mean 

thinking more like a antique restoration but all old stuff that look old lol

[PorkyPrimeCut]

I got a pack of 10. Here's the listing.... http://www.ebay.co.uk/itm/190820363680

I was pretty surprised how small they were, although the last time I saw one (maybe 3 years back, it's been a while since I picked up a soldering iron) I think it was about the same. I think that was in a Superfuzz clone kit. As daft as it may seem, I actually considered finding something a bit...er....bigger, just so it fit in with the rest of the build. Hell, I might still. This was never a practical, cost saving build. It was a bit of flamboyant fun (and I've read enough stuff on these boards to know how far that can go!!)
Ultimately, I just want to build something that sounds cool for a friend (and looks the part as well). The original idea was that he just roadtested it but things took a turn & now he wants the finished item. The man's a wizard on guitar, whereas I'm your average cowboy chords/psych fuzz kinda guy. I can't wait to hear how it sounds & I'm pretty sure he'll get 100% out of it, compared to my 20.

[digi2t]

its probably GE , I was thinking along the lines of all NOS meaning aesthetics, an old oversized Diode that looks the part if you know what I mean 

thinking more like a antique restoration but all old stuff that look old lol

Yup, oversized, like this baby...



That's what I used in my build. I was REALLY lucky, picking up 20 of these Sylvania 1N450's quite cheap some time ago. They look awesome!



They look like twin flux capacitors in my Superfuzz...

[mcknib]

Nice soldering on the tag board looks very pro

As advised check the fwd voltage on the diodes it should be around 0.3v to 0.5v ish test it then heat it up between your finger and thumb for a few seconds and it should drop slightly Germanium being affected by temperature.

Germanium's depending on the type range from 0.3v to 0.5v ish silicons as you probably know 0.7 and wouldn't change by applying heat from your fingers.

So the heat test is a good indicator for Germanium

Good article from AMZ-FX:

http://www.muzique.com/news/fake-ge-diodes/

and a GPCB vid

[PorkyPrimeCut]

I'll test the diodes today, although I have Vintage GE Flux Capacitor envy now, big time!!

The temperature thing. Yeah, I only found out about this after becoming convinced that all my builds had turned to shit from being in storage. Turns out they were just cold and I was a complete noob!

[PorkyPrimeCut]

So, I got OL in one direction & 2.58 dropping to around 2.54 after pinching it between my fingers. Germanium, I guess?

Just out of interest, will any GE diodes work? Could you give me some common to not so common examples?

[duck_arse]

would not the schottky 1N34 be a junction diode? and the germanium version would be a point contact type? so if you peer into the glass and see a whisker poking a crystal, as opposed to two barely seperated lumps (like in a 1N914/4148), would it not be safe to assume that it was a Ge?

[Cozybuilder]

These might be perfect for your project:

http://www.ebay.com/itm/121909174551?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[PorkyPrimeCut]

^^ They look great! ^^

Unfortunately I'm in London so postage would be twice the price of the diodes!

[PorkyPrimeCut]

Aside from the diode issue, I got some drilling done yesterday & decided to partly assemble it to see how it was shaping up....





Those knobs are just place holders (but actually work surprisingly well) & I'm yet to drill the jack input/output holes.

Still, I'm happy with my progress.

[digi2t]

Very nice. Clean and neat. If you had mounted the board on the lower half of the enclosure, it would have cleaned up the look even further not having the mounting screws showing.

Personally, I would have forgone the LED. Trust me, you'll know when this sucker is on. 

With no LED, I would have opted for a Carling footswitch, like this one;



and some full size CTS pots, like this;



to complete the vintage mojo look. If you can find some grey coax wire, that would really complete the look.

[PorkyPrimeCut]

Funny. You've pretty much highlighted my 3 issues with this build.

Those pots were a mistake & were supposed to be full-sized & solid shafted (I might still replace them). The ones you pictured look nice. Are they old or new, but made to look old?

The footswitch was a quandary as the wiring diagram I'm referring to has 6 pins but I wanted the LED. Getting my head around wiring it for a 9-pin switch will no doubt cause me some problems.

I initially wanted to mount the PCB at the bottom but thought it'd be a pain in the arse if you had to open it up, what with the wires effectively being attached to both pieces of the enclosure. It'll be easier to service this way & I like the look of those 2 little black screws.

As to the grey coax wire, do you mean the shielded stuff used in the Burns originals? I bought a metre of the stuff