Shaka 1590BB Project Done - Check It Out / Q for Aron

[Paul Marossy]

I "finished" it last night at 2:00AM. It's not working quite right, yet. I found one mistake on my PCB layout, I have the coupling cap connected to Pin 7 instead of Pin 6. That probably explains the splatty, gated sounds I was getting last night...  :oops:
I will make that correction later today, and then  I expect to work as it should.

Anyhow, here is my usual picture essay of my new project:
http://www.diyguitarist.com/DIYStompboxes/ST1590BB.htm

Please note that the PCB layout linked there has this same mistake described above. I will get that fixed as soon as possible.

[Alex C]

That's breathtaking, Paul!  I absolutely love how you used the stomp switch and input jack to secure the tube mounting bracket.  Wonderful!  I love the amount of time you spend planning and organizing before actually beginning your builds.  I get so impatient and I tend to go one step at a time and constantly run into problems.  Great photoessay too!  I love it.

Alex

[jimbob]

Awsome build! The whole site is an inspiration! Anyway, could this be done w a Taiwanese "B" you think? Sounds like a nother challenge.

[Paul Marossy]

Thanks guys.  

I actually didn't do all that much planning. I designed the two PCBs "by hand" based on where I thought they would end up in the enclosure. The tube placement was still a problem, though. I had my AutoCAD drawing open and I was moving stuff around in the hopes that I could get it all to fit in such a way that I could place things they way I usually do on my projects. Then the thought occured to me that if I rotate the tube approx. 45 degrees, it would all work. So, with that breakthrough, I figured I would go full steam ahead. So, armed with my full scale print out of everything, I realized that everything would hinge on actually making the tube socket arrangement work. (It's easy to draw stuff on paper...)

So, my first thought was that I need to make some kind of bracket to hold the tube socket, without drilling holes through the top of the enclosure, and actually with no extra holes in the enclosure. Since I had to drill a hole for the bypass switch and the input/output jacks, that was my answer. I could just use those holes to mount the bracket. So, the rest is history, as they say.

As far as the actual design of the graphics, PCBs and the general layout, I think I probably spent about 5 hours or so, all done with AutoCAD. (I think AutoCAD is a great tool for stuff like this. I design my PCBs myself since most of the time those autorouting programs produce results that I don't like. At least Eagle does. It's a cool program, but to me it's a pain in the rear to use. I can get the job done quicker just doing it myself, and I can have exactly the layout that I want). I did all of this while I was at work, in between working on paying projects and answering phone calls, etc. That's probably why I made a mistake on one of the PCBs...  :oops:

Fit everything in a Hammond 1590B size box? Now I think you're pushin' it!  :wink:

[Paul Marossy]

BTW, I forgot to mention, a BIG thanks to Aron and tomboy for their pictures of the Shaka Tube circuit inside of a Hammond 1590BB enclosure. That really helped me pull this thing off.  

[Peter Snowberg]

    Another beautiful PJM build.

That bracket is a masterpiece. :!:

[Fret Wire]

    Another beautiful PJM build.
That bracket is a masterpiece. :!:

I second that.
Paul, you seem to have excellent probem solving skills. For some it's work, others it's natural. I've noticed it on your amps and other builds. I'm sure a Pro or two has taken note, and saved the pics to their hardrive.

Nice work!

[Lonestarjohnny]

That's another well thought out build Paul, and the outside looks just as good !,
Johnny

[Fp-www.Tonepad.com]

WOW!

[Phorhas]

that piece of work is for the DIY hall of fame under the mechanical challenge category

[Thomas P.]

this - as all your other stuff - is really great!!!

[Paul Marossy]

Thanks guys.  
I agree, that bracket is a work of art, ain't it?  :wink:
Seriously though, that's what makes the whole thing work...

As for problem solving skills, I get that from what I do for a living - mechanical engineering (I'm not a PE, yet. Maybe one day...). On a daily basis, I have to figure out how to fish ductwork thru complicated structures, figure out how to mount things and overcome all sorts of other obstacles that are presented to me. This is the same sort of thing, except on a smaller scale. My job also helps me to design PCB layouts, as they are quite a lot like designing ductwork to fit in a floor truss system. You have to find ways to route the ductwork in the trusses without crossing anything. If you do have to cross anything, it has to come down below the structure and back up again, not unlike a jumper on a PCB...  

By the way, my splatty sound was attributed to one mistake on my PCB and two questionable solder joints. I usually don't have a problem with bad solder joints, but once in a while I get one.

[Phorhas]

funny thing, a couple of day before you posted this, I had a similar idea about making a Batt cavity for hammond boxs. it's folded metal sheet that secure into place by the footswitch,,, funny...

[Paul Marossy]

That's a good idea Phorhas. It's very easy to work with a sheet of aluminum, and you can do a lot of things with very rudimentary tools because it is such a workable metal (unless we are talking about some kind of hardened aluminum alloy). All I used was a hacksaw and a vise, well, alos a Dremel Tool, but that was for the PCB brackets. The only thing you would have to do is make sure that there is no way for the battery to get shorted out on the battery holder.  

[StephenGiles]

Paul, what sort of temperatures are you working under this time of year? People possibly overlook this aspect - 100F?
Stephen

[sir_modulus]

I actually didn't do all that much planning. I designed the two PCBs "by hand"

sure to you.....his "I did no work" is like my "I sweated for 9 hours crunching papers and throwing them around till I went to tone pad of GGG to get the layout"

[Paul Marossy]

Yes, that is a good point. It can get up to 115 deg. F here. I only play in a controlled environment, though, usually around 75-77 degrees so I don't anticipate it being a problem. I could always use my Bulldog if need be since it has all those ventilation holes drilled in the sides of the enclosure.  :wink:

[Paul Marossy]

sure to you.....his "I did no work" is like my "I sweated for 9 hours crunching papers and throwing them around till I went to tone pad of GGG to get the layout"

Well, I have had some practice. I've probably designed about twenty PCBs now. When I first started designing them I was crumpling up papers, too. I usually do a hand sketch first, though, before it goes into AutoCAD.

[Paul Marossy]

Just a few notes on the performance of this pedal the way that I have it laid out.  I had a little concern that I might have a some hum due to the relatively close proximity of the tube to the input and output jacks. Initially, I did have a little bit of hum due to an unshielded wire that ran from the bypass switch, under the preamp tube and to the input of the circuit. And, I had another unshielded wire that ran from the bypass switch effect out to the volume pot that ran in parallel with the AC wire to the power supply board. So, tonight, I decided to change those to shielded cable, and now I really can't hear any hum at all. So, all that to say, if you use a similar layout to mine, use shielded wire on the input/output jacks, and the wires to the input and output of the circuit.

Another thing: On my earlier Shaka Tube build, I used a 390pF cap in parallel with the gain control instead of the specified 250pF and a 4.7uF cap after the 220 ohm resistor connected to Pin 2 of the opamp instead of the 2.2uF as specified on the schematic. Also, I used a 50K pot for the tone control instead of the 100K as specified. On this latest build, I built it exactly per the schematic, and I think this one sounds better than my earlier one. It seems to sound a little more articulate. I used a grounded circuit input true bypass on this one, too.

Which leads me to how it sounds: killer! Seriously, I just love the way this one sounds with a NOS RSD 12AT7 tube that I recently acquired (German manufacture). I think this thing has as much gain as the new manufacture 12AX7 I had in it for testing, but it sounds better. Out of curiousity, I measured voltages, too. Here is what I had:
Since my 13VAC 800mA wall wart puts out 15 volts when attached to this circuit, I used a 10ohm resistor in series with one leg of the power supply to get me 12.8VAC. On V+, 11.8V, V-, -14.6V and bias -13.6V. This is where I think it sounds the best to me.

Anyhow, I hope this babbling is useful to someone...  

[Paul Marossy]

Aron-

Just curious about one thing. I'm wondering about tube longevity. I use my ST all the time. With it in a non-ventilated enclosure now, I'm wondering how long I can expect my tube to last... My enclosure does get fairly warm to the touch.
Do you use yours often? If so, have you had to replace the tube yet? I know that preamp tubes can last quite a while. Maybe I'm just concerning myself with something trivial?

BTW, for everyone else, I have corrected my PCB layout, so everything should work fine now.