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The Apollo: A Frankenbean monster

Started by jubal81, September 27, 2011, 06:45:33 PM

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jubal81

This started out as a Sunking build (hence the name) and just kept evolving.

After days of tweaking and testing, it ended up being a SK running into a Rump Roast powered at 18 volts by a Road Rage. Whew!

When I first powered up the Sk, it was a little harsh for my tastes. I've never been a huge fan of diode-to-ground clipping. So I added some series resistance (3rd knob from left) and a 2n2 cap across the diodes.

The Sk controls are trimpots and I control the gain, tone and volume with knobs from the Rump Roast half. It took a long time to dial in the sweet spot on the Sk, but it really does what I want it to do and sounds fantastic from very light OD to the heavy stuff.

I also ended up using component choices based on a lot of the work I've seen in other build reports here, namely using TLE2072 opamps and LM313 diodes. I tested a lot of other configurations, but ended up settling on those anyway. Also, there was mention of possibly using a BZ385-1.2 in place of the (very expensive) LM313s. I tried it out and the difference was absolutely razor thin, so I fully recommend giving them a try.

This was also my first etched enclosure job and might be my last. My shoulder is still sore from all that sanding. I screwed up three transfers before I got a good image and had to sand em off to try and try again.

Anyway, here's the pics, including my typical rat's nest wiring style:


"If you put all the knobs on your amplifier on 10 you can get a much higher reaction-to-effort ratio with an electric guitar than you can with an acoustic."
- David Fair

rullywowr

Nice job!  I love the "diode clipping station board" where you have a dip socket ready for a'swappin!  Can you give more details on the BZ385-1.2 diodes?  Never heard of them.  I am about to order some 313H (for about 3.50 a piece) but if these work good that would be great!



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nzCdog

YOWSAH!  Love it... Interesting to read about your diode experiments... I must try the cap and series resistance tricks sometime.  Wiring is epic!  Nice work! :)

Haberdasher

Holy cow, noiice!  That's a great job, there.
Looking for a discontinued madbean board?  Check out my THREAD

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jubal81

Quote from: rullywowr on September 27, 2011, 07:05:54 PM
Nice job!  I love the "diode clipping station board" where you have a dip socket ready for a'swappin!  Can you give more details on the BZ385-1.2 diodes?  Never heard of them.  I am about to order some 313H (for about 3.50 a piece) but if these work good that would be great!


http://www.mouser.com/search/ProductDetail.aspx?qs=2OtswVQKCOEGEvC6B0QNZA%3D%3D

Sorry, it's LM385BZ-1.2. 67 cents each at mouser. They seemed just a hair rougher than the 313s, but with a cheap, tiny ceramic cap across them I'm pretty sure I'd never be able to tell them apart if I were blindfolded.

Honestly, the diodes didn't make as much of a difference on tone as I expected. Pedal sounded great regardless.
"If you put all the knobs on your amplifier on 10 you can get a much higher reaction-to-effort ratio with an electric guitar than you can with an acoustic."
- David Fair

raulduke

Jesus!

Thats beautifull work and design there mate.

Top Gun Etching!

stecykmi

very cool build. great info about the LM385's too.

bigmufffuzzwizz

Holy cow you fit so much in there! I really like the etch, you worked hard for it!
Interested how you set it up, it's cool you got it how you wanted it in the end. I put that circuit away for a rainy day...
Owner and operator of Magic Pedals

jubal81

Thanks for the nice words, guys. Worked pretty hard on this one.
"If you put all the knobs on your amplifier on 10 you can get a much higher reaction-to-effort ratio with an electric guitar than you can with an acoustic."
- David Fair