Mojito Deluxe Boneyard (#metoo) - Update

MichaelW

Well-known member
Build Rating
5.00 star(s)
Inspired by @Dan M's build report of this pedal, I got stoked about building this board that I've been sitting on for quite a while.

Main reason it's taken this long to make to the top of the build list has been a couple of the rather uncommon components that has taken some time to find.

Mainly the CA3130EZ and the BA482 clippers.

I finally did find the opamps in the past couple of weeks (in two places of course) and now I have a few spares.

I dug through the old threads where @Chuck D. Bones talked about substitute diodes and decided to go through my meager stash to find a suitable substitute
and the closest thing I found was the MA858's (in terms of Vf). So that's what's in there now. I may play around with some of the other alternatives, like using half of the diode pair in a JFET or BJT transistor

But it sounds pretty darn good as is, I might just leave it!

Really cool distortion pedal, it's got more gain than I generally know what to do with but it's thick and chewy all the way through the range.
I'm liking it with the gain around 9 o'clock and boosting it with the Closed Circuit Booster Limiter I just finished.
Checking it out with my P90 Tele it's pretty kicking. Big and wooly on the neck pickup, snarly and spitty on the bridge.

The internal boost is also very functional and usable (as opposed to some other distortions with a built in boost...cough,cough,JHS, cough)

The only other substitution I made was 1n4001's instead of the 4004's. From what I can find from the data sheets these have the same Vf range and since they are employed with the 4148's as clipping pairs I don't think it will make a lot of tonal difference.

Thanks @Dan M for pushing off the fence on getting this built! Nice add to the collection.

Using Tayda's Matte Violet. It's much more subdued in person than in the picture, cool color!

I pushed the footswitches out a bit for a bit more room.

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Do you, MichaelW, offer time-management skills courses? I want to build as prolifically as you do!

Also, where did you source the IC? I want to pick up a few more.
 
Do you, MichaelW, offer time-management skills courses? I want to build as prolifically as you do!

Also, where did you source the IC? I want to pick up a few more.
Can't help you with time mgmt. , I'm pretty set in my ways at this stage in my life, basically, wait until the last minute then cram to get things done:) (Not recommended strategy btw)

I found the PDIP version of the CA3130EZ at Smallbear
And the SMD version at Mouser

I got the Mouser one first and was planning to use an adapter board but then found the ones at Smallbear.
 
That was fast! It takes me 2-6 months to build a pedal.

It seems the common theme in all of the reviews is: The sound keeps its tone quality and does not get thin or tinny or fizzy when you raise the gain or activate the boost. I don't have any other pedals that match it.

It's difficult to describe in words.

@Feral Feline I used an IC from tayda: CA3130EZ
 
Update:

Ok, since I wasn't building today, I needed a wee bit of "bench time" fix and walk away from working for a bit.

So I decided to try some different soft clippers in the Mojito.
I have a bunch of TO-92 2N5457's that are out of spec that are just sitting around.

I soldered the Drain and Source legs and tried them in the soft clipping diode spots in the Mojito. These measured ~.820-860 on my GM328.
So a skootch lower than the MA858's I had originally in there which were in the mid 900's.

Whoa! I LIKE how they sound. (Yah, I know that I'm not supposed to hear any difference in clipping diodes...hahah)
I don't think it's "just" the Vf, or maybe it is I don't know but overall the gain is smoother than it was before.

I don't know what this pedal is "supposed" to sound like with the BA482's but the 2N5457's are definitely a great option.

They're staying in!

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IMG_3387.JPG
 
Update:

Ok, since I wasn't building today, I needed a wee bit of "bench time" fix and walk away from working for a bit.

So I decided to try some different soft clippers in the Mojito.
I have a bunch of TO-92 2N5457's that are out of spec that are just sitting around.

I soldered the Drain and Source legs and tried them in the soft clipping diode spots in the Mojito. These measured ~.820-860 on my GM328.
So a skootch lower than the MA858's I had originally in there which were in the mid 900's.

Whoa! I LIKE how they sound. (Yah, I know that I'm not supposed to hear any difference in clipping diodes...hahah)
I don't think it's "just" the Vf, or maybe it is I don't know but overall the gain is smoother than it was before.

I don't know what this pedal is "supposed" to sound like with the BA482's but the 2N5457's are definitely a great option.

They're staying in!

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View attachment 31166
This was going to be my goto method as Mr. Bones said it’s the closest to the real deal. But I ended up scoring some diodes. Glad it worked out for the better using those transistors. This is absolutely in my top five favorite sounding builds.
 
You guys are making me want one of these. I didn't know Jfets had a Vf that high, do you by chance know what a run of the mill 1n4148 or 1n914 measures on your same meter? This makes me more interested in fighting with jfets if I'd have a use for the out of spec ones.
 
On the same meter (kit based Mega GM328 Transistor tester) 4148 came in at .689mv and 914 came in at .690mv.

So "relative" to the 5457's they're a lot lower.

I wish there was some way I could find out what the "If" is on that tester. It's not in the spec's anywhere that I can find.
 
Do you have another meter? If so you could measure the current while the other tester is testing the diode.
Will that work? I thought about that. The tester "auto detects" what kind of component it's measuring. How do I "trick" it into thinking it's measuring a diode? I was actually wondering if it would work by actually connecting a diode with jumpers then using a DMM with jumpers on the legs of the diodes. Maybe I'll play around with that during my "lunchtime bench fix" today hahaha
 
Thanks Chuck. When next I need more CA3130, I'll be sure to try eBay.

I just got some in my Small Bear order, taking advantage of the 22%-off sale, but that 22% is gonna get eaten up by shipping and duty-fees. C'est la vie 🤷‍♂️
 
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