Mojotone Studio One

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M Fowler
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Mojotone Studio One

Post by M Fowler »

I broke down a got the Mojotone Studio One kit.

Short two parts one was no big deal the other was a big deal, the fuse cap. :) I used the radial 2.2 cap but replaced the 1uf with an axial cap and the 10uf with axial cap instead of radial caps. The Dijon .22uf cap is huge and didn't fit that tight space well so I used a M150 cap I had instead.

Component board was 3/4 of a hole off from predrilled chassis holes. :roll: Board hit input jack.
Mojo uses good components so no other problems.

Looking the schematic and layout over I decided there was too much over the board wiring so I added 3 turrets to the end of the board for B+ wiring to go under the board.

Added stanchions to the relay board for support. Don't like chicken head knobs and was low on gold Marshall style knobs so used MXR style knobs.

I think the site list this as a 5 hour build so far I have two days in to it because it took a while to understand the circuit and layout. Especially the rely board since there was no instructions for that included in kit but I did notice the board is now advertised on Mojo with instructions so I downloaded that. No wonder other forums show a guy posted in 3 different forums the problems he was having and he was clearly a newb and his photos showed horrible wiring job. :D
IMG_0932.JPG
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

This is how mojotone wired the amp which is fine but I wanted to wire it different.

You can see that I have a different chassis not the standard 18w Marshall chassis, mine doesn't have the large PT cutout, they drilled my chassis different as far as tube socket holes and input jack hole was moved on mine. Nice of mojo to give me to hole block off plates for future project since I have a different chassis they are not needed but still in the kit.
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

Got some more wiring done today and will try finish up early this week.
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

Studio One Finish.JPG
Finally finished the amp and even the foot switch works. :)
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Berger
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Re: Mojotone Studio One

Post by Berger »

Thanks for the thread! It was nice to see one of the mojotone kits.

Thoughts on how it sounds?
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

Thanks I took lots of photos on this build.

I tried 12AY7 V1; 12AX7 V2-V3; and 12BH7A power tube.

The clean channel is clean and useable but I want to try a 12AX7 there next.

The dirty channel is accessible by push/pull switch on the clean volume pot or via the foot switch.

The dirty channel has some good harmonics going on.

These are not loud at 1 watt so and is intended for recording or bedroom playing.

The dirty channel will make you a Rock Star in your own mind. :D
Berger
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Re: Mojotone Studio One

Post by Berger »

So is this along the lines of the AX84 Firefly or the Marshall 1 watt that was made?
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

Seems to be along the same line as the Marshall 1. Yeah some of the AX84 schematics have a 4 gain stage preamp.

V1 is used for clean channel.

V2 & V3 four gain stages into TMB tone stack then to the 12BH7 tube.
Berger
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Re: Mojotone Studio One

Post by Berger »

Ok, thank you for the info!
RockinRocket
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Re: Mojotone Studio One

Post by RockinRocket »

I saw this a while back and was interested as a 1watt amp was on the to do list.

Can you share how they did the power section for the 12bh7? LTPI? Cathode biased?

Marshalls DSL 5c 5 watt 12bh7 amp uses the typical Marshall PI with a 10R cathode bias resistor on the 12bh7.
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

MOJO1580_applications.pdf
MOJO1580_applications.pdf
Here is the data for the Mojo OT
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RockinRocket
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Re: Mojotone Studio One

Post by RockinRocket »

Thanks! That does ring a bell. I did see those pdfs on their site a while back. I really wanted to use the output transformer but saw the cathodyne PI and I really wanted a LTPI. I got discouraged as I'm no where at that skill level to figure it out. Nothing wrong with the cathodyne and probably should just build one :D
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

MOJO-1580-OT.pdf
The kit is reasonably priced for all the parts you get.

I have a room full of transformers, another room full of chassis and a garage full of even more but I figured the kit was a good way to go plus I get schematic and layout with it.

The PT is their GA-5 transformer.
GA 5 PT MT-FENDER-MOJO779.pdf
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M Fowler
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Re: Mojotone Studio One

Post by M Fowler »

Been adding front and back panels to popular mocha stained cabinet today. Camera lense was dirty looks like spots on the cab, no. :D

Going to order some nice handles for these cabs rather then the black rubber Fender ones I have on hand.
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dorrisant
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Re: Mojotone Studio One

Post by dorrisant »

Very nice, Mark.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
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