# Jfet Orange MkII preamp pedal



## mnemonic (Apr 26, 2021)

Hope you don’t mind non-pedalpcb projects!  Pedalpcb boards are my favorite since the documentation is great, easy to work with, great selection, and very few if any errors on the boards and docs. But living in the U.K., shipping and customs fees are high so I only sporadically order boards.

I really dig making preamp pedals and I recently discovered pcbguitarmania in Europe (probably old news to some of you guys). They’ve got a bunch of preamp pedal PCB’s so I’ve ordered a few and this is the first one I’ve built. I was a bit nervous about it working since all their projects tend to have a lot of spelling errors or other errors in the build docs (such as the BOM and ‘shopping list’ not lining up)but it works first time. Also my first time using these SMD j201’s on an adapter board. I think I’ll use these for all other j201 needs as they sure are a lot cheaper than though hole j201’s.









please don’t pay too close attention to the soldering on the footswitch breakout board, I’ve never actually used one before but after seeing a poll thread here where most of you guys love them, I decided to try one out. I was kinda iffy if I wanted to keep it so I went with the deathbyaudio school of footswitch soldering and I didn’t use much solder there (so I could salvage the switch if I decided I didn’t like it). I guess those solder joints are not load bearing so it’s probably perfectly solid as-is. 

this is one of those jfet workalikes for the Orange Graphic MkII preamp. I’m actually very pleasantly surprised by the sound.  With the FAC and bass turned up it gets very doomy and thick sounding, yet also cleans up very well with just the guitar volume knob. Cleans are also very nice with the gain turned down. I think it probably has a lot more gain than the real deal since I don’t really feel the need to go past 5 or 6 for full on doom distortion, and I’m pretty sure the real amps are by no means gain monsters.

one odd thing about the project, it specifies a 1p12t rotary switch for the FAC control but the original amp only had 6 positions. Only 6 positions work on this also (7 though 12 are silent), and that is even reflected on the schematic/build docs. Weird, maybe a 2p6t rotary was meant to be spec’d?  Maybe 12t rotaries are just easier to source?


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## music6000 (Apr 26, 2021)

Was it this type :


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## mnemonic (Apr 26, 2021)

music6000 said:


> Was it this type :
> 
> View attachment 11299


Yep that looks like it. I bought two in case one was broken. It’s larger than the ‘mini’ rotary that the dwarven hammer uses.


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## music6000 (Apr 26, 2021)

mnemonic said:


> Yep that looks like it. I bought two in case one was broken. It’s larger than the ‘mini’ rotary that the dwarven hammer uses.
> 
> View attachment 11302
> View attachment 11303


If you look at my picture, See if your's uses the same type of Washer with lug.
You can put that in different holes located in the Pot & it reduces how many positions you want, 6 to 12 from memory.
Do a dummy run with you spare one to see which hole you need!


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## mnemonic (Apr 26, 2021)

music6000 said:


> If you look at my picture, See if your's uses the same type of Washer with lug.
> You can put that in different holes located in the Pot & it reduces how many positions you want, 6 to 12 from memory.
> Do a dummy run with you spare one to see which hole you need!


Ah cool it works!  I will pop mine open and add that washer later on.

suddenly the 12 position switch makes sense.


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## fig (Apr 26, 2021)

Great job!

What's the final word on the switch wiring board?


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## mnemonic (Apr 26, 2021)

fig said:


> Great job!
> 
> What's the final word on the switch wiring board?


It works good, I’m not sure if it is any more reliable than just wires going to the switch.  It may have been slightly quicker to wire up though. I think speed in assembly may be its only benefit?


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## fig (Apr 26, 2021)

mnemonic said:


> It works good, I’m not sure if it is any more reliable than just wires going to the switch.  It may have been slightly quicker to wire up though. I think speed in assembly may be its only benefit?


Yeah, when the pads align they are spot on.  I've used those ribbon cables with them on a couple builds...they LOOK nice, but are fragile and difficult to trim to length. 

Other layouts just don't need or work well with them. Variety eh?


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## finebyfine (Apr 27, 2021)

Awesome job, this looks awesome! Been wanting to do some preamp projects and have also been wanting my first one to be a doomy orange joint. Also feel you on smd transistors - the price difference for the rarer to-92s is insane and now that I’ve done it I’m constantly looking for sot-23 versions.


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## Feral Feline (Apr 28, 2021)

Great choice of knobs!

Good looking build. I've been eyeing the MKII.

I've got a few PCBGM boards, there was a minor mix-up with my order but it was rectified and more than compensated for. While he's certainly a little disorganised, I put the typos and misspellings in the docs down to ESL (dude is Czechian IIRC, at least that's where my order came from).


Do you happen to know if this MKII's based on a Bajaman design?


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## peccary (Apr 28, 2021)

I like pre-amps as well. They don't get the love that fuzz and distortion do and but I have a lot of fun with them. 

There is just something I love about that old label maker style along with those knobs, too. It's like a sci-fi b movie or something. That aesthetic just does it for me.


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## mnemonic (Apr 29, 2021)

Feral Feline said:


> Great choice of knobs!
> 
> Good looking build. I've been eyeing the MKII.
> 
> ...



this one appears to be just a copy of the original schematic but with the tubes replaced by j201’s, the bajaman one looks like it’s more of an ‘inspired by’ design. Never tried any of his pedal designs so it may well sound more authentic than replacing tubes with j201’s.

I got annoyed with the knobs since they’re numbered 0 to 9 and if I put the zeroed out knob on 1, all the way up is about 9.  So I sanded off the numbers and just put a line on them. Easier to read also.


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## music6000 (Apr 29, 2021)

mnemonic said:


> this one appears to be just a copy of the original schematic but with the tubes replaced by j201’s, the bajaman one looks like it’s more of an ‘inspired by’ design. Never tried any of his pedal designs so it may well sound more authentic than replacing tubes with j201’s.
> 
> I got annoyed with the knobs since they’re numbered 0 to 9 and if I put the zeroed out knob on 1, all the way up is about 9.  So I sanded off the numbers and just put a line on them. Easier to read also.


If there like the ones available in Australia, that whole ring is only held in place by low tack adhesive, mine lifted straight off!


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## FrendanBraser (Apr 30, 2021)

Built a couple of their boards before. I'm the same I'm UK based so I've opted for their stuff on the occasion. Been eyeing up this board for a while but they have also just released preamp boards for a rockerverb and a matamp GT120MV. they have one of the best selections this side of the Atlantic but they by far are the boards I've had the most issues with. Too many errors not just with their documentation but their boards too.


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## Chuck D. Bones (May 3, 2021)

Looks good!  I too like the retro labels.

I usually don't fill up the holes completely when soldering the breakout board to the stomp switch.  Like you say, there's no mechanical load on the solder joints.


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## mnemonic (May 4, 2021)

One of these days I’ll learn how to silkscreen some labels. They will still probably be very utilitarian though as I like the look.


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