JHS Superbolt clone PCB and the missing JFETs

Hello solderers and pedal maniacs!

Here is my last build: a JHS SuperBolt clone! As you may know, I have already did a clone of this pedal, but I have finally designed a PCB for it!

Here are some pictures:

 

I used a Supro logo that was laser-cut with some double tape to make the "Supro" sticker. I think it makes a really nice look!

I changed the position of potentiometers and the switch (which was rather odd in my first clone). So there is: Volume, Gain, Hi/Lo Switch and the Tone knob.

Here is one gutshot:

Here is the clean PCB:

As usual, I used top notch quality PCB with immersion gold pads. It makes the SMD soldering easier and I find the white and gold look really satisfaying as well 😃

I also designed it so it is possible to use both SMD and through-hole JFETs:

If you are interested, you can find the PCB here:

 Buy the PCB
The PCB was designed a bit ago, but when testing I never managed to get a good sound out of it, even after testing multiple components values... A real nightmare!

Then I finally realized why recently: my JFETs were fakes! 😱

Today, through-hole JFETs are not manufactured anymore. Most of the JFETs you find online are fake, usually restamped transistors. Indeed, most of the transistors used today are SMD and through hole transistors are somehow a relic of the past.

For some types of transistors, there are still some applications were big industrial players use them in their through hole version. Unfortunately, it is not the case for JFETs and manufacturers have seen their volume decline, hence making it economically not viable to make them anymore.

So how can we DIYer deal with that? I mean, JFETs have an amazing saturation sound that make them quite close to tubes by some aspects.

Basically, I see two options today for DIYers: using SMD JFETs if the PCB allows it, or using adaptater boards. Let's review both options!

How to solder SMD JFET transistors

This is the easiest option. You only have to learn how to solder SMD JFETs and believe me, it is not as hard as it seems.

Follow these simple steps. Equipment-wise, it is way easier if you use a fine solder tip. If you have the Hakko soldering station I recommend, this solder tip is amazing for SMD soldering.

First, place a bit of solder on the pad. Put as little solder as your can :

Then, place the transistors with antistatic tweezers. I use this set of antistatic tweezers that is very amazing.

Finally, solder the middle pad of the transistor quickly. Try not to heat it for too long!

You can finally solder the last pads of the transistor:

And you are done!

Using an adapter board

There are some "mini boards" that can replace through-hole JFETs with SMD.

They are very practical for boards that do not include SMD pads.

You can buy them here or if you need a large quantity of them, you can make them here directly. It is a it cheaper regarding shipping costs for Europe.

Just solder the SMD transistor like before:

Then use a bent pinheader to have a weird-looking through-hole transistor :)

The only problem with these "through-hole" transistors is that they do not fit into sockets. Pay attention to heat as well!

There you go, two solutions for replacing your missing through hole JFETs!



I hope this was useful to you. Post a comment for any question!

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