BJF pedals - Moodysounds Forum

Är säkerhetsaspekten (inbrottsskydd) något att tänka på?

Xangeli — Sat, 06 Jun 2026 07:44:16 +0000

Vi bor i ett område där det varit en del inbrottsförsök i grannskapet. När vi nu ska byta fönster via Fönsterpro, bör vi be om något extra när det gäller säkerhet? Är standardfönster tillräckligt säkra

J-fet compressor mods?

SebasCruz — Thu, 07 Aug 2025 14:13:01 +0000

Hi all! I'm about to build the j-fet compressor kit and I was trying to find info on the two modifying components included: a vintage ge diode and a 180k resistor. Can you please tell me where they go and what they would do differently? Thanks so much!

Sebastian

BJF Fuzz 109

Hellrow — Sat, 28 Dec 2024 11:16:57 +0000

Hejsan!
Har en DIY BJF Fuzz 109 som jag är väldigt nöjd med.
Jag har fått problem med att den glappar när den är avslagen, när det är på funkar den galant.
Jag har kollat alla sladdar till switchar och ström men kan inte hitta någon dålig lödning.
Är det någon som har en aning var jag ska börja felsöka?
Tack på förhand!

Vibravibe hastighet

snybbe — Thu, 02 May 2024 18:10:08 +0000

Hej! Tips hur man kan sänka lägsta hastigheten. Har provat med 250k, men blev inte bra

Blue Berry mods question

SebasCruz — Sat, 10 Feb 2024 22:55:04 +0000

Hi!

I built the blueberry as a gift to the bass player in my band. He loves it and he really likes the low end almost fully CCW on the nature knob. But wishes to be able to dial in more treble. According to the website, N1 and N2 can each get a C50K pot. It's also suggested to change C14 to 22nF and R18 to 2K0. Since the package did not come with these parts, I was wondering if the supplied parts for modification can also be used and what would the difference be? I received a 220nF (can I use it for C14?) and a 4K7 resistor (can I use it for R18?)

Thanks a lot and looking forward to the answer!!

Bone Bender 2

GeorgeH — Fri, 29 Dec 2023 17:40:38 +0000

Hi @björn
Im looking at adding a bias pot for your Bone Bender 2 kit, to get a more gated sound and maybe overbias the transistor for a fuller sound. Basically some some diffrenet textures. Is this possiable with your design and which pot value should I use and connect it to which trimpot? T1 or T2?

Thank You and Happy New year!
George

Bone Bender 1

Björn — Thu, 21 Apr 2022 20:20:47 +0000

Hi there,

About this kit

The description is here

https://moodysounds.com/wp-content/uploads/2017/11/Bone-Bender-1-description-and-working-theory-text-.pdf

Now there are of course questions:

Can the germanium transistors be substituted and if so with what recommended partnumbers?

Answer: yes any NPN germanium transistor with enough gain ( say hfe 70 and upwards.)

Question

If I have two transistors with different hfe, one higher and one lower which one comes first and which one last?

Answer:

This is a sound preference and chances are there would be minimal difference and the curious can mount sockets and decide.

There are ofcourse something like 40 times as many PNP germanium transistors made so we will be looking at projects to come for those.

For those starting with tubes NPN transistors were just slightly easier to get a grip on ;) but PNP was the first... so we'll have a look at transistor history later aswell.

I can see what I can do making a list of older NPN types

What about leakage current?

Answer

Leakage current can be modeled as resistans between collector and base and actually in many older circuits leakage cuurent is calculated with and

and you may see a circuit that would not work without leakage such as the buffer used in FZ-1. It does work because leakage current provides a voltage enough to bias the transistor. We'll have a closer look at this in a coming pdf

So now in the Bone Bender 1 circuit there is a bias network that set linear operation in a wide range of leakage from very little to quite a bit.

Have great fun

The dynamic range and talentboosting

Björn — Mon, 19 Oct 2020 10:02:49 +0000

HI there,

I and Albin talked about what JFet’s can be used for in a possible musical kit and one property of J fets is that they can be used as variable resistors with applications such as Compressors,Constant Volume Circuits. Limiters, Voltage Controlled Filters,Tremolo et.c.

Now the resitive range of a J Fet is limited while it can be enhanced with linerization feedback. Designs that have wide range usually require matched devices and advanced linerization to achieve range of 80dB but the circutry needed for that is far bigger than a guitar pedal

and so looking at musical applications, a common one is that of a ’Talent Booster’ a sort of mild compression that just equalizes small dips in response to make playing more fluent.

Typical applications for compression

Compression is used in studios and radiobroadcasting in the latter often a series of up to 12 compressors set very mildly and this is why records always sound bigger on radio than they do on stereo. Compression is used to decrease the dynamic range of instruments and for electric guitar the dynamic range is about 80dB

or 10000 times between the weakest and the strongest. Typical dynamic range of a cassete player is a mere 35dB for small ones to 50dB. A plucked note on an electric guitar results in a transient that is 20dB ( 10 times) higher than the mean value of the decayed note and this gives the guitar it’s caracteristic sound.

As a comparison a pålayed not on an organ has no transient but the note swells to final value. Musically the transient of a guitar is often used to set rythm of songs. Now having 80dB dynamic range is a bit awkward and makes transients very sharp or weak parts unheard and so musicians tend to like a dynamic range much smaller

40dB (100 times) to 6dB ( 2 times) or even less: heavy distortion or fuzz can diminish dynamic range to as low as 3dB and then all notes are at equal volume and you can precisely hear a difference between the weakest note and the strongest.

However in an expriment I made at NAMM with 35 musicians including one vilonist where I asked them to play the loudest note they were going to use and I set onset of distortion right there and then asked them to play and later asked them if they felt comfortable with the dynamic range and all were.

The dynamic range was then typically reduced to 20dB to 40dB meaning you still had the transient but the following decay would be louder than normal and of course that works like a ’talent booster’

Of course modern CD and home music theaters can allow dynamic ranges up to 120dB but let’s look at human hearing and then what cause hearing damages is sudden transients. Human hearing is frequency dependent and volume dependent in that at low levels the ear hears mostly around most sensitive area at 1KHz and because of this

early HiFi goit ”loudness” compensation that increased bass and treble and then often to follow the setting of the volume control. As sound levels increase the human ear eventauilly reaches a maximum and starts to compress mainly around most sensitive area ( 1KHz) but bass and treble can increase in volume: this is why sounds set for high volumes usually are more midrangy than sounds set at low levels and also why at low levels a sound that is slightly louder or more trebly is percieved as better. Eventually the human ear reaches a point where all frequencies are compressed. The huma ear can do this dynamically but is slow in response and so sudden transients can cause hearing damages. This explains why people can listen to loud concerts without hearing damages but that sudden increases in volume such as explosions or jet engines starting can give hearing damages. A beautiful thing is that the human ear can recover but only if left to heal.

One can then argue if a dynamic range of an electric guitar ( or any musical instrument) is better at 80dB dynamic range than at 40dB?

Interestingly humans do not only hear with the ears but also absorbs sound as vibrations. This is why sound is said to be better at high volumes. One can argue at what sound level is music most enchanting? Possibly that also depends on type of music.

However this above hints why mild compression can work as a talent booster and also make the played music more comfortable and in every day playing the diminishing of dynamic range making for more comfortable playing.

The J Fet compressor kit has a mild compression and when set as intended with the trimmer there is no ducking at transients but weak parts of the decay are amplified

A studio rule of compression is set compression level so you cannot hear that it is on but miss it when it is off. Obviously there are many famous recordings using ’over compression’ so that transients give a clipped sound.

Further on compression use in studios, sometimes even on distorted guitars it can be useful to add a small amount of compression and partly affects the musician with a feeling of playing louder but it can also make the recorded guitar track easier to mix so that no weak parts are lost.

There are a number of technical points of interest with this circuit in terms of amplifier techniques to some extent explaind in the product text

https://moodysounds.com/produkt/jfet-compressor-kit/

Have fun

Bjorn

BJF Reverb

moody — Sat, 09 Feb 2019 14:34:33 +0000

We are about to finish the BJF Universal Reverb kit. A circuit to which you are able to connect any (almost) reverb tank unit to. So it is an analog reverb with two outputs and controls for dwell, mix and tone. The pcb can go in a 1590bb box but the external reverb is of course bigger. Enough to make a pedal board on its own:) I hope we have the kit up by end of Feb. Questions about the pedal, welcome here!

A Musician’s Approach to Biasing Fuzz Pedals

Björn — Thu, 29 Nov 2018 01:50:26 +0000

A musician’s approach to biasing fuzz pedals

Here’s how I’d set up the bias for any of the above fuzz pedals ( except Square wave)

Set a gutar amplifier up for about 1/4WW to 1 W and hook up the fuzz pedal and connect an electric guitar ( I’d usually use a Telecaster- something single coil is a little easier to work with ) with volume on full.

Then listen to hum as produced through the amp and adjust trimmer for loudest hum and then turn down volume control on guitar slightly and listen and adjust if necessary to make hum gradually go up and down while turning the volume control on guitar.

The hum that is caused by guitar picking up magnetic fields makes for a test signal that can be used to set up performance of the fuzz.

Note how sound changes if bias is slightly of and cutting out sound….