Mutron III

A few people have requested this, and I hope they all don't mind making links :o)  LED/LDR layouts are such a pain!

A very well regarded envelope filter that many think is the best sounding one of them all with this being based on RG's Neutron project files due to the unobtainium status of some of the original parts.  I have modified this slightly from the original because I didn't like the idea of the Gain pot and first opamp stage being permanently in the signal path of your effect chain, and there's really no reason why it should be now DPDT and 3PDT stomps are available so cheaply.  So I have made this one true bypass so just use your preferred method.

Some people have used two LEDs or vactrols to make this but I have opted for a single LED with the LDRs on either side, so you can just bend them to face the LED as you see in some Univibe type effects.  To get the best out of it the LED and LDRs need to be in darkness which obviously isn't a problem when the effect is boxed, but for testing before being boxed you will want to put a cover of some sort like a small purpose made cardboard surround to keep out the unwanted light.

For LDRs Javi suggested the GL5539 which is available cheaply and in quantity on eBay and is 40-100k light, 5M dark resistance.  But I'd suggest socketing them, and probably the LED as well so you can try a few in there and stick with the combination which sounds best for you.

The trimmer was included simply to allow you to fine tune the brightness of the LED which should allow you to tweak the best setting out of it.

The effect needs a +/-9V supply and so I have shown the usual voltage inverter board.  You can add 5 rows to the main board if you prefer but I thought this would make more sense and allow people to get it in a 125B pretty comfortably with the supply board stuck on an inner wall somewhere out of the way.  You can also omit that entirely and use a +/- 9V supply if you have one, or two batteries if you prefer.

The original included a rotary switch for the Mode selection, but there are only 3 selections and so this is easily accomplished with a DPDT on/on/on toggle which again saves lots of space.  If you go with my choice here make sure the contacts change as shown in the diagram.  Some of these switches have the opposite contacts in the middle position, and so if you get one like that you can still use it but you'll need to swap the poles.  So lug 1 becomes 4, 2 becomes 5, 3 becomes 6 and vice versa.  Then it will work fine.  And don't forget the link you need between lugs 2 and 4.

I couldn't find any marketing blurb for a 1972 effect (the year I was born) so for fun here's the patent blurb instead:

A sound effects generator for modifying a sound generating signal is comprised of a voltage-controlled filter having a variable peak response frequency for transmitting at a maximum amplitude those frequency components included in the sound generating signal that correspond to the instantaneous filter peak response frequency. The peak response frequency is determinable by a control voltage applied to the voltage-controlled filter; such a control voltage being proportional to the envelope of the sound generating signal as extracted by a control voltage generator. The filter peak response frequency is thus varied in accordance with the varying envelope of the sound generating signal.

Eh?  Start again please but slower.

And I have to say it really does sound fantastic in this vid.

And as per Javi's request this is as per the original with a 4 pole 3 way rotary switch for Mode, and with a simplified bypass that leaves the first gain stage in circuit.  Just a DPDT stomp is required for bypass, or SPDT if you don't want LED indication.  I left the charge pump board separate though because I just can't face adding any more links to it! :o)

Mutron Micro V

As Javi liked the idea of the simplified controls I thought it would be worth adding a layout for the original pedal too.  It may seem strange with it being a "stripped down" Kraken, but it actually worked out a column wider using the Kraken layout as a template because removing the Attack pot means a resistor needs to go from the 3rd to the 15th row, but what can you do? :o)  Anyway the option is here if anyone wants to build this instead.

Madbean Kraken

We had a request to do the Mutron V or the Madbean Kraken so I decided to go with this one for the extra controls.  Info from Brian about his modification:

The Kraken is a modified Mutron Micro V™ envelope filter. The Mutron Micro V™ is the “little brother” of the more fully featured Mutron III™ having only a Range pot and a Hi/Low switch for the filtering. The Kraken expands the controls to include Attack and Decay for the envelope response. This is the only alteration to this classic and great sounding envelope!

Controls
Range: This controls the intensity of the envelope dynamics generated by your pick attack. Higher settings yield greater sensitivity, which in turn drives the intensity of the swept filter.
Attack: This control lets you dial in finer adjustments to the attack of the envelope. It is interactive with the Range pot.
Decay: This control determines how long it takes for the envelope to sweep the filter. Higher settings yield longer decay times.
Hi/Lo: This switch controls the range of the filter that is swept. Hi is thin and resonant. Lo is full and dark.

Mods
Try a pair of diodes with lower forward voltage for D1 and D2. This may improve sensitivity to picking dynamics. You can use 1n34a, BAT41 or BAT46.
Try a higher value pot for the Decay control for even longer decay times. Suggestions are 250kB or 500kB.


I can't find a vid of the Kraken and so here's the Mutron V.  I will swap this for a Kraken vid when someone here verifies this and posts one for me :o)

EHX Bassballs

Little something more for the bassists.. Should work nicely on guitar too.

Mad Professor Snow White Autowah

I did this as a bit of an experiment.  I want to build one and this has always been one of those that would prefer to do on a PCB, but I thought I'd still like to put a layout together to see how small I could get it using my methods and as I have I may as well put the results on here.

At 20 x 29 is may just fit in a 1590B if you aren't using a battery and have the stomp switch mounted right at the bottom, but with it having 4 pots, I think I'd probably opt for a 125B which should be a more comfortable fit.

Avoiding 19 links is another of the reasons why I would prefer a PCB :o)

Info about the great sounding original:

BJF design guitar and bass Auto Wah / Voltage Control Filter pedal

Hand-made in Finland premium quality auto wah pedal.

The SNOW WHITE AUTOWAH (SWAW) circuit is based on a 1991 BJF rack mount remote wah circuit and is tuned like a real wah.

The circuit was redesigned with envelope controls and built into small size pedal.

It has very fast tracking and accuracy rarely found on auto wahs/ envelope filters. With the four knobs you can have total control of the effect.

SWAW works both with guitar and bass and you can fine-tune the pedal to suit your instru-ment, your playing style and your taste of tone.

The pedal has a unique decay control for the filter frequency fall speed. You can set it to be fast for wah effects on every note, or slower for a more traditional auto wah sound.

Like all Mad Professor pedals SWAW is hand made in Finland using only premium compo-nents, to give years of trouble free operation with superb musical tone.

Controls

SENSITIVITY: Sets the filter trigger level, tune this carefully to fit your guitar/bass output and your playing touch.
You can further change the sensitivity from your guitar volume knob while playing.

BIAS: Controls the filter resonance frequency. When Sensitivity is turned fully off the Bias can be used as a sweepable filter.

RESONANCE: Controls the sharpness or Q-factor of the filter.

DECAY: Controls how fast the filter frequency falls back to resting point (that is set with the Bias control). This can be set fast (CW) so you get the wah effect on every note or slow for a more traditional auto wah sound.

PLAYING: Please take time to get used to the controls and as this is a voltage control filter it will react to your playing touch. The envelope control circuit is carefully designed to follow the dynamics of guitar/bass and it might take some time to master the Auto Wah playing technics.

Try also adjusting guitar volume between 8 and 10 to further expand use. 

Modded version as per the improvements discussed below in the comments:

Danelectro French Fries

Quite a nice sounding and simple AutoWah.  Thanks to Bernardduur on FSB for the scheme.

Short but sweet:

It's a '70s style auto wah like you haven't heard since you tossed your bell bottoms. 

Seamoon Funk Machine V2 with buffered blend

After John K got better results putting a buffer before the circuit I thought it would be a useful to do a second layout incorporating a blend pot.  This almost certainly will make the effect more useful with bass, and if you want the effect 100% you can simply leave the blend pot in the extreme counter clockwise position.

For info about the effect see the original Funk Machine V2 post.

Seamoon Funk Machine V2

The FUNK MACHINE is a synthesizer that can be used with any amplified musical instrument. Bass Guitar ... Guitar .. . Fender Rhodes ... Harmonica ... Horns .. . Clavinet.

The FUNK MACHINE is primarily designed for use with Bass Guitar, but you will find that all other instruments will work very well. On Bass Guitar you get a sound that Is heard everywhere in recording these days. The unusual sounds coming from the Basses of Larry Graham, Sly Stone, Tower of Power, and Stanley Clarke are characteristic of the sounds of the Funk Machine.

On Guitar the FUNK MACHINE gives an effect similar to a WA WA pedal, the difference being that the FUNK MACHINE is electronically triggered by the players attack on the strings as opposed to the mechanical and foot action on the WA WA. The FUNK MACHINE gives a fender Rhodes a sound similar to a Clavinet, but because of the very low output of the Rhodes in some cases the signal generated by the piano is not strong enough to trigger the FUNK MACHINE on the extreme high notes on the piano.

Unlike most control knobs that are associated with electronic apparatus the FUNK MACHINE does not get its best effect by turning both controls to their full on position. In fact the FUNK MACHINE would get its worst effect by doing so. To get the best results read the instructions carefully.

1. Turn both controls on the FUNK MACHINE off.

2. Turn the volume control on the instrument to its full on position.

3. The FUNK MACHINE is voltage controlled meaning that the harder the note is struck the greater the FUNK EFFECT. Bear this in mind because as you adjust the controls you are as much responsible for the sound as the FUNK MACHINE.

4. Strike a low note on your instrument in a repetitive manner, (Bass Guitar "D" string, Guitar "A" string). At the same time you arc striking a low note on your instrument in a repetitive manner slowly turn the FILTER RANGE control clockwise until the FUNK EFFECT is heard. Remember that the further the FILTER RANGE control is advanced, as well as how hard the note is being struck determines the amount of effect.

5. It you play Bass Guitar the FREQUENCY SHIFT control will move the range of the FUNK MACHINE into a lower frequency range that will easily accommodate the open "E" string on a Bass Guitar. A little experimenting with the FREQUENCY SHIFT and the FILTER RANGE control will yield great results.

6. NOTE FOR BASS GUITAR: The FUNK MACHINE can be used as a sub-harmonic bass filter which will cleanly lower the bass response by two full octaves. To accomplish this simply turn the FILTER RANGE control off and use the FREQUENCY SHIFT control only.

7. Unplug the unit when not in use to increase battery life.

A helpful hint for the FUNK MACHINE as well as your other effects is to use a Y cord from your guitar into the second channel of your AMP. By splitting the signal you don't loose any of the natural response from your AMP while using effects.

Demo of the V1 Funk Machine without the Frequency Shift conrol, but should still give you a good idea of what to expect.

Dunlop Q-Zone QZ1

Based on Analogguru's schematic, I really don't know much about this other than it's supposed to be a cocked wah effect but it was a request and looks like something a bit different.  At least it's a bit of a detour from the usual dirt pedals! :o)

I couldn't find many demos out there either but here is one I found on Youtube: