Sunday, 26 January 2014

The Tone God Finish Line

Another interesting and simple design from The Tone God archives. Should make a nice quick project to build.

From the Tone God's site: A simple ten part non-selective frequency tripler. It creates octave-like sounds on lower settings and on higher settings generates a metallic swell effect through out the decay of the note(s). It is particularly noticeable with using bent multiple notes.
The Drive control affects how much signal is going through the tripling portion of the circuit. When used at higher settings initial picked notes will pass unaffected but then go through the decay portion of the tripling. The Sym control affects the symmetry of the tripling which controls what portion of the decay cycle the tripling is occurring. The Level control affects the final output amount.

Thursday, 23 January 2014

Barber Small Fry

With 4 internal trimmers this was a pain to keep 1590B friendly.  As it sits it's 22 columns wide and so will just fit in if you file the sides down a bit (and insulate the side of the box next to the board with electrician tape or similar to avoid shorts).  It will however fit in vertically with the components facing down without too many problems.  The original was in a 1590BB size box with 4 external pots and a switch and so people may want to keep it in that size box anyway, but the option is there for 1590B if you want to cram things in.

The diode switching in this is unusual.  It has 7 diodes in the feedback loop plus a germanium to ground after the output of the first opamp stage which are controlled via the switch.  In one position you have 2 + 2 anti-parallel silicon diodes in the loop to give you a common symmetrical clipping that you have seen before.  In the centre off position you get 4 + 3 anti-parallel silicon diodes in the feedback loop which gives you asymmetrical clipping, and in the other position you get the 4 + 3 again, plus a germanium diode to ground after the first stage.

On top of that you also have the Dynamics pot which can bring 2 more germanium diodes, 1 + 1 anti-parallel, gradually through the sweep of the pot.

Lots of clipping options there!

Burn is the drive control, the Tone control is a simple low pass filter before the second stage and you then have further Bass and Mids trimmer controls on the board.  The other trimmers are for Presence and Note Shape.

Anyway, here's the interesting bits that Mr Barber writes about his original:

Three way toggle- This new control allows three distinct styles of symmetry to allow a perfect mate to your amps character.

8 knob control for tonal versatility-The Small Fry uses eight (including internal trim pots) control knobs as follows, Volume, Tone, Dynamics and Burn. Internal controls for Note shape, Bass, Midrange and presence. These controls allow the Small Fry to produce sounds ranging from sweet subtle sustain to smooth singing California amp style tones!

Unique controls- The note shape allows you to adjust your sound from tight and focused to a big round vintage tone, The dynamics control has earned a great reputation over the years for setting the transfer to smooth singing overdrive or raspy growling deep dynamics, continuously!

Barber adjustable phono style recovery stage- Most of our op-amp based overdrive pedals use a cool old style phonograph circuit to recover the frequencies lost in the overdrive stage, this worked great for vinyl and now works great for guitar overdrive! 

Wednesday, 22 January 2014

Millennium Bypass 2

I did this a while ago but when I was searching for it last night I could only find a tag version, so I want this in its own post to direct people to when they want true bypass and LED indication with a DPDT stomp.

This also works fine with a 2N7000 mosfet but it will need rotating 180°.

The Tone God Blade

..and i'm back. Been a one hell of a month with kazillion things going on... Here's something quite cool i ran into. Haven't had time to build it yet myself, but it is quite high on the priority list. According to the information provided with the schematic (here), this seems like a highly tweakable crossover with impressive control over the waveform. The schematic suggests a use of a diode bridge, but i think we'll be just fine with four schottkys...

From the creator: Blade uses a diode bridge recitifer in the feedback loop of an inverting opamp to create crossover-like distortion. There are five controls. Drive adjusts how much signal is fed into the loop, Depth controls how strong the effect is, Sym (Pos) and Sym (Neg) affects the symentry of the signal by setting the level on the positive and negative sweeps of the signal, and a Level output control.

Tuesday, 21 January 2014

Ibanez TS808 with Bass Control

Request.  This layout adds a Timmy type bass control to the TS808 (but with the lugs swapped round so bass increases as you turn clockwise) .  I could have just added this to the existing TS808 post but think it's worth separating them to show two distinct build options.  I managed to shift things around so that the board ended up exactly the same size as the 3 knob version so there is no board size compromise if you prefer the extra tone control.

It may be worth experimenting the the 220n and 220R filter at Tone 2 so the Bass and Tone pots compliment each other to your liking.

And for those who really like the Timmy, this version uses both the Timmy Bass and Treble controls.

Saturday, 18 January 2014

Lotus Pedals THD+N

On a roll now :o)
Info from the manufacture about his original Jerkulator copy:

Short for Total Harmonic Distortion + Noise. The THD+N is a Lo-Fi Fuzz with with Harmonic Distortion measurement is excess of 80% which are sweepable between even order and odd order harmonic distortion.

Lotus Pedals Snowjob

I think we've seen this somewhere before.  Many times.
Info from the manufacturer about their original:

SNOWJOB, a dual mode underdrive, what the hell is an underdrive you ask, hold on, we will explain.  An underdrive is similar in function to an overdrive, except instead of driving the amp it drives from the guitar, adding harmonic content to fill the space between the notes.  The SNOWJOB is a dual mode underdrive, with the toggle to the left (white snow mode) the pedal is extremely transparent, almost acting like a boost, but full and rich with headroom to spare.  With the toggle to the right (yellow snow mode) the pedal is a bit more aggressive, adding musical harmonic clipping to the spaces between the notes, like a tube amp on the brink of destruction, right in that sweet spot.

Monday, 13 January 2014

Creepy Fingers Doomidrive

Request, with thanks for forum member 'doomidrive' (just to confuse matters :o) for the pictures and information to allow us to do the trace.

A popular effects used by Hendrix and Page amongst others, here's the short but sweet overview:

A faithful reproduction of the vintage Univox Uni-Drive circuit with original NOS transistors and bottom control with some added modern improvements. 

Friday, 10 January 2014

Rick Holt Vibracaster

Moving on from the Valve Caster, and as recommended by Neil McNasty, here's Rick Holt's Vibracaster.
The tube components are very similar, but the Gain, Tone and Volume controls have been removed and components selected for unity gain and a simple LFO added.

There are lots of mods suggested for this on diystompboxes but I've just based this on the original schematic Rick posted for the 12AU7 tube.  The mods should largely be easy to implement if anyone wants to, it's a pretty simple circuit and even with a few extra rows or columns added it should still be 1590B friendly.

When someone builds it will they post a vid on youtube so I can add one to this post.  Ta! :o)

Matsumin Valve Caster

Request.  Matsumin's popular circuit using a 9V powered 12AU7 tube in a mojo and compact layout.  The white wires are for the offboard connection to the tube socket.

Thursday, 9 January 2014

Providence Sonic Drive SDR-5

Another one from Providence and another which is most definitely inspired by the TS808.  Based on the clips I've heard, like the Stampede it also sounds pretty good and so I have no doubt a few people will fancy throwing one of these together.

Manufacturers info:

An Overdrive with greater presence

Based on the old SDR-4 which has a uniquely characteristic fast attack and effective edgy sound, a newly added feature cuts out unwanted elements which can affect the presence of your sound. This gives a punchy cutting sound with a full, enhanced low midrange, and provides a new level of presence that represents an evolution in overdrive sound. Even with distortion, the sound and balance of each string remains clear. And in a band environment, a full and vibrant sound can be realized without being masked by the sound of other instruments.

FAT Switch

The FAT switch can be used to control the low frequency range. Turning the FAT switch ON raises the gain in the low frequency range, enabling the production of a particularly fat sound.

Tuesday, 7 January 2014

Providence Stampede OD SOV-2

And this is the one I did the bipolar voltage converter for! :o)

This pedal uses a 9V supply which is then converted to +/-15V using a 5V regulator into an expensive NMA0515SC 5V to +/-15V converter, plus a couple of inductors which is another unusual component for us to use.  So I preferred the idea of using components I was more familiar with and which could be obtained at a lower cost and in any quantity.

So you're going to need the bipolar converter layout I did from yesterday.  This will take you a bit above the +/-15V used by the original which may give you a little more headroom, but if you want to drop it a bit further consider putting a polarity protection diode in series with the 9V supply to the charge pump.  That will drop the voltage around 0.7V before conversion to get things a bit lower.  I think if you do that and use 1N4001 instead of 1N5817 in the charge pump you'll be very close to the required number.  Or just have a bit of extra headroom, it's up to you.

You can either make it all on one board, or I reckon it would be easier to keep the converter on a separate daughter board which can be tucked away somewhere in the box.

The diodes are unknown, here is a pic posted by Olof who posted the schematic on Freestompboxes if anyone has any ideas:

It has been suggested that the red and blue one may be a 1S1588, which I think is one of the unobtainium diodes in the Analogman King of Tone.  And the other has been suggested to be a 1N4249.  If you can get them to try then all the better, if not then just use a 1N4148 and 1N4001 combination which I'm sure will get you 99% there if not all the way.  Or experiment and let us all know how it turns out! :o)

Manufacturers description:

A wide dynamic range of overdrive sounds.
The Providence SOV-2 Stampede OD pedal is designed to deliver natural overdrive without obscuring the inherent characteristics and tone of the guitar being used. It features a special bipolar power supply that powers the internal circuitry with boosted voltage, providing a wider dynamic range than possible with conventional 9-volt powered overdrives. For singing lead tones and solid, chunky rhythms, there's nothing like the SOV-2 Stampede OD.

Monday, 6 January 2014

Bipolar Voltage Converter

This will be a useful little circuit for anyone wanting voltage doubling and negative voltage from a single charge pump.  I've done this with a particular layout in mind, but I think it may come in handy for a few effects that require +/- supplies, which can now be accommodated with a small daughterboard.

I don't know if this will work with our more commonly used ICL7660S although the pinout does appear to be the same.  The schematic called for LT1054 which are more expensive, but I only paid about £5 for 5 on eBay a while ago and so they can still be had for a reasonable price without being fleeced too much.  If you do want to try the ICL7660S then it may be worth omitting the cut between pins 1 and 8 to enable the frequency boost so you don't get noise.  The LT1054's oscillator typically runs at 25kHz.

Using the 1N5817 diodes shown should give you around +/-17V, but if an effect calls for +/-15V then you could always opt for using 1N4001 diodes instead.  The extra voltage drop will get you closer to 15V.

Wednesday, 1 January 2014

Wattkins RF Drive

Yet another Dumble-in-a-Box slightly modified Zen Drive but always worth adding these to the library.  I think this is purely a DIY project though and not something that has ever been sold commercially.

Worth building for those who like Zen's and its derivatives I would say.

JC Maillet Super Full Wave Octaver

Built this to see if it delivers. It does. Sounds sort of like an inverted, bastard brother of the Green Ringer. Just a bit sleeker in its overall feel. All the information needed on this design (and more) is available at JC's site.

A snippet from the page: Ever wonder what F(x) = |x| sounds like ? Of course I'm speaking in terms of the DC-Transfer function of a non-linear wave-shaper circuit ... for those who don't know Spice or network theory very well - this transfer maps out the quasi-static change in DC conditions everywhere in the circuit (currents and voltages) as the input source (current or voltage) changes in same manner ... this mapping, I should add, totally ignores the frequency dependent behavior of the circuit - it's doing the test at DC (0hz) ... this stuff is routinely used to uncover the harmonics generating capability of non-linear analogue gain stages ... 

To build yours with only one pot, you'll need to swap the lower left hand side 15K resistor with a 100K and replace the "Control" pot with another 100K resistor. I'm calling the pot "control" as it doesn't have a designated name on the schematic or in the description. There also added 1M pulldown resistor at the input, as well as added polarity protection diode. I used LM358 opamp, but i do believe you should be fine with JRC4558, TL072 or any other dual opamp with the same pinout. Oh. I also recommend to use 10K lin pot for the level. That's why it is listed as linear on the layout.