“1982 ~ 302 pages

Scarce title. This fascinating book covers everything you need to know to design and troubleshoot analog synthesizers, including detailed information on SSM and Curtis (CEM) synthesizer chips. A definite must-have for the analog synth enthusiast, filled with schematics and technical information, as well as a few photos of Moog and E-mu Modular systems.

Is the most comprehensive book available dealing with analog circuitry for music synthesizers.
Discusses design of synthesizer elements so that the reader can begin to design his or her own system.
Details the custom ICs used in the majority of synthesizers
Describes construction methods
Gives secrets of many special-effect devices used by musicians.
Is written for studio engineers, musicians, computer and electronic music hobbyists
Contains a minimum of mathematics



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Speak&Spell-New Circuit Bending Modifications-CV input

the old S&S completely rebuilt for noise/experimental
saved green wiring from my first bend on that machine
rewired… rebuilt… expanded… now has 18 controls…
(used 1loop/hold bend from the Reed Gazala book… everything else is my own custom bends)
today added attenuated CV input for modular sources(LFO/Noise/Sequencer CV)
triggering glitches on external timebase
(not the points from anywhere online considering none of them worked on this pcb design)
working like a charm with 3.5mm modular
recorded about 3-4+ hours of source during this overhaul process
could add internal LFO yet running out of space in the case….
so will create some 9v modular utility box for use with that machine
almost never crashes now plus it can auto-generate variable glitches for hours
using specific settings combinations
mission accomplished and performs way beyond original expectations
added added 2xleds… LED1 for power LED2 reacts for in circuit gain/distortion level peak & external CV
(LED2 can be used in the future for gate/trigger output jack)
added 1/4″ output instrument jack from ARP Quadra PCB
that old S&S is officially an instrument now
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Circuit-Bending Alien Instruments

http://www.zhagun.ru/Circuit_Bending_Bu … uments.pdf
taking a look again at Reed’s bendng book…
or should eye say Re-Reeding :P
tripped on power wire yesterday with case open on S&S
busted on of my original custom bends on that machine
no clue at all where it went
can’t find that spot… annoying… frustrating
so adding the standard incantor glitches from that book
also adding LFO because want some blinky for timing
the getlofi guy gave me some tiny little 555 boards
at rodgers park circuit bending swap/jam in early 2000s
just dug up one of those for using in S&S
running out on toggle switches so better order more fast

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2019 N01ZE Future Reflections

cut my teeth on circuit bending long time ago
recently dusted off and rewired an ancient machine that circuit bent in the 90s…
retired it around 2002 when they became all the pop subculture rage
got in some box recently above the workbench & found 4 S&S machine plus 1 S&M
so…. took it apart my original bent S&S and completely rewired most everything…. considering it was fuct
(had extremely fragile total crap braided phone wire making the bends & hot glue)
yet hey that what had way back then for my initial bending projects………………………… mid 90s
also replaced broken switches
anyways been recording with while doing complete rebuild
this one is the 1978 first series Speak & Spell with bonus word cartridge
it gets some good noise loops
contemplating hacking one of the other units into eurorack module
back in the day had this one taking CV input
yet no fclue anymore where it is on the TI chip
and had obviously removed that at some time in the ancient past
anyone have experience bending these machines & info on cv input???
such as the TI chip Pinout/DataSheet TMC0280, later called the TI TMS5100
this machine is all manually poked bends/glitches from way back when…
made series of recording while working on this project yesterday & today
around 60 minutes worth
Happy New Years!
some new rough entertainment for the noise inclined listeners:

liking some of the noise sources getting out of that old machine
well it’s officially re-animated
making up raw source for hacking into samples…
these new Trax are all raw S&S w/FX
Merlin is next… it had batteries in it for at least 10+ years…. Corrosion… CV input/output intact
(used it as VCO/Sequencer)
breaking out some old machines for the new year
knocking off some dust & battery acid

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DBX 166 Modifications/Upgrades

These Mods clean up the DBX166 compressor making it high quality PRO Studio Gear.

PSU MoD: – Replace c3 ,c4, c7, and c8 with 1000uf-2200uf 35v caps
– Replace c5 and c9 with a .1uf film cap (preferably polypropelene)
– Bypass c6 and c10 with .1uf film caps
Channel 1:

IC MoD: – Replace chip OA1 with better ic (NE5532, OPA2132, opa2134, OPA2107, LT1358, or LME49860NA (My fav)) and install a gold plated ic socket.
– Repalce chip OA2 with better ic (LME49710NA, OPA134, OPA602, opa627, or LT1357) and install a gold plated ic socket.
– Replace the VCA IC1 with a THAT 2180AL08-U (lift pin 4, pin 4 should not connect to anything)
– Add a 47pf NPO ceramic cap from pin 3 of OA2 to ground (Suggested by Jim Williams)

Capacitor/resistor MoD:
– Replace c14 with a 22uf 35v bipolar cap
– Bypass that with a .22u film cap
– Note: c14 was originally a 3.3uf cap. You could fit in a film cap in there if you are carefull.
– Replace c25 with a 22uf 35v bipolar cap
– Bypass that with a .22u film cap

– Replace r17 and r18 with 22ohm metal film resistors
– Replace r1 and r4 with 1k metal film resistors
– Replace r3 and r6 with 7.5k metal film resistors
– Replace r2 and r5 with 10k metal film resistors
– Replace r7 and r13 with 2k metal film resistors

IC Control Voltage (Optional) MoD: Turns this compressor into a beast.
– Replace chips OA3, OA4, and OA5 with gold plated ic sockets and a better ic like a LT1124 or LME49860NA.

Peakstop switching MoD: Turns on and off the peakstop circuit.
– Drill a hole in the front plate about .25 inches diameter. Install and wire in a DPDT gold contact switch here. Lift one end of CR5 and CR6. Solder 2 wires. One to cr5 and one to cr6 and solder the other end of the wires to each center contact of the DPDT switch. Solder 2 more wires to the vacant holes of cr5 and cr6 and wire these to one side of the switch.

Channel 2:

IC MoD: – Replace chip OA6 with better ic (NE5532, OPA2132, opa2134, OPA2107, LT1358, or LME49860NA (My fav)) and install a gold plated ic socket.
– Repalce chip OA7 with better ic (LME49710NA, OPA134, OPA602, opa627, or LT1357) and install a gold plated ic socket.
– Replace the VCA IC8 with a THAT 2180AL08-U (lift pin 4, pin 4 should not connect to anything)
– Add a 47pf NPO ceramic cap from pin 3 of OA2 to ground (Suggested by Jim Williams)

Capacitor/resistor MoD:
– Replace c14 with a 22uf 35v bipolar cap
– Bypass that with a .22u film cap
– Note: c14 was originally a 3.3uf cap. You could fit in a film cap in there if you are carefull.
– Replace c55 with a 22uf 35v bipolar cap
– Bypass that with a .22u film cap

– Replace r117 and r118 with 22ohm metal film resistors
– Replace r101 and r104 with 1k metal film resistors
– Replace r103 and r106 with 7.5k metal film resistors
– Replace r102 and r105 with 10k metal film resistors
– Replace r107 and r113 with 2k metal film resistors

IC Control Voltage (Optional) MoD: Turns this compressor into a beast.
– Replace chips OA8, OA9 and OA10 with gold plated ic socket and a better ic like a LT1124 or LME49860NA.

Peakstop switching MoD: Turns on and off the peakstop circuit.
– Drill a hole in the front plate about .25 inches diameter. Install and wire in a DPDT gold contact switch here. Lift one end of CR5 and CR6. Solder 2 wires. One to cr5 and one to cr6 and solder the other end of the wires to each center contact of the DPDT switch. Solder 2 more wires to the vacant holes of cr5 and cr6 and wire these to one side of the switch.

DBX166 Service Manual


THAT 2180 Datasheet


THAT 2181 Datasheet


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TRIOXIN CloudMaker Granular Synthesizer

Started creating The V.S.R. “Trioxin” CloudMaker today
specifically for noise comp
Eye wanted drastically longer custom ranges with multipliers on grain size & rate parameters
up to 20 seconds on rate & 10 seconds on size
plus completely redesigned how the freeze/hold feature extracts 100ms samples from input
have some other functions that need adding
yet got the core engine constructed now
will make multiple revisions yet giving you first functional prototype

Added 2x ADSR
tweaked times
recording some demo trax…
http://www.n01ze.com/synthwizards/ARKIV … RIOXIN.rar

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BOSS DR55 (Schematics/Manuals/Mods)

BOSS DR55 (Schematics/Manuals/Mods)

DR55 does have an authentic sense of early 80s legendary nostalgia…
being BOSS’ first DR-machine and also quite a successful early programmable drum machine.
It has been used by New Order, The Cure, Chris Carter, Sisters of Mercy, Chris & Cosey, Soft Cell and Thomas Dolby.Boss DR-55: external trigger input mod

By default, the Boss DR-55 does not receive any kind of incoming clock. The ‘FS’ footswitch input takes a latching footswitch that starts and stops the existing clock, but that’s it. Although you can clock other equipment from the DR-55, it would be nice to be able to use an external clock to sync the Boss to, which would allow the Boss to trigger yet more devices with its CSQ and DBS outputs (active on Accented steps only and every step, respectively).

My mod as detailed here does exactly that. By replacing the existing FS jack socket, adding a small circuit, and replacing a jumper, we can safely trigger the DR-55 from an external trigger.

A quick internet search will turn up an existing clock input mod which is simpler to do and requires no extra parts; however, it puts the RAM at risk of damage from high triggers, and it does not sync the Boss’ own DBS output. It also requires ‘arming’ by hitting start before external triggering.

My own mod, though more complex, overcomes all these issues: the trigger input is protected, both the Boss’ trigger outputs maintain their correct functions, and triggering occurs without ‘arming’. The only two functional disadvantages of my mod are that you must set the Boss’ tempo to Fast, and to reset the pattern when stopped mid-way you need to remove the trigger plug. I’m going to blog another small mod which will overcome the latter inconvenience [EDIT: No I’m not! I sold both my 55s, thereby halting this particular project].
The Clock Modification in detail

Below is a diagram which shows everything you need to know about building this mod. Below that is a parts list. Key to this is the replacement FS jack socket; it needs to be TRS (ie. a stereo jack), with single pole changeover switches on the tip and ring contacts. I used a Lumberg KLBPSS3 (datasheet here, Farnell UK stock page here).

The additional circuit can be made very small indeed (3 rows * 8 holes on stripboard), and there is plenty of room for it inside the DR-55, particularly towards the right-hand end. The photos below illustrate my own placement.

There is one jumper to be removed, the one immediately to the right of the Variation switch. The replacement connections for the upper and lower point of this removed jumper are shown in the diagram, and you can see in the photos how I wired this up.

In brief: remove that jumper, solder the two points to two jack pins; build the extra circuit, and solder that to the jack and to the main PCB; replicate two of the pre-existing connections from the jack to the PCB. That’s it. I also stuck a small folded piece of card to the PCB to stop the extra circuit from shorting against components.
Boss DR-55 clock input mod


Boss DR-55 clock input mod revised
Parts list:

1 * TRS 2-pole changeover jack socket – eg. Lumberg KLBPSS3
2 * 47k resistors – I used 1/8W for their smallness
1 * 10nF capacitor – I used a ceramic, again for smallness, but polyester film etc. would be usual
1 * 1N4148 signal diode or equivalent
1 * BC549C transistor or similar standard NPN

Here’s the modified DR-55 (also incorporating my DC supply mod):
clock modded DR-55 overview

clock modded DR-55 overview

And here’s a close-up of the clock mod:
clock modded DR-55 close up

clock modded DR-55 close up


How to use your new trigger input

The new trigger input will accept any positive pulse over a couple of volts. It’s edge triggered, so the pulse can be any length over a couple of milliseconds. The operating principle is to use the DR-55’s existing clock, but to gate it on for a very short duration; normally when the clock is gated off again, the pattern resets, but the new jack socket enables us to disable that by breaking the reset connection when a jack is inserted.

As I mentioned earlier, the Tempo must be set to Fast (ie. all the way clockwise) for correct function. This is because the DR-55’s clock, once triggered, finishes its pulse cycle. If this is longer than the incoming trigger cycle, it will ignore the new trigger; if we set the speed dial to its fastest, we can clock the DR-55 at any rate up to its natural maximum.

The pattern will cycle round as usual, but if you stop mid-pattern, new triggers will continue where they left off. To reset the pattern at this stage, you need to unplug the trigger jack and hit Stop. This is not ideal, I know, and I will be making an amendment to correct this later [EDIT: project halted, see above. I have no current plans to do any further work on the DR-55].

For now though, this mod works fine, as shown in the (slightly rubbish) video below:

Boss DR-55: a 9V DC input modification

One of the drawbacks of the DR-55 as it comes unmodded is the power supply. In its original form, the DR-55 takes only batteries, and though this might be good for reducing cable clutter and having to find yet another wall-wart, it does mean you need to keep a regular stock of fresh AAs, and can guarantee that just when you want to use it, your DR-55’s batteries are too drained for the unit to function correctly.

Luckily, it is a relatively simple process to modify the DR-55 so that it takes a commonly-found 9V DC supply instead. I provide instructions for this below. It’s not the only way to do the job, but this is how I did it, and it works just fine. Modding the DR-55 in this way means it no longer accepts batteries, which means two things: 1) you will need access to a 9V adapter, and 2) pattern data will not be retained on power-off. Given that filling the memory of this humble machine can be done in less than five minutes, and I never use this outside my own home studio, I never found memory retention to be an issue. It would be possible to design a DC input that also catered for memory backup via battery, but I’m not going there.

There are two basic stages to this modification:

Making a 9V DC input: the basic voltage supply circuit
Installing the Mod: adapt some wire links on the output jack and PCB

Because the DR-55’s RAM can be killed by voltages higher than around 7V, we take a 9V input and regulate it down to between 5V and 6V. I chose to use a 5V regulator propped up with a diode to give around 5.6V, but you could also use a 6V regulator and omit D2. The input jack I used is a 3.5mm mono minijack of the kind often used for audio and CV interconnects, mainly because I had lots of them and the holes are easier to drill than the larger ones needed for a plastic-bodied insulated barrel connector. Use whatever type you prefer, but note the polarity of your incoming DC, and don’t connect the +ve to the case… with a tip-positive 3.5mm jack, the sleeve of the input jack is connected to the shell of the socket, so it makes sense for that to be the ground. Some barrel connectors do likewise.

Here’s the schematic:

Boss DR-55 DC input mod schematic

Here’s the final circuit built onto stripboard. It will be panel-mounted using the socket:
DR-55 DC input build

DR-55 DC input build
Installing the Mod

Now we have a simple DC input, we could just solder the +ve and Gnd outputs to the corresponding solder points on the main board – that is, where the battery clip attaches. Black is ground, red is positive. This works, but you still need to insert an audio cable to turn the DR-55 on. I chose to remove that ‘feature’, as there are no longer any batteries to protect from accidental drain. It’s a simple mod that just means a couple of wiring changes.

The diagram below shows the required re-wiring. The audio output socket is wired by default to both ground and audio signal, as well as having two pins wired to act as a switch when a jack is insterted. We want to retain the audio and ground connections, but not the switch. We remove those wires and instead bridge the corresponding points on the PCB.


Here’s a photograph of the full mod (note the wiring):
DR-55 DC input wired and complete


I damaged a track while desoldering the battery wires, which is why the red wire goes to the un-numbered hole next to point 9. They’re directly connected, happily.

Below are some photos of the hole I drilled for mounting the new DC input, and the final appearance when mounted and labelled with cheap Dymo (should have gone with black… oh well):
DR-55 DC input enclosure drilling

So there you have it. My humble DR-55 now works from a regular 9V DC wall-wart supply, and switches on whether or not its audio is connected. The hardest part is putting the DR-55 back together again…

or you can just use old hacked (w/ 9v battery connector)phone charger from cheap Samsung 5v pay as you go track phone…
operating power range from the service manual for BOSS DR55 is 4.5v to 6v
Works for me!

next step external trigger inputs & outputs for each drum sound
http://manuals.fdiskc.com/flat/Boss%20D … Manual.pdf

https://synthnerd.wordpress.com/2016/05 … input-mod/
it’s obviously not a TR808 or TR909 yet picked it up ages ago for $20 in the original box :P
replaced bad cd4011UB chip…
for getting the clock working on this old machine
was going to buy the CR55 DIY eurorack then remembered had this old gem

808 style BASS Kick Sustain mod:

Well, this weekend I met up with a friend of mine who also has a BOSS DR-55 Dr.
Rhythm (groovy, groovy, groovy).

So I say to him, ‘Hey, have you modified the bass drum decay?’, and he hadn’t so
we flipped the top off and had a look inside…

On my DR-55, in the bottom left (near the tone pot) there was a little trim-pot
which varied the kick decay, but on my friends there was only a resistor. Later
study of the service manual shows that only early serial number DR-55s have the
trim pot, so if you’ve a later rev. DR-55 here’s the extremely simple way to
modify the bass drum decay..

The resistor is in the lower left of the circuit board (looking from above),
just below the tone control. ‘BD’ is stencilled on the PCB next to it, and the
resistor is over a little stencilled trim-pot picture. The following ASCII
diagram should help you locate the right resistor.

l l Tone Pot.
o ^
^==/ <<– Resistor to be replaced.

Simply snip out the resistor, and replace with a horizontal trim-pot of several
K ohm. The trim pot goes between the three holes in the silly ASCII diagram
above, with the wiper terminal attached the middle/rightmost hole. I used a 2.2K
that I had floating around (what? your parts don’t levitate like mine? freaky),
and that gave a reasonable control range…

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Vox Treble Booster

The Vox Treble Booster was a simple silicon treble boost effect that plugged straight into an amp’s input jack. It allowed the user a boost in high frequencies for lead work. I laid this one out to use as a built in effect on a guitar (hence the lack of a power filtering cap and polarity protection). Note that the 10uF cap is on its side to reduce the height of the populated board. It should easily fit in a 1590A. If you want a volume control use a 100k pot with the Out pad going to lug 3. Lug 2 becomes the Out and lug 1 goes to ground. I found that I really didn’t need a volume pot though, as the effect level was right around unity.

Awesome perf/strip/pcb layout resource site:
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Replacing CR3032 Battery in BOSS SE-50


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Replacing Dead Battery in Digitech DSP 256XL

When the internal alkaline battery of the Digitech DSP 256XL fails, “Battery Failure, All Data Lost” will appear on the unit‘s LCD screen. Unlike other audio hardware, the 256 only wipes out saved patches; it doesn’t wipe its entire memory contents (like Korg’s M1 synth, for example).


.The internal battery died in my DSP 256 XL.The battery in the unit is an Energizer 4.5 volt #523 that is obsolete.The length is about 1 and 7/8″ long X 16.8 mm in diameter.

same battery/process as Digitech GSP21 as in the above video^


This month’s Test Drive puts us in the driver’s seat of yet another effects box. The DigiTech DSP-256XL falls into that category of the affordable, yet powerful effects boxes that, like most under $500, are designed for the musician. Even so, as many of you know, these little musician’s boxes are jam packed with high quality effects perfectly suited for radio production with price tags that don’t put your GM into cardiac arrest.

The primary features of the 256XL include 128 fixed factory presets, 128 programmable slots, up to four effects at once, twenty-six different effect configurations, and full MIDI capability. You get reverb effects, chorusing/flanging, parametric EQ, graphic EQ, and a not too often seen 4-tap delay.

Aside from its clean sound and numerous useable presets, perhaps the most impressive aspect of the 256XL is its ease of operation. When a program is selected, the 2-line, 16-character per line LCD display shows the program title on the top line and the effect configuration in use on the bottom line. PROGRAM UP/DOWN buttons scroll through the 256 memory slots in the unit, and if you hold the UP or DOWN button in, the unit shifts into a “fast scroll” mode for quick selection of any program (or adjustment of any parameter). In radio production, probably the most used parameter of an effects box is the wet to dry MIX parameter. If you’re the type that doesn’t care to get into the parameters of an effect and shop around for the MIX parameter before you make an adjustment, you’ll appreciate the MIX control knob on the right side of the front panel. If you’re looking for an effect for a voice track, let’s say, just set the MIX level to 12 o’clock (or 50%) and start moving through the different programs as you input the voice track. When you find one you like, it’s immediately on line and you don’t have to enter any “edit” mode to adjust the mix. The other two knobs next to the MIX control are INPUT and OUTPUT level controls.

Now, should you want to edit the program, that too is quick and simple. The two PROGRAM UP/DOWN buttons mentioned above are dedicated to program selection. Similarly, separate PARAMETER buttons are dedicated to program editing. There are two UP/DOWN PARAMETER buttons and two LEFT/RIGHT PARAMETER buttons. The LEFT/RIGHT buttons are used to select the parameter you wish to edit. The UP/DOWN PARAMETER buttons increase or decrease that parameter’s value accordingly. As you step through the various parameters, the entire top line of the display is dedicated to describing the parameter; so there is limited use of abbreviations which tend to confuse the novice effects editor. The bottom line of the display is reserved for the value of the parameter, and again, limited use of abbreviations helps to shorten the learning curve.

Once changes have been made to a program, the COMPARE button can be pressed to compare the edited program with the original. If you like what you hear, press the STORE button. You are given the option to store the edited program in the current position or to any of the other 128 user slots. The STORE button is also used to simply copy an existing program to another place in user memory. Once again, storing and moving programs is very easy, and the LCD display kindly guides you along the way with prompts such as “Storing,” and “Copying.” When you’re just playing around with a program’s parameters and then decide to go to another program, the unit will remind you that you’ve changed the program by giving you the option to save the changes before you go to the next program.

DigiTech’s 128 factory programs are stored in locations 129-256. User locations 1-128 come from the factory with copies of programs 129-256 in them, and these programs can be edited or completely removed. We thought it was nice of DigiTech to put the user locations at 1-128 instead of at the other end. This way, all your favorite programs, whether they be factory programs or ones you create, can be at locations 1 through 10, for example, making the program number easier to remember than, let’s say, 129 or 233!


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