The 4027-1 was an improved design over the original ARP 4017/4027 VCO's
The TTSH 2047-1 module is pretty straight forward to put together except for though those pesky SMD caps. They are tiny and one gave me a headache when it decided to fly off my tweezers onto the floor.
This is a packet of six 100n SMD caps viewed against a Australian 20 cent piece.
Pointless trying to find it. A new order from mouser beckons.
Half way there
1k87 Tempco Resistor.
One finished sub module.... two to go.
As a comparison, I'd thought it would be nice to see the TTSH 2047-1 against a original ARP 2047-1 sub module. This is a spare I have left over from a earlier restoration of a vintage 2600.
The original ARP (like the TTSH version) used three of these 2047-1 submodules. The rest of the VCO circuit is on the main
PCB.
The modern TTSH 2047 uses a 3046 IC. The vintage a CA3086 IC
The CA3046 transistor arrays consists of five general purpose silicon NPN transistors. Two of the transistors are internally connected to form a differentially connected pair.
The CA3086 transistor arrays also consists of five general-purpose silicon NPN transistors. We also have two of the transistors internally connected to form a differentially connected pair.
The pin outs of both look the same.The CA3046's probably have closer tolerances
than the older CA3086, however I wonder if CA3086’s can be used (if you can find them)?
As in the TTSH build the 2N3904 and 2N3906 transistors are pushed together for thermal contact.
The Power Supply Comparison
This is a follower to the previous synthesizer module size post.
There are an ever growing number of manufacturers and many different PSUs (power supply units) to match.
This is a brief comparison of the main brands.
Do email me is there are any mistakes or recommended changes.(I'll try to keep this page up to date).
These PSUs changed over the decades so are confusing at times.
As I work my way through the modules that I own I'll update this post.
Please let me know if there are any errors.
Buchla 200e
Power on a Buchla 200e module is delivered from a edac
306-010-500-102 connector.
The 200e cases come with a12 volt DC wallwart that connects to 3 DC-DC converters.
This is much safer & probably also helps in reducing background noise.
I've made some backup Buchla power supplies and the DC-DC converters that I have successfully
used are:Cincon CHB75-12S05 (for the 5V),and two CHB75-12S15 for the +15/-15 lines.
CHB75-12S12 for the +12V.
If +24 is requited use a CHB75-12S24 DC/DC regulator. These codes are Mouser numbers.
1 Black - quiet ground
2 White: -15
3 Red: +15
4 Dark Green: +12
5
Orange: +5
6 Brown: noisy ground
7 polarizing key - no connection (use this to correctly orientate the EDAC.)
8 Yellow: i2c clock
9
Green: i2c data
10 no connection - (I often use this for supplying +24v)
Serge being mostly DIY in the early days is super confusing and some of the early paperface
panels used whatever colour wiring was available at the time.
I have a number of early paperface panels and some use different colour codes
Early Serge (Paperface) number 1.
This used +12v, -12V, +6V, one ground.
The Serge colour convention on this old synth is:
-12V - White
+12V - Black
+6V - Red
0V - Green
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Here is a second system I have.
It's from the late 70's or early 80's I think ..
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The current Serge PSUs use these types of cases:
This is a PS4A - enough power for 4 panels
The connectors are 5 pin DIN connectors
There is an inline AC/DC converter with a grounded
AC wall cord at one end and a Molex connector at the other designed to
mate with the distribution board inside.
The power connectors for these modern panels look like this:
Sound Transform Systems offers a “M-Boat” chassis.
It is approximately 17” x 7” x 4.5” in dimension.
MBoats have a central power/indicator (called the “Obelisk”)
which has LED indicators for +12/-12v, as well as a power LED.
PSD vs Obelisk
the psd (power supply distribution) is for shop panels while the Obelisk
is for m-odules. The obelisk contains a PSD like distribution board -
but with only 4 connectors instead of 5.
Power Connector
The standard inter-connector used by STS is a Tyco Rectangular 4 pin Connector. The body and pins are sold separately.
Pin & Socket Connectors PLUG W/O EAR 4P inline is PN: 770078-1
Pin & Socket Connectors 24/18 AWG TN/BR SKT is PN: 770146-1
Pin & Socket Connectors RECPT 4P DETENT LOCK in-line is PN: 770075-1
Pin & Socket Connectors 24/18 AWG TIN/BRASS is PN: 770147-1
The PSD has the female connectors.
Pin 1 is at the point. Pin 4 is at the flat (for both male and female).
Pin 1 = Ground 1, Black
Pin 2 = -12V, White
Pin 3 = Ground 2, Green
Pin 4 = +12V, Red
STS also uses a 5 pin XLR connector for power distribution. Coming from
the power supply (PS4 for example) is a 5 pin female XLR. It is intended
to be plugged into a panel mount 5 pin male XLR connector which then
terminates to a male Tyco Connector (for plugging in power to the PSD). I
used an Aphenol panel mount 5 pin male XLR connector, PN: AC5MDZ for a
replacement part and it worked fine.
Here is what my PS4 XLR connector pinout is (note, I am not sure if this
is standard or not, i would assume it is, but I dont want to be
responsible for plugging anything in backwards):
Pin 1 = +12V, Red
Pin 2 = Ground 1, black
Pin 3 = -12V, White
Pin 4 = Ground 2, green
Pin 5 = Not Connected
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EuroRack PSUs.
The first rule one must never forget is the stripe = -12V.
When I was a newbee I made the cardinal error of plugging in my module backwards.
Mostly, the stripe will be red, but sometimes it's blue.
As eurorack manufacturers don't have to comply to any laws re the position of the stripe
it's really up to you to check with the manufacturer what the correct orientation is.
So be careful when you plug your module in for the first time.
The power distro bus is usually made up of 16 DIP header pins (2 rows of 8).
I've also see some older distroboards made from 10 pins (2 rows of 5).
Most these days ccome in the 16 pin format.
Counting from the -12V pins, the bus goes thus:
1. -12V
2. Ground,
3. Ground
4. Ground
5. +12V
6. +5
7. CV
8. Gate
So your PSU needs to supply +12,-12, & maybe +5v.
The connections between the module & bus is achieved with a 10 or 16 ribbon cable.
This is a 10 wire cable. for a module that only uses +12,-12.
The 10 pin header fits into the module & the larger 16 goes to the bus board.
Mos Lab : +12v/-12V see above The Kobol VCO is +/-15V
The Oakley power buss comprises of +15V and -15V lines with two
grounds. These grounds are not connected together as in the MOTM. They
are joined only at the power supply in pure Oakley Modular.
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Modcan A & Cyindustries (Cynthia)
The Modcan-A format uses a module height of 9", and a horizontal unit of 2.25". Banana jacks are used.
A yellow jack indicates an output of some sort;
A gray jack is a signal input;
A white jack indicates a control voltage input;
A red jack is a trigger or gate input.
The format uses ±15V power. The power connector used is a 3-pin
MTA-156 connector.
It's very similar to the
MOTM format, in which a distribution board connected to the power supply
is connected to modules using short power cords with female connectors
on both ends.
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Building your own +/- dual power supply.
It's often difficult to find a PSU for non Eurorack Synths.
Anything from +/-9V to +/-15V.
For building a +/- 15 PSU you will need a
LM7815 +15V Voltage Regulator LM7815
LM7915 -15V Voltage Regulator LM7915
The Wall Wart should have a 15 VAC output.
The AC output of the wall wart is rectified it with diodes so that
positive voltage gets stored on the caps that serve the positive
voltage regulator (LM7815) and negative voltage gets stored on the
caps that serve the negative voltage regulator (LM7915).
Make sure that the caps have a voltage rating over 35V
And use as large a heatsink on those regulators as possible.