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by daverj
Thu Jun 04, 2015 10:42 am
Forum: Music Tech DIY
Topic: Help with adjustable reference voltage regulator
Replies: 6
Views: 410

When you say "14v amplitude" are you talking about measuring it with a volt meter set to AC volts? A 16V CT transformer should measure 16 volts RMS under full load, and higher with less load. The rectified DC will be different. How is the transformer connected? The dual primaries should be connected...
by daverj
Wed Jun 03, 2015 3:58 pm
Forum: Music Tech DIY
Topic: Wiring discrete +-12 and 0V cables to 10 pin euro female?
Replies: 5
Views: 305

You could try sending a PM to Graham Hinton, or contact him through his web site: http://hinton-instruments.co.uk He sells discrete wire cables that work with Euro for his aluminum bus bar power distribution system. I don't know if he sells the cables by themselves or only with the bus bars, but it'...
by daverj
Wed Jun 03, 2015 3:46 pm
Forum: Modular Synth General Discussion
Topic: How could I delay a trigger?
Replies: 10
Views: 1296

Doepfer A-162 is a dual trigger delay
by daverj
Wed Jun 03, 2015 3:40 pm
Forum: Music Tech DIY
Topic: Milky/White diffused lens LEDs
Replies: 9
Views: 362

Not ultra-brights, but these are red/blue with a clear/white diffused lens

http://www.digikey.com/product-detail/e ... ND/4745833
by daverj
Wed Jun 03, 2015 3:37 pm
Forum: Music Tech DIY
Topic: Linear Power Supplies - Fuses blowing on Powerup?
Replies: 11
Views: 503

What country are you in and what input voltage is it set for?

The HCC15 uses a 1.9A to 2A slow blow fuse for 120v, and a 1.0A slow blow for 220-240v
by daverj
Wed Jun 03, 2015 3:29 pm
Forum: Music Tech DIY
Topic: Anyone know if this solder has a flux core?
Replies: 3
Views: 319

Image
by daverj
Wed Jun 03, 2015 1:55 pm
Forum: Music Tech DIY
Topic: Burned resistors...what happened?
Replies: 15
Views: 736

Keep your eyes open for a sheet of hard rubber that you can use for a work surface. Back in the 70s I found a sheet of rubber that was used for making the soles of shoes that was about a foot or a foot and a half square. I used to place that down on my work area and tested boards sitting on that rub...
by daverj
Wed Jun 03, 2015 1:30 pm
Forum: Music Tech DIY
Topic: Oscillator identificaton?
Replies: 7
Views: 382

The ECG912 in the lower picture is the same as the uA3086 in the upper picture. The other chips are the same. And all the passives around them appear to be the same. So these two are the same circuit with the same parts. The wires connecting to one should be the same as the wires going to the other....
by daverj
Tue Jun 02, 2015 12:36 pm
Forum: Music Tech DIY
Topic: I2C DAC addressing (MCP4725)
Replies: 24
Views: 5738

In the early days of electronics a "breadboard" was literally a sheet of wood, often a kitchen bread cutting board, and parts were screwed down to it. It later grew to mean any type of prototype board. Around here it is usually used to reference a plastic proto-board like this: https://www.muffwiggl...
by daverj
Mon Jun 01, 2015 3:24 pm
Forum: Music Tech DIY
Topic: VC controlled glide
Replies: 7
Views: 423

Ken Stone has boards for a Serge VCS

http://www.cgs.synth.net/modules/cgs75_vcs.html
by daverj
Mon Jun 01, 2015 2:52 pm
Forum: Eurorack Modules
Topic: Module installation tips
Replies: 33
Views: 1086

Most nylon washers are thick enough that if you use them, you will probably need slightly longer screws. The normal Doepfer M3 screws are 6mm long. I supply 8mm ones plus nylon washers with my modules. I personally don't like the idea of using nylon screws for modules. They can easily break if tight...
by daverj
Mon Jun 01, 2015 2:48 pm
Forum: Eurorack Modules
Topic: mystery power issue
Replies: 52
Views: 5659

I've seen several different people in Europe and the UK here over the past couple of years mention that their Macbook tingles when they touch a connector, and that if they connect it to their synth or audio system the tingling is felt there too. And if they remove the Macbook power adapter and run o...
by daverj
Mon Jun 01, 2015 2:39 pm
Forum: Modular Synth General Discussion
Topic: Understanding CV, Gate, and Trigger compatibility
Replies: 15
Views: 3007

"one volt per octave" defines the amount of change caused by the voltage change. It doesn't define any specific notes at specific voltages. VCOs have a frequency control knob. When you feed in a control voltage you can turn that frequency knob so that any note you want can be at the specific voltage...
by daverj
Sun May 31, 2015 3:02 pm
Forum: Eurorack Modules
Topic: doepfer P9 power issue... -12V doesn't work
Replies: 6
Views: 433

It doesn't light up with all modules removed? So only one LED lights up on the bus boards? (the +5v LED won't light up, but the other two should) If that's the case, try unplugging the case from the wall and then poke around at the wires going from the power supply to the bus boards to see if anythi...
by daverj
Sat May 30, 2015 1:02 pm
Forum: Music Tech DIY
Topic: How do you cleanly snap off this header?
Replies: 19
Views: 741

Some of them have the pins flat in line with the other pins and some have the pins parallel to the other pins. (thin edge pointing towards each other vs flat side pointing towards each other) The ones where the pins are inline, the amount of plastic between pins is usually too small to split in half...
by daverj
Sat May 30, 2015 12:56 pm
Forum: Eurorack Modules
Topic: Module installation tips
Replies: 33
Views: 1086

10- If your power distro uses keyed headers, stop and double check the ribbon to make sure it was made correctly for use with a keyed header (many are not) 11 - if your power distro does not use keyed headers, double and triple check that you are plugging the ribbon in the correct orientation, and c...
by daverj
Sat May 30, 2015 11:54 am
Forum: Eurorack Modules
Topic: doepfer P9 power issue... -12V doesn't work
Replies: 6
Views: 433

If you added or moved a module since then, take it (them) out and see if it starts working. Remember that if a module is plugged in wrong, it can short one or both of the power rails, so the LED(s) won't light up. Otherwise try disconnecting all modules and see if it lights up. If not, then somethin...
by daverj
Sat May 30, 2015 11:41 am
Forum: Modular Synth General Discussion
Topic: oscilloscope newb confused, enlighten me please
Replies: 8
Views: 870

Via Muff's search: https://www.muffwiggler.com/forum/viewtopic.php?t=135468 https://www.muffwiggler.com/forum/viewtopic.php?t=133531 https://www.muffwiggler.com/forum/viewtopic.php?t=126999 https://www.muffwiggler.com/forum/viewtopic.php?t=122331 https://www.muffwiggler.com/forum/viewtopic.php?t=800...
by daverj
Fri May 29, 2015 2:40 pm
Forum: Eurorack Modules
Topic: Who here DIY's?
Replies: 24
Views: 704

Did you know we have a whole sub forum for DIY? (very active)

https://www.muffwiggler.com/forum/viewforum.php?f=17
by daverj
Fri May 29, 2015 12:33 pm
Forum: Music Tech DIY
Topic: I2C DAC addressing (MCP4725)
Replies: 24
Views: 5738

It's an MSOP package, which is extremely tiny. About 5 times smaller than standard DIP pin spacing. It's possible to solder by hand, but difficult. An evaluation board is a bit different from a breakout board, in that they generally waste a lot of space and sometimes have additional parts. A breakou...
by daverj
Fri May 29, 2015 12:00 pm
Forum: Music Tech DIY
Topic: How do you cleanly snap off this header?
Replies: 19
Views: 741

- Pull a pin out with needlenose
- cut though that pin's position
- trim broken bits off of both ends with a razor, or file, or sanding disc.
by daverj
Thu May 28, 2015 11:31 am
Forum: Eurorack Modules
Topic: Rails for rack ears
Replies: 4
Views: 253

deusletum wrote:Be careful when using wood for mounting modules. Some modules use the metal rails as a heat sink.
He's talking about stacking several 19" rack cages. Not mounting individual modules.
by daverj
Thu May 28, 2015 11:19 am
Forum: Music Tech DIY
Topic: 15VDC to +-15V "converter"
Replies: 16
Views: 825

What about these? http://www.mouser.com/ProductDetail/Mean-Well/T-40C/?qs=V9a8iPeg90ybxZ9%252b4FZ0Xw%3D%3D I can source it in Hungary, for a good price. That only has a maximum of 500ma of -15v. Plus you might want to search the forum a bit and read some threads where people discuss linear vs switc...
by daverj
Thu May 28, 2015 11:11 am
Forum: Eurorack Modules
Topic: Rails for rack ears
Replies: 4
Views: 253

Be aware that the first and last links are to rails with square punched holes that will require special hardware to use them. The rest of the links point to rails that have threaded holes and you just need the screws to mount the rack frames. Eurorack is 3U per row of modules. Doepfer sold rack fram...
by daverj
Thu May 28, 2015 10:59 am
Forum: Eurorack Modules
Topic: Noob question re. PSU
Replies: 6
Views: 253

From the 4ms web site: Specifications: Row Power 30: +12V @ 1.5A, -12V @ 0.75A, +5V @ 0.5A Row Power 40: +12V @ 1.5A, -12V @ 1.25A, +5V @ 1.5A Powered by laptop-style DC power supply: 2.1mm barrel, positive center, 15V-20V. A 90W power brick typically powers about 416HP (4 rows of 104HP). 4HP 24mm d...

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