Muff's Modules & More

[grantrichter]

OK, I have some opinions on this and have seen the results of doing things other wise. Definition: A "mil" is one 1/1000 of an inch. Used for little tiny measurements like wire diameter and PC board trace and plating thickness.

Let's start with accuracy. A quotation taken from the technical manual for the ARP 2600. This is the first calibration step.

<quote> 3.1 Power Supply Adjustment

NOTE- THIS ADJUSTMENT MUST BE PREFORMED PRIOR TO MAKING ANY OTHER CALIBRATIONS

1. Connect a digital voltmeter across the +15 connection and ground
2. Adjust R10 for exactly +15.00 volts DC
3. Connect the DVM across the negative supply connection and ground.
4. Adjust R13 for exactly -15.00 volts DC <end quote>

So lets figure out what ARP thought was needed. 15.000/0.009 = 1,000,000/600 or 600 parts per million worst case error.

When we have a resistor to a supply rail to offset the keyboard voltage by say 2 octaves. The supply rail can not have any more than 830 microvolts peak to peak of noise or the offset will be out of tune more than 1 cent.

Power Wiring:

Standard panel wiring calls for #24 American Wiring Guage (AWG) which produces a 10 degC temperature rise at 3 amperes. It has an circular area of 404 mils. At 700 C.M per ampere it has a rating of 0.577 amperes.

Ribbon cable uses #26 wire with a circular area of 253 mils. At 700 C.M per ampere it has a rating of 0.363 amperes.

Copper Traces:

Going with a three ampere at 10 degC rating, a minimum of 1 ounce copper plating is required with a trace width of 50 mils for power traces on a distribution board. Instead of being bussed, each ground cable should have a separate return path to main power supply ground terminal (star grounding).

Also, ideally, each power connector should be individualy bypassed with
0.1uF ceramic capacitors from ground to +15 and Ground to -15.

[Low-Gain]

response to same post from the other thread...

[Kodama]

[Low-Gain]

[Jason Brock]

So it's really the bus boards and ribbon cables that are lacking?

As noted in the other thread there are many DIY-minded Eurorack users who incorporate PSUs from Power One, Condor, etc. - the same exact types that some 5U and Frac users have.

[Mitchk1989]

I know you've had some issues with the common 12v supplied eurorack uses in the past, but at the same time, I certainly hope you don't just say "fuck it, I'm going to put a big disclaimer on my modules that says they'll only work if you have a high end DIY case"...

I mean, in the end at least for me (the end consumer) all the other manufacturers manage to make their stuff work properly in a monorocket case...

Please don't take this the wrong way - your current modules are great (I have two anti-oscs, a borg, and a boogie on the way), but the proper response to the issue in the uncle tri2 should not be to say "Euro-rack infrastructure is not stable enough for advanced designs" but instead to find a way to make it work and fix the issue, the same way all the other manufacturers somehow manage with the same juice flowing in.

[de_raaf]

can be true
but with the story of the unkle it seems to me it was prototyped on 15volt, and not enough tested enough on the regular 12 volt euro supply???
anyhow know pretty much nothing about technical stuff, but that what i read a bit through the lines about that story

making things better if ofcourse better for everyone!

love the euro wiard i have, and hope to add more in the long run.

[felixer]

[Low-Gain]

Make note of the 50mil traces on +/- rails &.
Also note the method of grounding how most of the dirty noise gets left back at the 6800uF caps. Next rev will have a fast-on for running a ground wire back to the Power entry module pre filter caps to reduce radiating noise even further.

Toss a 14V-0-14V transformer @3-4A and you got yourself a pretty good starting point as far as i'm concerned. Obviously this doesn't accommodate +5V but i dont support tapping off +12V to achieve said voltage. I'd rather pay the extra $$ to have a secondary winding on the transformer for a separate supply circuit.

[intellijel]

[Low-Gain]

[intellijel]

Explain to me how this is not a ground loop then?

[Low-Gain]

Wow... some fast photoshop work you got there.

I'll take some measurements and show you that it's an antenna.

[intellijel]

[CursedFrogurt]

[felixer]

[LoFi Junglist]

[Low-Gain]

[Low-Gain]

[felixer]

well, i'm one of those fools that still builds valve amps. mainly for that special breed called 'guitarists' and it's all point-to-point. with really thick copper wires in the powersupply and grounding rail. all designed around the 'shortest path/dirt downstream' concept. just a thought ....