Re: [AH] Some new Oakley Projects > Please don't forget us old fogey 5U guys for the new stuff. We're not

From Oakley Sound via analogue
Sent Tue, Jul 2nd 2019, 08:07

 >  I'm wondering if a module could be made "modular" in that the guts 
would be on one (or however many) PCB with a connector to the front 
panel holding the switches, LEDs and controls...

I think there are some folk doing just this, but these days with the 
tiny upfront costs to make PCBs, it's actually easier to make a separate 
design for each format. One of the reasons for doing so is that because 
of the panel shapes available, some things that ergonomically will work 
well on a euro panel would be too crowded on a 5U panel, and vice versa. 
This also applies to the two main 5U formats, MOTM and MU, as the wider 
width of MU can allow more features to be added to a specific module 
unit width.

 > Are there "standard" voltages and power connectors for 5u?

Sadly not. MU, MOTM and Modcan B all have different power connectors. 
MOTM is superior since it allows for bigger cables and two types of 0V. 
However, one can easily make convertor cables should the need arise.

Many MU modules have +5V too.

Personally, I would have liked to have seen a five (or six) way 0.156" 
Molex as standard: +15V, 0V (1), 0V (2), 0V (3), -15V, (+5V)

 > Is this the original Moog modular format?

No. Moogs used edge connector things that also carried other signals for 
their inter module connections. The supply voltage is +12V and -6V as 
well as other voltages for lamps and the later op-amp based designs.

 > I've done electronic design and I was a little disappointed to find 
that Eurorack is +/-12V when the traditional "standard" op-amp voltages 
are +/-15V.

Op-amps will work on anything really. Most can run on a 36V supply to be 
divided as you wish. +/-5V is also common although not yet in modular 
systems. Pro audio stuff will sometimes run +/-18V but this does get 
very close to the maximum 36V for many op-amps.

+/-12V is in itself not a bad thing. But making the nominal audio signal 
in eurorack 10V peak to peak was perhaps not well thought out since the 
overhead is now reduced to just 5V or so. Op-amp outputs can rarely get 
above +/-10V when run from 12V. Personally, I would have chosen 2V p-p 
for nominal audio levels and made all the inputs, CV and audio, more 
sensitive.

Tony

www.oakleysound.com