[sdiy] coupler module

[Peachey, Dave]

Martin,

To add to the (wish)list of facilities:
a)  You might want to consider adding a microphone input of some description
(for the all-important treatment of your vocalisations using all the
exciting wave shaping modules people on the list have been discussing
recently) - you could give it variable sensitivity for different mike types
and, go on, add a 48V phantom power supply as well!!
b)  If you're going down this route, an input envelope follower circuit of
some description (with some sort of gate/trigger derivation to allow for
triggering of on-synth envelope generators, sequencers, etc.) would also be
useful.
c)  Others thing could be some form of headphone output, a simple stereo
power amp output to drive speakers, etc . . . .

On a more practical note, however:
a) is balanced operation really necessary given the unshielded nature of
some (particularly those banana-jack-based modular synth) "internal"
connections?
b) as you're connecting to the outside world, would it not be easiest to
scale down to 'normal' line level outputs (+/- 100mV) without having
multitudinous options?
c) do you really need to EQ your synth at this point?  Surely EQ can be
undertaken within the body of your synth (OK, I'm thinking primarily of
modular synths with a variety of filter options/modules available) or, for
live playing, at the mixing desk/amplification point?
d) yes, certainly some form of overload output level detection but can't see
the need for effects send/return

Personally, I'd make this unit as simple as possible because I can't really
see you losing the need for a small dedicated mixer of some sort - do you
really need to reinvent that particular wheel in this context?  Or am I on
the wrong track entirely?

Cheers
Dave

> -----Original Message-----
> From:	Czech Martin [SMTP:Martin.Czech at micronas.com]
> Sent:	Tuesday, August 26, 2003 9:34 AM
> To:	Sdiy (E-mail)
> Subject:	[sdiy] coupler module
> 
> *** WARNING : This message originates from the Internet ***
> 
> Every synth needs a coupling module to the tape machine or mixing desk.
> 
> I plan to build some soon, containing:
> 
> -4 balanced inputs, 2 balanced outputs (trafo or electronic)
> -2 or 4 (several) unbalanced inputs (for other synths)
> -input or output scaling circuits (the analog synth can have +-13V or
> +-100mV
>  as extremes), the usual levels are -10dBu = 0.245 V RMS ~ 0.35V peak
>                                  or   6dBu = 1.55  V RMS ~ 2.2 V peak 
> 
>  assuming that 0 dBu = 0.775V RMS and sine wave form.
>  So gains of 37,    0.29,  5.9 , 0.045
>           or 0.027, 3.4,   0.17, 22    (reciprocal)
>  can be needed, so a range of 37 to 0.027 seems to appear.
>  This is no problem since resistor networks can be changed
>  if necessary. Plug in connections of resistors on the PCB
>  seems to be a good idea.
> 
> -A good question is if any EQ is needed. Shelving bass and treble
>  and perhaps some mid bell shaped EQ.
> 
>  I'm not sure if this needed. It could save a mixing desk.
> 
> -Another question is if any external effects send/return is needed
> -Certainly a level meter plus overload indicator with hold/reset
>  is needed for the line out.
> 
> If all features are build, I end up with a little mixing desk.
> That is certainly too much. 
> 
> So what is your practical experience?
> What is needed?
> 
> Martin Czech
> 
>  


The Royal Bank of Scotland plc ('the Bank') is regulated by the Financial 
Services Authority and is a member of The Royal Bank of Scotland Marketing
Group.  The only packaged products (life policies, unit trusts and other
collective investment schemes and stakeholder and other pensions) the Bank
advises on and sells are those of the Marketing Group, whose other members
are Royal Scottish Assurance plc and Royal Bank of Scotland Unit Trust
Management Limited, both regulated by the Financial Services Authority.

The Royal Bank of Scotland plc. Registered in Scotland No 90312.  Registered
Office: 36 St Andrew Square, Edinburgh EH2 2YB. 

Agency agreements exist between members of The Royal Bank of Scotland Group.

This e-mail message is confidential and for use by the addressee only. If
the message is received by anyone other than the addressee, please return
the message to the sender by replying to it and then delete the message from
your computer. Internet e-mails are not necessarily secure. The Royal Bank
of Scotland plc does not accept responsibility for changes made to this
message after it was sent. 

Whilst all reasonable care has been taken to avoid the transmission of
viruses, it is the responsibility of the recipient to ensure that the onward
transmission, opening or use of this message and any attachments will not
adversely affect its systems or data. No responsibility is accepted by The
Royal Bank of Scotland plc in this regard and the recipient should carry out
such virus and other checks as it considers appropriate.