Search found 10 matches

by matthias
Sat Apr 16, 2011 9:47 am
Forum: Pro Audio Design
Topic: summing mixer with monitor control
Replies: 13
Views: 28270

Re: summing mixer with monitor control

Hi Roland, I've finished all the metalwork pcb design is finished ~70% had redesigned the switching logic for the illuminated buttons here are some pics... http://www.cmaudio.net/forum/summingbox1.jpg please note: the meter illumination is white (not blue) http://www.cmaudio.net/forum/summingbox2.jp...
by matthias
Sun Nov 07, 2010 11:27 am
Forum: Pro Audio Design
Topic: VCA Compressor Gain Reduction Limit
Replies: 26
Views: 51559

Re: VCA Compressor Gain Reduction Limit

isn't there a chance to do this with a simple voltage regulator? a lm317 or something like that? or are there other disadvantages?
by matthias
Tue Aug 17, 2010 3:26 pm
Forum: Pro Audio Design
Topic: summing mixer with monitor control
Replies: 13
Views: 28270

Re: summing mixer with monitor control

here's an updated schematic including the headphone amp
it's based on the ti tpa6120a2 using the schematic from Per-Anders Sjöström

I also made a frontpanel layout...

Image
by matthias
Mon Aug 16, 2010 3:42 pm
Forum: Pro Audio Design
Topic: summing mixer with monitor control
Replies: 13
Views: 28270

Re: summing mixer with monitor control

that's no problem for me... if there are some klicks I think I can live with it... I'm not sue if I will use NE553x opamps in the end.. I still have some opa134, ad797 and opa2132 here and will try them out... regarding the datasheet of the 1646 the output gets inreased by 6db. so I will have to dec...
by matthias
Sun Aug 15, 2010 5:10 pm
Forum: Pro Audio Design
Topic: summing mixer with monitor control
Replies: 13
Views: 28270

Re: summing mixer with monitor control

Hi Wayne, thanks for your help...

regarding the 300R resistor and the 6,8n cap
this RC-filter is adapted from the neumann card schematic
it's a -6db lowpass filter at 78 khz ... honestly I don't see any reason why not to omit these components.
by matthias
Sun Aug 15, 2010 12:07 pm
Forum: Pro Audio Design
Topic: summing mixer with monitor control
Replies: 13
Views: 28270

summing mixer with monitor control

hello, now I have some time and can go on with my summing mixer project... I changed the concept and will use the input transformers of a Neumann 475 0-ohm summing card.. the features: -> 16 balanced inputs 8 of them switchable from 0db to -30db -> 4 unbalanced inputs -> stereo master insert with by...
by matthias
Sun Jan 31, 2010 5:04 am
Forum: Build
Topic: Mid Side M-S Matrix Construction Information
Replies: 121
Views: 432795

Re: Mid Side M-S Matrix Construction Information

Thanks for your help, Roger! regarding the 1240/1200 I still have a lot of 1200 and 1206 ics but no 1240 and 1246 so I want to use them if that's possible... if you look at the specs in the datasheets the 1200 has a slightly better noise performance I always thouht this is the best line receiver to ...
by matthias
Sat Jan 30, 2010 4:20 pm
Forum: Build
Topic: Mid Side M-S Matrix Construction Information
Replies: 121
Views: 432795

Re: Mid Side M-S Matrix Construction Information

Wayne, thanks for the great pcb !! I'm just building the MS-Matrix and still have a few questions: 1) C1 C7 C17 C26 etc... are not mentioned in the BOM they connect between V+ and V- are they needed or not? 2) can I replace the 1240 with a 1200 line receiver (when i add the cap and cut the connectio...
by matthias
Mon Jun 22, 2009 4:07 pm
Forum: Pro Audio Design
Topic: another active Summing Mixer designed for my needs
Replies: 5
Views: 12407

Re: another active Summing Mixer designed for my needs

thanks for your reply. I have some balanced and unbalanced units and I interchange them from time to time (rack space is limited here). I decided to build an active design to factor out all the problems you can have with a passive summing circut. I also want to use the bunch of that 1200 and 1646 ic...
by matthias
Mon Jun 22, 2009 6:01 am
Forum: Pro Audio Design
Topic: another active Summing Mixer designed for my needs
Replies: 5
Views: 12407

another active Summing Mixer designed for my needs

Hello, since I'm not really satisfied about the way all current DAW's (I use Logic at the moment) are integrating external effects I'm at the point where I decided to build my own summing mixer. inspired by the outstanding mixer from Roland (radiance) and the great assistance of you guys here, I'd l...