mixer done...UPDATE: New pics, frontpanel + meterbridge done

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radiance

Well-known member
Joined
Jun 4, 2004
Messages
3,228
Location
the Netherlands
Ok, took more than a year from the idea in my head to finished (well, almost) product.
EDIT:  frontpanel + meterbridge done, new pics.
Blue9.jpg


Blue1.jpg


Blue3.jpg


Blue6.jpg


Blue8.jpg


Blue7.jpg


Blue4.jpg


The whole proces of asking questions, learning things, building/testing + more inside pics can be found here...

http://www.groupdiy.com/index.php?topic=27992.0

Please don't take all schematics for granted without reading the whole thread because most of the time it's not what I actually used for building this mixer.

Here a picture of the front, followed by a description ....

Blue5.jpg


10 stereo channels with rotary switch for selecting: mute, master, group1, group2
Toggle switch for switching between: stereo or dual mono
2 sub groups with rotary switch for selecting: master, or the other group,
so you can route like this: Channel> group1>group2>master
Sub groups have two inserts with switch, toggle switch switches between insert1 > insert2 or insert2 > insert1
Insert 1 has wet/dry control
Master has two inserts with switch, toggle switch switches between insert1 > insert2 or insert2 > insert1
Master has also a MS mode which is for both inserts.
Master level attenuator (from +3 dB to -19dB)
Monitor level control
Monitor mute switch
Monitor mono listen
Headphone level

Thanks to the following people in no particular order: JohnRoberts, NewYorkDave, Svart, Samuel Groner, Wayne Kirkwood, JohnRoberts, Harpo, John Hardy, JohnRoberts and Keith....did I mention  JohnRoberts?
 
Thanks for the kind words...
...here some pics of the external PSU which delivers:
+/- 15V for the THAT line drivers/receivers
+/- 24V for the 990 summing amps and the opa604 buffers
+20V for relays and lamps

AbovePSU4.jpg


AbovePSU3.jpg


24VPSU.jpg

+20V PSU on vero board with heatsink on top  ;)

backsidePSU.jpg

 
RedNoise said:
wow!!!what a heatsink!!!Cnc machine @ home??? ;D

Nope..that's an 4mm drill hole + countersink. I just drilled the holes like in the vero board, only bigger.


RedNoise said:
No need to heatshrink the jumpers for safety?

Spacing is about 2mm so it should be fine.

At first I thought that this LM338 would get quite hot but even without the heat sink it only gets mildly hot even thought all lamps and relays together can suck 850mA....but that was probably a rough estimate I made
 
congrats to this unique build. :thumb up
You left enough venting space between heatsink and loading cap so this don't get cooked and/or dry too early?
 
Haha I remember when you said WOWOWOWOW to my franken mixer NYD rendition

You deserve a WOWOWOWOWO^WOWOWOWOWO or something like that :)

I'm really happy to see you tie this all together!

Best,
Richard
 
Maybe a stupid question, but is it really necessary to have a separate torroid for each PSU? Even if I lets say needed +/-15V and +/-12V and I've got a torroid with 2x15 / 2x18V secondaries and enough juice to power two psu boards, it could be done with a single torroid, or am  missing something?

thanks!
christoph
 
Harpo said:
congrats to this unique build. :thumb up
You left enough venting space between heatsink and loading cap so this don't get cooked and/or dry too early?

There's no space left between the cap and the heatsink. I just got carried away in my quest for making it look nice I guess...
OTOH, this heatsink only get's mildly warm, maybe 35C / 40C max...and the cap is rated for 105C..

keefaz said:
Very nice!  :)
So, what will you add in the remaining 2U space in rack, vu-meters ?

Exactly...only I still need to wire the meter output. There are meter buffers for both groups & the master output.

crisotop said:
Maybe a stupid question, but is it really necessary to have a separate torroid for each PSU? Even if I lets say needed +/-15V and +/-12V and I've got a torroid with 2x15 / 2x18V secondaries and enough juice to power two psu boards, it could be done with a single torroid, or am  missing something?

thanks!
christoph

You're probably right.
I got some price quotes for a multipple secondary toroid ( 2 X 15V, 2 X 24V and 20V) and these where much higher than buying three separate ones.
I should have looked into that more carefully, but the PSU was more like a side project. My brain was constantly thinking about the mixer..
However, regulating 24V down to 15V does genereate a lot of heat. This way it's all pretty cool inside the PSU case.
The 990 opamps OTOH get really hot, almost too hot to touch. I think they're 50C or so.
 
Magnificent work Radiance. Actually it was coming across your detailed description of a gssl build that led me to this forum in the first place, and for that I am eternally grateful  :eek:
 
You're probably right.
I got some price quotes for a multipple secondary toroid ( 2 X 15V, 2 X 24V and 20V) and these where much higher than buying three separate ones.
I should have looked into that more carefully, but the PSU was more like a side project. My brain was constantly thinking about the mixer..
However, regulating 24V down to 15V does genereate a lot of heat. This way it's all pretty cool inside the PSU case.
The 990 opamps OTOH get really hot, almost too hot to touch. I think they're 50C or so.

That's good to know, since I plan my next ssl with an external psu but just one torroid - should work with 'just' 15/12V needed. But I'm sure you're right about 24 and 15V - this step is probably to large.

thanks!
christoph
 
crisotop said:
That's good to know, since I plan my next ssl with an external psu but just one torroid - should work with 'just' 15/12V needed.

Just build a 2 X 15V external PSU and leave the 12V part (both regulators and some..) on the GSSL board.
That worked for me....
 
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