Author |
Message |
gusjdt
Joined: Apr 12, 2006 Posts: 55 Location: San Juan
G2 patch files: 1
|
Posted: Mon May 21, 2007 11:04 pm Post subject:
Main output Bus |
|
|
I usually see a main output bus on most synths, or something that has the Master Volume control. Does that circuit take the output from VCAs or can you connect the output of a VCA straight into a keyboard amp and not get any weird results? If I _do_ need some sort of main output bus, does anyone know where I can find schematics for a circuit like that? _________________ A new disturbing study has been found that proves that studies are disturbing... |
|
Back to top
|
|
|
Mikmo
Joined: Dec 01, 2005 Posts: 150 Location: Copenhagen - Denmark
|
Posted: Tue May 22, 2007 12:51 am Post subject:
|
|
|
I run the output of VCA's either directly to my Mackie mixer as a Line level signal, og to a smal (audio) mixer i have as a module that also expects line level signals.
So i think you can run it directly to your amp.
If it is too loud you can just turn the " initial gain" knob (or whatever it is called) on the VCA down.
I have a small 3 channel audio mixer in my modular to mix serveral VCA outputs before sending them to the mixer / amp. This is to avoid having too many cables going to the Mackie mixer, but it is also useful for other things, like splitting a sound, sending it to two different filters and combining it again. Or mixing the output of two VCO's and noise before sending it to a filter. Actually i'm going to build a couple more of these
I just started the second cabinet of my modular. A lot of the space in it is going to be occupied by "utility modules" like audio mixers, CV mixers, mult's, an external input module with envelope follower and gate / trig. extractor, simple attenuators for CV. Not very fancy, but very usefull. _________________ Stay Cool
Mikael
http://www.mikmo.dk |
|
Back to top
|
|
|
doctorvague
Joined: Mar 14, 2007 Posts: 281 Location: new mexico
Audio files: 2
|
Posted: Tue May 22, 2007 3:51 am Post subject:
|
|
|
Mikmo wrote: | I run the output of VCA's either directly to my Mackie mixer as a Line level signal, og to a smal (audio) mixer i have as a module that also expects line level signals.
So i think you can run it directly to your amp.
If it is too loud you can just turn the " initial gain" knob (or whatever it is called) on the VCA down.
I have a small 3 channel audio mixer in my modular to mix serveral VCA outputs before sending them to the mixer / amp. This is to avoid having too many cables going to the Mackie mixer, but it is also useful for other things, like splitting a sound, sending it to two different filters and combining it again. Or mixing the output of two VCO's and noise before sending it to a filter. Actually i'm going to build a couple more of these
I just started the second cabinet of my modular. A lot of the space in it is going to be occupied by "utility modules" like audio mixers, CV mixers, mult's, an external input module with envelope follower and gate / trig. extractor, simple attenuators for CV. Not very fancy, but very usefull. |
Ditto almost all of what you said Mikmo.
And thus the modular cliche "you can't have too many mixers". I have 3 Blacet mixers and they probably get used more than any other modules I have. One I use pretty much as a dedicated output mixer as you describe. The Blacet Mixer/Processor kicks ass. His VCA mixer not so much.
It would be nice to have a dedicated final stereo mixer with pans and balanced outs and optionally sends and returns. I've seen a few out there in people's systems. I mean a module, not a Mackie.
Another simple utility module I'm going to build is a rotary switch selector to quickly select between CV sources for instance. Not too glamorous but seems like it would be useful. AND it can have a chicken-head knob
Phil |
|
Back to top
|
|
|
RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
|
|
Back to top
|
|
|
fonik
Joined: Jun 07, 2006 Posts: 3950 Location: Germany
Audio files: 23
|
Posted: Tue May 22, 2007 6:06 am Post subject:
|
|
|
i am using a more simple mixer: just a unity gain inverting configuration without ac coupling. thus i can mix even control voltages... it may not be that special audio circuit but i never noticed any drawbacks.
if you need a PCB take a look at ken stones dc mixer:
http://www.cgs.synth.net/modules/mixer.html
_________________
cheers,
matthias
____________
Big Boss at fonitronik
Tech Buddy at Random*Source |
|
Back to top
|
|
|
doctorvague
Joined: Mar 14, 2007 Posts: 281 Location: new mexico
Audio files: 2
|
Posted: Tue May 22, 2007 9:54 am Post subject:
|
|
|
Wouldn't this design have a maximum gain of around .5 due to the 20K input resistor and 39K negative feedback resistor ratio? I assume that's intentional... |
|
Back to top
|
|
|
bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
Audio files: 1
G2 patch files: 1
|
Posted: Tue May 22, 2007 10:40 am Post subject:
|
|
|
Max gain of 2 surely? ... which, I think, is a standard for some people - good to have that bit extra, especially in a mixer.
I think you def. want an AC coupled mixer (ie blocking caps) for output to exterior world, but DC mixers are really useful within the system too. Just make sure you know which is which!
Q on:::: Headphone amps
Anyone got any good links?
I checked the PAIA one but don't currently have an NE5532s
Is a TL072 enough?? I did have a quick check through the datasheet for current driving capabilities... must check again..
Otherwise, LM386? _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
|
Back to top
|
|
|
bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
Audio files: 1
G2 patch files: 1
|
|
Back to top
|
|
|
doctorvague
Joined: Mar 14, 2007 Posts: 281 Location: new mexico
Audio files: 2
|
Posted: Tue May 22, 2007 12:05 pm Post subject:
|
|
|
bugbrand wrote: | Max gain of 2 surely? ... which, I think, is a standard for some people - good to have that bit extra, especially in a mixer.
|
oops
you're right Bugbrand. My math was sdrawkcab
And extra gain is good sometimes |
|
Back to top
|
|
|
goodrevdoc
Joined: Sep 11, 2006 Posts: 288 Location: Philadelphia, PA
Audio files: 1
|
Posted: Tue May 22, 2007 12:11 pm Post subject:
|
|
|
Quote: | Q on:::: Headphone amps
Anyone got any good links?
I checked the PAIA one but don't currently have an NE5532s
Is a TL072 enough?? I did have a quick check through the datasheet for current driving capabilities... must check again..
Otherwise, LM386? |
Tl072 should do fine for NE5532. Also of note, try this:
Headphone Amp
It's for guitar, but could easily be adapted for modular use. Also, LM386 is a popular choice, just google to find stuff.
-justin |
|
Back to top
|
|
|
gusjdt
Joined: Apr 12, 2006 Posts: 55 Location: San Juan
G2 patch files: 1
|
Posted: Tue May 22, 2007 12:24 pm Post subject:
|
|
|
Thanks, I might just use a mixer at the end to mix the VCAs as mentioned before. Thanks for the replies! _________________ A new disturbing study has been found that proves that studies are disturbing... |
|
Back to top
|
|
|
funkyfarm
Joined: Jan 21, 2007 Posts: 583 Location: France
Audio files: 3
|
Posted: Thu May 24, 2007 6:41 am Post subject:
|
|
|
bugbrand wrote: | Also to note::
that MFOS one is inverting -- I'd recommend adding a further invertering unity gain stage.. |
?!
it seems that mfos wasted half TL in order to to save a couple of resistors ?
|
|
Back to top
|
|
|
Coriolis
Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark
|
Posted: Thu May 24, 2007 7:31 am Post subject:
|
|
|
You mean: Why have a stereo headphone amp on a mono signal? Yeah - would it be possible to feed both channels with the same mono signal, but from one opamp?ยจ
It does look a bit like a waste...
C |
|
Back to top
|
|
|
RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
|
Posted: Thu May 24, 2007 12:01 pm Post subject:
|
|
|
OK - I admit it. I'm cheap. TL084 $0.78 each TL082 $.76 each (digi-Key)
The last mixer I made I used a TL082 and made it into a stereo mixer based on that MFOS circuit. The two pennies I saved on the op-amp paid for the two resistors for the second channel - and I'm better off 'cause I avoid the bad karma for leaving unused in/outs.
As for inverted output - I'm using it to mix to my monitors, so I just listen while standing on my head. |
|
Back to top
|
|
|
fonik
Joined: Jun 07, 2006 Posts: 3950 Location: Germany
Audio files: 23
|
Posted: Thu May 24, 2007 11:00 pm Post subject:
|
|
|
RF wrote: | OK - I admit it. I'm cheap. TL084 $0.78 each TL082 $.76 each (digi-Key)
The last mixer I made I used a TL082 and made it into a stereo mixer based on that MFOS circuit. The two pennies I saved on the op-amp paid for the two resistors for the second channel - and I'm better off 'cause I avoid the bad karma for leaving unused in/outs.
As for inverted output - I'm using it to mix to my monitors, so I just listen while standing on my head. |
what about TL07x? they are low noise. might be better for the audio path without being more expensive... _________________
cheers,
matthias
____________
Big Boss at fonitronik
Tech Buddy at Random*Source |
|
Back to top
|
|
|
|