PLAN B analog blog

Got a question for the group, please give me input.  

One thing that's pestered me about most Eurorack line mixers is they
have this overall output level pot which I feel is at best an option,
at most a redundancy, if nothing else another pot you need to deal
with along with the level pots - and they all omit something tey could
slap in the same space as the output level pot that I feel would be
much more useful:  a fifth buss input to stack mixers together so you
don't have to take one of the input channels to do it? 

Do you guys see a need for a mixer that is stackable at the risk of
removing the output level pot?

I'd gladly lose the output level pot for a stereo buss input.  I'd also really like channel 
phase switches (although I realise this gets expensive in panel space) and the previously 
mentioned PFL headphone monitoring.  
In ideal world I'd also like the outputs to be on 1/4" jacks instead of minis (having to 
remember 1/4" to mini leads for live shows is a pain) plus an easy option of accessing the 
outs from the PCB (i.e. an edge connector) so that it would be possible to add your own 
output sockets on the rear of a Eurorack.

Thighp.




--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can 
figure that out)" <peter@...> wrote:

>
> Got a question for the group, please give me input.  
> 
> One thing that's pestered me about most Eurorack line mixers is they
> have this overall output level pot which I feel is at best an option,
> at most a redundancy, if nothing else another pot you need to deal
> with along with the level pots - and they all omit something tey could
> slap in the same space as the output level pot that I feel would be
> much more useful:  a fifth buss input to stack mixers together so you
> don't have to take one of the input channels to do it? 
> 
> Do you guys see a need for a mixer that is stackable at the risk of
> removing the output level pot?
>

woooaaa!!
do you Remember me reading your mind by sending you an email during the last winter 
about some 1u high multiple strip that could be out of the main synth case(to save space 
for powered modules?
Well there you've read mine with that and I was gonna post something that could be along 
that general idea... I was thinking though to add on the side of each input a 3 way switch 
that would have 1) OverDrive, 2) signal off 3) signal on(no OD).. Because I find it annoying 
on my doepfer mixer that it starts to OD at some point but all that with a pot which makes 
it hard to use wisely live for drastic effect...you know a sudden noise surge in your face 
kinda thing instead of going up progressively (no matter how fast you twist your wrist)
And also maybe at the general out another 3 way switch with +xxdb -xx db and no 
change

So to come back to the main topic, I'm all for it to be able to stack up other mixers, very 
VERY Handy!!!

g.

--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure that out)" 
<peter@...> wrote:

>
> Got a question for the group, please give me input.  
> 
> One thing that's pestered me about most Eurorack line mixers is they
> have this overall output level pot which I feel is at best an option,
> at most a redundancy, if nothing else another pot you need to deal
> with along with the level pots - and they all omit something tey could
> slap in the same space as the output level pot that I feel would be
> much more useful:  a fifth buss input to stack mixers together so you
> don't have to take one of the input channels to do it? 
> 
> Do you guys see a need for a mixer that is stackable at the risk of
> removing the output level pot?
>

I'm going to address ThighpaulSandra's, Dan's and Gabe's (three people I have a lot of respect for, btw) points together here.

Dan's point:

I don't see Doepfer expander as an end-all solution.  When you don't need more than four inputs, then this module isn't of much use.  I think the way to do it is a AUX in - an input channel with no level control.  You take the output of the first mixer into the aux in, your set. If you don't need more than more signals mixed together, you've got the other one free and fully functional to mix something else. It let's you expander without an expander, if that makes any sense. The only problem I'm having is trying to determine where than aux in should be routed.  If there's a A out, a B out and an A+B oeut...where to I send the aux in if it doesn't have an output channel slector switch?  I'm thinking into all three is best?

Gabe's point:

The three way attenuator is going on the Model 18 and that's still
happening, but thats not going to go on this one. I was thinking
instead of along the lines of a switch for stereo placement. A bit of
history:

Thighp's's points:

This is all coming from a discussion I had with Norman Fay regarding
an idea he'd like to have put onto a mixer which seemed very solid and
I've elected to go with it.  We'll keep that under wraps for now, but
along with his idea I went ahead and added a Channel A/Channel B
routing switch to each channel so that the output of each could be
routed to either an A output or B output.  There will be as well a
summed A+B (let's call it 'mono') output. This is one thing the Buchla
mixers had which was very useful (even though the center channel was
180 degrees out of phase with the other two (that won't happen on this
one). This isn't a pan - it's a switch and again this mixer I'm
discussing is not to replace the model 18, it's another one - just an
in-patch mixer for combining signals before it gets sent out of the
system. This will be the model 9, and it's going to be 14HP wide and
it'll be priced fairly.  In all, this will be a dual function module.
 A mixer and something else which all mixers could do but haven't thus
far. (thank Norman for this). 

The issue is there are already a host of these types of mixers in
Eurorack.  Doepfer, A. Systems and A. Solutions each has one. Deiter's
and A. Sys are identical.  Four in, one out with an output level pot.
 Tom Carpenter's is different, and does serve a purpose although it's
limited - unity gain only, but you get six input channels and it only
takes 4HP.  It's a good trade-off.  

Anyway, if I am going to do a line mixer, it'll have to be unique and
I think we've come up with something which fits that bill.  I'm
submitting artwork to my PCB house next week, i am going to hold off
on that until this art is done and get the two run together. This
mixer is too easy to put together to put it off.


- P



--- In PLAN_B_analog_blog@yahoogroups.com, "gabu_004" <gabu_004@...>
wrote:
>
> woooaaa!!
> do you Remember me reading your mind by sending you an email during
the last winter 
> about some 1u high multiple strip that could be out of the main
synth case(to save space 
> for powered modules?
> Well there you've read mine with that and I was gonna post something
that could be along 
> that general idea... I was thinking though to add on the side of
each input a 3 way switch 
> that would have 1) OverDrive, 2) signal off 3) signal on(no OD)..
Because I find it annoying 
> on my doepfer mixer that it starts to OD at some point but all that
with a pot which makes 
> it hard to use wisely live for drastic effect...you know a sudden
noise surge in your face 
> kinda thing instead of going up progressively (no matter how fast
you twist your wrist)
> And also maybe at the general out another 3 way switch with +xxdb
-xx db and no 
> change
> 
> So to come back to the main topic, I'm all for it to be able to
stack up other mixers, very 
> VERY Handy!!!
> 
> g.
> 
> --- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure
that out)" 

> <peter@> wrote:
> >
> > Got a question for the group, please give me input.  
> > 
> > One thing that's pestered me about most Eurorack line mixers is they
> > have this overall output level pot which I feel is at best an option,
> > at most a redundancy, if nothing else another pot you need to deal
> > with along with the level pots - and they all omit something tey could
> > slap in the same space as the output level pot that I feel would be
> > much more useful:  a fifth buss input to stack mixers together so you
> > don't have to take one of the input channels to do it? 
> > 
> > Do you guys see a need for a mixer that is stackable at the risk of
> > removing the output level pot?
> >
>

This is somewhat covered by Doepfer's A138x: http://www.doepfer.de/a138x.htm

Yes, there are times I wish there was one more mixer input pot rather than a overall level pot.

--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure that out)" wrote:
>
> Got a question for the group, please give me input.
>
> One thing that's pestered me about most Eurorack line mixers is they
> have this overall output level pot which I feel is at best an option,
> at most a redundancy, if nothing else another pot you need to deal
> with along with the level pots - and they all omit something tey could
> slap in the same space as the output level pot that I feel would be
> much more useful: a fifth buss input to stack mixers together so you
> don't have to take one of the input channels to do it?
>
> Do you guys see a need for a mixer that is stackable at the risk of
> removing the output level pot?
>

I think the unity gain input is much more useful than an output level
pot, personally.  I'd definitely go for that.  I have a couple of
serge MIX2 modules which have this feature, and it's very useful to
have & adds versatility.

As the m12 filter has an input level pot, as long as the mixer isn't
going to overload internally when all of the ins are cranked up full,
I don't think the output pot would be missed at all in use.

A simple dual attenuator (passive) or dual reversing
attenuator(active) might be a useful future utility module.

--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure
that out)" <peter@...> wrote:

>
> Got a question for the group, please give me input.  
> 
> One thing that's pestered me about most Eurorack line mixers is they
> have this overall output level pot which I feel is at best an option,
> at most a redundancy, if nothing else another pot you need to deal
> with along with the level pots - and they all omit something tey could
> slap in the same space as the output level pot that I feel would be
> much more useful:  a fifth buss input to stack mixers together so you
> don't have to take one of the input channels to do it? 
> 
> Do you guys see a need for a mixer that is stackable at the risk of
> removing the output level pot?
>

Clipping at all inputs at balls out:

This is a tough one.  I can say without any doubt that unless signals
come from the Model 25 Attenuator with those intentionally set at +6dB
amplification, then no mixture of Plan B signals will clip at unity
gain.  But all bet's are off for the umpty-ump modules made for
Eurorack which who knows what their output levels are.

Mixers are summers - adders if you will. They are btw one of the most
common circuits in electronics, they are used whenever CV signals are
combined with manual controls.  For instance, the M15 has a 5 input
summer for it's freq pot, fine freq pot, two bipolar VC inputs and the
1V/oct input.  The FM in comes in at a different place in the circuit.

Anyway they add the voltages together.  It's not linear, but the
overall level of the output is greater than the high levels of the
input.  You can actually amplify a single signal by bringing it into
multiple inputs of a single mixer.  However, the outputs of all of my
audio signals are set for the quoted Doepfer standard of  +/- 5 volts
(10 volts RMS).  Given my output buffers can pass signals up to +/-12
(24 volts RMS), with a range of about +/- 11 before weirdness starts,
I think there is plenty of headroom for mixing.  Running signals
within a volt or so of the supply voltage of a TLO op amp can cause
some funky things to start happening, among other things clipping.

hope this helps-

- P





--- In PLAN_B_analog_blog@yahoogroups.com, "NoRMaN PHaY"
<vietgrove@...> wrote:

>
> I think the unity gain input is much more useful than an output level
> pot, personally.  I'd definitely go for that.  I have a couple of
> serge MIX2 modules which have this feature, and it's very useful to
> have & adds versatility.
> 
> As the m12 filter has an input level pot, as long as the mixer isn't
> going to overload internally when all of the ins are cranked up full,
> I don't think the output pot would be missed at all in use.
> 
> A simple dual attenuator (passive) or dual reversing
> attenuator(active) might be a useful future utility module.
> 
> --- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure
> that out)" <peter@> wrote:
> >
> > Got a question for the group, please give me input.  
> > 
> > One thing that's pestered me about most Eurorack line mixers is they
> > have this overall output level pot which I feel is at best an option,
> > at most a redundancy, if nothing else another pot you need to deal
> > with along with the level pots - and they all omit something tey could
> > slap in the same space as the output level pot that I feel would be
> > much more useful:  a fifth buss input to stack mixers together so you
> > don't have to take one of the input channels to do it? 
> > 
> > Do you guys see a need for a mixer that is stackable at the risk of
> > removing the output level pot?
> >
>