Help on Yamaha EMX2000 powered mixer

[Raglan]

Hi

Grateful for some help. I recently bought a used Yamaha EMX2000
powered mixer without a manual. Figured out just about everything out
EXCEPT the limiter function, which is puzzling the hell out of me.

In the section labelled "power amp", the mixer has two little slotted
pots without knobs (accessible by screwdriver). Above them is the
label "limiter" and two LEDs. Between the two pots is the label
"level". The pots are calibrated from +18dB to +4dB (anticlockwise to
clockwise).

Now, I would have thought that these pots would set thresholds above
which a limiter would kick in, for speaker protection and the like.
The mixer's block diagram (which I've been able to find online)
implies that.

However, these pots don't seem to work like that. Instead, turning
them down (anticlockwise) reduces the output of the power amps, even
if the volume is already very low. It's as if they're simply extra
gain controls. What's the point of that?

Can anybody who knows the Yamaha EMX series clue me in?

Many thanks

Raglan

[Phil Allison]

Post by Raglan
Hi
Grateful for some help. I recently bought a used Yamaha EMX2000
powered mixer without a manual. Figured out just about everything out
EXCEPT the limiter function, which is puzzling the hell out of me.
In the section labelled "power amp", the mixer has two little slotted
pots without knobs (accessible by screwdriver). Above them is the
label "limiter" and two LEDs. Between the two pots is the label
"level". The pots are calibrated from +18dB to +4dB (anticlockwise to
clockwise).
Now, I would have thought that these pots would set thresholds above
which a limiter would kick in, for speaker protection and the like.
The mixer's block diagram (which I've been able to find online)
implies that.
However, these pots don't seem to work like that. Instead, turning
them down (anticlockwise) reduces the output of the power amps, even
if the volume is already very low. It's as if they're simply extra
gain controls. What's the point of that?
Can anybody who knows the Yamaha EMX series clue me in?

** My best hunch is that you have misread the labelling. The limiter is
non adjustable and simply acts to prevent amp clipping - the two leds show
when it is operating.

The trims are probably for level calibration of the main line outs.




.............. Phil

[Raglan]

Post by Phil Allison

Post by Raglan
Hi
Grateful for some help. I recently bought a used Yamaha EMX2000
powered mixer without a manual. Figured out just about everything out
EXCEPT the limiter function, which is puzzling the hell out of me.
In the section labelled "power amp", the mixer has two little slotted
pots without knobs (accessible by screwdriver). Above them is the
label "limiter" and two LEDs. Between the two pots is the label
"level". The pots are calibrated from +18dB to +4dB (anticlockwise to
clockwise).
Now, I would have thought that these pots would set thresholds above
which a limiter would kick in, for speaker protection and the like.
The mixer's block diagram (which I've been able to find online)
implies that.
However, these pots don't seem to work like that. Instead, turning
them down (anticlockwise) reduces the output of the power amps, even
if the volume is already very low. It's as if they're simply extra
gain controls. What's the point of that?
Can anybody who knows the Yamaha EMX series clue me in?

** My best hunch is that you have misread the labelling. The limiter is
non adjustable and simply acts to prevent amp clipping - the two leds show
when it is operating.
The trims are probably for level calibration of the main line outs.
.............. Phil

Thanks: that's a good theory, and certainly seems to be borne out in
practice. But I remain baffled by the calibration of those pots: +18dB
to +4dB. That's backwards, as one might expect of a limiter threshold
but not, surely, of a trim pot.

Raglan

[Phil Allison]

"Raglan"

Post by Raglan
Thanks: that's a good theory, and certainly seems to be borne out in
practice. But I remain baffled by the calibration of those pots: +18dB
to +4dB. That's backwards, as one might expect of a limiter threshold
but not, surely, of a trim pot.

** Not if the dB level being referred to is indicated by "0 dB" on the LED
ramp - given that it also comes after the trimpot.





............. Phil

[Raglan]

Post by Phil Allison

Post by Raglan
Hi
Grateful for some help. I recently bought a used Yamaha EMX2000
powered mixer without a manual. Figured out just about everything out
EXCEPT the limiter function, which is puzzling the hell out of me.

[snip]

Post by Phil Allison
** My best hunch is that you have misread the labelling. The limiter is
non adjustable and simply acts to prevent amp clipping - the two leds show
when it is operating.
The trims are probably for level calibration of the main line outs.
.............. Phil

Whoa, all is revealed.

Ray, who coincidentally posted another EMX2000 question to the group
yesterday, has kindly sent me a PDF of the manual (love to know where
he found it). Turns out Phil is almost exactly right.

The trim pots are calibrated backwards because they are thought of in
the manual as adjusting the sensitivity of the inputs to the power
amp.

Whew.

Raglan

[Ray]

Pages 8 & 9 of the user manual explains what those 2 little pots (located
under the "limiter" LED lights) do. From what I can tell, those 2 pots DO
act as a gain control, by which you can adjust (and thereby limit) the
amount of signal being sent from the mixer to the power amp. The idea (I
think) it that if you find that the limiter keeps kicking in, you can reduce
the amount of signal being sent to the power amp without having to adjust
your faders. I'm not quite sure why you wouldn't just reduce the master
fader to achieve the same affect - I guess Yamaha just wanted to give you
some additional flexibility/functionality. (ex. In case you are recording
the performance using the ST 1 bus and you don't want to reduce the
recording level just but you need to reduce the signal being sent to the
power amp).

To tell you the truth, I haven't had to adjust those pots yet - I don't
think I've ever gotten the limiter to kick in.

Hope this helps,

ray

Post by Raglan
Hi
Grateful for some help. I recently bought a used Yamaha EMX2000
powered mixer without a manual. Figured out just about everything out
EXCEPT the limiter function, which is puzzling the hell out of me.
In the section labelled "power amp", the mixer has two little slotted
pots without knobs (accessible by screwdriver). Above them is the
label "limiter" and two LEDs. Between the two pots is the label
"level". The pots are calibrated from +18dB to +4dB (anticlockwise to
clockwise).
Now, I would have thought that these pots would set thresholds above
which a limiter would kick in, for speaker protection and the like.
The mixer's block diagram (which I've been able to find online)
implies that.
However, these pots don't seem to work like that. Instead, turning
them down (anticlockwise) reduces the output of the power amps, even
if the volume is already very low. It's as if they're simply extra
gain controls. What's the point of that?
Can anybody who knows the Yamaha EMX series clue me in?
Many thanks
Raglan