Share your knowledge on these two classic MPCs
By dtirer Tue Jan 01, 2013 8:48 pm
People seem to have conflicting feelings on weather the MPC ins / outs are balanced. So once and for all, is this accurate?:

Inputs - BALANCED
8 Individual Outs - UNBALANCED
Stereo Outs - UNBALANCED (???)
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By SimonInAustralia Tue Jan 01, 2013 10:06 pm
From a quick look at the schematics, it seems that the main Rec/Record Ins are balanced, other audio inputs and outputs are unbalanced...


MPC60
Rec In (mono) = Balanced
Stereo Out (L/R) = Unbalanced
Assignable Mix Out (1-8) = Unbalanced
Echo Mix Out (mono) = Unbalanced
Echo Return In (L/R) = Unbalanced


MPC3000
Record In - Analog (L/R) = Balanced
Stereo Out (L/R) = Unbalanced
Individual Mix Outputs (1-8) = Unbalanced
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By SEED78 Wed Jan 02, 2013 11:59 am
shiz are the inputs really balanced?

I always assumed they were unbalanced - I might try using a Radial phono DI rather than a unbalanced phono stage in that case...
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By SimonInAustralia Wed Jan 02, 2013 12:40 pm
From the MPC3000 manual...
COMMENT: The audio input jacks on the rear panel are
balanced inputs having a high, low and ground connection
using a standard stereo phone jack:
Ground Low High
However, standard mono phone plugs will work fine—the low
connection will simply connect to ground.



In reality, with short cable runs (up to 10-15 feet), unbalanced should be fine.

For longer cable runs, and lower level signals, the balanced cable (with balanced circuits on each end) can cancel out radiated electrical noise that might be picked up by the cable.
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By SEED78 Sat Jan 05, 2013 1:56 pm
This is from the MPC3000 manual:

strangely the outputs are all 600 Ohm, which is balanced standard - which is curious.

record inputs, like you said manual says balanced in - so kind of like balanced in AND balanced outs - not what I expect at all!

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By SEED78 Sat Jan 05, 2013 2:10 pm
from my tech regarding the outputs

all outputs are unbalanced but have a impedanced matching a balanced signal

but they are not balanced outs

ic104 m5238 debalances the signal

so all outputs are unbalanced they use the ne5532 opamps

which drive a 600 ohms load

now i here talk of the seperate outs being not as good as the stereo out

just checked the schems identical circuits the only difference is on the stereo out theres a volume control

which the seperate outs dont have as its fixed volume
By dtirer Sat Jan 05, 2013 6:40 pm
ah very interesting! Good to know

SEED78 wrote:from my tech regarding the outputs

all outputs are unbalanced but have a impedanced matching a balanced signal

but they are not balanced outs

ic104 m5238 debalances the signal

so all outputs are unbalanced they use the ne5532 opamps

which drive a 600 ohms load

now i here talk of the seperate outs being not as good as the stereo out

just checked the schems identical circuits the only difference is on the stereo out theres a volume control

which the seperate outs dont have as its fixed volume
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By SimonInAustralia Sat Jan 05, 2013 8:17 pm
SEED78 wrote:strangely the outputs are all 600 Ohm, which is balanced standard - which is curious.

I don't think it is strange.

It is pro audio gear, using pro audio signal levels.

I think you are incorrectly associating balanced connections with only pro audio signal levels/equipment, and unbalanced connections with only consumer audio signal levels/equipment, which is not necessarily the case.

Lots of pro audio gear uses pro audio dBm signal levels, with unbalanced connections.
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By SimonInAustralia Sun Jan 06, 2013 12:50 am
SEED78 wrote:as far as I know most other samplers of that era didn't output at 600 ohms - thats not standard at all...
Didn't you say above that it is a balanced audio standard?

Are there any standards that relate directly to sampler output levels? If so, what are they, who sets them, etc.?

Each manufacturer, and model, seems to implement it's own specs.

What difference does the MPC3000 600 ohm output impedance actually make when connecting two pieces of equipment, compared to other equipment that might have a different (50 or 100 ohm?) output impedance?

I don't know why you are getting so hung up on output impedance.

The actual signal levels are much more important than the impedance.

The MPC3000 outputs seem to be pro audio level, not consumer levels, which make sense to me for the type of studio gear it is.

It is designed to connect to a studio mixer/recorder, not a home stereo system.
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By SEED78 Sun Jan 06, 2013 11:03 am
noone is getting 'hung up' bro.

600 Ohms output IS pro, but out of all the sampler brands Akai was one of the few to offer that in a SAMPLER specifically. if that matters to anyone other than me is another matter...