DIY main L/R inserts doable on an old Mackie CR-1202?

since the 1202 is somewhat ubiquitous in the audio world as a cheapo small format Swiss Army knife mixer, i was just wondering if anyone had attempted a L/R insert successfully before i go opening it up. the key factor would be having the inserted effect be audible in the headphones - i.e., insert needs to be before the point on the L/R where the headphone amp picks off the signal (have to use headphones 95% of the time at home).

just a thought, i've never seen anyone mention a mod like this so i'd suspect that it might not be practical for one reason or another...

this is NOT the US-made Mackie MS-1202, then?

just verifying in case this was a typo.

I guess it is the MS-1202, but of course I can't confirm.

The manual of the MS-1202 contains the schematic - if you haven't have that already it could be of help.


I understand you want to have the effect on the whole mix so then putting it on the mono-ch. inserts or in front of the line-channels won't do it for you. OK.

I guess the most practical is to put the effect after the main-outs and use a separate headphone-amp - small cheap boxes for that purpose could be more interesting than starting to drill in the MS-1202.

BTW, the headphone amp in the '1202 is actually nothing more than another output-opamp but then 'doubled' (two opamps in parallel & then summed with low-valued resistors) to drive a lower load.

BTW#2, it's quite packed inside, so wouldn't know of a decent place to put those insert-jacks (last time I looked at least :wink: but it's been a while I was inside that box).

But that's all from the mechanical side. 'Electrically' it's quite easy I think. The headphone-amp gets the signal before the master-pot. If you make the insert at the point where the headphone-section takes the signal from the main audio you should be fine. Just to be sure, check for the input-impedance of the headphone-amp - maybe it could be too low to be driven from your insert-FX-box.


Abnout what kind of insert-effect are we talking BTW ?

Bye,

Peter

if this is the first generation 1202 ( flat, not wedged..)..then just lift C67 ( right channel ) and C68 ( left channel ) and put your insert there. just after that point is where the headphones are taped
I have the schematic on pdf, if you need it, but its big 1,1M

johan

yeah, i flailed - it's an original flat stylee MS-1202 - thanks for the tip, Johan, i'll try it out! i imagine i can scrounge up a 1202 schematic

Clint, it's for slapping an RNC compressor across the L/R mix - i can just put it on the output and monitor downstream but i was hoping for a more elegant solution tha would let me use the headphones since at home the wife doesn't much let me use speakers to play back the same thing over and over and over...


i'll report back on the results - should be pretty straight forward.

[quote author="blakbeltjonez"]
Clint, it's for slapping an RNC compressor across the L/R mix - i can just put it on the output and monitor downstream but i was hoping for a more elegant solution tha would let me use the headphones since at home the wife doesn't much let me use speakers to play back the same thing over and over and over...


i'll report back on the results - should be pretty straight forward.[/quote]

If it's for late-night low levels anyway then who knows, maybe the RNC-outputs can directly drive your headphones, especially it's one of those 'higher Ohmic' types.
The headphone out of the MS1202 is nothing more than two parallel opamps (but from a reasonably current-potent type), so if the RNC comes close and your levels are not too high it may function fine.