Mackie SR series

[matt222]

Hi

Can anyone please clarify what the differences are between the Mackie SR32.4 and SR32.4 VLZ PRO desks and whether any differences would effect the quality of results when using only synths etc and no mics/preamps.

[Mike Stranks]

I've just checked the schematics for these mixers...

... in both cases, you WILL be using the mixer's onboard preamps...

Like very many other manufacturers, Mackie routes all inputs through the preamp with suitable 'damping' on the line inputs to accept true line levels.

So... check the specs for the inputs... that'll show what differences there are - if any. But I suspect for all practical purposes it won't make any discernible difference.

[matt222]

Thanks Mike

I have the SR24.4. VLZ PRO and have always been happy with the results. However, I've run out of inputs now but am unsure of the differences between the 2 versions. For how serious I take my music, I doubt I'll find as good a 32 channel mixer for that sort of money?

[matt222]

Just received an SR32.4 VLZ ( non pro version ).

I have to say, it sounds warmer and fuller to my ears than the pro version!

Just can't seem to get a signal from Aux send 5. Is it possible for 1 of 6 aux sends to fail; completely?

[resistorman]

Just can't seem to get a signal from Aux send 5. Is it possible for 1 of 6 aux sends to fail; completely?

Sure. It could be as simple as a broken jack or solder joint, but as bad as a fried IC. Also, Mackie used press fit ribbon cables that caused me no end of problems when I lived in Key West due to salt air corrosion.

[Hugh Robjohns]

Just can't seem to get a signal from Aux send 5. Is it possible for 1 of 6 aux sends to fail; completely?

Yes, of course it is.

Resistorman has listed the main culprits: knacked output socket or its soldering is a possibility, as is a fried output driver op-amp. The wire links were indeed a common problem in desks of that era, but I'd expect you'd have trouble with more things if that was the cause.

However, checking the Aux send with the different solo monitoring modes might give some useful clues.

Can you hear the aux 5 signal on the headphone monitoring if you hit the Aux 5 master solo button? What if you switch the desk solo mode between PFL and AFL?

If the aux send signal is present in PFL mode but not AFL then it's probably a blown output driver IC.

If the signal's not present in either case it's probably a problem with internal jumper wires.

And if the signal is there in both cases it's probably a knackered socket or a dry solder joint around the output socket,

I have a copy of the SR24-4 service manual if that helps. Assuming a similar construction, the output op-amps are NJM4560s and the outputs are impedance balanced.

The op-amp for Aux 5 is U31, with the output from pin 7 and the input on he non-inverting input pin 5. The linking jumper cable pins are J40-5 to J41-5.

You might also want to check the output coupling capacitor C92 which is a 25V, 47uF electrolytic. It's possible that got buggered if someone managed to send phantom power down the Aux output!

H

[matt222]

Thank you for the help.

I've tried finding a signal as you advised, but it it's nowhere to be heard. It does seem Aux send 5 is completely inactive.
Opening the desk up and attempting investigation/repair is something I will avoid as my experience in this field is zero. I've only just got it and I'm really happy overall as it sounds warmer than my VLZ PRO version!

If I can still get a good sound from my Bigsky across the desk using one send and 2 returns, I'll be happy!