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Module puzzle: 8 modules, 3 lunchboxes (API & APHEX)
Old 26th May 2006
Gear Addict

Module puzzle: 8 modules, 3 lunchboxes (API & APHEX)

Ok, here's the deal

I got 1 API 6B lunchbox and two 4B-1 Aphex lunchbox. I got 8 modules (1 API 512c preamp, 1 API 553 eq, 2 B&B MP-1 preamps, 4 Aphex cx-1 compressors) so there's no need to use the 3 lunchboxes at the same time but... (and here comes the riddle)

- Aphex lunchbox 1 has an other configuration than Aphex lunchbox 2 (both have trs in and out, no xlr). The internal level selection is the same though: input high, output high.
- Apparently, Api lunchbox has an other configuration than both of the Aphex lunchboxes.

- API 512c preamp works in the API lunchbox and in Aphex 1 lunchbox, apart from the fact the Aphex lunchbox has no phantom power. In Aphex 2 lunchbox using a balanced cable gives no signal. Using a standard XLR to unbalanced jack, and pulling the jack half out works though.
- API 553 eq works in API lunchbox and in Aphex 2 lunchbox, but in Aphex 1 the input or output is too high (I guesss the input) and boosting a frecuency gives distortion, only cutting works.
- B&B mp1 preamps work in Aphex 2 and in the API lunchbox. In Aphex 1 there are some strange background noises, although the signal is present.
- Aphex cx1 compressors work in Aphex 1. In Aphex 2 the signal is too weak I didn't try in the API because I'm afraid to damage the modules, since pin 15 (phantom power on the API lunchbox) is in use for "ext. meter out".

1. what ARE the differences in configuration between these three lunchboxes?
2. How can I get these modules in only 2 lunchboxes? Solutions?

I will post a picture later of the three lunchboxes. Aphex 2 lunchbox seems to have been modified (there is already a photo of the inside of this lunchbox here on geekslutz
there you can see 2 soldered lines for each module. Aphex 1 lunchbox doesn't have these soldered lines.

Let's start the logic.
Old 26th May 2006
Registered User

Do you have the pinouts for both boxes?
If you don't have the pintouts - then aren't you heading for trouble as those connectors house :
DC in, ground, Phantom in, Balanced in +, Balanced in -, Balanced out +, Balanced in - (at least)
and they all could be on different pins

No wonder you have connection problems..
Do you have a multimeter?
Old 26th May 2006
Gear Addict

yea, I have pinouts of the api 512c and of the aphex cx1. The cx1 should work in an API lunchbox but I am worried about pin15, thats phantompower for the API, and an ext. meter out for the aphex. Can the aphex modules be burned by the phantom?
The strange thing is: these 4 types of module have 4 different behaviours, so 4 different pinouts? I dont have pinouts for the API 553 eq en nobody knows of the existence of those aphex preamp modules (they even have no serial number).

Old 24th June 2006
Lives for gear
Berolzheimer's Avatar

The cx-1s aren't preamps, they're compressor/ expanders, they're not unknown around these parts. can't you just disconnect or cut the phantom connection to them?

Oh whoops, now I se that you were referring to another aphex module as a preamp. Those I haven't seen.
Old 2nd July 2006
Gear Addict

Ok, I cut pin15 of one of my aphex cx1 compressors and put it in my API lunchbox.
There is a signal, i can change the input gain untill it clips, but the compressor responds very weakly, only a few db of compression with max input gain and max treshold. So it seems that the input level of the compressor section is way too weak.
My question is: can it have something to do with a possibly different hot-cold-ground wiring of the input of these lunchboxes?

thanks in advance,

btw: thanks to a fellow gearslut I was able to identify these mysterious mp1 modules as rare B&B preamp modules. Their design seems very simple, I wonder if it couldn't be copied for a DIY project. Same applies to my api 553 eq.
We need some api 500 form factor DIY projects!
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