Aphex CX-1

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stinky

Active member
Joined
May 24, 2007
Messages
40
Location
Champaign, IL
Does anyone here have any information on the Aphex CX-1?

It's a "500 Series" style module.  Compressor and expander.  I just had one come
across my bench and I do not know if its working properly.

Any help or info would be great.  I've been cruisin the net for a while and I have yet
to find a lot about it.  I spoke with Wayne at Aphex and he told me they don't have
any copies of the old service information. 

Thanks
Dan
 
Aphex are particularly unhelpful when it comes to service information!

It's my recollection that they produced a series of API retrofit (i.e. 500 series modules) for a short period.
As well as the compressor module they also did an EQ module as well.
So the pinout etc. will be exactly the same as API. Same voltage rails.
I would guess your module is probably based on the 1537A chip.

They eventually did an Aural Exciter module but by then had gone over to the DBX racking style - same front panel dimensions as the 500 series, but a deeper chassis (and therefore longer PCB) and some extra power rails.
 
Thanks barclaycon.


Yeah it does have the same API pinout.  I've got it powered up and it seems to
pass audio, but it distorts before it compresses.  And there are two buttons
that I'm not sure what they do, but it just seems to turn all the leds in the meter
on. 

Thanks, if you come across some more info I'd be indebted to you.

dan
 
Hello, I have a couple of Aphex CX-1 that do not work. When connecting to my Purple Audio Box, LED lights up and does not pass any sound. I don't have the schematic and I do not know where to start, any help or info would be great.
Thanks. Alberto
 
Ok, thank you Denyle,
I cut the Pin 15 and now sounds and works ok, but the bargraph only works in normal mode, it doesn't work in Compression or Expansion mode. I probably burned a component, I got the schematic, now patience.
Also I'm going to recap my compressors. This units do not have transformers and I saw that you've put Jennsen transformers and have explained:

R114-change to 470K.
C110-change to 0.33uf. I used a tant but schematic says "S" (stacked film).
FB201-? fb201=R236=150R for NON-transformer version. I believe it's just a ferrite bead. I can't tell from the CX-1 schematic how it's incorporated but on the EQ2, it shows FB-2 in series with a 10R resistor, followed by the high side of the xformer. Jensen still sells the FB-2. Presumably, it's a 2 hole ferrite core and I'm not sure if you use one or both.
C233-that big coupling capacitor can probably be removed now. (I haven't tried this yet) A good place to stick that 10R resistor.


and I don't understand the FB201 (R236) change. In my units this is a 10R resistor. I only need to change this one for another one of 150R?
Sorry for my English Thanks in advance and best regards
Alberto
 
R236=10R or ferrite bead (depending on unit) according to the cx-1 docs. 150R for versions without OT only.

However, if you look at the EQF2 docs, it shows a series ferrite bead followed by a series 10R resistor and no series capacitor. It looks like the amp in the EQ has less gain though. You should check for dc before removing c233, or just leave it in to be safe.

My meters don't work in gain reduction mode either, probably for the same reason. I never attempted to troubleshoot. I'd guess start by checking R264, R265 and working back to R222, R223 then IC10.
 
Hey Guys,

Just wanted to add a note about the meters for those having trouble with them. This may or may not be your problem, but the meters on these units display information somewhat differently than most other compressor/limiters/expanders that I have or have used (that's quite a lot, btw). As I haven't been in front of my CX-1s for over a year (don't ask), this will be from memory, but if I remember correctly they display compressor output level, not compression level, ie: you will not see how many db of compression on the display, but when the expander is engaged you will see downward expansion displayed on top of audio level, on the same meter, at the same time. It can be deceiving/confusing/irritating and I often disable one of the circuits momentarily just to get a handle on what's going on visually.

On another note, there is a jumper setting (or in some units a micro switch) labeled Pre/Post that changes the position of the input gain pot. Depending on your usage and connectivity, this jumper can absolutely make this unit very hard to setup and use, so beware!

Hope that helps somewhat!

Jeff 

 
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