Alice AM21 and ACM 8302P Modules

[kerrravon]

Hello Ted,

I have recently acquired some old Alice channel strips. AM21 strips from a quad mixer and ACM 8302P strips.

Would you happen to remember what DC voltage they run at and any info about the mic pre’s and EQ’s would be amazing.

many thanks
Ed

[Ted Fletcher]

Hello Ed, This is delving back a good many years! The AM and ACM modules all ran on 15-0-15 rails and these appeared on pins 13 and 15 of the edge connector, but there the memory fails. Usually audio ground was on pin 24… but don’t bank on that one. I’m afraid I don’t have any circuit details from those days, but the mic amps were conventional transformer input using mostly Sowter transformers. In the mixers we used quite simple EQ; variations on Baxendall HF and LF with sometimes a simple tuned mid.
Send me a picture of the modules and it might well jog more memories!

[kerrravon]

Hello Ted, Great, thanks very much for that info. I will get you some pics of the modules.

The AM modules were from a quadrophonic mixer made for the manor studios (virgin records old place) so i was told.

Ed

[kerrravon]

Hi Ted,

Sorry about the delay with these photos. I have the am21’s running. Sound great. Any info again much appreciated.

Ed

[Ted Fletcher]

Thanks for those pictures…. brings back memories.
The AM21 modules most likely were originally at one of the ILR radio stations. The 8-track routing maroon module is later, yes could have been from ‘The Manor’….. but it was a long time ago!

[kerrravon]

Thanks Ted,

How would you best describe the mic pre’s . Are both module’s pretty much the same?

Thanks

[Ted Fletcher]

In terms of circuitry they are almost the same.
The mic amp is a neat little discrete transistor class-A design that sounds very good… it’s streets better than the later IC mic amps that everyone now uses (except myself and a couple of other designers). And don’t forget, these mixers were built to a very exacting spec. and had to pass both the IBA Code of Practice, and the BBC spec for on-air continuity mixers.
I have had a look and I don’t have circuits for these mixers. 😥

[kerrravon]

I couldn’t agree more. I’m really enjoying the results. They sound fantastic. Thanks very much for all your help Ted.

Ed

[shred]

Hi, I owned that mixer for many years!
An Alice 16:4:(2)?
I sold it to a 20 ish guy studying sound engineering somewhere.
I was told ex Virgin Manor.
I obtained it via our bassist Rupert of Finchley.
Nina Hagen’s (now) guitarist Bob was devastated when I pipped him to the post buying it.
Apparantly there was an associate inline/passive mixer that was dumped in a street skip.
Myself and J. Lambert of Roundhouse Studios & Joe’s Garage often worked on it.
I believe I replaced some 741 op amps with TL071s.
We made a flying ribbon lead that allowed modules to be worked on live, on the ‘bench’.
I think it had limiters.
I was expecting to emmigrate this year and after having retained the schematics/lead for so long, I may have finally binned them.
Then again, I just may have reprieved them, but they could be difficult to locate.
Did the Floyd grace those faders? – I did.

[shred]

Now I think about it, I remember a large jackfield/matrix in the top RHS corner.
Also, in the centre, there sat unusual small VUs, that were not needles but vertical axis cylinders that spun to give a reading.

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