calrec pq1253-8 modules..... racking

Hello everybody,

i purchased a pair of these modules off ebay a while ago and they finally arrived.

does anybody have schematics for them? i get the impression that they are essentially the same or similar to the pq1549 that jakob cloned.

they have a lundahl 1530 mic tranny and another unlabelled 1521 transformer... is this a 'line' input transformer or an output transformer..

im hoping that these are all i need plus a bit of power etc.... to have a mic pre and eq, i have heard that similar modules need other bits (vca card) and (output card) to make them work is this true??

hopefully ill have em ready to go by the time fabios boards arrive,

will start studying the pq1549 schematic in the meantime....

thanks everyone

harry,

The other transformer is probably an insert-output-driver tranny, i.e. a standard line output device. Check area around it and see if you can find Calrec'e favourite negative-impedance-drive circuit.

Don't expect it to be easy to get racked without specs/schemo - there is sooo much going on at the edge connectors of Calrec's.

If you find the schematics, make sure to post them here!

Jakob E.

thanks for your reply Jakob,

ill definentely post schematics if i find em.... there are another 50 modules that were sold in this lot so i might try and contact those ebayers to see if they have any info.... hopefully one of em lurks around here too.

as for the vca cards etc.... did the pq1549 utilise these?? i have got the feeling that they might be necessary :sad: as there are two edge connectors on the back of the modules so probably one to the vca card and one to the routing / output stages.... anyhow im hoping that it is possible to use the modules without the cards.....

[quote author="spacecho"] as there are two edge connectors on the back of the modules so probably one to the vca card and one to the routing / output stages.... anyhow im hoping that it is possible to use the modules without the cards.....[/quote]

It's never as simple as that with calrec - there's a lot going on in there. You NEED the module schematic with aproppiate pin-out in order to do anything with these.

On the other hand, you won't need the dynamics module - the input module can be patched to use without dynamics.

http://www.gyraf.dk/schematics/Calrec_UA8000_mic_input.gif
http://www.gyraf.dk/gy_pd/calreq/calr_eq_only.gif

Jakob E.

cool,

looks like im gonna learn something in the process of getting these going... might take a while though

i worked out the pinout to my dynamix 3000 channels without schematic but then again these are much more complicated....

i might try and contact calrec also, i hear that they are very helpful in offering support.

thanks Jakob

There are no dynamics or vca cards with the 1253-8. The upper connector carries functions for the input and the lower carries functions for the eq and output. It is more complex that this of course as there are many pre/post features which can be jumpered or made use of. It can get messy if you don't plan ahead. If I remember correctly, the 2 input trafos are for the mic amp...it's a hi gain/low gain thing which is to meant to maintain proper input impedence for noise reasons (you can hear a relay switch when going from -20 to -30 sensitivity). The line input should be transformerless (I have to check the schems though...) and is triggered via a switch (which you must add). Output is unbalanced from the module.

In our board, low-gain mic in is transformerless, high-gain is via transformer. Take a looh at the above schematic - it's really nice to see a single-deck elma-switch used to it's max.

Jakob E.

I have a lot of respect for Calrec's engineering. They do so much with seamingly simple parts, design and layout(s). Top notch stuff IMO (which is why I own a bunch of modules :green: ).

Looking at the diagram for 1253-8, the 2 transformers are for high level and low level mic input and the line input is transformerless. This is/was a BBC spec'd issue I believe. Also, the gain strapping is for different levels than your diagram...-14db, -10db and 0db. I'll scratch up the info needed to wire these up later on today and post it.

Looking at the diagram for 1253-8, the 2 transformers

Click to expand...

Could we have a copy? Please? Pretty please?

Harry could sure use it - and me, well, I'm just addicted..

:razz:

Jakob E.

Hi,

i got a pair of these from a friend and now i'm trying to rack them too, but i don't have a clue what to do.

Did you manage to rack them yet Harry?

I got this note from my friend which should explain the pin-connections but i'm not getting it:

" (if pin aren't mentioned they're not connected)
Connector A:
10- i/p from b card (needs linking),
11/12- set range +/- 3dB,
14/21- pre filter output and filter input (need link),
15- -16A,
16- +16A,
17- center rail,
18- oL,
19- +5L,
22/23 pre eq o/p and eq i/p (need linking),
31 o/p (unbalanced),
32 chassis.

Cannector B:
1- line select,
2/3 mic high/low select (link),
9- o/p to card A,
10- centre rail,
11/12/13 gain set (no link 0dB, 11-12 -6dB, 11-13 -10dB),
19- 51 (probably and L not a 1),
18- 01 (probably and L not a 1),
17- centre rail,
16 +16A,
15 -16A,
22/23 line i/p,
31/30/29/28 mic i/p "

Well while writing it i'm now understanding a lot better now .. But somethings still ain't clear to me...

- what is the center rail, grounding??
- i/p = input and o/p output, right?
- seems like -16A and +16A is something about the needed power, but it can't be Amperes, so what does it mean?
- what is 19 -5L, 18- 0L, 18- 0L, 19 +5L, somehow powerconnections but what does it mean?

regards,

Niklas

Your information has some errors. Give me a bit more time to post a diagram.

Hi Niklas,

ive been so busy... my calrec's are collecting dust with my audix modules and g1176's.... might get around to working on them soon (im renovating at the moment)

i'm afraid i haven't got any info on them yet.

will pass on whatever info i find on them..

post some pics when they r racked.

peace

Hi Guys,

i'm sorry to hear that Harry, but my racking will take sometime too. And there's still the 9k on the way, just waiting for the pot..

@temmytones, thanks for the work.

Do you have the schematic? Or do you know what those powerconnections mean.
I'll probably need something like 48V for phantom and 18 or 15 V for the boards right?
What would the best way to supply them? Would a powersupply similar to the 9k supply work? Or maybe a JML thing...

Thanks a lot for your help,

Niklas

Any new information anyone?

tom , do you have the schematic ? If so could send me a copy, please?

Niklas

I have one of those 1253-8 modules too

Tommy, would be great if you could post the schematic.

About the voltages needed I think +16 and -16 "A" means audio and are volts, and 5L and 0L are logic power: +5V and logic ground.
center raiol would be ground but not sure...

best regards,

Synthi

thanks synthi,
for explaining these terms to a newb

Hi,

This is the first time I have posted images here (or anywhere on the Web for that matter!), so I hope the links work OK.


I have been doing a spot of module racking myself......


A Calrec M-Series PQ module and support PCBs on the test bench:
http://groupdiy.twin-x.com/albums/userpics/10140/normal_1180_TEST_PCBs.JPG

PCBs and a couple of modules; a slightly different view:
http://groupdiy.twin-x.com/albums/userpics/10140/normal_1180_PCB_ASSEMBLIES.JPG

The module carrier unit with the lid off showing the internal stuff:
http://groupdiy.twin-x.com/albums/userpics/10140/normal_1180_UNIT_OPEN_TOP.JPG

And finally a completed module carrier from the outside:
http://groupdiy.twin-x.com/albums/userpics/10140/normal_1180_UNIT_ISO_VIEW.JPG

Cheers.

Hey that looks great, but do have a schematic for that?

What powersupply did you use? Did you make extra PCB or did you use one

from an other project?

regards, Niklas

Thanks Niklas.

My employer owns the copyright of the schematics, PCB artworks & mechanical designs associated with this project.

The backing card that the module plugs into and the associated interface card were specifically designed to fulfil the needs of correctly interfacing a Calrec M-Series PQ module with the "outside world".

The PSU cards (one does +/-17V, the other does +5V & +48V) are general-useage PSU assemblies. The transformer is to a custom-spec.

Cheers,

Thanks Gareth,

I understand you cannot give your interface and psu schematics, but may be you can give us the original calrec schematic for the mosdule, or at least the correct pinout?

Also, do you sell that interfacing cards and trafos? do you have the same kind of cards for useing with the pq1347 modules too?

Thanks,

Synthi