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labcoat man

Member
Joined
Jul 25, 2005
Messages
15
Location
Australia
HI ,

wondering if anyone can point me in the right direction or has the following information.

ive just acquired one SSL 'SL615E' Dual mic pre module with front panel (gain, phantom power etc all there) . Otherwise knows as SSL E series mic pre's I believe. I think they often come in stand alone racks of 8 or 12. Same type used to be used by BBC at the Hippodrome theatre in London.

Im trying to find information / schematics so I can hook it up (main thing I need to know is power requirements, and in and out connections and where it all goes!). Im no great techy but am confident enough to do this once the info is there.

Any help would be much appreciated as my web searches haven't been very successful.

thanks In advance.

tim
 
No and no.

The 615 is an outboard version. The original E-series was 82E01.

The 615 might have been transformerless, can you confirm that? -The 82E01 used in the E-series used a Jensen transformer for the input.

They had a rack of the 615s for external mic input overrun at a local mobile truck, but they didn't like them so they sold them and got something else instead.

You should be able to figure it out reasonably easily, measure continuity between pins and the pins 7 and pins 4 on the 5534s. Ground should be easy enough also. From the pad switches to the edge connector there should also be continuity on a couple of pairs of pins. These will be the inputs.

Output is almost certainly electronically balanced, there might be a small hybrid circuit 'wafer' nearby, and continuity from two of the pins to the edge connector.

Keith
 
Thanks Keith and thanks John for your reply

Im still waiting on the arrival of the unit but from photographs it looks to have 1 transformer per channel in it (I hope it does cause that was one of the attractions and I thought $50US for two transformers is not bad anyway) . Hopefully Im not looking at a canned capacitor that looks like a transformer...., which did cross my mind but it looks like a xformer to me.

http://i8.ebayimg.com/01/i/04/4f/8b/1e_1_b.JPG

hopefully that might show you a pic.

Thanks for the tips on determining ins and outs, I think I can do that,
only thing that confuses me is determining the power supply requirements by measuring continuity? Will I be able to determine the actual voltage required?

Sorry if this is an ill informed question , my past experience of hooking things up has been with a knee bone to thigh bone diagram in front of me and hasn't required too much brain power.

Bummer that BBC weren't so keen on them but all in all it was cheap and will definitely improve on my desk pre's so Ill look forward to giving them a try.

cheers

Tim
 
Hi labcoat man, did you have success with your pre? I found a SL615E real cheap, and I'm planning on racking it up soon. Did you ever find a schematic?

Thanks

Rob
 
These were a bit of an oddball, I don't have any schematics but might be able to help given some photos. From memory they are very straightforward, balanced in balanced out.

(I remember working on them but that was about 20 years ago!)
 
>> You should be able to figure it out reasonably easily, measure continuity between pins and the pins 7 and pins 4 on the 5534s.

> determining the power supply requirements by measuring continuity? Will I be able to determine the actual voltage required?

They are (according to Keith) 5534 chips. They are rated like +/-9V to +/-22V, but in studio apps they are universally fed +/-15V or +/-18V, either will be fine.

So find the 5534 pinout (actually, any single opamp with the same number of pins). Find the supply pins. Be sure you know which is + and which is -. Use an ohmeter to find card connections with very low resistance to the 5534 supply pins. It may be zero ohms, it may be 10 ohms, even 47 ohms, but lower-R than any other pin. Good idea to verify by eye: follow the traces.

Quadruple-check the polarity!!! Look at the bypass cap near the power trace. Getting the rails backward may not blow-up the vintage 5534 chips, but it will burn-up any small series resistor and burst the bypass caps, a real stinky mess.

Ground is usually everywhere and comes out on multiple pins.

Mike inputs go to transformer, or pad or Phantom.

Count the transistors and chips and multiply by 10mA. This will usually over-estimate the supply demand (I would expect 2 Q and 3 5534 to suck ~16-20mA, not 5*10mA= 50mA) but if you just have one or a few, you don't need an exact current number (the smallest supply you can find will be plenty). If you score a few dozen, rig one socket with a couple 1 ohm resistors, measure the actual current, swap a few cards to see if they vary much, and round-up 50%-100% to allow for dynamic current when the whole horn section wails at once.
 
[quote author="PRR"]They are (according to Keith) 5534 chips. They are rated like +/-9V to +/-22V, but in studio apps they are universally fed +/-15V or +/-18V, either will be fine.

So find the 5534 pinout (actually, any single opamp with the same number of pins). Find the supply pins. Be sure you know which is + and which is -. Use an ohmeter to find card connections with very low resistance to the 5534 supply pins. It may be zero ohms, it may be 10 ohms, even 47 ohms, but lower-R than any other pin. Good idea to verify by eye: follow the traces. [/quote]

Yes they will be 5534s, never used anything else.

There should be at least 10 ohms, possibly 22 ohms, between the connector and the op-amp pins, a carbon resistor was fitted to all SSL cards to stop the board burning up if the op-amps went short circuit.

Have fun!
 
Hi, thanks for the help guys...

Kieth, The SL615E uses Jensen JE115K-E Transformers.

100_0091.jpg


I've pretty much figured it all out, except for the 48V pins. I've marked the ones I think they are, but I don't want to hook em' up until I'm sure I won't fry something. What's a good way to trace the phantom pins? I checked the phantom switch, and I think I've traced it back to pins 13 and 14, but I can't be sure without taking it apart. Also it seems SSL likes to put two pins with the same voltages next to each other, so 13 and 14 look like a good guess.

100_0094.jpg


This set of pre's are well worth the price tag (I found them for $100!). Only tested my voice with a dynamic mic so far, but they sound really good, 70db of gain, super quiet, and a really cool LED meter. I'd like to find a few more.

100_0098.jpg


Rob
 
Find a digital ohm meter with Range Hold. You must jam it into a high resistance range so only a very low current will flow. Common Auto-Range meters will crank the current quite high trying to resolve a low-R connection. Any strong DC current will magnetize your input transformers, a very bad thing.

Jam the meter into the 0-200K range.

The two IN terminals will read near-short to each other.

With Phantom OFF, the two IN terminals will be Infinity to any other point.

With Phantom ON, either two IN terminals will read 3K4 to the +48V line. There may or may not be paths to other points, but this should be the lowest resistance (not counting the other IN terminal) and should be awful close to 3K4. (Some older gear avoided the 3K4 standard until it became a DIN standard: it could be 2K7 or 4K and still be "correct".)
 
$100 is a bargain! Now I see the photos I remember them well - they are basically a pair of '01 style mic amps as used in the E series 4k channel strip.

I can't remember what the preset controls right next to the edge connector are for though? Output balance adjustment perhaps?
 

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