SSL SL 502 EQ HEADROOM?

[antonin93]

Hello
I received a custom rack containing 2 SL510 compressors and 6 SL 502 equalizers from an SSL 5000 console
SL510 works perfectly
SL502 saturates and limits to -4dB, I have the impression that the headroom is limited? the modules are made to operate at -18dB FS?

thx

 

[Matt Syson]

These modules have an internal operating level of -14dBu which is obtained on the versions that have the 'balancing option' by 'losing 14dB over the input unbalancing amplifier sub board, and then being boosted by 14dB to get the balanced output. I happen to have a bunch of them here that I am supposed to be working on for a client today. I designed a motherboard for these compressors and EQs with the unbal/bal circuits available on the motherboard since not all these modules have the original SSL sub boards. Like many modules that originated from full mixers people that 'just' put them in a box forget to ensure the original operating levels are preserved. In the case here, the comps HAVE the sub boards but the EQs do not so require the services of the motherboard mounting amplifiers.

 

[friedd]

hi @Matt Syson ,
i've read quite a few topics in here about this but can't find any links pointing to external info about these sub boards that doesn't turn into a 404 error.
I understand DIY RE stopped making them a few years ago,
is there any place i can buy those bal/unbal sub cards pcbs ? populated or not.
Or should i make them myself based on the "Balanced Input/output option" section of the schematics ?

thanks !

 

[Matt Syson]

The 'sub boards are actually a small ceramic 'board' that has surface mount components mounted on it so they are effectively an 'integrated circuit. The actual design is similar to the INSIDE of a THAT 2646 chip but was designed and made specifically for SSL. AMEK used similar mini circuits but of course they are different to the SSL implementation. The component values on these 'hybrid' circuits are not shown in manuals because they are treated as a plug in 'integrated circuit'. The module schematics don't tell you all the information that you need to actually make a fully working circuit. I am actually working on the rack here today but my house is cold so it is slow going!.

 

[friedd]

Hi there,
bumping this topic up.
Would be great to have more info on getting those modules to work at proper level.
Would a simple attenuator on the input and something like a "boost" on the output side could work ?
I suppose there's a better way of doing it ?
Thanks.