SSL 4K E mic input

[dustbro]

What about adding a line/d.i. section like the other layout posted?

Still trying to knock out the beta. I ordered parts about a week ago and some things were on backorder till the first week of November. I'll keep this thread posted on any updates if you would like.

 

[signalflow]

What about adding a line/d.i. section like the other layout posted?

If you want all the extras then Dustbro's layout would make more sense.  My version is very basic and serves 1 purpose which is all I needed it for.

-Casey

EDIT:  Dustbro, I would defiantly be interested in the progress of your layout especially the sound.

 

[helterbelter]

It's not really DIY, (and also not G), but :

http://cgi.ebay.nl/ws/eBayISAPI.dll?ViewItem&item=280416411045&ssPageName=STRK:MEWAX:IT

The seller has got a second one seperately listed....

 

[Nage]

Anyone know where to get PCB's for this project?

 

[mpc3000limited]

Anyone know where to get PCB's for this project?

No PCB's were made, this is a design Signalflow kindly posted a self etch file of his layout -BUT as claimed nobody has tested it yet. If you want a SSL pre-amp project that is tested & has Pre made PCB's try the SSL 9K (Gustav sell's the board's in the white market) but fair warning the MAT-02 is becoming sparse and a little difficult to buy if not expensive. Good luck

 

[Morning_Star]

SignalFlow.  I'm about to etch my boards but how about adding just the line level to the etch file???  Please.  I wanna use the two channel for the output of a passive 8x2 summing buss as well.

 

[signalflow]

The layout that I made has no part of the line in section.
Check out the schematic and you'll see what I'm talking about.
mine is a pre-only, the other layout in this thread has the line input.

-Casey

 

[TheGuitarist]

Well if someone DOES make a pcb, i'm in for up to 8. As ever, depending on price. Be cool for a 500 series one... actually that would be awesome!! With a trim pot so we can drive the pre nicely of course.

If i could design pcbs... i would, unfortunately, i can't. Lame.

 

[gemini86]

Well if someone DOES make a pcb, i'm in for up to 8. As ever, depending on price. Be cool for a 500 series one... actually that would be awesome!! With a trim pot so we can drive the pre nicely of course.

If i could design pcbs... i would, unfortunately, i can't. Lame.

good thing the design is already done... just needs to be etched. Why not give it a try?

 

[TheGuitarist]

Ok i actually might give it a crack, never done it before but hey. How hard can it be. Won't be done til the beginning of next year (full time job and all) but hey. It seems like there will be a few different versions of this. I'm going to give signalflows one a shot, nice and simple.

Any ideas for a trim pot for the output?

Also just wondering what the optional caps are for.

 

[signalflow]

Any ideas for a trim pot for the output?

Also just wondering what the optional caps are for.

Optional caps are from the THAT1646 data sheet. They add common-mode rejection to the output, you can leave them out and just put a jumper in place of the two caps.

Here is the description from the datasheet, edited for content.

"The outputs are DC coupled to the output connector, so this dc will appear directly
at the output of the system.  The output common-mode offset of a 1646 may
be reduced by adding capacitors in the feedback loop. These capacitors ac-couple the common-mode feedback loop.
This changes the loop operation from servoing the common-mode output current at audio frequencies to
servoing the common-mode output voltage to 0 at
DC. This results in much lower common-mode output
offset voltage, as indicated in the specifications
section. These capacitors are typically high quality
non-polarized electrolytic capacitors."

And here is the horses mouth: http://www.thatcorp.com/datashts/1600data.pdf

The cost of the caps is very minimal and I would suggest leaving them in.

As for a trim pot someone with abit more smarts might be able to answer that question.  But a good place to start is to check out the original schematic and then do a search to see if anything comes up.

-Casey

 

[TheGuitarist]

I checked the schematic... it has a line trim.. which is a linear 25k pot but i'm guessing the mic trim would have been the fader.

I don't see why that wouldnt work. Just might need some help choosing one. Anyone have any suggestions for a PSU?

At the moment my solution is the JLM world transformer and the ac/dc kits. But $100 a PSU seems a bit excessive. Its just 15v and 48v right?

 

[mitsos]

you can get an SSL9K PSU board from Gustav for 5 euro. Then, of course you need the parts and trafo... should cost you about $50 at most.  Also, I'm working on a 4 rail PSU (bipolar, phantom and one more positive rail in case you want to add LEDs, relays, or anything else). It's mostly done, I just posted it in the LAB to get some opinions and if it's OK, I'll post an etch file.

 

[Morning_Star]

Glad to hear about your psu design mitsos.

I'm going to finish ordering and building my passive summing box this month and then I'm etching the signalflow mic pre boards and stuffing them.  Then I'll do the psu and get some help with output transformers.

I think I'm going to add a/b switching for the mic pre inputs like the Trident S20 has.

 

[signalflow]

I checked the schematic... it has a line trim.. which is a linear 25k pot but i'm guessing the mic trim would have been the fader.

I don't see why that wouldnt work. Just might need some help choosing one. Anyone have any suggestions for a PSU?

At the moment my solution is the JLM world transformer and the ac/dc kits. But $100 a PSU seems a bit excessive. Its just 15v and 48v right?

The addition of the fader might also require more of the circuit  as well this could be done on some proto board and just jumpered between the main board.  This I am not too sure of, but I don't think just stuffing a pot in the mix would take care of it properly but again someone with more smarts on the subject could fill in the blanks.

This board requires a + and - 15VDC  as well as +48VDC for phantom power. One of SSLtech's pwer supplies could eaisily handle powering 2 of these.  Also mitsos power supply board would work nicely too when it's ready.

-Casey

 

[TheGuitarist]

Might make a side thread about it.


Anyone know of any suitable output transformers? Or even if one will benefit the pre? No point in adding one if its not going to do much.

 

[Whoops]

How about the G series SSL preamp,
does anyone have a schematic?

 

[signalflow]

How about the G series SSL preamp,
does anyone have a schematic?

I think someone linked to it on the first page. EDIT: My bad thought someone did but after going back I see that it's not.


Ok, so I'm getting my parts order together for this and I want to use a stepped switch so I'm going for a 1 pole 12 pos Lorlin.  I know by the schematic that the original pot was a 250K log, soooooo can I use the calculator on this page to figure out the values of the resistors for the switch?

http://homepages.tcp.co.uk/~nroberts/atten.html

It asks for the value of the attenuator which is 250,000 and then for the # of pos which is 12 and it gives me the values of the resistors.

And that should be that.  Or is there another way that this needs to be done?

Thanks,

-Casey

 

[signalflow]

Bump for even a hint.

-Casey

 

[peterc]

500 series version?

Pads for Jensen 115ke & 115epc, Cinemag CMMI10pca &  Lundahl 1578 transformers. I used a 5532 balancing output stage, added phase, phantom & pad switches.

Anyone like this idea? Comments please....

Peter