SSL 4K E mic input

Any news on this project?

my non500 version is almost done, doing some minor layout adjustments and all will be ready.

-Casey

Great news Casey,
can't wait for it.

signalflow said:

my non500 version is almost done, doing some minor layout adjustments and all will be ready.

-Casey

Click to expand...

Hi Casey, I'm ordering the components at the moment, and I will etch some boards of your layout with a help of a friend, I will post here my findings soon.

Did you by change did some adjustments to the layout lately?

thanks

Tiago

Whoops said:

signalflow said:

my non500 version is almost done, doing some minor layout adjustments and all will be ready.

-Casey

Click to expand...

Hi Casey, I'm ordering the components at the moment, and I will etch some boards of your layout with a help of a friend, I will post here my findings soon.

Did you by change did some adjustments to the layout lately?

thanks

Tiago

Click to expand...

Tiago, yes I have done some adjustments. I'll get a new version uploaded tomorrow.

Re-did the phantom circuit and added 2 more iron choices.

Proto PCB's are actually in the mail from seedstudio as I reply. I'm hoping to have a few up and running by the 1st of febuary.

-Casey

EDIT:

http://c1.ac-images.myspacecdn.com/images02/137/l_b13ddd05317947188f2ee955bbca175c.png
http://c1.ac-images.myspacecdn.com/images02/139/l_859df26e2b08434f8b841255be0bb9c4.png

added the etch file and the component placement to the post above. Here is the BOM

-Casey

Thanks a lot Casey,
Should I etch using this layout, or wait for the new one with the adjustments?


Is there anyway of controling the output level?
What I mean is that I would like to distort this preamp , but lowering the level at the output so I dont clip in the converters.

Thank you so much for your work and documents

Yes you can etch this layout it has the adjustments I was referring to.

I suppose you could stick a pot between R5 and the input pin of the 1646.  Might be able to get away with another 10k lin pot here.  

Lift R5 on the side closest to xformer. Tie Pin 1 of the pot to the lifted side of R5, bridge pin 2 to pin3 and connect pin 3 to upper pad of R5.

There is probably a better executed solution for it than that.  Give it a go though.

-Casey

edit:  You might find this to be helpful as well.

http://www.uneeda-audio.com/pads/

maybe using a T atenuator pad, like those from classic API?
what do you think?

http://classicapi.com/catalog/product_info.php?cPath=48&products_id=210

thanks

signalflow said:

Yes you can etch this layout it has the adjustments I was referring to.

I suppose you could stick a pot between R5 and the input pin of the 1646.  Might be able to get away with another 10k lin pot here.  

Lift R5 on the side closest to xformer. Tie Pin 1 of the pot to the lifted side of R5, bridge pin 2 to pin3 and connect pin 3 to upper pad of R5.

There is probably a better executed solution for it than that.  Give it a go though.

-Casey

edit:  You might find this to be helpful as well.

http://www.uneeda-audio.com/pads/

Click to expand...

Ive seen that t-pad but I'm not sure if 600 ohm is the best choice.  There is a formula in the link i posted to calculate the value of the pad.

-Casey

Hey guys...

This is NOT a G-series mic preamp. No G-series ever cam\e with a transformer mic pre.

This is the E-series mic preamp.

(there's no such thing as a G-plus mic pre either... the 'plus' was a few bolt-on goodies, but the preamp remained G... andwas completely unlike this one, with a dual LM394 front end, and a switched gain).

Keith

SSLtech said:

Hey guys...

This is NOT a G-series mic preamp. No G-series ever cam\e with a transformer mic pre.

This is the E-series mic preamp.

(there's no such thing as a G-plus mic pre either... the 'plus' was a few bolt-on goodies, but the preamp remained G... andwas completely unlike this one, with a dual LM394 front end, and a switched gain).

Keith

Click to expand...

I know it's not the G series, just made more sense to me to keep updating this thread. 

Just to confirm. This is the G series schematic correct?
http://www.ka-electronics.com/images/SSL/ssl_82E149.pdf

Mine is strictly the E series dual 5534 with a transformer and THAT output.

On a more exciting  note my proto boards arrive today.  I'll post a pic here when I get them!!

Keith, after re-reading this I hope to not come off as snarky.  I like many others here totally value and rely on your knowledge to help us make sense of things.

-Casey

Oh, no worries... no snarkiness taken! 

No, that's the OTHER E-series (transformerless) schematic... the '149.

The G series was the 249, I think, and had a step-switched gain control, instead of the dual-gang pot, as shown in the schematic which you posted.

Keith

So the G series mic pre schematic still eludes us. Or is the only difference the stepped gain switch?

Ohh and here is what I got in the mail today


Sorry about the quality camera phone, also I might have been driving but we wont dwell on that. 

The silk screen is wrong it should read RS-8201E.  Not sure where the 241 came from. Oh well this batch is for testing and my personal use.  If all works out okay then if some folks want some I can do a run.  I know Bruno has his 500version but not everyone has a rack for that.


-Casey

This Thread should be renamed to "SSL 4K E series Mic input"

Whoops said:

Some Info from Keith aka "SSL Tech"  , here is the complete thread:

http://www.audioasylum.com/scripts/t.pl?f=pro&m=4483


" (...) E-series are 82E01 or 82E149
The original was card number 82E01 which used a Jensen transformer.
Later on came the 82E149, which was the first of the transformerless designs.
The first 'G' series input card was different in that it used a stepped attenuator instead of a variable gain control.  (...)  The G-series (from memory) used a solid-state differential front end with a matched pair of parallel transistors for low noise . (...)  "


So basically we are really talking about a series "E" mic preamp and not "G",
the schematic for the 82E01 is the one Hobiesound posted:

hobiesound said:

schematic for the ssl 4k mic pre : http://www.ka-electronics.com/images/SSL/ssl_82E01.pdf

Click to expand...

Click to expand...

Can anyone comment on how they sound??
I take 4 if they sound killer.
Thanks.

Whoops said:

This Thread should be renamed to "SSL 4K E series Mic input"

Click to expand...

That is entirely up to the OP.  But if the only difference between the 149 is a gain switch instead of a gain pot, then it's just a matter of doing some work.  If not then we still need a schematic for it.  Whoops, didn't you say y'all had a g series where you were?  Maybe You could retrace the mic pre or take some high res photos?

3nity said:

Can anyone comment on how they sound??
I take 4 if they sound killer.
Thanks.

Click to expand...

A few pages back Peter described his as "big and ballsy" with the Jensen xformer.
The first prototype I did was with the cinemag and it was just smooth all the way across.

I will say it had alot of gain!

-Casey

The version with two opamp stages (http://www.ka-electronics.com/images/SSL/ssl_82E01.pdf) has a couple of advantages.

- Spreading the gain over two stages helps keep a healthy amount of feedback gain available for both stages at all gain settings. Even with the 1:10 ratio of the Jensen, asking a single stage to produce 40+ dB of gain AND sound good is pushing it a bit.

- The use of a linear 10k gain pot should mean better channel-to-channel tracking of gain (and the 10k linear is easier to come by).

- With this arrangement, the first stage provides most of the gain at lower settings while beyond the halfway point, the second stage supplies most of the additional gain.

- Note also how the gain pot is isolated from DC and how a separate DC path is provided around the first opamp - nice!

signalflow said:

That is entirely up to the OP.  But if the only difference between the 149 is a gain switch instead of a gain pot, then it's just a matter of doing some work.  If not then we still need a schematic for it.  Whoops, didn't you say y'all had a g series where you were?  Maybe You could retrace the mic pre or take some high res photos?

Click to expand...

Don't know if the only difference between the 149 and the 249 is the change from a Gain Pot to a Gain switch.
I will see if I can get some pics.

Better would be to see the schematics

Whoops said:

Better would be to see the schematics

Click to expand...

Agreed.

-Casey