SSL 9K & 4K (E Series) 500 / 51X NEW BOARDS Mic Pre Thread 2011

[AyoK]

Yes good point!
Thank you Carsten

 

[gnarmageddon]

I hit a snag here ordering the pots. AML doesn't have the 2k2 20mm 2-gang potentiometers and I'm coming up with zilch for an alternative. Is there a substitute part possible?

Closest I can find are dual-gang pots rated for 2k.

 

[culteousness1]

2k as a substitute should be fine if you consider the usual part tolerances of potentiometers.

But are you sure that AML isn't out of stock temporally? It could be worth to email Colin at AML if you haven't already done.

Otherwise you can check your search engine of choice with the exact part number of the original OMEG pot.

Again, an updated profile including your location would make it easier to suggest alternative suppliers.

Hope this helps,
Carsten

 

[gnarmageddon]

But are you sure that AML isn't out of stock temporally? It could be worth to email Colin at AML if you haven't already done.

I've got emails in. Fingers crossed.

Otherwise you can check your search engine of choice with the exact part number of the original OMEG pot.

If anyone has the original OMEG pot #'s (i've been digging for them) I'm most appreciative. The closest I can seem to find for a 20mm, dual gang 2k2 with through hole mounting is this guy here: http://cpc.farnell.com/omeg/pc2g16eco2k2a/pot-dual-gang-lin-2k2/dp/RE04428.

Again, an updated profile including your location would make it easier to suggest alternative suppliers.

Done and done.

 

[culteousness1]

If anyone has the original OMEG pot #'s (i've been digging for them) I'm most appreciative. The closest I can seem to find for a 20mm, dual gang 2k2 with through hole mounting is this guy here: http://cpc.farnell.com/omeg/pc2g16eco2k2a/pot-dual-gang-lin-2k2/dp/RE04428.

Sorry, but I don't have the exact part number either.  You can check the following web page for reference.
If I am on the right track, the part number is something like: PC2C20BU.

The potentiometer you stated has the wrong taper law as it is linear instead of anti-log.

Cheers,
Carsten

 

[gnarmageddon]

Colin emailed me back and said they're expecting a new shipment in January. I think I'm good waiting four weeks for the 'right' part instead of rubbing a rabbits foot on a substitution.

 

[gnarmageddon]

Yes, I had to learn to count, too.  My original BOM called for 25.  The correct number IS 27.

Mouser decided to mess with me.... Hard.... I'm building two of these and they sent me 55 of them. Ironically, "55" is about the number of times I A/B'd the boards and schematic to make sure I wasn't leaving a cap off.

 

[gnarmageddon]

http://imgur.com/uyAs4un

Just waiting on the pots to arrive - everything else is good to go. Did a military green powder coat on the fp's with pad printed demarcation. #BadAssery

 

[Whoops]

But are you sure that AML isn't out of stock temporally? It could be worth to email Colin at AML if you haven't already done.

Yes, I was going to advise that, I was sure Colin would order more, since he is the only supplier of this pots for the community for a long time and he is not going to run out of costumers for that product soon.

Hope the pots get in stock soon

 

[gnarmageddon]

Got a pair of both potentiometers on the way. Meter bridges are done, just waiting to solder in the pots and have the moment of truth firing them up.

 

[gnarmageddon]

haha  ! I've fixed it

I took a razor and fixed it and now it works great without blowing the resistor.

Walk me through this if you can - one of my two blew the R1 on initial power-up. All solder joints appear okay. Should I try with the meter board removed?

 

[culteousness1]

Should I try with the meter board removed?

Did you remove the unwanted copper on the meter board as advised?

 

[Stagefright13]

Hey Bruno! Ya sent me 2 prototype boards for 9k with A paper highlighted in green to show me A silk screen error. I think it was diodes? I have all the diodes in.  Don't remember. The board says version 3.9 I have the 2 ganged pots in and 3 ganged pots, Mat  02's ya sent me. All the relays and A bunch of caps and stuff. Just need to order some wimas and chips. Had to move my studio A couple times so things got lost! And thanks for the pres finally I will be able to use them soon and send samples!

 

[bruno2000]

Hey Bruno! Ya sent me 2 prototype boards for 9k with A paper highlighted in green to show me A silk screen error. I think it was diodes? I have all the diodes in.  Don't remember. The board says version 3.9 I have the 2 ganged pots in and 3 ganged pots, Mat  02's ya sent me. All the relays and A bunch of caps and stuff. Just need to order some wimas and chips. Had to move my studio A couple times so things got lost! And thanks for the pres finally I will be able to use them soon and send samples!

D305 and D306 are backwards on the silkscreen of V3.9.  There is also a mod to adjust the gain of the HPF.  Send me your email in a PM.
Best,
Bruno2000

 

[Tedrummerx]

Hey guys, just finished up a pair of 9k pres and they are sounding incredible! One thing I'm noticing is these pres are pretty hot, even with the pad engaged and gain all the way down, its too hot for loud sources like drums. Is this just common with the 9k? Has anyone tried to modify the pad circuit? Also thinking of maybe using a couple inline xlr pads on those loud sources like drums.  Any opinions? Thanks!

 

[Vac11]

Thanks Bruno2000 for this amazing project. Im very happy with the sound of these preamps.... Everything was OK and pre was alive on the first on...

M.

 

[TillM]

Hey guys, just finished up a pair of 9k pres and they are sounding incredible! One thing I'm noticing is these pres are pretty hot, even with the pad engaged and gain all the way down, its too hot for loud sources like drums. Is this just common with the 9k? Has anyone tried to modify the pad circuit? Also thinking of maybe using a couple inline xlr pads on those loud sources like drums.  Any opinions? Thanks!

That's my question too.
I also want to use the 9k pre for my drums.
Hope someone can give a advice.

I'm also looking for the 4k pcb boards, so if someone also wants to order and Gustav will do it, please pm me.

 

[Whoops]

That's my question too.
I also want to use the 9k pre for my drums.
Hope someone can give a advice.

I'm also looking for the 4k pcb boards, so if someone also wants to order and Gustav will do it, please pm me.

You can increase the PAD atenuation by changing the PAD resistors,
the board used 2x 10k8 and 1x 2k2K resistor to form a U Pad.
I don't know how much attenuation that provides, so find that out.
I guess it's 15dbs because R1 is 5 times R2.

Then increase the level of atenuation by changing those 3 resistors.

For example if it's a 15dbs pad, try increasing it to 20, 25 or 30 dbs pad.

A good reading on PADs:
http://www.uneeda-audio.com/pads/

 

[TillM]

You can increase the PAD atenuation by changing the PAD resistors,
the board used 2x 10k8 and 1x 2k2K resistor to form a U Pad.
I don't know how much attenuation that provides, so find that out.
I guess it's 15dbs because R1 is 5 times R2.

Then increase the level of atenuation by changing those 3 resistors.

For example if it's a 15dbs pad, try increasing it to 20, 25 or 30 dbs pad.

A good reading on PADs:
http://www.uneeda-audio.com/pads/

thank you so much for this advice !
So this means, i can leave r1 with 2k2k and use for r2 a resistor that increase the pad.
Dumb question but isn't R1 and R2 not the same resistor ? so this must be mean for me, that the pad just is 6db.
Edit: I see it on the shematic, now I understand. Thank you very much !


My next question, can I use this switch ?
http://de.farnell.com/multicomp/2as4t2a1m6re/switch-toggle-spdt-mom-off-mom/dp/1550114

I ordered the pcb today.

 

[Whoops]

I would take the 3 resistor out and use 2x 680ohms for R1 and 1x 150ohms for R2,
it will make a 20dbs PAD.