SSL 9K Mic Pre

[Nadege]

hello,

I have a couple of question regarding this project.

1) Which kind of diode to use for the +/-18 to +/-15 voltage drop?
2) Does anybody have a picture or a drawing which can show how to wire the rotary switch to the main PCB
3)How to wire the +48v phantom with a switch to the input XLR (I believe it's using two 6.81 resistor? But need to be sure.

Thanks for the help

 

[Nadege]

any idea?

 

[drpat]

You can use any 1N400x diodes.

As far as the rotary switch issue goes, it's so easy, I doubt that anybody would actually take the time to draw it up. One wire goes to the common on the switch, and the other goes to the common on the resistor ladder. If you did a series string of resistors, one goes to the common on the switch, and the other connects to the beginning of the string, which is the lowest value resistor. Now do the other deck the same way.

Phantom connection: Tie one end of the phantom resistors together and take that to one contact of the switch. connect each of the other two ends of the resistors to your + and - on your input jack. Now connect your 48VDC to the other side of your switch, and you're golden!

 

[fucanay]

Anyone try to run these at 15V? I have an extra 15V transformer I want to use instead of the 18V. What are the disadvantages to running these at lower voltage?

Matt

 

[warpboy]

Hello,
By looking at diyaudio forums, I was reading infos about the Mat02 transistor , that is I think is an expensive part, and another part that seems to be similar the SSM2210. the features seems really identical and this part is three times less expensive....Any infos about the possibility to use a ssm2210 in a ssl9k mic pre project?
Sorry if I'm wrong, but it would be so nice if this part could correctly operate :green:

 

[shabtek]

@fucanay: signal has max swing of




+/- 15v (30vpp) before clipping as opposed to 36vpp. translates to less headroom...will most likely work well with 15volt rails

@warpboy that AD part is supposed to be a drop-in replacement, should work well though is a different package: get the dip and use a socket in the pcb---you will need to clip off a few socket legs and slightly bend to get it to fit. keep track of pin-out and orientation

 

[Arie89]

Hey, big newbie here, but just wondering how much a channel of DIY SSL would set me back? I love DIY but can't always afford it lol....

Thanks!
Arie.

 

[clintrubber]

Out of curiousity, is the original SSL-schematic of this preamp available somewhere ?

The search-function here didn't... etc

Thanks,

Peter

 

[signalflow]

Was wondering if anyone has used the audio maintenance 2k2 dul rev pots for this project and if so how they wired them up. Here is the link.

http://www.audiomaintenance.com/acatalog/om-01-060_extended_info.html

Thanks for any help you can lend.

 

[basscakes]

I just got the the AML pots and have ordered most of the other parts, but I am having 2 problems---
Cant seem to find 50K resistors for r81 and r117 Am I losing my mind?
Also, will these inductors be fine? Mouser Part # MICC/N-150J-00
Thanks in advance...

 

[MartyMart]

[quote author="basscakes"]I just got the the AML pots and have ordered most of the other parts, but I am having 2 problems---
Cant seem to find 50K resistors for r81 and r117 Am I losing my mind?
Also, will these inductors be fine? Mouser Part # MICC/N-150J-00
Thanks in advance...[/quote]

E12 series resistors will give you 47k and 56k, I think E24 gets you a 51k and I would think that's close enough.
You could measure a few to get a "closer" to 50k value .. but I've never seen a 50k r !
Or wire in series a 47k and 3k3 ....
I've just ordered inductors from Rapid and they were quite small, like 1N4001 size , From other posts and the PCB space these look right, they were 24 pence, so 44 cenys or so.
MM

 

[basscakes]

I figured that 51K was probably fine, thanks for the info! As for the inductors, I am going to try the ones I posted from Mouser, but if they show up and are the size of a Kosher Dill, then I will find something else. They were a cross reference for the part part on the BOM I used.

ONE more question... I think the Toroids from Digikey have gotten out of hand price wise, so I was thinking of using the ones from Antek (par Metal guys) but I am not very good at figuring out what power rating I need. I was going to get a 20-0-20 but I am not sure what VA I need to power 4 pres using Keith's PSU...

 

[MartyMart]

[quote author="basscakes"]
ONE more question... I think the Toroids from Digikey have gotten out of hand price wise, so I was thinking of using the ones from Antek (par Metal guys) but I am not very good at figuring out what power rating I need. I was going to get a 20-0-20 but I am not sure what VA I need to power 4 pres using Keith's PSU...[/quote]

I've asked a similar question and it seems like 30VA/35VA should be fine and dandy for 4 !
MM.

 

[basscakes]

Looks like I have a choice of 20VA or 50Va, so 50VA it will be...

 

[MartyMart]

[quote author="basscakes"]Looks like I have a choice of 20VA or 50Va, so 50VA it will be...[/quote]

That's fine so long as you're not thinking of a 1u rack case !! :wink:

 

[basscakes]

[quote author="MartyMart"]

That's fine so long as you're not thinking of a 1u rack case !! :wink:[/quote]

The height is listed at 1.6 inches... So I would assume the 20VA is more than fine for 2 channels, as I am going to build 2 channels and then decide if I want more channels (got a bunch of boards), or move on to something else. I should probably only build 2, as I have plenty of clean sounding pres and not much for "Tone Painting". Choices, Choices...

 

[kato]

The 20VA toroids from par-metal actually spec to 25VA.

Seems that you should be able to power 4 channels with one AN-0220.

 

[basscakes]

Thanks Kato, I appreciate the help. I will report back on my experience with these later.

 

[marshman]

This seems like perhaps the new help thread for the SSL9K, so I have a question.

I have built a pair of these and they both seem to be working fine with one small exception. When I move the gain pots, I get a scratching noise. I have replaced the pots with spares and I still get the same thing, which leads me to believe it is something electrical, not mechanical.

I am using all wima and nichicon caps, and the 2k2 pots from Audio Maintenance. I have the JLM go between on the input as well.

Anyone else have this problem? Any ideas, suggestions?

Thanks!

Marshall

 

[kato]

Hey Marshall,

I've read that "scratchy pot" when the pot isn't actually scratchy is the result of DC getting into the amplification stage. In other words, something is wrong with your servo circuitry.

Unfortunately, I don't know how to help you troubleshoot this but hopefully this can steer you in the right direction. Let us know if you find a solution,

Kato