SSL 9K Mic Pre

[kato]

[quote author="mitsos"]
Then I bought these recently to check if I killed one of the MATs. Still waiting for them after about ten days, hope they'll get here!
[/quote]

Thanks for the eBay seller link. I just ordered a couple.

I've had items shipped via Media Mail take 10 days to get to Florida.
And 12 days to get to Hawaii. So that's probably no cause for concern just yet - coming from Taiwan. His feedback is 100% positive. Hopefully all will work out.

Good tip. It's hard to find the LM394 in the US.

 

[RedNoise]

Hi there!!
LM394 directly replacing Mat02???No resistor change , or something like that??

 

[kato]

[quote author="nielsk"]I believe paralleling the extra transistor would lower the noise floor somewhat, & not be to difficult to adapt a wire wrap socket to the dual footprint.[/quote]

Niels, you can pretty easily clip off two pins of a DIP8 socket (pins 4+5) and fit it pretty easily in that footprint. I was surprised how easy it was. Some bending required.

Don't know about the THAT chips. But if it works, do let us know!

That's a difficult to obtain part. Although Futurlec has IC versions of the LM394. Not sure it will work, but the pinout looks to be the same.

@Rednoise - yes. It's been mentioned in another thread but I can't find it now. The LM394 is functionally equivalent (just a pair of matched transistors), and a drop in replacement. Others have reported success doing so.

 

[geoff004]

[quote author="mitsos"]Still waiting for them after about ten days, hope they'll get here!
[/quote]

Yeah - thanks for the link.
I ordered a pair too.
Maybe you could post when you finally get them so we'll have some idea about how long they'll take to arrive.

And could someone tell me what LED use to indicate phantom power on these things and how to hook it up? I can think of one way, but I don't imagine most LEDs can handle 48v.

 

[kato]

re: LM394 from ebay seller in Taiwan

Mitsos, mine arrived today - 8 days. Just FYI.

 

[flintan]

[quote author="geoff004"]And could someone tell me what LED use to indicate phantom power on these things and how to hook it up? I can think of one way, but I don't imagine most LEDs can handle 48v.[/quote]

I would connect the led to somewhere else than from PP 48V. But it's not the led that suffers from high voltage, the biggest drop will be on the series resistor so if you use a something 2W resistor it would be ok i guess.

 

[geoff004]

So I just finished my 9K pre (2 channels) and.....
it really does sound great!

Here are a couple things I did - maybe this can help others:

everything got mounted in a middle atlantic 1 ru case. I wouldn't say it's tight, but there's not really any extra room.

for the +15v I used the diode trick listed on page 7, but there's a little more. I used 1N4004s - 4 in each direction instead of 2. Then I also added a 3.9k resistor between both the + and - and the ground. This gave me a voltage of +15.5volts. I built this all on a little PCB board - maybe 1.5" x 1.5".
checking voltages before hooking everything up is key. I also checked my -18v with a 3.9k resistor between it and ground to check the proper voltage.

I ended up using the Antek AN-0222 transformer - seems to do a good job. Mounting it was tricky. It's just kinda wedged in place between the edge of the rack case, the power switch, the AC outlet and the fuse. I bolted it to a piece of aluminum angle. But I also had to grind the top of the bolt down so that it'd fit in the case. It's not going anywhere.

I used the ebay replacement for the MAT-02 listed above and it also seems fine. I don't have any other reference as far as those amps go, but I will say that I wouldn't hesitate using the pre for makeup gain with a passive summer. I'd also say that it easily sounds as good as my gourmet 500 series pres.
Other than the LM394, the power transformer and the rack case, everything came from Mouser.

I also built the stepped attenuator switch in place of the traditional pot. I don't mind the size of the steps.

The pre does seem to have an amazing amount of clean, quiet gain - I look forward to plugging my R121 in to it.
Thanks to everyone who's posted alternate parts, BOMs and other hints. It's really nice when things work when you turn them on for the first time.

 

[RedNoise]

Hi Goef!!!
some pics???
thx!! :green:

 

[geoff004]

Does any know what rating fuse I should be using? I put the smallest one I had in it - I think a 1.5a / 250v.
Picts:

 

[3nity]

i wouldnt use more than a .5A!!!
The metal bar at the left...is it touching the toroidal?
I would avoid touching the toroidal from top!

 

[khstudio]

[quote author="3nity"]
The metal bar at the left...is it touching the toroidal?
I would avoid touching the toroidal from top![/quote]

I saw that too. :shock:

That is NOT a good idea :!: :!: :!:

 

[geoff004]

[quote author="3nity"]The metal bar at the left...is it touching the toroidal?[/quote]

It only touches the chassis and the rubber pad on the top of the toroidal. Maybe I'll wrap it up too just for good measure.

 

[kato]

Looks good. I'm not too worried about the metal bar. It just like attaching a toroid to an enclosure, also metal.

I like the big heatsink. Is that one heatsink for all three regulators? I'm not quite sure how you did that.

Your hookup wire looks especially thick. A little more difficult to work with I would think.

.33A fuse is plenty. Nice work! Kato

 

[geoff004]

[quote author="kato"]
I like the big heatsink. Is that one heatsink for all three regulators? I'm not quite sure how you did that.
[/quote]

the heatsinks were individually bolted on to the voltage regulators. then I bent the leads over, then soldered them in to place. It seemed like the best way to make it all fit - and still keep everything separated. The output holes below them are still easy to get to.

 

[s2udio]

[quote author="kato"] I'm not too worried about the metal bar. It just like attaching a toroid to an enclosure, also metal.[/quote]
I would be !! ,especially if it makes a "shorted turn" through the toroid.
Just shorten it a bit to the outside diameter of the transformer
and put a bit more insulation under the bar so the windings dont short
to the metal at some time in the future :wink:

 

[khstudio]

The Metal bolt can only connect to the chassis on ONE Side!!!

If that top metal bar (that's connected to the top of the bolt) touches the chassis you'll be in for a surprise. :!:

Note: this has never happened to me but I've read about the rules & warnings SEVERAL times.

Good luck. :razz:

 

[geoff004]

I totally get it now - the closed loop causing a 'shorted turn'.
Basically I went through and removed any chance of making a loop with a lot of electrical tape - I didn't want to have to change anything on the inside, being that it's tight already.

I'm glad I posted the pictures.
Thanks all.

 

[uncle]

Hello,
If I use OPA2604 instead of TL052, can I power SSL9k with +/-24V in order to get better headroom?

I'm going to use LM394 instead of MAT02, also

thanks

 

[khstudio]

[quote author="uncle"]Hello,
If I use OPA2604 instead of TL052, can I power SSL9k with +/-24V in order to get better headroom?

I'm going to use LM394 instead of MAT02, also

thanks[/quote]

From what I've heard (from Pro engineers) is the SSL9k pre kicks ass as is!!!

You'll also have to change the 5534's to OPA604's... who knows, it may be killer. Just make sure ALL components can handle 24v.
You may also have to add or adjust the IC's stabilization caps (feedback caps) if you get oscillation from the 2604's.

This is all the help I can give.
Good luck.
:green:

 

[rolo95]

[quote author="Neeno"]I hope this can help you...
This is a little pdf file i've done with all the documentation you need for the ssl9k and a parts list too...

http://www.studio21.ch/diy/ssl9k/DIY_9k_preamp.pdf

I'm also drawing the frontplate of the original ssl9k 4 channel preamp.
I would like to build a preamp unit like the original one... but i have some difficulties develop a little board with all the switches (i don't have good pcb skills... ) and a little board with the monitoring section (i think is a little summing amp with an headphone amp)... so if anyone can help me i will appreciate it...

Neeeeeeeeeeeno[/quote]

Link dont work