DIY Mic Pre Kits, Lunchbox Mic Preamp Kits, Power Supply Kits

SC1-mk2 Mic Preamp Kit


Now, with optional Input Transformer option!
Improved design, improved performance, design refinements.
Uses the same "footprint" as the original SC-1, so you can use this new kit in our 1u SC-1 Rack Case.
Have 2 channels of clean/uncolored preamp and 2 channels of "flavored" preamp
Local PSU regulation for a 2nd-level filtering of power supply.
DC Servo, Dual Buffered design
THAT and Burr-Brown chips
Using uMetal shielded Input Transformer for excellent magnetic shielding
6dB gain steps in the lower range, and 4db gain steps in the upper range for more precise control
Using standard 0.1" pitch pads for power and XLR connections, Molex 0.1" compatible
Bourns, conductive plastic potentiometers
Grayhill, mil-spec selector switches
0.079" thick PCB with 2 oz. copper, Solder mask, silkscreen, plated-through holes, Lead-free Rohs

More ordering choices, more package deal combinations for better discount!
Flexible ordering with or without PSU, Rack Case, Input Transformers, etc... to fit your DIY budget.

More photos:

_________________

I'm Drooling! It looks like you pulled a fast one on us.

Now I'm going to have to save up some more money.

Are these ones just as flat or is the transformer giving it a darker feel?

How is the brake up when overloading the input? Is it like hitting a Neve to coaks some good harmonics out of otherwise clean source?

_________________
Mulmany

Make it safe to look like an idiot,
cause it might just sound amazing.

There's a loading resistor on the secondary of the transformer. Right now it's set to give some heft and depth to the low freq, while at the same time keeping the high frequencies remaining clear and clean. Hard to describe... I'm not big on flowery words.

You can change the load resistor to give it a darker sound, to the extent that you can start dulling the high freqs a bit.

Either way, with an input trafo, it does have a different flavor/mojo compared to a non-trafo SC-1mk2 or SC-1.



Don't forget the Neves also have an output transformer that adds to the flavor. This one does not have an output transformer.

You can turn down the gain and adjust the TRIM knob down and feed the pre a larger signal if you want to saturate the input trafo more.

_________________

This caught my attention... would it be possible to put a potentiometer in there for "variable flavor" lol?

I guess so.... wire it as a rheostat. The load resistor also affects the free gain caused by the trafo. i.e. more loading, more attenuation of the signal... which then I guess you can turn the preamp GAIN knob UP to compensate for it. Hmmm...

I think a 10K pot value should do it... don't forget to put a series resistor so there's at least a minimum value at the extreme end of the pot... and you don't short the secondaries to 0 ohms.

It's DIY... experiment. I have not personally tried using a pot. But I have tried different resistor values in that location.

I will have to try that one of these days!

_________________

Mmm sounds interesting. You seem kinda hesitant at first? Anything to watch out for in doing this?

hopefully I'll be able to afford a pair of these soon and try it out maybe

No, not hesistant. I just didn't thought of using a pot permanently in that location

While testing the prototype, I did wire a small trimmer so I can adjust the trimmer and listen for the sound I like, then I removed the trimmer and measured the resistance across it and substituted a fixed resistor. Never occured to me that somebody may prefer a different sound than what I picked and therefore would want a different value.

_________________

Ahh ok cool.

I figured that pre's like the twinfinity use that "variable tone" knob as a big selling point. Could be a pretty cool feature if it works well.

i can't wait to hear what the mk2 sounds like!

I can't believe it. You went ahead and did exactly what I was hoping you would do! Even the better footprint on the end of the board for the xlr wires...

I still have one original SC-1 to put together completely....I'm pondering if you have some suggestions for a clip of some sort to use with the xlr mount on the older boards?

But otherwise WOW!!!!!!! Such a surprise to see this come about I'm glad I didn't buy 4 SC-1's and still have two empty slots in my rack. I really hope this raises the profile of your kit I'll have to do some math on the cost...but I think there's a great possibility you'll be making me poorer quite soon!

Great minds think alike

I had to test the new circuit on my TS-2 preamp first, before implementing it on the mk2. Then did a prototype mk2 board, test, then a couple of weeks of waiting again for the production boards.



You can use flying leads with the male/female disconnect on the cable itself.

_________________

Hehe...best to assume they're great minds, rather than crazy addled ones!

You know, one day you'll have to make a preamp with tubes, 2520 opamp and THAT1510 compatibility you know Just to make sure you cover all the options...... I'd be more excited though if someone came out with a tube compressor or something similar though... In terms of kits out there there are a lot of preamps, but not much in the way of things like compressors.

Though true, there are not too many tube preamp projects out there, although I did notice a new one of those the other day from another company.



Sounds like the easiest way. Though I have found of late where I live it has been impossible to buy headers. I'll see how I go..might be able to find something different.

Just slapped down the money for two channels with transformers on the table, so I hope it's worthwhile in the end owel. The global financial situation is not so happy PP is quoting me a rate of 61cent us to the aud, so this transaction is a little painful! (But then again I generally wont get a hideous bank fee charge when using PP, so sometimes it's worth the slightly less than great exchange rate) But I guess it means I can fill my rack and not worry about whether or not the world economy crashes into a brickwall again. I suppose on the plus side, if it does, I can sit in a corner and record audio to my hearts content with my SC-1's...

Stratman

Thanks for the order. I appreciate it.



See this link I posted yesterday. Talk about coincidence.
http://fivefishstudios.com/forum/viewtopic.php?t=439

Not promising anything. I haven't worked with tubes before. But have compiled several vintage books here about the subject so we'll see. I'll start playing around with them.



Thanks for your order. Yes, it is crazy right now.

And then I had to make the painful choice of increasing my kit price on top of all these slowdown.

I realized after paying expenses and TAXES, and looking at the negative number for "income" (and this is me not even drawing a salary in this startup), and the amount of work/time I've put into this... I realize I'm running a hobby not a business. I didn't make any money, and worked myself to death, and only the government benefited from all my hard work. Thanks to the big check I wrote to them.

<rant> Meanwhile, the government is using the money I gave them to rescue these stupid banks who made unwise/risky business decisions. These bank executives should be in Vegas, not Wall Street. But then, even casino operators wouldn't want these bank executives working in their companies.

Right now, almost everybody is afraid and in FREEZE spending mode. Not moving, not buying. When consumers don't buy, businesses don't sell anything. If businesses can't sell, they can't pay salaries or buy supplies from other businesses. So they had to layoff workers, which adds to more consumers not buying. It's an endless spiraling down the abyss. It's FEAR spreading around, getting bigger and bigger.</rant>

I almost decided to close shop. If I didn't make any money, at least I don't have to work so hard to not make money.

But several people have emailed me still requesting my out-of-stock preamps and I love doing this and want to continue doing this, so the only other choice to make is raise prices a bit when I reopen or start selling preamp kits again.

So again, thank you for your order! I appreciate it very much! I do hope you enjoy the new preamps!

_________________

There is the Pico compressor kit (sorta,you get a pcb and ICs)
based on a THAT corp chip but it lacks the detailed instructions Owel offeres with his kits.