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Thursday, May 22, 2008

New PCB for SC-1 Solo Mic Pre Kit + DC-DC Converter PSU

Thursday, May 22, 2008 11:04:38 PM (Central Daylight Time, UTC-05:00) ( )

So I'm getting ready to send out the new DC-DC prototype... and with the new PCB size, it will fit the smaller case that I wanted to use in the first place.

I created a combined PCB of the SC-1 and this new DC-DC PSU... The whole PCB is sized so it fits perfectly inside the case, and just needs to slide right in. So we'll see how it goes.

I did a little Photoshop trickery to make it look a little realistic... it's not perfect, but good enough.

I'm trying to minimize wiring work, because this is the most tedious of all jobs. So the only wiring work that needs to be done here is for the input and output xlr and the LED power ON indicator.

Alrighty... ordered some 10pcs of prototype PCBs from the factory. Should be here in a week.

These prototype PCBs alone costs $18.60 each. I hope I didn't make a mistake on these board layouts otherwise, that's wasted money.

We'll build 4 prototypes and if they all work, and no bugs... we're going into production very soon... maybe the final production PCB will be ready by end of June. I still need to figure out what to do with the case (finishing)... maybe use a silkscreen to label the front panel. I'll have to outsource that to a factory.

If this gets launched in June, it will also mark the 1st anniversary of FiveFish Studios. We launched the SC-1 kit about the same time last year.

The SC-1 Solo will not be sold as a kit but as a finished product, complete with case, wall wart, etc.

Yes!... it is RED. and it looks great.

So far, this is the biggest sized PCB I've ever ordered. Hope to populate this board and test it ASAP. I can't wait.

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Wednesday, April 02, 2008

SC-1 Solo Preamp (Prototype) powered by 12VDC wall wart (or battery)

Wednesday, April 02, 2008 7:22:20 PM (Central Standard Time, UTC-06:00) ( Power Supply | Project Kits | Recording | SC-1 Preamp Kit )

I'm making CAD measurements of trying to fit an SC-1 preamp plus a Mini-IO module in my extruded aluminum "brick case"... hmmm.. its a tight fit, the TRS jack is almost hitting the top of the case, and the soldered terminals touching the blue trim potentiometer of the SC-1.

I'm concerned about the terminals touching the blue potentiometer. It's plastic so it's non conductive so maybe it's not even an issue. If the case has an extra 0.1" height, it would have been fine. But given this TRS jack is the hi-Z input, I'm afraid it might have side effects.

For sure a VU-meter will fit inside without problems.

Unless I can find a slightly taller case, the SC-1 Solo will probably consist of the SC-1 and a VU meter, plus the PSU board. (at least, for this 1st prototype I'm making.)

My eventual goal is to find a case that will be tall enough to fit an SC-1 plus the IO-module (with input/output transformers)/Mini-IO, and maybe even the VU meter. Now, that would be some hot SC-1 Solo product!

Okay...did the CAD drawings, created the CNC programming then tested it on some .125" scrap aluminum. Looks good.

Loaded the "real" panel and let the program run... X fingers!

Yes... everything fits like a glove! No more manual drilling with a drill press or filing around to make everything fit.

Of course, it takes hours of prep work on the CAD/CAM, testing and final setup... and only about 3 minutes of actual CNC time on the router. Shocked

Some photos:

Did the rear panel CAD/CAM/CNC today... I goofed up making measurements on where the DCJack holes should be... so had to do some fudging with a manual file. It's okay... this is just a prototype. But I fixed the CAD drawings to reflect the proper dimensions.

Some photos:

The DC-DC Power Supply installed on the rear panel.

XLR jacks installed

I do have one concern here and that is... with the XLR jacks so near to the DC-DC PSU, will it affect the preamp's performance? From my limited bench testing, it doesn't seem to be... but the proof is in the pudding... so we'll see how this prototype performs.

I have seen one preamp though (and I'm not naming names) and they have a DC-DC PSU, and a microprocessor, and it's associated crystal clock, and 2 preamps crammed into one small case.

By comparsion, what I have is "roomy" compared to what's inside this other preamp.

And finally... a preview of things to come. Rear View of the SC-1 Solo case.

Arghhh... those XLR bolts are too shiny! Will have to replace them in the final prototype with stainless steel bolts to cut down the bling factor.

I'm also using a flat head stainless steel screws to attach the plate to the main case... but I can't properly chamfer the hole openings because the plate is only .036". If it was thicker, I can get away with it. So the (4) corner screws will have to be replaced with pan head screws (also stainless steel)

All these "minor" fixes will be done as the very last step.

SC-1 Solo Preamp

Features:
- Low-Noise, transformerless, High-Quality Mic Preamp
- All solid-state design, using chipsets from THAT Corp and Burr-Brown
- Soft-start, slow ramp-on +48V phantom power
- Crystal clear Red LED indicator for phantom power
- Electronically balanced input and output stages
- 12-position Grayhill gain selector switch
- Gain range from +6 to +72dB, in 6dB increments
- Input RFI protection
- Input clamping protection
- Output surge protection circuit
- Output RFI protection
- Powered by a linear, regulated 18-0-18 Volts supply, with +48VDC for clean power delivery
- Reduced clicking and popping when changing gains
- High quality Bourns, sealed, conductive plastic potentiometer for volume control
- High quality C&K PCB Mounted switch
- Gold-plated, machined, low-profile IC sockets
- Use of high quality 1% Metal Film resistors, and high-quality ceramic and electrolytic capacitors
- With 5-LED VU Meter
- Neutrik XLR input and output jacks
- Powered by 12VDC wall wart

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Wednesday, March 26, 2008

DC to DC Switching PSU (12Volts to +/- 18V & 48V)

Wednesday, March 26, 2008 6:31:57 AM (Central Standard Time, UTC-06:00) ( DIY | Power Supply | Project Kits )

It's done :) My switching DC-to-DC PSU.

I've been working on this design on and off since October 2007. Several prototypes later, and many $$$, I'm happy with it. All output voltages are regulated and adjustable via multiturn trimmers, +18, -18 and it's a true +48V phantom power... all derived from a single 12Volt input. Outputs are short circuit protected. Just a big spark, but keeps on ticking. Nothing gets blown.

http://farm3.static.flickr.com/2322/2365867488_5f14133bbd.jpg

Powering my preamp and my I/O module (input and output trafo, pad, polarity) with Active DI, via 12V wall wart. No hashing sound, no RF leak, no noise. (Well, okay... when you're at 66-72dB gain... but could be caused by everything not in a metal enclosure.)

http://farm4.static.flickr.com/3068/2352224005_5dc492842c.jpg

Output on all 3 rails are typical like below:

http://farm3.static.flickr.com/2376/2365001131_8b2c1a26ac.jpg

Switching spikes on the DC output of about 0.06Vpeak-to-peak, and interval of 33.333Khz. I can set switching freq. to about 60Khz but the spikes get larger.

So I compromised for smaller spikes at a lower switching frequency... i.e. smaller spike/transients, less RFI energy emitted, less chance that it will interfere with sensitive mic pre circuitry.

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Thursday, March 20, 2008

Mic Preamp SC-1 with Cinemag input/output transformers

Thursday, March 20, 2008 3:54:00 PM (Central Standard Time, UTC-06:00) ( )

Yes!... got some time to do some electronics work today... away from the purchasing role.

Finally built and tested the final, final, FINAL prototype of the IO-module. And it's great.

Man, I love the sound of the Active DI going through the input transformer. Actually, love the sound of anything going through it.

Some pics:

Now, I haven't sent the PCB out for mass production yet, but I have (4) prototype PCBs left. I'm keeping (2) so that leaves (2) extra ones...

I know somebody out there is waiting for this patiently... you're getting these PCBs way in advance of the others.

I'd need to drill some square cutouts first on it... like this

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Tuesday, February 26, 2008

ATI X800XT Fan Upgrade for Mac G5

Wednesday, February 27, 2008 5:47:28 AM (Central Standard Time, UTC-06:00) ( )

So I bought this AT X800XT card... back when it was $499... the first one after a few short months, the fan got noisy and was dying... I sent it back to ATI, then ATI sent back a faulty unit (blocks appearing on the screen), so I had to resend it back again and then I'm good again for a few months.

This morning, my 2nd monitor (A Samsung) wouldn't come up. Just black. At first I thought my monitor died... bummer. That got me thinking... maybe I should get another 23" Cinema LCD :) The prices have fallen down to $799. (I got mine back at $1999).

Then just to be sure it's the monitor, I swapped things around... and lo and behold, my Samsung monitor was working!

I opened the G5 case, and see that the video card fan was totally dead... not spinning. NOT GOOD. I don't know how many days I've been running with this fan not spinning.

So today I pulled out the X800XT card and put back in my stock video card (fanless) just so I can continue working. It's a good thing to have spares.

I'm not going to bother sending this back to ATI again. I bought some replacement aftermarket fan and will try to fix this thing instead. Remove the junk ATI fan and use another one instead.

Will update this post as I go....

I just hope the 2nd video port isn't permanently damaged.

I just noticed today that due to the failed fan on my video card, it almost fried the components at the bottom of the PCB. Yes, it smell burnt. I was kinda disappointed when I saw this. I'm thinking maybe my video card is fried (literally).

Remove the old crappy fan from my ATI card. This fan sucks. Do you hear that ATI?????

You can see the old thermal paste sticking on the cpu. So we'll need to clean that out.

And here's the clean chip. I just used an old cotton shirt, and an old toothbrush. Wiped it clean and made it shiny.

I'm using a Zalman VF700-Cu Quiet VGA Cooler fan. It's pretty cheap. $20 I think.

It also comes with some blue small heatsinks for the other chips (RAM?) on the card.

The connector of the Zalman fan isn't compatible with the headers on the video card.

So what do you have to do? Get a cutter, cut the wires on the new fan, cut the wires on the old fan and solder them together a'la Frankenstein. :)

I used some heatshrink tubing to insulate the connection. You can see it in the photo below, along with the new blue heatsinks.

Then... the moment of truth... Put it in my G5 and see if it still works. (Remember, the parts at the bottom of the PCB smells burnt and looks a little crispy.

And the result....... IT STILL WORKS! Now my second monitor works, and not shutting down (turning black). I've got good video on both monitors! :)

So that's done... total time, maybe 30 minutes.

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