Test & Measurement interface for Soundcard

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#42
Neither, but it will entertain many.
Click to expand...

But mine measures better than yours, so.......


I personally use the FFT analyzer to look at the distribution of harmonics when designing an amp. I have also seen the "interface" change this spectrum. My first interface was a 50 K pot wired across the 8 ohm load resistor. The wiper of the pot went to the sound card. I noticed that the frequency response of a SS amp known to be flat to nearly 1 MHz changed with the pot setting. A 500 ohm pot fixed that, and is what I have been using for 5 years.
 
#44
It sounds like the big brown trucks from UPS will busy. I am expecting deliveries from Mr. Millett Mouser, Digikey and Allied. BTW the polyfuse on the BOM is not in stock at Digikey, it is in stock at Allied.
I Hope that all of you experienced test bench hands are willing to share your techniques.
DT
All just for fun!
 
#45
Got mine today.

Looks like Digi-key found out there was demand for the meter. It's up to $61 ea and non-stock. No good price breaks that would allow us to make a group buy, cover shipping, and still save money.

I guess I'll start stuffing it with everything I have in the shop, and then order what I don't have.

I found the data sheet here:

http://www.redlion.net/Products/Groups/AnalogInputs/MDMV/Docs/09002.pdf

I've got meters that are electrically compatible, but they are all too big to fit the opening.
 
#47
TheGimp said:
Got mine today.

Looks like Digi-key found out there was demand for the meter. It's up to $61 ea and non-stock. No good price breaks that would allow us to make a group buy, cover shipping, and still save money.

Yes Digi-key sucks,It looks like they have 16 in stock now, however the price is still $61. I spoke with a CSR and they are not willing to drop the price unless we have a quote or screen shot reflecting the lower price ,I do not ,so if anyone does please save it and pm those to fellow diyAudio mates placing an order, myself included that would be much appreciated.

Thanks
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#53
I use the M-Audio Audiophile USB for measuring loudspeakers with the ARTA suite of software, and it has done well; I intend to use it with Pete's interface to start up the learning curve on measuring amplifiers.

The Audiophile USB is discontinued, but appears regularly on eBay. Also the Emu 0404 USB, of which I've only read about, should be a good current production choice -- one plus is both balanced ins and outs, something my card lacks.

Regards,
John

BTW, my PCB got here today. Thanks Pete!
 
#55
Thinking about using batteries for mine. Anyone know much current it draws. BTW, You can substitute the 50V .1uf caps for 63V, they are in stock at Mouser and they have the same lead spacing. Mouser also has the That corp balanced driver and receiver, I think.

Thanks

JimS
 
#57
Has anyone completed this project yet? For me it will be the exception rather than the rule. It will be all neatly in the box, no wires stretched out across the bench. Is a plan needed to keep all the pieces parts including that $61.00 30-pin connector neat and clean in a row in the face plate? Not too tall not too short, just right!
I do not want to attempt Mr. TubeLab’s propane torch disassembly technique.
DT
It is all just for fun!
 
#58
I thought Digi-Key had the rt angle connector.

Two orders sent out last Wednesday. I spent the weekend in SC taking care of my dad and just got back this evening.

I had one part on back-order and forgot the right angle connector. DigiKey said they would add the connector to the back order. I think the bo was a driver (DRV134PA).

I may be delayed because I didn't order resistors, thinking I had them all. Not.

Oh well. Another order will probably be in order.
 
#59
grufti said:
Those are all easy. It is the 30-pin right angle connector that's driving me crazy.
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That connector should be available at Digi-Key. Note that it is a "Value-Added" item - that means they do not have it in stock until you order it. They get full-length strips from Samtec (100 or more pins long) and cut them to the desired length after you order them.

Beacuse of that, they will always show up as "zero inventory" and initially as "backordered". But unless they are out of the base (full-length) material, they will still ship them to you (cut to size) in one day.

Pete
 
#60
TheGimp said:
I think the bo was a driver (DRV134PA).
Click to expand...

Newark shows over 1,000 pcs. DRV134PA in stock. Yes, I know it's a pain to have to order parts from several distis to find the parts you need...

I gotta tell you, the semiconductor industry pulled back so hard during the onset of the "economic downturn" that we're in a horrible supply crunch now. I needed to get a battery charger IC to fix a headphone amp, and had to source them from a disti in Europe... for an American IC.

Pete
 
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