Test & Measurement interface for Soundcard

I especially like tubes on days like this -- 5 below in upstate NY, low teens here in NJ.

We had to make an unscheduled trip to West Virginia with about 5 hours notice. We left Ft Lauderdale yesterday afternoon. It was 84 degrees and raining. We drove like crazy people and stayed just ahead of the storm. We have arrived at Sherris mothers house just as the snow is starting to fall. 6 to 12 inches are expected by Sunday. My flip flops and T shirt aren't going to cut it here, and there are no tubes in sight.

The white stuff is headed your way too. NJ could see 6 to 12 inches by Monday.
 
has anyone used anything other than the M-Audio cards? I cannot stand M-Audio as a company and refuse to use there products. had a very bad experience with them once. I discovered a bug in there software for there then new Audiophile 7.1 card. when you adjusted one of the controls in the software. (balance or volume cant remember now) would cause the card to emit a loud white noise type sound. I called there tech support and after getting the run around and finally getting to someone that understood what i was trying to explain....there response...oh yeah, we know about that. and i asked if there was a software update coming out to fix the issue...there response...and i kid you not....no, we don't care!

I was floored! and when pressed about the issue, he just got very snippy and said if i don't like it, return it. so i did...

Zc
 
Do you also collect cars for the front lawn?

I am sure that there are plenty of places in this state that fit the stereotype shown in movies, but this little town of 5,000 is relatively civilized. I haven't even the usual "redneck lawn ornaments" (car engine hanging by a chain from a tree) here that we have in Florida.

I cannot stand M-Audio as a company and refuse to use there products.

I have the same opinion of them as a company after buying one of their high end cards (Dman 2044) several years ago. Right after I got it they decided that there would be no further driver support for the card. This rendered my $200 card worthless once I upgraded my Windows ME machine to XP. Their answer was to buy a new card, but they offered no discount or even an allowance for my $200 brick that was about 2 months old.

I used some other sound cards for a while but got lucky when I got mis-printed add in the mail from the Guitar Center offering the Audiophile 2496 for $99. Of course they refused to honor the add, but Sam Ash music had a match price policy and they did meet it! It is a very good card, but when I wanted an audiophile 192, I went to Ebay. I got one for $67 (no box or software).
 

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The ESI Juli card has a following, I considered this one. I bought an E-MU 1212M on sale at Frys Electronics. These cards only have stereo (2) inputs and outputs.
In any case if you are buying a card to use with Pete’s interface get one with balanced ¼ inch TRS inputs and outputs.
DT
It is all just for fun!
 
First: Great Board Pete! One to definately do!

Need big tube amp here! Hit -36 C or 31 F a week ago overnight. Didn't warm up much during the day. In the last 4-5 days has slowly warmed up to -12 to -13 C or about +5 to 10 F and started snowing yesterday. Just had an inch before since beginning of Dec. Usually snows around Nov 1 but was quite warm all Nov. Usually more snow here as usually 6-12 in. now. I'd say 2-3" now and it sure feels balmy. El Nino come back, as its supposed to cool off again in 5 days. I've seen it rain here every month of the winter (rare though) in last 25 years. Winters seem to have gotten warmer but still too long here! It does keep crime rate (B & E , Vandalism etc) very low in winter. I guess good time for projects.
It can hit 37 C 100 F in summer (rare again) Usually 20's to 30 C for high or 70-80's F An increasing number of people have air conditioners. I'd say 70%
 
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Hello All,
The USPS and UPS delivery trucks have made their stops and the backorders have been filled. The interface is complete and looks just like Mr. Millett’s photographs sort of. Some of the resistors and capacitors are different colors.
The testing begins.
Back to the topic of the thread; there was frost on the windshield this morning, this afternoon was sunny and low 50’s F.
DT
All just for fun!
 
Just got my package. Nice proffessional looking kit as you would expect forom Pete!

That said, I was doing some browsing. That always gets me into big trouble! And I have to admit i'm really tempted by the super cheap Rigol 50MHZ 1052E, and 100MHZ 1102E DSO's.Lots to read on the net about these. Some seem to like them just as well or better than the expensive TEK TDS starter DSO scopes. How would something like that compare to Audio Tester on the PC? How about the FFT function? Either of these would suppliment a new BK 30MHZ analog scope, and mainly be used for tube equipment. I'm getting alot of pleasure from that new analog scope BTW. Super Geek thrills!
 
George, Unscheduled trips are usually not good.

Sherri's mother fell down the stairs, so we zipped up here as quickly as possible. There was no harm done, and I bounced down the same set of stairs last night. Thank God for thick carpet. I have already fixed the broken rail, but some long term changes need to be made.

Snow is just melting off here now that we got last Friday....I-26 was turned into a parking lot

We turned north off of I-26 on to I-77 in Columbia SC. I-77 was shut down by a semi crash in southern WV about 2 hours after we passed through. Some people were stuck out there for 10 hours. We got lucky, the worst weather we saw on the whole trip was rain in Florida. It took us 3 hours to go 50 miles.

I left warm and rainy Fort Lauderdale to enjoy what the TV is calling the "Blizzard of 2009". :D The total snow fall here was about 10 inches over 3 days. That is better than people a few hundred miles east of here got. The temperature has ventured above freezing today for the first time since we got here, but a lot of the snow has already melted from the roads because of sunshine and salt.
 
What are the general feelings about using an digital oscilloscope for things like THD measurement?

It depends on the scope. Many older digital scopes have 8 bit A/D converters (including my Tek 2213) which limits the dynamic range to about 48 db. Useful, but not good enough for analyzing that SS amp with .000001% distortion. If you can see the individual harmonics and gather information about their relative amplitudes, then it is useful. Absolute amplitude may not be too accurate, but you can do a lot without perfect absolute measurements. It is also possible that your scope has more bits too. Each additional bit of resolution should gain you about 6 db more dynamic range.

We have some Agilent Infinium scopes at work that are actually Windows XP computers with 4 X 16 bit 100 MHz "soundcards". You can surf the web on your scope. Special software can do FFT's and even demodulate complex RF signals. Nice but they cost something like $25K!
 
It depends on the scope. Many older digital scopes have 8 bit A/D converters (including my Tek 2213) which limits the dynamic range to about 48 db. Useful, but not good enough for analyzing that SS amp with .000001% distortion.

This is an 8-bit Tek TDS1001B, 40 MHz (entry-level unit). Cheap, but nice to have around and interfaces with a PC.

I'll be measuring my Tubelab Simple SE ! ;-)

If you can see the individual harmonics and gather information about their relative amplitudes, then it is useful. Absolute amplitude may not be too accurate, but you can do a lot without perfect absolute measurements.

Great, I'll post what I find. I think I'm reading a little less than 2% THD on my Simple SE with some JJ 6L6s and Edcor CXSE transformers...

Dave