John Curl's Blowtorch preamplifier part II

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some random comments --- at the really low end and for profits - where pennies count most -- two wires from each headphone driver would go into 3 wires to plug. Cheapest way... less copper.

But then you have to add extra labor to strip, splice and solder the leads together at the Y split.

I also found a pair of cheap Sony half in/half out "headphones," their MDR-W08's. They also run 4 wires all the way to the jack. So far at least, none of the exceedingly cheap headphones I've checked have a common ground lead.

Seems they use less copper by simply using less copper (the wires inside are quite small in equivalent gauge). The cable construction is like zip cord. Two coaxial leads extruded together side by side. And it makes sense. You don't have to have someone strip, splice and solder the 4 leads off the headphones to the 3 leads in the cable. Instead, you just place an overmold at the Y split and split the leads to feed the drivers. The overmold keeps them from splitting any further.

se
 
Steve E,
You just described the construction on the Sony headphones I am looking at exactly. I wouldn't have thought that they were using a coax cable until it was said earlier. just thought it was a twin lead wire, but I am sure you must be correct. the set am looking at are MDR V-150 models. The kids have some other models but they look like the same construction on the lead wires.
 
Steve E,
You just described the construction on the Sony headphones I am looking at exactly. I wouldn't have thought that they were using a coax cable until it was said earlier. just thought it was a twin lead wire, but I am sure you must be correct. the set am looking at are MDR V-150 models. The kids have some other models but they look like the same construction on the lead wires.

Yeah, that same construction is used on most all cheap double entry headphones. Now, for single entry, something like a shielded twisted pair would more likely be used. And I've seen three twisted litz wire configurations as well.

se
 
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Mooly, I hope that you now do understand WHY you have to specify the operating conditions for what you want. I still would not use an op amp in any case.

:D but if you had to use one was really what I was getting at... think of it as making the best of a bad job... surely there must be one that you have worked with and tried and could live with 90% of the time.
 
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Pavel!!!!!

A used good condition AP System 2 like I use is available for under $8,000.

The software you are using seems to be able to be used with an external sound card to almost match the AP, but it does make up for that by doing a few other things except of course digital audio. But the prices start at $25.00!

Frrgg...

I've been playing with Virtins and it is VERY versatile. But I've had some stability issues with the software, although it *could* be my lab system (Win XP SP3).

jan
 
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I bought Virtins Multi-Instrument SW in Nov 2012 (the price is higher than stated by Ed, but still very very affordable).

Virtins Technology: Turn a PC into Virtual Instrument - Home

I can confirm it had some minor stability issues, but they disappeared after proper installation of card driver.

I agree that the SW is extremely versatile and offers many options of measurements and parameters that most SWs for soundcards do not offer.
 
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Skull Candy don't sell headphones, they sell an ongoing revenue stream for themselves based on making crap headphone cables. Their " warranty" is they'll replace defective headphones for half of retail list (selling replacements direct to you for what they sell them to retailers for so they lose nothing). My teenagers have gone through 5 or 6 pairs in 8 to 12 weeks on average, I looked at the cords hoping to replace them or resolder the connectors - the cords can't be repaired or replaced - far too flimsy for their purpose. Their now a forbidden brand in our house...... 3 or 4 wires don't matter when 1 or 2 break easily and quickly.......
 
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I bought Virtins Multi-Instrument SW in Nov 2012 (the price is higher than stated by Ed, but still very very affordable).

Virtins Technology: Turn a PC into Virtual Instrument - Home

I can confirm it had some minor stability issues, but they disappeared after proper installation of card driver.

I agree that the SW is extremely versatile and offers many options of measurements and parameters that most SWs for soundcards do not offer.

Key for me is simultaneous play and record from different programs. I see ASIO devices require the full pro version.

BTW I find things like $100 just to get bigger FFT's a little "cheezy" considering the best code (FFTW) is free.
 
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OK, now that OP AMPS have been discussed, here is my solution to most buffers. Audible Illusions and Parasound have used it INSTEAD of an OP AMP and we have made the audio reviewers very happy. When they are happy, then I have done my job right.
 

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I bought Virtins Multi-Instrument SW in Nov 2012 (the price is higher than stated by Ed, but still very very affordable).

Virtins Technology: Turn a PC into Virtual Instrument - Home

I can confirm it had some minor stability issues, but they disappeared after proper installation of card driver.

I agree that the SW is extremely versatile and offers many options of measurements and parameters that most SWs for soundcards do not offer.


Thanks for the info. I'll start with the $25 signal generator as we have been using a discrete piece in my test kit.

Now can you tell me how to measure jitter to better than 200 ps for less than $10,000!
 
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OK, now that OP AMPS have been discussed, here is my solution to most buffers. Audible Illusions and Parasound have used it INSTEAD of an OP AMP and we have made the audio reviewers very happy. When they are happy, then I have done my job right.

Appreciate you sharing that John.

I guess its like you say, you have to draw up your detailed specs first.

For my intended use I don't think that would be suitable because the loading on the buffer is non constant with pot rotation. Also DC offset has to be low, because there are no caps coupling the four pots used.
 
Now can you tell me how to measure jitter to better than 200 ps for less than $10,000!

What center frequency? What kind of jitter? What measurement method? ;)

Unless someone is seriously involved in designing "breakthru" digital/analog gear, which will be sold in numbers afterwards, I don't see how small or one man operated company can justify the purchase of AP toy.
IMHO, the main reason to have one is so that you can print nice graphs with that Ap logo in the top right corner, just like everyone else (including mags) does ..

Best,
 
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What center frequency? What kind of jitter? What measurement method? ;)

Unless someone is seriously involved in designing "breakthru" digital/analog gear, which will be sold in numbers afterwards, I don't see how small or one man operated company can justify the purchase of AP toy.
IMHO, the main reason to have one is so that you can print nice graphs with that Ap logo in the top right corner, just like everyone else (including mags) does ..

Best,

I am finishing up an AES 3 master word clock.

If you look at my website Edward Simon & Co. » Home you might see that an AP is not one of my more expensive tools. We explain things in that the turret press cost more than the building, the press brake costs more than I paid for my house and the panel saw, engraver and some of the test equipment costs more than my car.

I only buy tools when the cost of the material it processes costs more than the tool.

So I have spent more on metal than the Turret press and press brake cost.

I used the AP when I was selling used amplifiers from a large sound system replacement. I showed the graphs for each amplifier listed. I did get a message from one potential buyer who after looking at the posting wanted to know if they worked? I did have two folks with DJ in their ID want to return the amplifiers after purchase. When told they had to pay return shipping one kept it. The other returned an amplifier that no longer worked. Some how 120 VAC had gone into the balanced input! (We had lots of spare input cards and it sold for more money to the next buyer!)

So even the AP has paid for itself! Of course the best reason to own an AP is that we do work for consultants and since we have one and they don't we rarely get complaints when we document a change we wish to make.

(I also have a complete pistonphone kit and offer to calibrate their calibrators!)
 
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