The usual: there's no need to drive pin 3 with an actual signal. Just connect it to ground at the same spot where the op amp's noninverting input is grounded. If you have a buildout resistor on pin 2, add one on pin 3 too. That's all you need.
Pin 1 goes straight to chassis, as usual.
Pin 1 goes straight to chassis, as usual.
Got a schematic for that, perhaps? It's a theoretically elegant solution but practical implementation seems to pose a number of potential problems.
I do but I promised Jan Didden that he could have it first for Linear Audio. I wouldn't see which potential problems you're referring to. It works very well.
Wouldn't bandwidth vary with volume? Fault protection?
I'm happy to wait for Jan, of course.
I'm happy to wait for Jan, of course.
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Bruno, since you're online:
- what do you think about standard (metal encased) XLR connector vs non-encased (plastic only)? is there any disadvantage to the latter (shielding)?
I mean http://www.directproaudio.com/images/products/neutrik-nc3mpp.jpg
and
http://sigma.octopart.com/5377101/image/Neutrik-NC3FD-H.jpeg
- since I'll be using the group buy case which has an (3 mm thick) aluminum inside panel that can separate the amps from the supply, would you think that would provide some screening? that is in case I go for a "lesser" SMPS 🙂
- what do you think about standard (metal encased) XLR connector vs non-encased (plastic only)? is there any disadvantage to the latter (shielding)?
I mean http://www.directproaudio.com/images/products/neutrik-nc3mpp.jpg
and
http://sigma.octopart.com/5377101/image/Neutrik-NC3FD-H.jpeg
- since I'll be using the group buy case which has an (3 mm thick) aluminum inside panel that can separate the amps from the supply, would you think that would provide some screening? that is in case I go for a "lesser" SMPS 🙂
Bandwidth would vary by a factor 2 between zero volume and unity gain. I don't think that from, say 20MHz to 10MHz is going to be an issue 🙂
@mrpp: I use whichever XLR I have at hand. The most critical item is the pin 1 to case connection (which is a tad better with all-metal parts).
Re screening, ask yourself what you're going to screen: magnetic interference, capacitively coupled noise or conducted emissions. Which screening mechanism is useful will follow.
@mrpp: I use whichever XLR I have at hand. The most critical item is the pin 1 to case connection (which is a tad better with all-metal parts).
Re screening, ask yourself what you're going to screen: magnetic interference, capacitively coupled noise or conducted emissions. Which screening mechanism is useful will follow.
hey Bruno,
is in your opinion, simply pot from low shelf quality, equal to all those super clean passive preamps ?
I am very happy owner of hypex ucd400hg just upgraded with HxR, at the moment I use temporary NHT PRO passive volume controller (balanced in/out) as a volume attenuator.
I also have khozmo shunt attenuator based volume controller (unfortunately unfinished diy🙁 ..) and I am in the need of passive attenuator (as for my knowledge it's most transparent idea to have it passive). I run small online mastering studio, so transparency tool is a paramount.
What would you suggest for me to look into ?
as a pre for hypex (monitors are at the moment - PMC TB2)
I had an experience with ldr attenuator and L/R imbalance was unacceptable.
thanks for answer, and big kudos to your company, product and extraordinary customer service
Only in this particular circuit. I'd never use the same pot in a passive preamp or before a buffer (=normal circuit).
I'm normally no fan of passive attenuators but I've been pleasantly surprised by a 5kohm Penny & Giles pot that a customer of ours is using as preamp in their listening room. Sonically I can't fault it, except that the results vary with the attached power amp.
If you can wait out the summer the demo circuit will be published.
I'll wait patiently🙂
as for hypex ucd hg, is passive good enough ? (NHT PRO)
shall I sell khozmo shunt attenuator ? is it possible to have transparency and not 'burn' too many $$$$ ?
the thing is I also need 3 inputs with source selector
and 2 outputs (1 for sub, switched on/off) within 1 box, and I can't afford pro high end like dangerous music or avocet ..🙁
hence research in diy
as for hypex ucd hg, is passive good enough ? (NHT PRO)
shall I sell khozmo shunt attenuator ? is it possible to have transparency and not 'burn' too many $$$$ ?
the thing is I also need 3 inputs with source selector
and 2 outputs (1 for sub, switched on/off) within 1 box, and I can't afford pro high end like dangerous music or avocet ..🙁
hence research in diy
regarding screening... my understanding (which can be wrong given the amount of knowledge I have about this EMI/RFI thing) is that what differentiates men from boys when it comes to SMPS is mostly radiated noise. or isn't it?
just out of curiosity... this puzzles me. what makes a good passive attenuator? I mean what differentiates good ones from bad ones? your reply implies they're not all born equal.
Dude did you ever read the "Intelligent Chip" thing from Golden Sound?
Both 6moons and Positive Feedback review dorks got fooled by Golden Sound...
PATHETIC
What morons... they even created a logo that was almost identical to Nipper.
I was so discussed at PF I called RCA Victor over their stupid logo and reported it to their TM lawyer...
I noticed the logo changed about 3 months later... LOL
The reviews on the "Golden Sound" snake oil products.
goldensound
6moons industry featres: Golden Sound's Intelligent*Chip
6moons audio reviews: Golden Sound Ultra Tweeter
http://www.6moons.com/audioreviews/photoncannons/photoncannons.html <-- the two posts are coverups of the original GLOWING REVIEW (original review was yanked and replaced with their fancy C1/C2 error checking review to make them seem smart... ******* idiots...
ABSOLUTELY PATHETIC
PS: Sarajan actually wrote an apology piece for his idiocy and in it he blamed smoking good quality marijuana as his excuse for running around with it proclaiming it's magic. All of which has been removed from the site.
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Where's my earlier reply!? OK, forget the asinine LED-based
preamps, the LED noise modulates the signal and is unacceptable for precision use. The best possible atten would use a switched shunt array of vishay H-series resistors and a great switch like a Shallco. This setup is about $4k retail, not including the buffer circuit it resides in. But discrete stepped ladders are the top. Ayre's best circuit is very elegant...
preamps, the LED noise modulates the signal and is unacceptable for precision use. The best possible atten would use a switched shunt array of vishay H-series resistors and a great switch like a Shallco. This setup is about $4k retail, not including the buffer circuit it resides in. But discrete stepped ladders are the top. Ayre's best circuit is very elegant...
hmm... they didn't yank it...
auroville35
http://positive-feedback.com/Issue18/intelligentchip.htm
I shouldn't be so hard on the guy. He seems like a nice person and all and seems to have really good taste in clothing...
LOL
He's not an EE so... I guess he has an excuse... (didn't take physics 11 in high school bro? LOL)
But not this John Curl character.
auroville35
http://positive-feedback.com/Issue18/intelligentchip.htm
I shouldn't be so hard on the guy. He seems like a nice person and all and seems to have really good taste in clothing...
LOL
He's not an EE so... I guess he has an excuse... (didn't take physics 11 in high school bro? LOL)
But not this John Curl character.
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c'mon guys, this thread has had its share of off-topic discussions but I really don't want to see David Clark being bashed here, that'd be a non-challenge 🙂
No, no, it would be great.
Short, to the point, lots of nice (or horrible) graphs and, last but not least, many manufacturers would pay NOT to get reviewed. How can it fail?! 😛
Another question on this topic, if I may :
When the pot resistance approches zero, the gain does the same (which is the desired effect to mute the output). Doesn't one run into stability problems for the op amp ?
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