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Old 30th September 2011, 02:23 PM   #481
Jokener is offline Jokener  Germany
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Well, I want to use it on my computers' Asus Xonar HDAV outputs.
Because the HTPC has a BluRay drive and the Asus Soundcard has all the necessary licenses and codecs for BluRay playback.
And where I would otherwise have to take the analog signals from the outputs, the Buffalo III allows to grab the I2S signals from the card and produce nice and clean sound from it.
If there were any other DACs capable of this, those would be an option.
I just haven't found any.

And the Buffalo III has (with accessories) the ability to process all the channels at once.
When I only need one Buffalo III where I'd need 3 (5.1 = 3x stereo) other DACs...
I just don't see too much competition.

But we're drifting deeply into the off-topic :-)
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Old 1st October 2011, 02:27 PM   #482
regal is offline regal  United States
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I spent an hour reviewing the nvnavguy website, I am changing my tune, that dscope is amazing and this is the first headphone amp I have every seen developed from groundup with a such a great tool, the documentation is incredile, we actually know where the amp starts clipping with a giving power into different loads.

I have one stupid question. As far as scaling up from a semi-portable to a higher power amp, would it be possible to run the tests for thd vs voltage/load for 15V rails?

The "high much power do we need" section on the website actually rules out a few popular headphones for the 110 dB peak recomendations. It would seem the most elelegant solution to the issue would be to use two boards full balanced, I think this would make it an amp that really would match/beat any other SS design for a fraction of the cost. It would basically increase the power between 2x to 4x (depending on the phones impedane/sensitiviy) and propably handle any dynamic headphone made.
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Old 1st October 2011, 08:51 PM   #483
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Quote:
Originally Posted by regal View Post
The "high much power do we need" section on the website actually rules out a few popular headphones for the 110 dB peak recomendations. It would seem the most elelegant solution to the issue would be to use two boards full balanced, I think this would make it an amp that really would match/beat any other SS design for a fraction of the cost. It would basically increase the power between 2x to 4x (depending on the phones impedane/sensitiviy) and propably handle any dynamic headphone made.
With the usual downsides of requiring cans rewired for balanced driving and an additional inverter stage. Plus minimum sensible load impedance is doubled (so it would mainly make sense for some of these 600 ohm offenders, not at all for orthos).
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Old 1st October 2011, 10:32 PM   #484
MrSlim is offline MrSlim  Canada
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Quote:
Originally Posted by regal View Post
I spent an hour reviewing the nvnavguy website, I am changing my tune, that dscope is amazing and this is the first headphone amp I have every seen developed from groundup with a such a great tool, the documentation is incredile, we actually know where the amp starts clipping with a giving power into different loads.
Welcome to the Dark Side..

Quote:
I have one stupid question. As far as scaling up from a semi-portable to a higher power amp, would it be possible to run the tests for thd vs voltage/load for 15V rails?
RS has mentioned before that 15V rails might be a bit too much for the 4556's and that he was still planning on using 12 V for the real desktop version.

Quote:
The "high much power do we need" section on the website actually rules out a few popular headphones for the 110 dB peak recomendations. It would seem the most elelegant solution to the issue would be to use two boards full balanced, I think this would make it an amp that really would match/beat any other SS design for a fraction of the cost. It would basically increase the power between 2x to 4x (depending on the phones impedane/sensitiviy) and propably handle any dynamic headphone made.
In a balanced configuration, is there any extra current draw on any individual channel, as there is in a bridged configuration? I can understand the 2x power, since you are driving the transducers in a positive and a negative direction with a pair of amplifiers, but how does it get to 4X?
Also, what is the real gain in sound quality from a balanced config? I know this has been discussed at adnausum elsewhere, but given the low cost of the O2, the cost of comparing unbalanced to balanced would be quite low.

Hmm.. you've got me thinking, but I guess RS would have to weigh in on whether it would work, but I wonder if 2 boards would fit in a B3 case.. it might if you left off the batteries, since they're the tallest components on the board..
There would be the issue of how to handle the volume control for 2 channels..

Last edited by MrSlim; 1st October 2011 at 10:44 PM.
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Old 2nd October 2011, 01:14 AM   #485
qusp is offline qusp  Australia
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@ jokener, the ackodac AKD18P is another 8 channel sabre 9018 that has actually been out for longer but is lesser known, with much more comprehensive control (ipad, pc, wifi remote control of ALL registers), input options (hires usb, coax, proper aes not fake, hdmi) and signal routing than the b3; impedance controlled pcbs and more appropriate digital interconnections (all are on smd mini bnc, actually designed for signals in that range, unlike pinheaders). not a simple or cheap build though.

@ mrSlim, yeah thats a funny one. people seem to think its automatic, my understanding is yes there is the potential to x4 due to the impedance seen by the output being halved and thus draws more current, but that also means you have a lot tougher time to put as much voltage across it and first the power supply must be capable of it. I prefer 'a balanced/bridged amp will put double the power into double the impedance'

btw mr Slim, ive been asked by a member to build an amp for them, can you estimate the time for an experienced builder to stuff the boards or anyone that has for that matter? I have said i wont do casework, although with all things just about being pcb mounted and pre milled panels there isnt much to it. it looks a very straight forward build, but looks can be deceiving. i dont plan to do any others and i'm not even sure if i'll do this one yet.

Last edited by qusp; 2nd October 2011 at 01:16 AM.
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Old 2nd October 2011, 03:03 AM   #486
MrSlim is offline MrSlim  Canada
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qusp:
RS told me that it takes him about an hour to build one (board stuffing really since he didn't do face plates etc), so I've been planning on being able to do it in about that much time. Of course, that doesn't account for all the parts ordering, etc and I'm doing some "baby" desktops too, which are probably going to be the fiddliest part of the whole thing since I'll be doing RCA's, 1/4 inch jack and the volume pot on flying leads off the board..
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Old 2nd October 2011, 02:00 PM   #487
qusp is offline qusp  Australia
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thanks,yeah thats about what i figured, although i'm not looking at getting much practice, i spend enough time sniffing solder fumes as it is. yeah i'll probably be doing a baby desktop myself with one of the pcbs i got as a present for a friend, he doesnt need a portable amp, certainly not one as ermm substantial as this one, but will love one to connect to his mixing decks, i plan to use the usb output on his mixer and add an opus and simple instrumentation amp for bal-se, perhaps even some onetics line transformers
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Old 2nd October 2011, 02:38 PM   #488
MrSlim is offline MrSlim  Canada
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Originally Posted by qusp View Post
thanks,yeah thats about what i figured, although i'm not looking at getting much practice, i spend enough time sniffing solder fumes as it is. yeah i'll probably be doing a baby desktop myself with one of the pcbs i got as a present for a friend, he doesnt need a portable amp, certainly not one as ermm substantial as this one, but will love one to connect to his mixing decks, i plan to use the usb output on his mixer and add an opus and simple instrumentation amp for bal-se, perhaps even some onetics line transformers
heh, I know what you mean about solder fumes.. With the number of O2's I'm building, I've been debating building up some kind of DIY fume extractor.. (saw one on MAKE I think)
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Old 2nd October 2011, 09:15 PM   #489
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Originally Posted by MrSlim View Post
heh, I know what you mean about solder fumes.. With the number of O2's I'm building, I've been debating building up some kind of DIY fume extractor.. (saw one on MAKE I think)
First link on google search for "solder fume extractor"

Solder Fume Extractor
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Old 2nd October 2011, 10:31 PM   #490
MrSlim is offline MrSlim  Canada
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Originally Posted by dewasiuk View Post
First link on google search for "solder fume extractor"

Solder Fume Extractor
yeah.. I saw that, and did a little more research.. from what I understand, to do it right, you need a Hepa filter to filter out the particles of flux that are actual irritants.. the Carbon filters don't do anything.. Just a fan to blow the fumes away is probably just as useful..
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