DAC progress
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randy@matrixq.com
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Hmmm...Don't think I'll be ditching my Foreplay anytime soon. Is that a recycled mp3 shoved in a plastic tube?
denti alligator
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From your posts today, Doc, it looks like you're back working on the DAC. Any progress you're willing to report, or any enticing details to share?
John has been working on the latest board which, if it works as planned, will offer a basic dual power supply with the option to upgrade to multiple supplies, SPDIF input with the option to upgrade to USB and a choice of display options for the sample rate. PJ and I are laying out a new concept for the tube output that follows some of our recent work to improve the transient response and bass control of all of our tube designs. If at all possible I will bring a prototype to RMAF to show in the Can-Jam room.
denti alligator
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2wo said:
I don't quite understand. How would the music files be played, if not with a operating system platform?
Finished up the repackaging of the DAC to take to RMAF, the last thing we had to get complete for showtime. Looks nice and neat on two chassis connected by an umbilical. Power supplies on first chassis tested fine, but when I connected the DAC board in the second chassis to the power supply it had some residual charge and we saw the LEDs on the DAC board flash. Oops. Fired it up and we got a little bit low reading on the - rail side indicating something was pulling too much current, i.e. overly bright LEDs, then *wink*, no LEDs on that side. Arrgh! The board ran great with exactly the same power supply on a really shaky breadboard for over a year! Overnighting a bag of transistors to replace one that seems blown and have some spares on hand, and crossing our fingers that the transistor is all that blew and we can take this puppy to RMAF...
Grainger49
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Just like having an out of town guest to hear your system and one channel goes out.
I have confidence in Chez Bottlehead to get it running.
I have confidence in Chez Bottlehead to get it running.
2wo
New member
denti alligator said:
It is the soundcard I mostly want to get away from. The soundcard gives you the SPDIF out. I use a Lunix based Vortexs box which uses the Squeezbox software to play the music, out the USB port. A PC running something like Foobar, or a Mac and itunes would work the same way...John
Oh boy, well, hoping it's an easy fix as this is one of the things I most want to hear at RMAF.
Just to clarify, this is running 24/192 in NOS mode, correct?
Have you tested this with an Audiophilleo usb-spdif converter by any chance? If not, would it be ok for me to bring mine to the show?
Would love to hear this in combination with the Smack and some balanced hd-600s or AKG K-601s, but can't remember if you have the latter or not.
-- Jim
Just to clarify, this is running 24/192 in NOS mode, correct?
Have you tested this with an Audiophilleo usb-spdif converter by any chance? If not, would it be ok for me to bring mine to the show?
Would love to hear this in combination with the Smack and some balanced hd-600s or AKG K-601s, but can't remember if you have the latter or not.
-- Jim
We won't have the final version with SPDIF, USB, multiple power supplies, automatic sample rate detection, display, etc. ready for RMAF This is our R&D prototype that we have been running for the past year. If it can be fixed today it will be connected by TOSLINK directly to a Mac Mini using Amarra 2.3 and thus will be maxxed at 24/96 NOS mode. It does however demonstrate some very interesting ideas developed by John Swenson that revolve around use of an FPGA and PCM 1704 DACs, and our best stab at a single stage shunt reg'd and active loaded output stage. The production version will be ready hopefully not too long after RMAF.
Luckily I just took out a couple of transistors (aka three legged fuses). DAC is up and running and sounding better than ever now that all the DAC and tube output bits are close together in one chassis. Working up a playlist this afternoon that should let folks get a feel for what she can do at both 44K and 96K, and then we pack and ship the gear to Denver tomorrow.
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