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Post by Deleted on Jan 24, 2010 10:36:44 GMT
Wait a little longer to see if SC publishes a USB adaptor to go with the SC DAC ? BTW, Windows 7 and Creative Media Sorce Player 5 is a very nice combination via SPDIF !  XXHE would need to be bloody good to beat this playing "Carly Simon-No Secrets" in 24/192. P.S. Bostich (reflected) from Yello-Touch, sounds pretty bloody good too! |
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Post by bpgoa on Jan 25, 2010 19:24:37 GMT
Hi Chris, I haven't built it yet, had no chance. I was hoping to make a start tonight, but I had a ridiculous 5 hour meeting today, and feel like I pulled a muscle in my brain  Best leave hot solder and small components until I can think straight. I hope you and adrian remembered to order the PSU board, I know I didn't pillock!Oh, and I get the impression that Adrian is kean!  not that keen  ... but now that I have all the component's I'll get on with it... in fact I made a start earlier soldered all the links and resistors (except for the erranious resistor on the input board) yes... I ordered a HA PSU and transformer... is there just one post that tells me what mods for this are required .. those threads are mental Adrian |
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Post by Deleted on Jan 25, 2010 21:00:20 GMT
Adrian
There are no mods required for the PSU when used with this DAC. Just follow the instructions that came with the PSU kit.
Alex
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Post by bpgoa on Jan 26, 2010 9:34:58 GMT
Adrian There are no mods required for the PSU when used with this DAC. Just follow the instructions that came with the PSU kit. Alex Except use the sf14 diodes that some cool guy sent me?  Alex... where do i put the diodes??? |
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Post by bpgoa on Jan 26, 2010 12:58:18 GMT
Will Yes, the documentation is pretty good. I didn't need to refer to the scanned copy on my P.C. It could be worthwhile pretinning around the holes for the Blue LEDs in the switches to aid solder flow when they are soldered while in situ. Alex P.S. Check that the little bit of track isn't missing on the DAC board's output I.C. Either pin 2 or 3 on one of them from the 180R. I can't remember which.I imagine they have corrected that by now, though. this track is still missing on my pcb... |
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Will
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Post by Will on Jan 27, 2010 10:16:02 GMT
Adrian There are no mods required for the PSU when used with this DAC. Just follow the instructions that came with the PSU kit. Alex Except use the sf14 diodes that some cool guy sent me? Alex... where do i put the diodes??? You can use the SF14 to replace the normal 1n4001 diodes that do the rectifying on the PSU. You can also get a small gain in SQ (at least when used feeding the SCHA, so may help the IV stage) by placing a 470pF film cap across the AC coming into the PSU board. |
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Post by bpgoa on Jan 27, 2010 10:29:33 GMT
You can use the SF14 to replace the normal 1n4001 diodes that do the rectifying on the PSU. You can also get a small gain in SQ (at least when used feeding the SCHA, so may help the IV stage) by placing a 470pF film cap across the AC coming into the PSU board. cool... thanks... will try both.. The boards are fully stuffed now... so mounting in a cheap Maplin case for testing... will take some photo's when complete... but it's going to be a hash up ;D Decided to not mount the switchboard (leave inside for testing and setup) and only fit the RCA input and output to the back chassis... I'm never going to use Toslink!! I may even get brave and take out the circuit for the switching prior to the receiver altogether.. going to make sure it works first How's yours getting on Will |
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Post by jeffc on Jan 27, 2010 11:36:46 GMT
Guys, Sorry for disappearing for a while. Travel with work, catch up, long weekend away camping and otherwise preoccupation with building larger V2 versions of my dinky V1 cardboard NXT panels.  . Going now and ........ but very very different sounding to boxed or even OB speakers based on normal drivers. Still test mules and 1.8 m tall V3 version planning well underway. Here's a pic, off topic I know, but......  Anyway, SC-DAC parts arrived for some of the mods that Alex and Alfred are well ahead on, and now with quite revealing speakers, hopefully I can report findings with some certainty. Alex, for the XDAC3 filter scheme that Alfred has tested and preferred, are the 740R and 500R resistor values posted in the circuit diagram approximates or would 750R and 470R/510R values suffice? Sorry if I've missed posts on this, these values being readily available. cheers.. jeffc |
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Post by Deleted on Jan 27, 2010 11:52:56 GMT
Jeff
The values you mentioned would be fine, however I would recommend doing all the other mods before trying that.
Alex
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Spirit
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Post by Spirit on Jan 27, 2010 12:46:16 GMT
Damnit Jeff... wish TPA would hurry up and release B2... I need an excuse to come round again it would seem |
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leo
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Post by leo on Jan 27, 2010 20:42:28 GMT
NXT panels, bloody hell, I remember having to repair a load of these (pro ones which came with a sub) they was fitted with a duff batch of exciters
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Will
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Post by Will on Jan 27, 2010 21:20:51 GMT
Here is the pcb for the oscillator circuit that Alex came up with. If you follow the link below, there is a bit more info, and an alternative layout with a ground plane. Either layout is suitable for single sided etching. PCB is 2.35"x1.25" sites.google.com/site/willsaudiostuff/home/oscillator-board |
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leo
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Post by leo on Jan 28, 2010 20:46:55 GMT
Nice! I like wouldn't mind some of these, can think of a lot of uses for these even without the XO  |
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Post by Deleted on Jan 28, 2010 21:01:29 GMT
Leo
It could be wise to insert a link in the supply rail to the I.C.
You could then fit a 1 ohm resistor,and quickly measure the voltage drop across it to ensure that no more than say 35mA is being drawn, then if O.K. replace with a wire link.The 1uF cap across the 3.3V or 5.1V Zener diode is not critical, and could be anywhere from 470nF to 2.2uF.
Likewise, the 2.2K resistor value could be varied to fine tune the output voltage. An additional PCB output pin is provided to permit use without the oscillator module.
Alex
P.S.
The Zener Diode MUST be a 400mW type, NOT a 1W type.
(You will need >10 x the current through a 1W Zener.)
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Will
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Post by Will on Jan 28, 2010 21:10:47 GMT
Once I pull my finger out, I'll be doing the supply only version. Simple change, and as you say Leo, useful in all sorts of places.
It'll probably be next week now.
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Post by jeffc on Jan 28, 2010 21:45:36 GMT
a tweak update After an initial listen, I replaced the 68nf PE cap on the DIR9001 filter and the 22nf MKP1837 PP cap I'd stuck at the S/PDIF input with 68nf MKP1837s. Good thing about these caps is they're small and thus neatly fit the available spaces. 2 changes made in one go but .... outcome... sound improvements not subtle... Whereas the sounstage of the NXT panels was somewhat recessed and behind the panels before, its now been moved forward quite a way in front and wider, instruments with more vitality, texture and weight, vocals more fleshed out. OK what's next? Out with the 4 x LME49710's in the I/V stage and in with the OP134s. Then I spose I need to get some dinky Will/AK regulator PCBs 8-)etched or try making some point to point on small vero boards I have. ;D cheers..jeffc |
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Post by bpgoa on Jan 29, 2010 10:50:23 GMT
You can use the SF14 to replace the normal 1n4001 diodes that do the rectifying on the PSU. You can also get a small gain in SQ (at least when used feeding the SCHA, so may help the IV stage) by placing a 470pF film cap across the AC coming into the PSU board. Will, Is that one Cap across the +15 -15v connections? or 2, 0v to -15v 0 to +15v and 470pf? ( seems quite low ) A. |
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Post by Deleted on Jan 29, 2010 11:06:15 GMT
You can use the SF14 to replace the normal 1n4001 diodes that do the rectifying on the PSU. You can also get a small gain in SQ (at least when used feeding the SCHA, so may help the IV stage) by placing a 470pF film cap across the AC coming into the PSU board. Will, Is that one Cap across the +15 -15v connections? or 2, 0v to -15v 0 to +15v and 470pf? ( seems quite low ) A. Adrian The 470pf 100V capacitor is mounted under the PCB, across the 2 outer terminals of the incoming AC from the transformer. It helps to further reduce rectifier switching noise. Alex |
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Post by jeffc on Jan 31, 2010 5:47:58 GMT
selector PCB switch soldering This is actually mentioned in the text box with the photos of stuffed PCBs on p22 of the build instructions. Which of course .... I didn't bother to read.  If you make an ~30 degree bend about half way along the thin LED pins, longest pin (anode) toward the ribbon cable housing at the top, and don't push them through the holes, the pins spread out nicely on the pads for easy soldering. like this  My SC-DAC now has pretty blue lights. The other 2 LEDs I know I've stuffed and will have to replace. ;D cheers.. jeffc |
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Post by Deleted on Jan 31, 2010 7:22:00 GMT
No bloody wonder I had trouble initially getting my blue LEDs to work.  I used the magazine article itself from October 2009 page 39 , where there was no mention of bending the Blue LED leads. I must admit that I did see some reference to this in the amended copy included with the Jaycar kit, but I knew better, didn't I ?  |
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Spirit
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Post by Spirit on Jan 31, 2010 8:23:04 GMT
The other 2 LEDs I know I've stuffed and will have to replace. ;D Just don't kill it before tomorrow night!  |
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Post by jeffc on Jan 31, 2010 8:46:10 GMT
No ........ its workin' just dandy and I won't mess with it ..... and now I've played with the CDP remote changing tracks, even the yellow and green LEDs that I "thought" I'd stuffed are working , albeit the green LED being a little dull. Can now move on to building a couple of the 3.3V AK "cricket" supplies for a CVXO and to supply the DAC Vdd ...... and swapping in the recommended OPA134's into the I/V stage as mentioned before. cheers.. jeffc |
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Post by Will on Jan 31, 2010 9:52:59 GMT
Nice clarification of the change to build Jeff. I placed the switches on the 'wrong' side of the pcb, as I'll only use them for for selection initially.
The psu only version of the oscillator board will be posted in the next couple of days.
Out of interest, what opamps are you guys thinking of using in the osc/psu?
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Post by Deleted on Jan 31, 2010 10:10:28 GMT
Will
As I have a couple of spare OPA134, I will most likely try them or the LME49710 initially.
Alex
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Post by bpgoa on Feb 1, 2010 8:25:22 GMT
Hi Guys... thought I'd give my first impressions of the DAC.
mods made to original design
MKP Caps used
on spdif input 68nf
on the receiver chip 68nf
filter stages of the analogue outputs
across the input to the PSU Board
Gold off board RCA connectors
680 ohm resistor
My view on how it sounds....
Unit was finished on Friday (two days ago) and was run non stop since then. This review is based on listening on the Sunday morning. It is being compared to the DAC internal to my Music fidelity xray player. sources.. an unmodified Squeezebox and the said cd player were used as a source.
with the CD as a source.. (the source is important as the DAC locks on to the clock within the spdif signal)
the top end doesn't sound as bright with the soundstage slightly closed in.
the vocals sound softer and fuller ...
the bass sounds a little more laboured
The presentation sounds overall further in front of the speakers but not as dynamic.
With the squeezebox as a source..
it sounded better than the internal DAC, but compared to the cd as a source (same track and the squeezebox track was a flac of the cd) sounded more muddled in the midrange,. i'm going to have to look at that squeezebox.
Questions...
do we think it'll start to sound sweeter as time goes on.
what will JLH boards do to the sound
Thoughts please
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Best leave hot solder and small components until I can think straight.
... but now that I have all the component's I'll get on with it... in fact I made a start earlier 
. Going now and 
