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Post by PinkFloyd on Jan 3, 2009 15:17:25 GMT
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Post by Deleted on Jan 3, 2009 20:29:26 GMT
Mike
Looks like a fun DAC to play with. Not earth shattering performance, but nevertheless, an interesting little DAC, perhaps leading to bigger and better ?
Alex
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leo
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Post by leo on Jan 4, 2009 14:22:06 GMT
Once you have it and after I've gotten rid of this damn bug I've some mods for you to try if your up for it
BTW, I've not tried that particular board you've ordered but I do know the dac chip well , the circuit you provided makes it easy for modding.
Its actually a good starter dac tbh, its not going to beat everything out there, the TDA1543 has its limitations but should provide a bit of fun
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Post by PinkFloyd on Jan 4, 2009 14:45:15 GMT
Once you have it and after I've gotten rid of this damn bug I've some mods for you to try if your up for it BTW, I've not tried that particular board you've ordered but I do know the dac chip well , the circuit you provided makes it easy for modding. Its actually a good starter dac tbh, its not going to beat everything out there, the TDA1543 has its limitations but should provide a bit of fun Probably not a lot to do to it other than choose your favourite "signature" cap and maybe faff about with different resistors? |
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leo
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Post by leo on Jan 4, 2009 15:08:59 GMT
Once you have it and after I've gotten rid of this damn bug I've some mods for you to try if your up for it BTW, I've not tried that particular board you've ordered but I do know the dac chip well , the circuit you provided makes it easy for modding. Its actually a good starter dac tbh, its not going to beat everything out there, the TDA1543 has its limitations but should provide a bit of fun Probably not a lot to do to it other than choose your favourite "signature" cap and maybe faff about with different resistors? Theres a bit more  as you can imagine , a dac as simple as this only has a limited amount of things to try, your right in saying most are component swaps which I'd leave to you. This dac uses a passive I/V stage, basically the current to voltage is done with resistors. Passive I/V has the advantage of not having op-amps on the output, the downside is that you loose the drive of an active output stage. The schematic shows the dac is ran as standard 5v with a pair of 1k's I/V and a single 1k VREF , this is going to give quite a weedy output, probably be a little flat and closed in. I'd suggest swapping the 5v regulator to 8v , swap the I/V resistors to 2k7 and the VREF resistor to 1k5. IMO this particular dac works much better like this, you should hear more dynamics etc You can't obviously just alter the resistors without upping the reg voltage or it will clip |
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leo
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Post by leo on Jan 4, 2009 15:14:06 GMT
Stacking is another way people try to get around these dacs limited output when using passive I/V, stacked increases current. It also makes dac chips and regulation run much harder, heat increases a lot so heatsink are essential. Using stacked chips also has a different sound, some prefer stacked yet others prefer it without. |
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leo
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Post by leo on Jan 4, 2009 15:19:10 GMT
How about using a battery as the power supply? Would it help in making better conversion from digital to analogue? Certainly worth trying a battery to feed the main onboard regulation, some will like linear supplies better, others prefer bats A dac as simple as this appreciates clean supplies, filtering etc is non existant on here so a bad PSU will make the thing sound like shit |
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rickcr42
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Post by rickcr42 on Jan 7, 2009 20:24:27 GMT
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Post by rickcr42 on Jan 7, 2009 21:33:36 GMT
Full Monty diyparadise.com/dackit/1545bdackit.htmldiyparadise.com/ssiv.htmldiyparadise.com/mar06/gg.htmlaccording to the site the Monica 2 is "superceded" by the monica 3 though if this means you can no longer obtain the pcb's for V2 I am not sure. Personally I would take the "2" over the "3" because it has a more open architecture which makes twaking individual stages or cobbing in various proof of concept circuits a snap. The 3 is more of an integrated DAC having the PCM DAC,the USB Interface and the IV stage all on a single board which for some is maybe a better option (build by the numbers,box it and forget it) but leaves little room for experiments without doing some onboard modifications,a must for some hobbyists,zero interest for others as ong as the devicw works as advertised and I can only assume it does going by the universally glowing reviews. If V2 boards are NOT available ? I see no reason you can't do a Vero-Board or Uni-Board build since all the "parts" have through the hole attachment points (no SMD ) and to tell you the truth I have yet to hear a triple or double layer pcb DAC that SOUNDS better than the same design sans pcb and in fact have heard the exact opposite enough times to question the validity of the complicated over the simple AS LONG AS you follow good layout practices. Recommended "tweaks" would be to use copper foil tape to shield the digital ICs (connect ALL to a single point at the lowest Z section of the ground plane ).avoid any socketing of the ICs,do all bypassing/decoupling right ON the IC pins (even if it means going down underneath the pcb) and if using a mains supply for the V+ buss going the high-current.CLC filtered raw DC route with proper AC line filters pre-power transformer. What all these simple DACs have in common is a propensity for Phillips chips.no oversampling filter hence simple layouts,a VERY small footprint (most anyway),way smaller than they look in the pics. What separates them is NOT the design per se but the method so look more at the BOARD LAYOUT than the parts used which is usually the "hook" than snags the fish and that is usually just more of the same old design by pretty colors/named parts Other than that you are on your own bubba  |
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leo
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Post by leo on Jan 8, 2009 1:58:03 GMT
I actually got a M3 here Rick, it uses DIR9001 spdif receiver and TDA1545 dac
They also do the USB version
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leo
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Post by leo on Jan 8, 2009 2:02:38 GMT
Heres also a TDA1543 based dac I knocked up on matrix, output coupling caps are Siemans MKV, its based on PD's dac, Ricken I/V resistors, caddock 132, wanky Blackgates etc Dac chip is underneath board, the 8pin DIL ontop is a comparator for the SPDIF. Each IC has its own reg , separate reg for receivers digital and analogue pins Powered by batts or linear  |
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leo
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Post by leo on Jan 8, 2009 2:16:18 GMT
Seeing as you posted a link to that remote vol control, I'm thinking of trying one of those Lightspeed vol controls at some stage, you ever tried one of those Rick?
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rickcr42
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Post by rickcr42 on Jan 8, 2009 2:59:18 GMT
nope but I am trying to find a reason to build one,especially the Nelson Pass version ;D SWEEEEEEEEEET ! Damn fine build broheim  I need to get one of those puppies on the bench (the DIR) and do some damn comparing to the CSxxx devices.......if I ever get a moment of peace in my lifetime again that is |
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leo
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Post by leo on Jan 8, 2009 12:03:32 GMT
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rickcr42
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Post by rickcr42 on Jan 9, 2009 0:12:03 GMT
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Post by PinkFloyd on Jan 15, 2009 22:11:48 GMT
Oh man, this thing sounds like absolute TURD as is! I wasn't expecting miracles but I certainly wasn't expecting this kind of crap sound..... compressed, low output, extremely veiled..... urgh! It's not often you come across pure turd on a stick but this thing is it!
Leo...... I will take a photo of the PCB and you can show me what resistors to change to get the output a bit higher.... hell, I'm at full volco on the SCHA and only getting moderate levels.
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leo
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Post by leo on Jan 16, 2009 1:42:08 GMT
Pure turd on a stick, is it really that bad  You'll need a pair of 2k7's, a 1k5 , a 8v reg and ditch those signal coupling axial tants for something else that will fit, tants are ok for decoupling but suck balls in the signal path Once we have located the resistors to be changed and if it sounds any better I'd try removing those green filter caps (seem to be 2n2,2200pf) and see what you think, some people may curse at removing those but it should sound better |
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Post by Deleted on Jan 16, 2009 1:49:59 GMT
But will it end up sounding good enough to want to listen to it ? |
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leo
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Post by leo on Jan 16, 2009 1:50:12 GMT
BTW Mike, once its had some bodging done it maybe worth trying it with one of those MF buffers, remember that dac you have has no active output stage |
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leo
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Post by leo on Jan 16, 2009 1:58:22 GMT
But will it end up sounding good enough to want to listen to it ? Maybe, maybe not  The one I built here on vero is seriously not too bad, of course its not as good as say the Sabre but I've certainly heard much worse that cost more than my Sabre and this put together |
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leo
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Post by leo on Jan 16, 2009 2:01:02 GMT
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Post by Deleted on Jan 16, 2009 2:48:29 GMT
Leo
That one looks quite interesting, particularly with free shipping. The photos and schematic look reasonable. If the U.S.A. hadn't caused the Aussie dollar (and GBP etc.) to nosedive, I would have been tempted to have a play.
Alex
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rickcr42
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Post by rickcr42 on Jan 16, 2009 3:40:38 GMT
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Post by PinkFloyd on Jan 16, 2009 21:35:01 GMT
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Post by PinkFloyd on Jan 16, 2009 21:39:47 GMT
Spot the difference time..... it would appear the one I have differs slightly from the one I originally posted in this thread..... My one:  The other one:  |
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as you can imagine , a dac as simple as this only has a limited amount of things to try, your right in saying most are component swaps which I'd leave to you.
