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Post by hifijunkie on Nov 4, 2009 9:18:23 GMT
Hey Pinkfloyd! Can you tell me whether Aune DAC would improve SQ in a popcorn hour ?? moreever, i don't need an amp as i already have a wonderful amp in Bada. Just wondering if this thing can improve sound when connected to a popcorn hour player cos that is the main music centre for me now. My music is mostly 124 kbps so no lossless songs with me...
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Post by mcinen on Nov 4, 2009 10:05:04 GMT
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Post by PinkFloyd on Nov 4, 2009 14:57:39 GMT
No no no! First off you need a 20V DC power supply, secondly you are looking for "linear regulated" NOT switched mode ;D
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Post by mcinen on Nov 4, 2009 15:21:06 GMT
Oops, good point Thanks. Got any PSU suggestions then apart from the DIY one?
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Post by PinkFloyd on Nov 4, 2009 15:34:47 GMT
Oops, good point Thanks. Got any PSU suggestions then apart from the DIY one? Off the top of my head, No..... you could always use one of these you would also need some two core cable and a 2.1mm DC plug (centre pin is positive) I'll have a look round and see if there's anything a bit more suitable ;D
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Post by PinkFloyd on Nov 4, 2009 15:37:14 GMT
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Post by PinkFloyd on Nov 4, 2009 20:58:31 GMT
A quick update on the Aune.... I have been using it as my main audio player for a few weeks now and have no intention of reinstating a CD player / amp on my desktop... the days of power bricks, cables and clutter are long gone....Apple Lossless files on my hard drive and the Aune connected to the USB port is all I need to give me musical pleasure The AD-744/A still continues to please but I will definitely be rolling in more opamps in the coming weeks... I've got a couple of the new Burr Brown wonder chips on their way (along with Browndogs) and will try these as soon as they arrive. I'd like to retain the clarity the AD-744/A gives but would prefer a bit more depth to the sound, the AD-744 can sound a bit light at times..... It's good to live with an opamp for a few weeks and "then" roll in a different one.... I don't seem to get anywhere but confused rolling in one after another (power rolling).... give each a couple of weeks to cook and really get to know the chips signature over a wide range of music. Somebody asked about replacing the OPA2134.... I will be trying this too but one step at a time, you can easily over egg your pudding doing too much at once and totally lose track of what's doing what where ;D Trust me guys.... patience is a virtue when it comes to selecting the right opamp for your ears.... I could easily roll in, say, 20 chips in the next hour but the exercise would get me nowhere only closer to the nut farm. It may take me a YEAR to find the best chip for the job (and that "job" being the best suited to my ears) but it will be time well spent.... Anyways, enough waffling..... the AD-744/A will remain under the hood for another week or so until I decide what chip to try next. Mike.
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Post by Deleted on Nov 4, 2009 21:28:17 GMT
Mike Has your USB pen arrived yet, or are there still postal strikes in the U.K. ? Alex
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Post by PinkFloyd on Nov 4, 2009 21:31:09 GMT
Mike Has your USB pen arrived yet, or are there still postal strikes in the U.K. ? Alex Not yet Alex, it's coming from Japan, should be here next week
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Post by Deleted on Nov 4, 2009 22:52:33 GMT
Mike Has your USB pen arrived yet, or are there still postal strikes in the U.K. ? Alex Not yet Alex, it's coming from Japan, should be here next week Mike What the hell is wrong with U.K. suppliers these days? Even Downunder, I received my 32GB Corsair Voyager GT within 18 hours of ordering. 3 days later I saw an ad in a local PC mag, where I could have made a 20 minute drive, and saved another AU$30 by buying over the counter. Perhaps you should consider starting up your own businees and show the rest of the U.K. what availability without being ripped off, and service means ? Alex
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Post by PinkFloyd on Nov 4, 2009 22:56:47 GMT
Mike Has your USB pen arrived yet, or are there still postal strikes in the U.K. ? Alex Not yet Alex, it's coming from Japan, should be here next week Alex...... As I already stated TWICE...... it's coming from JAPAN ;D
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Post by Deleted on Nov 4, 2009 23:07:58 GMT
Not yet Alex, it's coming from Japan, should be here next week Alex...... As I already stated TWICE...... it's coming from JAPAN ;D Mike WHOA ! What I meant was , why should you need to order products like that from Japan? Aren't there any decent importers left in the U.K. that aren't either rip off merchants,or snake oil peddlers ? Alex
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Post by PinkFloyd on Nov 4, 2009 23:15:46 GMT
Alex...... As I already stated TWICE...... it's coming from JAPAN ;D Mike WHOA ! What I meant was , why should you need to order products like that from Japan? Aren't there any decent importers left in the U.K. that aren't either rip off merchants,or snake oil peddlers ? Alex Unfortunately....... No
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Post by Deleted on Nov 4, 2009 23:32:43 GMT
Mike WHOA ! What I meant was , why should you need to order products like that from Japan? Aren't there any decent importers left in the U.K. that aren't either rip off merchants,or snake oil peddlers ? Alex Unfortunately....... No Geez ! And to think that a little over 200 years ago, you guys thought you had shipped most of your crooks to Australia ! ;D Boy, am I glad we aren't still a penal colony . Could be fun though, throwing rotten tomatoes at the likes of Russ Andrews.
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matt7941
100+
Mmmmmmm... Pork scratchings.....
Say cheese!!!!!
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Post by matt7941 on Nov 5, 2009 0:00:16 GMT
Alex you are so right re rip off Britain.
The UK supplier that Browndog recommend sell the dual to Quad adaptor at an eyewatering £5.99 plus postage! It's only $4.95 (US) from Cimarron in the US and only $2.50 s&h and arrives within the week. The British supplier is therefore selling them at the equivalent of approx. $9.75 plus postage. The best part of 100% mark up over the US retail price. This by and large applies to all the Browndog products they sell.
Before anyone gets on my case this is only one example of what Mike and Alex have pointed out, I am in no way getting at this particularly profit conscious retailer.
I blame Thatcher and the neo-liberals! ;D (Draws breath, dons flak jacket and waits for verbals volleys to start flying.)
That's my two penneth, as my gran used to say. Back to the Black Sheep and the pork scratchings. MMMM.
Matt
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Post by mcinen on Nov 5, 2009 17:36:21 GMT
Oops, good point Thanks. Got any PSU suggestions then apart from the DIY one? Off the top of my head, No..... you could always use one of these you would also need some two core cable and a 2.1mm DC plug (centre pin is positive) I'll have a look round and see if there's anything a bit more suitable ;D Thanks but that Skytronic seems a little bit exaggerated. I just need a simple PSU that I can put on the floor and forget about it. I could build one if I find a suitable chassis. Btw, the transformer and PSU kit recommendation - I just want to double check are they valid for the 230V european network? I guess they are. The 2X115V confuses me. Why that and not 230V version? One thing that still puzzles me (being an electronics newbie) is that are "regulated" and "linear regulated" the same? I do know now to stay away from switched ones, though. Then regarding Aune's power demands. The backside says it takes 12-18V. So why not just build or buy a good quality 12V or 18V PSU? Is more the better (as long as you don't fry the device)? And realted to that, how much does the current matter in a device like this? Is the "default" 1A enough or is there a real benefit from 1,5A or even 2A? I guess this is not only Aune related but general useful information for anyone who wants to upgrade these el cheapo factory power supplies... Sorry for bombarding You guys with these but You seem to know much about these things
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Post by namklak on Nov 6, 2009 18:37:16 GMT
I'm a programmer, so I could be off on some statements. There is talk in this thread about trying to get one of the op-amp's output to be in class A mode. An op-amp is a monolithic piece of silicon, meaning is "gates" are generally well matched. It seems to me the discrete class A/B output driver with TIP4x transistors and 1N4148 diodes is way more guilty on non-linearities than a monolithic op-amp. Please tell me how my thinking it wrong? Yes, feedback can help correct these non-linearities, but I believe the more non-linearities in the topology to be fixed, the more Transient Intermodulation Distortion (TIM) artifacts will be present. Thanks, -BobK
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toad
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Post by toad on Nov 6, 2009 18:54:06 GMT
We listen with our ears not our statistics.
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leo
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Post by leo on Nov 6, 2009 18:56:24 GMT
I think some people like the added distortion Bob
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leo
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Post by leo on Nov 6, 2009 19:32:12 GMT
Am I right that to output bypass the AD744 pin 6 is removed from the opamp and pin 5 bent across to contact pad 6 (if using soic)? Correct! I, personally wouldn't want to be the one doing it with a soic chip though..... they are very small things.... a lot easier with a DIP chip..... just snip off the leg and bend the other one over to take it's place.... I will take pictures so you'll get the idea, give me a couple of days. I've heard talk of this but haven't actually implemented it... as yet.... I've always run my AD-744/A without the resistors..... I'll try the 2K2 thing next time I'm under the hood...... if you have a look at Xin's site there is quite a lot there about it www.fixup.net/talk/pop_printer_friendly.asp?TOPIC_ID=1231I ordered one from Rapid, it will be interesting to see if I receive the one in the photo The part of the mod mentioning the resistor is usually called classA mod, all you do is run a resistor or CRD from the output pin to the supply pin with worse psrr which could be -v or +v depending on the type of op-amp With snipping pin6 off and bending pin5 over to where pin 6 was you have bypassed the AD744 own output stage and now your running the output from the comp pin
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Post by namklak on Nov 6, 2009 20:13:23 GMT
I think some people like the added distortion Bob Hence the use of tube amps ;D
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leo
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Post by leo on Nov 6, 2009 20:15:52 GMT
I think some people like the added distortion Bob Hence the use of tube amps ;D I hope you stick around
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Post by namklak on Nov 6, 2009 20:30:07 GMT
The part of the mod mentioning the resistor is usually called classA mod, all you do is run a resistor or CRD from the output pin to the supply pin with worse psrr which could be -v or +v depending on the type of op-amp With snipping pin6 off and bending pin5 over to where pin 6 was you have bypassed the AD744 own output stage and now your running the output from the comp pin Some people connect the R to V- because they believe PNPs are less linear than NPNs. I like your explanation of "worse psrr" much better. I believe the R effectively bypasses the transistor it is on parallel with, yes/no? To do that on the TIP4x stage, I believe I would have to use a R value that is equal to or less than the impedance of my headphones, yes/no? For the right channel, I'd have to remove C40/41, D3/4, R36, bypass R37, then add a 32ohm R from the (schematic) left side of R39 to V-. Or I could just pretend there is NOT a non-matched Class A/B stage in my audiophile headphone amp. Or maybe I could buy a curve tracer and match the Qs and Ds. And I hadn't looked up the AD744, so thanx for the pin5/6 swap explanation. And to get U11 to operate correctly, the supply needs to be at least 16V, so shipping this thing with a 12V supply is bogus. I can't wait to put a bigger supply on this - anyone know the real current draw? Thanks, -BobK
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Post by PinkFloyd on Nov 6, 2009 21:01:53 GMT
The 12V is in "name" only.... if you measure the OP voltage it's around 21 Volts. I say to hell with facts and figures and prefer to use my ears to get the "tone" I like... the AD-744 is the nicest sounding yet.... I have plenty more to roll in (over 50 different types though I doubt I'll only try 5 or so) I like to report on the SQ of the chip "as is" (ie: rolled in without any further optimisation).... all most people want to do is roll the chip in and can't be arsed / don't have the technical knowledge to take things further.... that's OK with me, our ears are not oscilloscopes and if the sound is good to our ears why should we argue with the results? What comes across as "distortion" on paper may, and often does, come across as a pleasing tone to our ears.... what comes across as "perfect" on paper can, and often does, sound like turd.... musically uninvolving and sterile..... I'll stick with my ears, they have served me well for 48 years.... if it sounds good it IS good as far as I'm concerned and no machine will tell me different
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Post by namklak on Nov 6, 2009 21:34:31 GMT
The supply I got drops to about 13.5V when connected to the Aune. I tried two 9V alkaline batteries in series - NICE! More "transparent". The "18V" battery supply dropped to about 16.5V when connected and the Aune drew about 129mA, answering my own question. Actually, if I can get sonic improvement by doing nothing more than swapping a sockets op-amp, I'm all for that. I'm too busy to really screw with this like I'd like... But I do believe you need at least 16V under load for correct operation. -BobK
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