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Post by PinkFloyd on Nov 6, 2009 21:51:06 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 Bob, If you read through this thread you'll see that the supplier of the Aune said he used to ship 12V supplies but they sounded crap and he now ships 21V supplies.... have you had yours for a while?
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Post by namklak on Nov 6, 2009 22:10:13 GMT
Oh wow - I bought mine used - I was saving a buck, but
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Post by PinkFloyd on Nov 6, 2009 22:28:18 GMT
Oh wow - I bought mine used - I was saving a buck, but No worries mate.... simple case of obtaining a 20V supply
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Post by Deleted on Nov 6, 2009 22:30:11 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 Leo and Bobk Another interesting option with a "bodgied" AD744, would be to feed it into a buffer using matched pairs as in the LH0002 buffer's schematic, but replacing the 5K1 resistors with FETs as 3mA current regulators. I had a very nice sounding HA/preamp using the AD744 and buffer like that years ago. It would have been even better with the Class A mod. The buffer stage would of course be in the feedback network. Mike is right, the AD744 is a very nice chip. Alex
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Post by namklak on Nov 6, 2009 22:39:54 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 Bob, If you read through this thread you'll see that the supplier of the Aune said he used to ship 12V supplies but they sounded crap and he now ships 21V supplies.... have you had yours for a while? WTF!!! Here is what coolfungadget stated ---- The manufacturer recommended PSU outputs 24V here in China. I requested a lower voltage PSU for EU countries that outputs 20V here. The higher voltage, the better sound... I got a buyer from US returned this DAC for bad sound because I equipped his unit with a 12V regulated PSU... ---- Guess where I live - why can't he give a decent supply to the US? -BobK
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Post by Deleted on Nov 6, 2009 22:40:10 GMT
Mike I am looking forward to hearing what your ears like so much about "Yello-Touch" in a couple of weeks. BTW,Which track is your favourite ? Alex
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Post by PinkFloyd on Nov 6, 2009 23:05:06 GMT
Bob, If you read through this thread you'll see that the supplier of the Aune said he used to ship 12V supplies but they sounded crap and he now ships 21V supplies.... have you had yours for a while? WTF!!! Here is what coolfungadget stated ---- The manufacturer recommended PSU outputs 24V here in China. I requested a lower voltage PSU for EU countries that outputs 20V here. The higher voltage, the better sound... I got a buyer from US returned this DAC for bad sound because I equipped his unit with a 12V regulated PSU... ---- Guess where I live - why can't he give a decent supply to the US? -BobK Don't get your panties in a knot mate..... I'm sure, if you e-mail them and refer to this thread they'll send you a 20V supply free of charge ;D If they don't then let me know
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Post by PinkFloyd on Nov 6, 2009 23:06:30 GMT
Mike I am looking forward to hearing what your ears like so much about "Yello-Touch" in a couple of weeks. BTW,Which track is your favourite ? Alex Probably "Bostich reflected" and "Takla Maklan"..... let me know what you think Mike.
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Post by Deleted on Nov 6, 2009 23:18:04 GMT
Mike I will let you know, if the bloody thing turns up! They musn't be able to clearly understand written English, as I told them I didn't want numerous copies of the 2 Melody Gardot CDs that I have just received. Already, there is another one on the way. Does this last ditch reply to CD WOW support seem clear enough? Regards Alex P.S. Some of the sentences were in "bold" type.
----- Original Message ----- From: Alex Kethel To: CD WOW! Sent: Saturday, November 07, 2009 10:00 AM Subject: Re: CD WOW! Order Cancellation
Dear Support Perhaps I did not make myself clear, or there is some unfortunate language barrier ? I do want the Norah Jones deluxe CD , and Yello -Touch CD as originally ordered. I do NOT want numerous copies of both of the Melody Gardot CDs. I have already received both Melody Gardot CDs that I originally ordered. I have been advised that a further copy of "Melody Gardot-My One and Only Thrill" has already been despatched .There has been some kind of glitch in your system. Please note that I have already paid around AU$95 via Paypal for the 4 CDs that I asked for. Please despatch the Norah Jones and Yello Cds as ordered when they arrive in stock this month. Please sort this mess out, or you will have lost a customer permanently. Up till now, your service has been exemplary, and your pricing extremely good. I had already recommended CDWow to quite a few other people. Thanks Alex
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Post by PinkFloyd on Nov 6, 2009 23:33:18 GMT
Mike I will let you know, if the bloody thing turns up! They musn't be able to clearly understand written English, as I told them I didn't want numerous copies of the 2 Melody Gardot CDs that I have just received. Already, there is another one on the way. Does this last ditch reply to CD WOW support seem clear enough? Regards Alex P.S. Some of the sentences were in "bold" type. ----- Original Message ----- From: Alex Kethel To: CD WOW! Sent: Saturday, November 07, 2009 10:00 AM Subject: Re: CD WOW! Order Cancellation Dear Support Perhaps I did not make myself clear, or there is some unfortunate language barrier ? I do want the Norah Jones deluxe CD , and Yello -Touch CD as originally ordered. I do NOT want numerous copies of both of the Melody Gardot CDs. I have already received both Melody Gardot CDs that I originally ordered. I have been advised that a further copy of "Melody Gardot-My One and Only Thrill" has already been despatched .There has been some kind of glitch in your system. Please note that I have already paid around AU$95 via Paypal for the 4 CDs that I asked for. Please despatch the Norah Jones and Yello Cds as ordered when they arrive in stock this month. Please sort this mess out, or you will have lost a customer permanently. Up till now, your service has been exemplary, and your pricing extremely good. I had already recommended CDWow to quite a few other people. Thanks Alex All I can say is "wow"
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Post by mcinen on Nov 9, 2009 9:21:47 GMT
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toad
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Post by toad on Nov 9, 2009 13:08:54 GMT
I'd be tempted to stick at 20v or 21v. The Aune ran luke warm when I tried it at 22v I'd imagine it could get quite hot at 24v. I could detect no change in the sound signature between 20 and 22 volts.
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leo
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Post by leo on Nov 9, 2009 15:34:18 GMT
Just remember theres a dac in there, some required voltages could be as low as 3.3v, thats quite a big drop from 20 odd volts
I'd try the obvious thing if it sounds better at a higher voltage, run the dac and HA section separate , use the lower for the dac and higher for the HA, obviously needs some diy though
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Post by namklak on Nov 9, 2009 15:44:52 GMT
Sorry for not having all the correct measurements, but since this thread is active now... Coolfungadgets told me that he ships to the US the same supply he ships to the EU, except he adds a block that converts 110 to 220. He did indeed ship me that block. I measured this combination, and it is 20V UNLOADED. So I wanted to measure the supply with a load, but to do that with the aune, I'd have to disassemble it, which I didn't have time to do last weekend. I was able to measure the aune current draw- it draws 0.128A @ 16V (I did this with 9V batteries). I have on my desk a PC fan that draws 0.06A @ 12V (almost half the current of the aune), so I connected that to the supply. The aune supply dropped to 17V with the fan connected, which is probably drawing half the current of the aune. I will try to measure the supply with the aune connected this weekend. My point is, I believe some people think they need a bigger supply than the one shipped with aune, thinking that their current aune supply is 20V. Before you go building supplies at monster voltages, please measure what your current supply is doing while loaded with the aune. If your supply is like mine, it is probably not putting even 17V into your aune. I believe the aune can reach full potential at 18V (from a linear supply that can pump 1A). 22V is just extra heat (which is circuit aging) and 24V is premature death. It'd be great if anyone on this forum has an aune disassembled, with the coolfundaget supply, and can measure and post what the voltage is with the aune on. Thanks, -BobK
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leo
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Post by leo on Nov 9, 2009 17:10:28 GMT
If I had one of these it'd be stripped already
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Post by PinkFloyd on Nov 9, 2009 21:47:42 GMT
If I had one of these it'd be stripped already WHY?!! You haven't even HEARD the bloody thing Leo, why do you think you know what it sounds like and you can make it sound better? Fair enough, go to town on something if it doesn't quite meet your requirements (after you have heard it / have first hand experience of it) but to sit at a computer imagining how it sounds is not the way to do it IMO. Mike.
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Post by leo on Nov 9, 2009 23:44:35 GMT
Sorry but the sight of OPA2604 and a few other things is enough, I hate those 2604's, no matter what or how they are used
I give most stuff as stock a chance but there is some things I know I would have to change, if somebody hates Marmite they'll taste it no matter what its put in
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Post by Deleted on Nov 9, 2009 23:47:12 GMT
Leo Perhaps you should try Vegemite instead ? Alex
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leo
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Post by leo on Nov 10, 2009 0:30:29 GMT
Either Vegemite or Marmite, just as long as its not in every meal
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Post by cyteen on Nov 10, 2009 3:47:12 GMT
Since its just a matter of time before someone will want to start modding this thing:- Also how does the 'rca out' through an SCHA compare to the on board 'phone out?
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Post by Deleted on Nov 10, 2009 4:03:04 GMT
cyteen Depends on which version you are referring to. With the version using a JLH,the added RCA OUTS , especially when using a metal can LM4562HA, are not far behind my own Class A preamp. The Class A preamp has a more 3D presentation, as well as an extra "veil" removed. It is likely to be far better than many people are currently using, especially if a selector switch is added to give it greater flexibility. SandyK
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Post by cyteen on Nov 10, 2009 7:59:06 GMT
I ment to compare the headphone output of the aune stand-alone vs using the aune as a dac for the SCHA.
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Post by clausdk on Nov 10, 2009 12:40:09 GMT
I ment to compare the headphone output of the aune stand-alone vs using the aune as a dac for the SCHA. that was something I would like to know also.. How it performs as a DAC ?
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Post by devilduck on Nov 10, 2009 16:30:41 GMT
Pink have you tried the Aune with your AT W1000 phones? Are these two a good match?
They sound great with my AD700 and I was thinking of picking up a pair of W1000.
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matt7941
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Post by matt7941 on Nov 21, 2009 0:18:05 GMT
I've just read the link Mike inserted earlier in this thread to Xin's site. After reading Mike's comments about the disappointing opa1612 this seems quite pertinent.
They seem to feel that not only was the AD744 very good in class a mode with the output bypass mods, but that almost unbelievably the NE5534 with the same mods is even better. Has anyone tried any of these in the Aune? For the peanuts price of two of the TI NE5534APs it seems to good to be true. If this is the case I might even consider replacing the OPA2604s in my X-24K dac with some. Checking around the web the much maligned NE553x series seems to be having somewhat of a resurgence.
Matt
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