Dave
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Post by Dave on Jun 11, 2013 13:07:48 GMT
Hi Guys, Regular readers will know my knowledge of audio electronics is at the other end of the spectrum to my interest in the subject, in other words, not a lot . I read some time ago that I2S probably offered the best SQ while listening to file based music (thanks Javier ). I have kidded myself for a long time that my ancient ears and mid-fi kit enables me to appreciate the benefits of HiRes files and the addition of ribbon super tweeters so it seemed logical to me to go for I2S - bit of a challenge when you haven't a clue what it is . I had also read about Amanero boards (don't ask me ), 24/192 DACs at a reasonable price and galvanic Isolator boards around the same time so I did not take much encouragement to see if I could persuade someone to put them all together. The Amanero board interest started here: - rockgrotto.proboards.com/thread/8441 The reasonably priced DAC interest started here: - www.ebay.co.uk/itm/330886206404;jsessionid=BC6EDD9F9FA2E736BCE5369D37AB937B?ru=http%3A%2F%2Fwww.ebay.co.uk%2Fsch%2Fi.html%3F_from%3DR40%26_sacat%3D0%26_nkw%3D330886206404%26_rdc%3D1And this was the Isolator board: - www.diyaudio.com/forums/vendors-bazaar/228590-30-free-amanero-isolator-bare-pcbs.htmlNot really knowing one end of a soldering iron from the other I asked Dr. Jimmy Dripps at Tirna Electronics near Edinburgh if he fancied putting everything together for me, to which he answered "Yes". As my job got caught behind a project of some importance and even greater difficulty at Tirna I am still waiting for the finished assembly to be returned so I cannot offer any pics at this stage - but I will when I get it back. Meanwhile Javier has got his kit put together and is very happy with the sound he's hearing. And just in case there's any interest on this (headphone) forum, at the same time as this is going on I am building my own design of tonearm for my Technics SL1210 TT, completely built from carbon fibre. If there is any interest in that I can post pics of that but it is in the very early stages at the present time. Hope this is of some interest. Cheers, Dave.
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Deleted
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Post by Deleted on Jun 11, 2013 16:52:07 GMT
It has been known that an isolator whether pulse traffo or electronic will lower the noise floor of an DAC. Good to see that it still does technically. How much is that electronic isolator? Javier, how's the subjective sound with an isolator and without. Care to comment as another item is added into the signal path. Eventhough it's digital, that's going more away from KISS. And just in case there's any interest on this (headphone) forum, at the same time as this is going on I am building my own design of tonearm for my Technics SL1210 TT, completely built from carbon fibre. If there is any interest in that I can post pics of that but it is in the very early stages at the present time. Hope this is of some interest. Yes, please do post as that's what forum is all about. If there is no posting there will be no forum, right? Yeah, the fun part is important too and not just pure objective and subjective writing. There is no such thing as the "blind leading". Just have fun and that's very important to me at least.
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Javier
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Post by Javier on Jun 11, 2013 19:15:14 GMT
Javier, how's the subjective sound with an isolator and without. Care to comment as another item is added into the signal path. Eventhough it's digital, that's going more away from KISS. I've made too many changes at the same time to describe the effect of any of them individually. I'd say now it sounds as it should but then I'm not very good describing perceptions. Everything that should be there is there and in spades, beautiful little beast. IMHO adding an isolator is not against KISS. DACs are both digital AND analogue, isolating the DAC from the PC has measurable benefits as it stops electrical noise from reaching the analogue section and in my DAC in particular (Will's PK DAC based on the ES9023) it doesn't harm in the least as it is basically an async DAC meaning it upsamples all incomming signals to a frequency non realted to any fundamental hence the use of a 50.000MHz XO to drive an internal DPLL instead of a 45.1584 or a 49.152Mhz one. According to the manufacturer, the benefit of this method ESS likes to call "Hyperstream" which is used through out their range is a huge reduction in jitter. The ES9023 being a single 3.6V supply seems to have some extra sensitivity to common mode noise present on the incomming digital signals from the PC or through ground loops, Frans explained it in the other thtread, no idea how it would affect other DACs based on different ICs but I'd say they'd all benefit from using an isolator if they perform local reclocking be it sync or async, else jitter will be increased depending on isolator used and sample rate and XOs used in the source.
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solderdude
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Post by solderdude on Jun 11, 2013 21:06:42 GMT
I think the isolator circuit is more valuable then tinkering with other parts of the circuit. This is because of one simple fact... every PC/laptop e.t.c. produces common mode noise in the audible range and way above it (to the GHz range) Breaking that path electrically is paramount. And before one cries ... a laptop runs on batteries... it will still emit RFI as it is filled with onboard switch mode power converters.
This can be done in the best possible way (fiber optics) or with an isolator. TOSlink is also an option but because of the used components may induce jitter that may be audible in some of the older DAC's. Another BIG disadvantage is it's limited speed which limits the sample/bit rate. Real fiber optics do NOT have this disadvantage.
The isolator is a real asset and will at least improve things measurably (with EMI equipment this is easy to confirm). All one needs is a good USB receiver and DAC that can handle the formats out there. A decent (doesn't even have to be a super duper) linear power supply is also needed. This is a near perfect interface between digital and the analog path. Doesn't even have to cost you an arm and a leg as well.
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Javier
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Post by Javier on Jun 11, 2013 22:25:13 GMT
I can only add... amen!
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Deleted
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Post by Deleted on Jun 12, 2013 3:02:38 GMT
Thanks very much guys, you got me itchy backside now. I have always wanted an objective isolator as that is claimed to decrease technically the noise level very much by manufacturers and diyers but I'm not very sure how will it affect the sound subjectively as I like KISS. Now must try 1 or 2.
Thanks Dave for the link.
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Javier
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Post by Javier on Jun 12, 2013 7:54:30 GMT
Where would you connect the isolator in your DAC? Don't forget isolators add jitter,check their data sheets as some declare the value. It is important top reclock incomming signal after isolator. It works best with async chips like the ESS Sabre family or if you have an ASRC chip like in the X-DAC V3 (TI's SRC4192)
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Deleted
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Post by Deleted on Jun 12, 2013 12:05:08 GMT
Where would you connect the isolator in your DAC? Don't forget isolators add jitter,check their data sheets as some declare the value. It is important top reclock incomming signal after isolator. It works best with async chips like the ESS Sabre family or if you have an ASRC chip like in the X-DAC V3 (TI's SRC4192) Obviously, I will be using the isolator at the input to the DAC. Kill the noise before it do more "damage" to the signal technically. First plan to try it out with the MF V3 DAC but later maybe migrate it to any future Sabre DAC. But perhaps I will still keep it at the Amanero USB to the MF DAC as the SPDIF already has it's own isolating pulse traffo. I always like to keep it KISS as there is always side effect when something is added. Perhaps a pulse traffo isolator will give less jitter problem as the isolation is done passively.
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Javier
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Post by Javier on Jun 12, 2013 12:40:44 GMT
Have you connected the Amanero to the MF V3? ?
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Deleted
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Post by Deleted on Jun 12, 2013 16:17:24 GMT
Have you connected the Amanero to the MF V3? ? Connected? Just dreaming as have to read up loads of technical details before even can lay my paws on that as I'm just too busy to do that now. But I did put in my super Vregs though. Can immediately hear the difference of more details and hearing things that I'm not too aware before. Wow, the 3 dimensionality surely improves. Very obvious with Rebecca Pidgeon's Spanish Harlem.
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Javier
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Post by Javier on Jun 12, 2013 17:01:55 GMT
If you are on a (money and time) budget and want to play a little with the Amanero board to start learning I think this could be a good option (PCM only): [a href=" www.ebay.com/itm/TekDevice-Battery-Powered-I2S-ES9023-192K-24-Bit-SABRE-Premier-DAC-24192-Module-/390607577194?pt=Vintage_Electronics_R2&hash=item5af206a06aIt'll need a little work though. The XO that comes on the board is 49.152 which means async at 44.1 based (44,1, 88.2, 176.4 and 352.8KHz) and sync with 48K based (48, 96, 192 and 384KHz) so for true async and best SQ you'll need to source a 50.000MHz XO (for example Farnell ref # 1842143RL) and replace the deafault one. I'd replace also the two 2,200pF output caps with 4,700pF NP0/C0G (Farnell ref # 1740526), with 2,200pF the LPF will start way too high and plenty of garbage will get through. Additional tweaking could involve replacing the onboard regs if they are not too good. You'll be very pleasantly surprised how good this little bu**er can sound.
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Deleted
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Post by Deleted on Jun 13, 2013 7:11:36 GMT
Thanks Javier for the link. I have no doubt that that will be good sounding. However, I better keep the "inventory" at home lower as people at home are not too happy to what I have all over the place. So it's better I reserve the "space" for a highend Sabre than to have to explain again when I reach there.
Thanks again.
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Dave
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Post by Dave on Jul 6, 2013 9:27:32 GMT
Hi Guys, I have taken some pics of the inside of the Amanero kit build that I had done for me and will post them shortly, but I have a typical DaveK question. Because there is no volume control in the system using the Amanero other than the resident one in Windows (which I understand should always be at 100% for best SQ) I am left wondering if the SQ could be improved even more by putting a volume control somewhere in the system so that the PC could run at 100% volume. I would also like to be able to run the output from the Amanero to the headphone amp (Custom HiFi Cables HA10) as well as to my AK Class A mono-blocks but the added impedance is too much for the Amanero to cope with (IIRC). I have unearthed a Rothwell Attenuator and wondered if this would solve both problems for me. Do any of our more knowledgeable members have any opinions on this? I don't mind the 'suck it and see' approach but would hate to smoke the Amanero kit by doing something inadvisable . Cheers, Dave.
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Javier
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Post by Javier on Jul 6, 2013 19:59:03 GMT
I think what you need is a pre amp or something with a vol pot in it. The attenuator is constant AFAIK so it won't do what you want. As we are talink about the analogue domain, I'd try asking Frans.
Some DACs have integrated very high quality digital volume control with no loss of resolution but uynfortunately that is not the case of the ES9023 chip in yours.
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Dave
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Post by Dave on Jul 6, 2013 20:16:18 GMT
It's a long time since I took a look inside the Rothwell Attenuator but, IIRC, it is totally passive, no power supply. It has several (usual) sets of RCA inputs and two sets of RCA output terminals. On the front is one knob to select the input signal source and two to select the output volume, one marked 'Coarse' and the other marked 'Fine'. I can't see that using it would cause any damage (would it?) so I might dig out some more analogue I/Cs and see what happens. Dave. EDIT: - Well I've done just that and it works . I can get music out of whichever output I want (HP amp or speakers) providing the other one is switched off, and it 'does what it says on the box', namely attenuates the volume. With the attenuator coarse volume control on about 50% rotation and the PC foobar volume control set at 100% (0.00dB) I can get all the volume control I want using the attenuator's fine volume control, so result!! Cheers, Dave.
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