jkeny Posted July 30, 2011 Share Posted July 30, 2011 (edited) The ability of this DAC to drive headphones is just an aside & not what it was designed to do so I was not too concerned about it as it's main function is to drive amps/preamps. You also must understand that I'm not a full-time, manufacturer (ie I have a real job ) & don't have all the testing equipment to do this or the time to devote to what I consider side issues. If/when a fully fledged headphone amp with volume control & possibly balanced operation is produced, then I'll give the relevant specs that are important for driving headphones. At the moment, consider this a DAC that just so happens to drive headphones directly, as a happy coincidence! Yes, I believe Davewantsmoore is correct - a couple of hundred ohms but you also have to factor in driving capability of the output stage as a determinant of sound! So as he quiet rightly says, judging the sound of a source from a couple of specs is a mistaken belief. First post here so first Hello Everybody, just arrived in Oz a few weeks ago and happy to find a lively audio forum!It seems that I arrived in the middle of an argument though and I do not want to be controversial from the start. I am happy to learn that the output impedance is low enough to directly inject all power amps, which is just what I want to do in my system. However John, if you advertise the product as driving headphones adequately it is a different matter. I am happy that it can drive HD650 well since I have some of those too. But I have also a pair of Denon D2000 with 32 Ohms impedance... At this stage of the discussion, it sounds to me that an actual measurement of the output impedance would be satisfying for everybody and I am not sure why you seem reluctant to perform it. Anyway count me in as a potential customer and I would be delighted to get a chance to listen to one unit (Melbourne). I am not sure it is possible since I have just joined. Bill let me know. Edited July 30, 2011 by jkeny Link to comment Share on other sites More sharing options...
pretender Posted July 30, 2011 Share Posted July 30, 2011 John, this is direct, honest and more than good enough for me! Anyway I am not sure that I would trust putting sensitive cans with just computer volume control, one mouse slip on the volume bar and you are deaf... Link to comment Share on other sites More sharing options...
bhobba Posted July 30, 2011 Author Share Posted July 30, 2011 First post here so first Hello Everybody, just arrived in Oz a few weeks ago and happy to find a lively audio forum! Welcome. Anyway count me in as a potential customer and I would be delighted to get a chance to listen to one unit (Melbourne). I am not sure it is possible since I have just joined. Bill let me know. No problem - name added to list Thanks Bill Link to comment Share on other sites More sharing options...
davewantsmoore Posted July 30, 2011 Share Posted July 30, 2011 (edited) I doubt that you were really concerned about "basic specs" as they are all here anyway In Nada's defence, I not sure he was really out to get you .... he's just placing a bit too much importance on something that is unlikely to matter a bunch (regarding output impedance). I don't normally like to generalise, but, unless you are planning to connect a source directly to a power amp with a relatively low impedance (of which said manufacturer of low input Z power amp would be advising you not to connect sources directly) .... then the output Z of a source is really going to be a moot point up to even a modest number of K ohm. FWIW ... I'm not sure I've ever seen DC offset listed in the specs of a source device. ... and without at all attempting to disparage John, he's just a dude making a DIY DAC ... he aint' Sony ... and he's being particularly generous IMO ... so perhaps back off a bit?! I am happy that it can drive HD650 well since I have some of those too. But I have also a pair of Denon D2000 with 32 Ohms impedance... You'd really want a much lower output Z there .... with 200ohm from the source, into 32 ohms for your phones... you're on a damping factor of less than 0.2 ... no harm at all in trying .... you could try this too with a CD player, DAC or preamp of known output V/Z ...... but I'd be thinking they'd really need a HP amplifier (and a quite good one) .... or a preamp with a very low output Z :-) Edited July 30, 2011 by davewantsmoore Link to comment Share on other sites More sharing options...
Nada Posted July 30, 2011 Share Posted July 30, 2011 Nada, you don't know me! Let me worry about customers - it's not your concern. I doubt that you were really concerned about "basic specs" as they are all here anyway, if you bothered to read & think about things for a moment! John, Im sorry if any words have offended you in some way? I actually had thought that I had got to know you as a friendly bloke from our PM's. I check basic specs on all gear Im interested in and had checked your web page for them by the way but only saw Vrms listed? Did I miss something? I must say Ive never had problems like this before. You must be very busy with your day job and the audio business. Make sure you look after yourself there. Link to comment Share on other sites More sharing options...
davewantsmoore Posted July 30, 2011 Share Posted July 30, 2011 I give up ... I either fail to read the whole thread, or there's posts while I'm busy typing ... u crazy kids :-/ :-) Link to comment Share on other sites More sharing options...
jkeny Posted July 30, 2011 Share Posted July 30, 2011 Thanks Dave, Yes, I hope I put this in perspective - it's not a headphone amplifier, it's a DAC. I just wanted people to try it with their headphones as I discovered that it drives them well (except AKG701s) - even 32ohm Sony MDRs (not very high end, I'm afraid) with no loss of bass. I think whether it works for your headphones will depend also on the sensitivity of the headphones too. Link to comment Share on other sites More sharing options...
jkeny Posted July 30, 2011 Share Posted July 30, 2011 John, this is direct, honest and more than good enough for me! Anyway I am not sure that I would trust putting sensitive cans with just computer volume control, one mouse slip on the volume bar and you are deaf... Don't worry about maximum volume deafening you - it doesn't drive most headphones to ear bleeding levels, in fact with HD650 headphones it's max volume or slightly lower than max is just about right for my listening requirements. If it accidentally got turned up to max it wouldn't cause my ears any damage! As I said, it's not a true headphone amplifier but as one friend said to me if he had heard this before he built his own tube-based, tricked out headphone amp he wouldn't have bothered to build it Link to comment Share on other sites More sharing options...
Juicester Posted July 30, 2011 Share Posted July 30, 2011 Hey - anyone north of melbourne on this list? I'd love to audition it as well. In the market for a decent price/perf DAC. Chris Link to comment Share on other sites More sharing options...
bhobba Posted July 31, 2011 Author Share Posted July 31, 2011 Hey - anyone north of melbourne on this list? I'd love to audition it as well. In the market for a decent price/perf DAC. Hi Chris Just say the word and you are on the list. Stefan534 has kindly offered to coordinate guys listening to it in the Melbourne area. One thing I need to make clear because at least one person pulled out because of it - this is a USB only DAC. In fact that's probably the main reason for its stellar performance and great cost to performance ratio. What it has is a JK Battery Modified Hiface feeding direct into a Saber chip and straight out - no output stage or anything. Simple and elegant. Thanks Bill Link to comment Share on other sites More sharing options...
Nada Posted July 31, 2011 Share Posted July 31, 2011 Can anyone point me to where the info on battery life is to be found? How do we know when a recharge is due? Is there an indicator light or do we need to watch out for a decline in quality of does it just cut out? What about recharge cycles - how many cycles can the batteries take? How much do they cost to replace? Sorry if its already been discussed but Im over trying to dig for info on this thing. Link to comment Share on other sites More sharing options...
davewantsmoore Posted July 31, 2011 Share Posted July 31, 2011 https://sites.google.com/site/hifacemods/home/hiface-dac I believe ... the unit charges continuously if left plugged in ... only time you need to worry about it conking out is if you're running it without power source. Link to comment Share on other sites More sharing options...
jkeny Posted July 31, 2011 Share Posted July 31, 2011 (edited) Nada, that info is found on my website - battery life 10-15 years (when used in electric vehicles, based on daily recharging) - should be longer for low current usage in JKDAC. LED dims slightly but the recommended operation is to have the charger plugged in permanently (I have a new internal charger in the box now which introduces no noise). It recharges the batteries when the unit is turned off. A charge lasts for > 8 hours. If you always leave your devices turned on then this battery operated device is not for you. Edited July 31, 2011 by jkeny Link to comment Share on other sites More sharing options...
bhobba Posted July 31, 2011 Author Share Posted July 31, 2011 Hi Guys Just had a note from Dave Whatmore that he has kindly put up his hand to coordiante the audition in Tassie. That means we have a coordinater for all capital cities except Canberra and Adelaide. Anyone interested? Thanks Bill Link to comment Share on other sites More sharing options...
bhobba Posted July 31, 2011 Author Share Posted July 31, 2011 (edited) Can anyone point me to where the info on battery life is to be found? How do we know when a recharge is due? Is there an indicator light or do we need to watch out for a decline in quality of does it just cut out? What about recharge cycles - how many cycles can the batteries take? How much do they cost to replace?Sorry if its already been discussed but Im over trying to dig for info on this thing. Hi Nada You simply leave it plugged in and switch it on and off like a normal piece of equipment - when off it charges. Simple. I have run it for some very long periods - all day in fact - with no problems of it running down. The only issue is while charging it does create a bit of a buzz in my speakers so while listening I disconnect it from the wall and reconnect it when I am not listening. In practice I found it no problem at all. Thanks Bill Edited July 31, 2011 by bhobba Link to comment Share on other sites More sharing options...
Once was an audiophile Posted July 31, 2011 Share Posted July 31, 2011 Can anyone point me to where the info on battery life is to be found? How do we know when a recharge is due? Is there an indicator light or do we need to watch out for a decline in quality of does it just cut out? What about recharge cycles - how many cycles can the batteries take? How much do they cost to replace? Sorry if its already been discussed but Im over trying to dig for info on this thing. My car battery is 3 years old recharged every 2 weeks just a little bit Link to comment Share on other sites More sharing options...
davewantsmoore Posted July 31, 2011 Share Posted July 31, 2011 recommended operation is to have the charger plugged in permanently . It recharges the batteries when the unit is turned off. Ah. I stand corrected. Sorry if I mislead anyone. Link to comment Share on other sites More sharing options...
Nada Posted July 31, 2011 Share Posted July 31, 2011 Thanks for the info on the batteries and running the thing. It seems really convenient and well thought out. I cant think of too many days when Ive wanted to listen for more then eight hours straight so that suits me. Im really looking forward to a listen. Ive got a few more lazy questions that are really basic (Ive never used or heard a HiFace before) but might help other guys too; Do I need to download a driver if I stick to 92kHz max? With the audiophilleo a driver is only needed on Win7 above 92kHz so I wonder if its the same with this? If I need a driver does Windoze install it off the web automatically? Does it do 32 bits? Im hoping to play my 24 bt high res files using digital vol control so 32 bit capacity all the way through is what kdoot recommended. Is the device using SPDIF or I2S into the Sabre. Thanks guys. Link to comment Share on other sites More sharing options...
bhobba Posted July 31, 2011 Author Share Posted July 31, 2011 Thanks for the info on the batteries and running the thing. It seems really convenient and well thought out. I cant think of too many days when Ive wanted to listen for more then eight hours straight so that suits me. Im really looking forward to a listen. Ive got a few more lazy questions that are really basic (Ive never used or heard a HiFace before) but might help other guys too; Do I need to download a driver if I stick to 92kHz max? With the audiophilleo a driver is only needed on Win7 above 92kHz so I wonder if its the same with this? If I need a driver does Windoze install it off the web automatically? Does it do 32 bits? Im hoping to play my 24 bt high res files using digital vol control so 32 bit capacity all the way through is what kdoot recommended. Is the device using SPDIF or I2S into the Sabre. Hi Hugh You download the M2Tech drivers for all playback - its as easy as pie. It does 32 bits and will play your hi res stuff beautifully - in fact that way I have noticed a definite increase in quality - not as dry to my ears. It is I2S direct to the Saber. Oh and one thing I will mention is the Steve Nugent Overdrive has arrived. I haven't been able to try it yet because Clay needs to make a special I2S cable. It also has a SPDIF out but haven't been able to get a hold of a decent SPDIF DAC to give it a whirl - everyone is going for the USB or I2S PDX so a SPDIF version of that was not available. I only had my WFS which to be blunt IMHO is not really up to it. Anyway when I drop off the JK DAC I will bring that on over as well and we can check it out on your Ref 7. Thanks Bill Link to comment Share on other sites More sharing options...
Once was an audiophile Posted July 31, 2011 Share Posted July 31, 2011 Hi Hugh I haven't been able to try it yet because Clay needs to make a special I2S cable. Thanks Bill And the special i2s cable is ? ps:i had no idea that a special i2s cable is needed Link to comment Share on other sites More sharing options...
bhobba Posted July 31, 2011 Author Share Posted July 31, 2011 And the special i2s cable is ? ps:i had no idea that a special i2s cable is needed The PDX uses 4 bnc connectors - the Off-Ramp a RJ-45 connector - you need special cable to connect the two. Thanks Bill Link to comment Share on other sites More sharing options...
Once was an audiophile Posted July 31, 2011 Share Posted July 31, 2011 The PDX uses 4 bnc connectors - the Off-Ramp a RJ-45 connector - you need special cable to connect the two.Thanks Bill Cat 5 is cheap fits into a RJ-45 connector easily a bit of solder and bnc connectors are fitted 1 hr max with a coffee break Link to comment Share on other sites More sharing options...
Once was an audiophile Posted July 31, 2011 Share Posted July 31, 2011 (edited) Yes, Naggots, thanks for posting - no need to answer my email asking you for your impressions, I guess That's the sound of lower jitter that you're hearing - more defined sound stage, more analogue-like (in a good way), less "edge" & digititis. Mr.Jkenny is a modded hiface + opus dac (http://www.twistedpearaudio.com/digital/opus.aspx) be classified as a low jitter solution for audio? ps: all connected via I2S Edited July 31, 2011 by kajak12 Link to comment Share on other sites More sharing options...
Nada Posted July 31, 2011 Share Posted July 31, 2011 Hey - I found John's website and it answered some questions for me. Thought others might like to see this too: JKDAC has the following characteristics (Size in mm L:120 W:78 H:43): It's a modified I2S Hiface capable of 24/192 integrated with a 24/192 Sabre ES9022 DAC operates exclusively from 2 internal batteries completely portable - will run for >8 hours from fully charged batteries Only USB input - USB type B input socket Only RCA analogue outs Outputs at 2V line level for driving preamplifier or amplifier RCA outputs will also drive headphones external battery charger plugs into box Link to comment Share on other sites More sharing options...
naggots Posted July 31, 2011 Share Posted July 31, 2011 Been listening all day..... left iTunes playing all night......this Dac must've been running for 18hrs now on one charge. sounds fantastic, which software do you recommend, Bitperfect, Audirvana, Decibel or plump up the cash for Pure Music. the Mac Mini will be loaded with Lion, i'd like to run it headless with the iPhone remote...... my speakers are 101db sensitive so the iTunes volume is aggressive. will any of these players improve this so i can play the JKdac direct easily? Thanks, George Link to comment Share on other sites More sharing options...
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