no i cant, i already stated in the other thread i wasnt going to do instructions and i actually went against that in that post and gave you the info you need, sorry but past that is getting a bit ridiculous. at some point if you want to do something non-standard you have to do some thinking for yourself. buffalo or ackodac makes no difference its the same in this regard. i have posted various clues already and given my resistor values, which are the only changes; in this thread and the other thread and its not rocket science, i'll eventually post some more progress pics when i have made some more progress on the chassis, but its still not going to be a how to.
sorry but there is a reason its called DIY
sorry but there is a reason its called DIY
Last edited:
Anyways thank you for this info. I'm not very familiar with diy and because of this I was searching for help on how to connect them. Isn't this a purpose of this forum to help other people to obtain a good sound? I am not aware of diy in general, but either have no necessary knowledge to do a project by myself. Of course it is already simple to connect modules designed by smart engineers, but it is easy for experienced guys like you. There are a lot of compromise DAC/HP/Pre out there but trully great ones are ridiculously expensive. That is why I found this forum and diy comunity that can help to build something that will suit personal taste. Will try to understand how to do it myself but not sure if I'll be able to do this. And another point here is that I am little bit afraid to do this by myself because without knowing what you are doing you can damage pretty expensive boards (I mean DAC board for example) and get frustrated as well.
Sorry for my broken english.
Best regards
Alex
Sorry for my broken english.
Best regards
Alex
Last edited:
Qusp and opc, I need your suggestions.
Here are AKD12P, BAL-BAL amd BAL-SE schemes:
Here I've tried to understand on how to connect AKD12P with BAL-BAL in sense of Acko DAC with current diff output and BAL-BAL as I/V stage (also headphone amplifier and preamplifier).
So here are my questions:
1) is this scheme correct to pull out current mode from acko DAC and convert it with BAL-BAL?
2) where to connect the ground wire from an XLR output?
3) how to adapt BAL-SE board to this purpose (to make a DAC with both XLR and SE outputs)?
4) What affect have feedback resistors here and is 680R value the correct one to use BAL-BAL with AKD12P ?
Here are AKD12P, BAL-BAL amd BAL-SE schemes:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Here I've tried to understand on how to connect AKD12P with BAL-BAL in sense of Acko DAC with current diff output and BAL-BAL as I/V stage (also headphone amplifier and preamplifier).
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
So here are my questions:
1) is this scheme correct to pull out current mode from acko DAC and convert it with BAL-BAL?
2) where to connect the ground wire from an XLR output?
3) how to adapt BAL-SE board to this purpose (to make a DAC with both XLR and SE outputs)?
4) What affect have feedback resistors here and is 680R value the correct one to use BAL-BAL with AKD12P ?
1) yes, your schematic appears to be correct. Remember that Vout=Iin*Rf
2) Connect it to GND! Preferably back at the PSU inputs to the board.
3) This cannot be done directly connected to the DAC, but you could omit U5 and U6, and simply connect the outputs of the BAL-BAL to where the outputs of U5 and U6 used to be. This would make the BAL-SE board act as a simple balanced to single-ended converter, and would omit two unnecessary op-amps.
4) There is no "correct" value as those resistors set the gain of the stage. You need to know what output voltage you want (depends on the headphones) and what the input current is (depends on the DAC configuration) then you use the formula give in 1) to calculate what R value you need. Keep in mind that the lower the resistor value, the better. Don't aim for any more output voltage than you absolutely need.
Regards,
Owen
2) Connect it to GND! Preferably back at the PSU inputs to the board.
3) This cannot be done directly connected to the DAC, but you could omit U5 and U6, and simply connect the outputs of the BAL-BAL to where the outputs of U5 and U6 used to be. This would make the BAL-SE board act as a simple balanced to single-ended converter, and would omit two unnecessary op-amps.
4) There is no "correct" value as those resistors set the gain of the stage. You need to know what output voltage you want (depends on the headphones) and what the input current is (depends on the DAC configuration) then you use the formula give in 1) to calculate what R value you need. Keep in mind that the lower the resistor value, the better. Don't aim for any more output voltage than you absolutely need.
Regards,
Owen
Yes it will.
TiEX,
some of these answers may seem a bit abrupt, mainly because there is a level of knowledge required for some of these projects, the projects you're aiming for are not generally recognised as being beginner friendly. The reason you're having problems is not necessarily because you're inexperienced but because they aren't simple problems and there is no one right answer. Also be careful if you think that by going diy you'll save significant amounts, its a common misconception.
TiEX,
some of these answers may seem a bit abrupt, mainly because there is a level of knowledge required for some of these projects, the projects you're aiming for are not generally recognised as being beginner friendly. The reason you're having problems is not necessarily because you're inexperienced but because they aren't simple problems and there is no one right answer. Also be careful if you think that by going diy you'll save significant amounts, its a common misconception.
Last edited:
I refer you to my previous posts, particularly to the post in this very thread with my photos of my bal-bal which is setup exactly as you are talking about, ive referred you to this before, yet youve asked me variations on the same question 4 times now in just over 24hrs including a PM. i simply dont have the time for this. I understand there is a language barrier, that is an unfortunate fact that will make this even harder
i do not believe you should be attempting an ackodac build (particularly an undocumented version) and it is not the venue to support it here as your questions are more to do with the dac, not the amp and i do not intend to set a precedent of supporting it. AR2 who is one of the more ambitious builders here and myself personally have not had an easy time of it due to rather complex PSU layout and some PCM lock teething problems. This was a while ago now, but you should know how ambitious your plan is. you should NOT start with such a project, the ackodac is a good design, but a level of ability is assumed; it does not have the level of support of the twisted pear stuff and you clearly need a lot of support. there are very few AKD12P builders compared to buffalo and there are even less (i'm the only one) who have done what you plan to
the 680R resistor value i gave you is for a current buffered unity voltage gain IV conversion, as opc says without knowing what your headphones are this could be correct and it may not be. It is however probably best to stick to unity if you plan on using it as a preamp as well, the sabre already has a slightly hot output. i also find that this is enough for all but >300ohm headphones
i do not believe you should be attempting an ackodac build (particularly an undocumented version) and it is not the venue to support it here as your questions are more to do with the dac, not the amp and i do not intend to set a precedent of supporting it. AR2 who is one of the more ambitious builders here and myself personally have not had an easy time of it due to rather complex PSU layout and some PCM lock teething problems. This was a while ago now, but you should know how ambitious your plan is. you should NOT start with such a project, the ackodac is a good design, but a level of ability is assumed; it does not have the level of support of the twisted pear stuff and you clearly need a lot of support. there are very few AKD12P builders compared to buffalo and there are even less (i'm the only one) who have done what you plan to
the 680R resistor value i gave you is for a current buffered unity voltage gain IV conversion, as opc says without knowing what your headphones are this could be correct and it may not be. It is however probably best to stick to unity if you plan on using it as a preamp as well, the sabre already has a slightly hot output. i also find that this is enough for all but >300ohm headphones
Last edited:
thats ok mate, i'm sorry if i seem harsh, i'm not being mean, i do admire your courageousness, but as you said there is quite a bit of money involved here, the ackodac more than most because of lower quantities being built along with top shelf parts across the board, not least the teflon PCBs. in my experience it does reward the effort, but it would be unfortunate to see a brave new builder put off diy because of a major setback.
i dont mean to minimise the level of support that Acko gives, in fact he makes himself quite available for it, but it is nowhere near as popular so doesnt have the army of supporters, the much larger number of documented builds for inspiration etc and as i mentioned is not aimed at the same segment. casework is much much more involved as well.
anyway what you could do, i dont know if you were considering this and i dont know if you have the budget, is to commission Acko for one of the all on one board integrated builds without the IV, its not as diy, but you would be supplied a fully tested dac and provided you were able to test the wire previously (very important) it would then be a matter of just connecting them together. that isnt a cheap option though and though failure after that would be unlikely, you would still be faced with a more complex trouble shooting effort.
anyway whichever way you decide to go i wish you luck
so a build thread query/scenario for opc
on the note of using the bal-bal directly with any dac without filtering, i know you found with the NTD1 design that LPF caps at the input to soak up some of the energy at HF was of little benefit, we werent dealing with parts that are as twitchy or wideband as these opamps are; i wonder if you did, or perhaps can still easily try the wire out directly with say a 330-560pf styrene, pps film, mica etc cap in parallel with Rf, with the view to perhaps taking some of that HF loading off the VAS to see if this provides any benefit. i can easily try this out, but i dont have any means to see if it shows any benefit to the performance. it obviously wouldnt be as linear
i dont mean to minimise the level of support that Acko gives, in fact he makes himself quite available for it, but it is nowhere near as popular so doesnt have the army of supporters, the much larger number of documented builds for inspiration etc and as i mentioned is not aimed at the same segment. casework is much much more involved as well.
anyway what you could do, i dont know if you were considering this and i dont know if you have the budget, is to commission Acko for one of the all on one board integrated builds without the IV, its not as diy, but you would be supplied a fully tested dac and provided you were able to test the wire previously (very important) it would then be a matter of just connecting them together. that isnt a cheap option though and though failure after that would be unlikely, you would still be faced with a more complex trouble shooting effort.
anyway whichever way you decide to go i wish you luck
so a build thread query/scenario for opc
on the note of using the bal-bal directly with any dac without filtering, i know you found with the NTD1 design that LPF caps at the input to soak up some of the energy at HF was of little benefit, we werent dealing with parts that are as twitchy or wideband as these opamps are; i wonder if you did, or perhaps can still easily try the wire out directly with say a 330-560pf styrene, pps film, mica etc cap in parallel with Rf, with the view to perhaps taking some of that HF loading off the VAS to see if this provides any benefit. i can easily try this out, but i dont have any means to see if it shows any benefit to the performance. it obviously wouldnt be as linear
Last edited:
Someone in the last thread had built one into a case by Box Enclosures, case work is really a personal taste thing though imo. My case is going to need to fit usb interface and dac as well so whatever I chose won't be suitable for someone who's just building the headphone amp as a standalone device.
Current draw of the amp can be worked out by datasheets. I'd personally be ignoring that and select fuse based on transformer you're using. The idea being that role of the fuse is to protect the transformer in case of short circuit.
These painted stomp boxes look cool...
Hammond Mfg. - Painted "Stomp Box" - Diecast Aluminum Enclosures (1590 Series)
Hammond Mfg. - Painted "Stomp Box" - Diecast Aluminum Enclosures (1590 Series)
Sure that will work but let me think out loud for a moment to get my mind around the purpose of the fuse for my own understanding. I know we're a bit off topic here, but its important to get protection of these circuits right so we're not unknowingly taking risks.
What failure conditions are possible that we would like the fuse to protect against?
- Short circuit between transformer secondary and PSU or between power entry and transformer primary, fuse needs to protect against these as a minimum.
- Short circuit on output is hopefully catered for by short circuit protection in the LME49600.
- Any failure to earth should be managed by ELCB in switchboard.
What other fault in PSU circuit can be protected by the fuse? Some component failure assuming the PSU is tested before wired to amp. Which components are most likely to fail in a way the fuse would see enough current to blow?
I'm not directing these questions just at qusp, I'm also not saying that his approach above wouldn't work, it certainly would. Though maybe if a miscalc is made then some nuisance tripping will occur and you'll be tempted to put a nail across the fuse terminal and forget it until the amp starts burning.
well i waited, sure, but this would be covered by a smaller rated fuse as well
i would not want to rely on this to protect my amp and headphones. the amp is DC coupled. ive never had a failure condition take out the transformer
by which time there is a chance your whole system is dead, considering you are connecting directly to your dac you also have many other variables for failure, all of them before the tx will and often before your house switch even flinches
something like the borderline soldermask shorts we saw posted perhaps
I've never killed a tx, but ive killed my share of other components, i have always been directed to size the fuse for the load, not the transformer, the transformer is covered regardless. most components, not just this one, will be long dead before the transformer sees enough current.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.