Hi qusp:
nope, each amp has its own board.
What has changed is that both the SE-SE and BAL-SE have gone back to sharing a single supply. The only version that showed a meaningful improvement in channel separation with separate power supplies was the BAL-BAL version which remaines fully dual mono (if you used two supplies).
Because the other two amplifiers are SE output and share a ground at the jack itself, there's absolutely no benefit to running dual mono supplies since the shared ground is the dominant source of crosstalk between channels, and dual supplies do nothing to address that.
agdr:
You make a very valid point about using the BAL-BAL as an SE-BAL amplifier. It works perfectly with either a balanced or an SE input (if you ground the - terminal) so between the three designs, all four possible connection scenarios are addressed.
Cheers,
Owen
nope, each amp has its own board.
What has changed is that both the SE-SE and BAL-SE have gone back to sharing a single supply. The only version that showed a meaningful improvement in channel separation with separate power supplies was the BAL-BAL version which remaines fully dual mono (if you used two supplies).
Because the other two amplifiers are SE output and share a ground at the jack itself, there's absolutely no benefit to running dual mono supplies since the shared ground is the dominant source of crosstalk between channels, and dual supplies do nothing to address that.
agdr:
You make a very valid point about using the BAL-BAL as an SE-BAL amplifier. It works perfectly with either a balanced or an SE input (if you ground the - terminal) so between the three designs, all four possible connection scenarios are addressed.
Cheers,
Owen
ahh nevermind, i'm with you now. i had mistaken the bal-se top layer as the bal-bal top layer and skipped straight past the bal-bal thinking it was the SE-SE as its so tiny!! dude you're a man after my own heart with that layout, thats gonna fit in my portable perfectly, now lets see how long it runs
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the bal-bal version has possibility for dual mono psu, so we need 4 for that one if you choose to build dual mono, its not compulsory, but recommended for that build only, apparently opc found no benefit with any of the others.
hmm this is a bit of a confusing post, not only do i have nothing to do with distribution of this now closed GB (except for the bal-se version which is afaik still available), but i'm talking about the bal-bal version in the post you quotedpengboon said:
Owen, I don't know whether I'm just misinterpreting somehing (or maybe I'm just plain stupid
Cheers
Ignore this comment, I just went through the schematics again and re-read Owen's comments regarding shared supply vs. dual mono. While I do find it a little bit confusing that the PSU kit is only half of the PSU schematic, I also understand the reasoning behind it.
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only the bal-se version, unless someone backs out. the boards have been ordered already, so no. also it often confuses me in these threads just how few people will put in the minimum effort required to read even the page they are posting on
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i don't mean to be harsh, but it just gets a bit old having to answer the same questions over and over again when they could be avoided if people just read a few pages, or at the least search the thread they are posting in.
but yes i got my fair share of hazing too when i first joined, though my post had zero to do with being new, i would have done the same to anyone and the same thing is common across any forum, not just this one.
anyway the anticipation is building, not far off now, I have all the chips and some of the passives ready and waiting, although i tell you what i wish this used the opa1632dgn or had alternate pads for it, because i found another bunch of them now too, so i have 10 of them; while i only have some recycled soic8 ones. i guess i'll have to knock up a pcb of my own to use them.
but yes i got my fair share of hazing too when i first joined, though my post had zero to do with being new, i would have done the same to anyone and the same thing is common across any forum, not just this one.
anyway the anticipation is building, not far off now, I have all the chips and some of the passives ready and waiting, although i tell you what i wish this used the opa1632dgn or had alternate pads for it, because i found another bunch of them now too, so i have 10 of them; while i only have some recycled soic8 ones. i guess i'll have to knock up a pcb of my own to use them.
>>the anticipation is building, not far off now, I have all the chips and some of the passives ready and waiting
Agreed, qusp. I am so anxious I have turned to (re)wiring headphone cables and rereading ancient threads. Being retired is not all it is cracked up to be but it leaves plenty of time for anticipation. It has been a number of years since I had ALL of the parts ready before the PCB even shipped
BTW, qusp, I hope you know how much we appreciate your sheparding this project and others. I seem to recall reading that you encouraged Owen early on. Thanks.
Agreed, qusp. I am so anxious I have turned to (re)wiring headphone cables and rereading ancient threads. Being retired is not all it is cracked up to be but it leaves plenty of time for anticipation. It has been a number of years since I had ALL of the parts ready before the PCB even shipped
BTW, qusp, I hope you know how much we appreciate your sheparding this project and others. I seem to recall reading that you encouraged Owen early on. Thanks.
i'm already preparing to make the components order from element14 for the SE-SE version
i'm having some problem finding the X7S 1uF capacitors, can i replace them with X7R 1uF without degrading the sound quality?
and is it safe to use 100mW resistors instead of 125mW? i suppose they should be okay but just wanna make sure.. they are significantly cheaper than the 125mW susumu (the other specifications are the same: thin film, 0.1% tolerance)
i'm having some problem finding the X7S 1uF capacitors, can i replace them with X7R 1uF without degrading the sound quality?
and is it safe to use 100mW resistors instead of 125mW? i suppose they should be okay but just wanna make sure.. they are significantly cheaper than the 125mW susumu (the other specifications are the same: thin film, 0.1% tolerance)
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Thanks for thatLooks like the BAL-BAL board can also make a great SE-to BAL converter by grounding one input and changing the feedback resistors to 2K.
It's what I'll be doing to start with to drive the headphones.
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