"The Wire" Power supply
BTW, this is a very nice little power supply. I think most folks should really consider it as the size is nice and pairs well with the amp. The SMD diodes are a pain until your realize you need to dump a bit more heat on them than the rest of the SMD parts. At least that was my experience. For some reason, soldering the anodes first also seemed to help. Not sure why.
In any case, be aware the space for the big electrolytics is limited if you deviate from the BOM. I had some extra Elna Simic's in the parts bin which I was able to make work, but, just barely. I had to elevate them off the board a bit. Not ideal from an inductance stand point, but, it worked fine. Doing this eliminated the ability to use the Molex headers. BTW, if I had a wish, it would be to include headers for the power output connectors (as well as power input on the amp itself). The trimmers are a bit tight next to the heatsinks, but, still quite usable.
As for transformers, I went with an Amveco 62053-P2S02 (Digikey: TE62053-ND) 15VA part with dual primaries and dual secondaries (each secondary is 15VAC at 1A). An expensive part, but, I love the size of these things! I used them before in my gamma2.
As for performance, at 121.3VAC from the wall, I am getting 18.8VAC at the regulators (output locked in at +/- 15 at the respective rail). So, I suspect this is right about perfect as it gives some overhead to allow the regulators to stay in regulation. I have not measured them, but the heat sinks for the regulators are barely warm. Touch them all day if you like without fear of pain. Nice.
Anyway, I would seriously consider this part if you are considering "The Wire".
BTW, this is a very nice little power supply. I think most folks should really consider it as the size is nice and pairs well with the amp. The SMD diodes are a pain until your realize you need to dump a bit more heat on them than the rest of the SMD parts. At least that was my experience. For some reason, soldering the anodes first also seemed to help. Not sure why.
In any case, be aware the space for the big electrolytics is limited if you deviate from the BOM. I had some extra Elna Simic's in the parts bin which I was able to make work, but, just barely. I had to elevate them off the board a bit. Not ideal from an inductance stand point, but, it worked fine. Doing this eliminated the ability to use the Molex headers. BTW, if I had a wish, it would be to include headers for the power output connectors (as well as power input on the amp itself). The trimmers are a bit tight next to the heatsinks, but, still quite usable.
As for transformers, I went with an Amveco 62053-P2S02 (Digikey: TE62053-ND) 15VA part with dual primaries and dual secondaries (each secondary is 15VAC at 1A). An expensive part, but, I love the size of these things! I used them before in my gamma2.
As for performance, at 121.3VAC from the wall, I am getting 18.8VAC at the regulators (output locked in at +/- 15 at the respective rail). So, I suspect this is right about perfect as it gives some overhead to allow the regulators to stay in regulation. I have not measured them, but the heat sinks for the regulators are barely warm. Touch them all day if you like without fear of pain. Nice.
Anyway, I would seriously consider this part if you are considering "The Wire".
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nice work Jake, yeah she's tiny alright!!; you'll find its not quite as touchy with balanced input due to the cmmr, but i agree with everything else you said about the lack of a sound character to this amp and the need for a good source. haha the klhozmo is 3 times as big as the amp!! did you use the stock 317/337, or go with lt1085/1033?
the bass is sooooo controlled, i agree. didnt matter what cans i through at it for testing either
the bass is sooooo controlled, i agree. didnt matter what cans i through at it for testing either
is the pre order on now?
count me in:
1. ONE FULL kit BAL-BAL
2. PSU (does it include the transformer, or pcb only?)
count me in for those two..
any price estimation yet?
will the BAL-SE and BAL-BAL have any sound differences? i thought they would sound difference since the opamp is not the same
btw, how big is the output power of the BAL-SE version? i can't seem to find the answer in the first post
nb: i don't care what kind of balanced pins are on the board, since i prefer to use panel mount jacks. with the design of the previous pcb, it's pretty hard to make a decent casing if you insist on using pcb mount input output jacks
count me in:
1. ONE FULL kit BAL-BAL
2. PSU (does it include the transformer, or pcb only?)
count me in for those two..
any price estimation yet?will the BAL-SE and BAL-BAL have any sound differences? i thought they would sound difference since the opamp is not the same
btw, how big is the output power of the BAL-SE version? i can't seem to find the answer in the first post
nb: i don't care what kind of balanced pins are on the board, since i prefer to use panel mount jacks. with the design of the previous pcb, it's pretty hard to make a decent casing if you insist on using pcb mount input output jacks
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no way, balanced version will pull up to >1A thats max and you are using a shunt, so your placid would have to be capable of supplying the ~250ma for the dac and 1A for the amp continuously (not a chance). also i'm confused, the dac needs 5v, this will need +/-15 and +/-20-22v. you will burn the dac regs momentarily
is the pre order on now?
count me in:
1. ONE FULL kit BAL-BAL
2. PSU (does it include the transformer, or pcb only?)
count me in for those two..
guys, you really should read the thread, i mean its only the last 5 pages or so for this version.
pcb only, or full kit, kit does not include transformer, that would add considerably to the shipping and really imo for the bal/bal you should use 2 , as i think it was confirmed going with the option of supplying the buffer section separately with higher voltage.
I would think so yes, the 2 chips do 'sound' different, though not hugely in the same type of implementation i would think. both are excellent and very very transparent. but just having balanced output will change the sound in my experience. generally cleaner with a bit more bass authority. hard to believe with this amp, because it already really commands respect from bass drivers. (I use multidriver in ears jh13 mostly)
output depends on what the load is, but its capable of up to +/- 250mA @ +/- 15 rails, but with unity gain and a 3vrms source, you are looking at the potential for about 750mW per channel. you can of course change the gain with a few resistors, but even the bal/se version has easily enough power for hd600 when fed with a balanced source and the bal/bal version will be significantly more powerful
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Sorry, I meant to say on the same Placid BP as the IVY III of course. But I guess that wont work either because of the current draw. Thanks.
qusp, thank you for your response..
i did read the posts from couple pages back, but then i got confused with the order of some members here, stating PSU in their order. if i order full kit, then it means the psu pcb is included, right? hence my order will be one BAL-BAL PCB ONLY (i hope opc will provide BOM along with the package
)as for the output power, i'm planning to use this for my wharfedale id1 isodynamic headphone 150ohm (REALLY power thirst), which i currently hook up to gainclone LM3886 (68Wx 2 output power i believe?). using this gainclone, i need to crank up the volume to 2-3 o'clock
maybe i should be more specific, will this amplifier (BAL-BAL version), drive my headphone sufficiently?
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The Khozmo is the SMD version of the product. Seemed most appropriate for an SMD-based amplifier.
Hi Guys,
Glad to see the preliminary orders still rolling in. I'll update the list with everything that has been added over the past few days.
I've got all the routing and placement done on all three variants, so I'll be posting the preliminary layouts this evening for comments. I've done away with all on-board connectors, and instead used smaller plated-through holes spaced at 0.1". That way, you can use a header or just bare wires if needed. From all the pictures I've seen of people's builds, nobody ever seems to use the on-board connectors.
Once the PCB's are done, I'll spend some time getting prices together on each of the kit variants. I would expect the BAL-SE version to be about the same price as before, and the SE-SE version to be a little less. The BAL-BAL version will cost a little more since it uses twice the number of LME49600 buffers, and they aren't cheap!
I'll be bumping up the parts quality across the board, so all resistors will be thin film 0.01%, and all caps will be X7R or NPO where possible.
I'm still up in the air about the power supply, and I need to decide if I really want to force people into more expensive regs when I personally don't feel that it's needed. I'll think about it a little more, and see how it fits in with each board.
As a side note, do people want each board to have dual-mono supplies as an option (e.g. a different supply for both left and right channels)? I will provide a 0R jumper for those looking to run a shunt reg on the front end, and some other supply for the output devices.
Regards,
Owen
Glad to see the preliminary orders still rolling in. I'll update the list with everything that has been added over the past few days.
I've got all the routing and placement done on all three variants, so I'll be posting the preliminary layouts this evening for comments. I've done away with all on-board connectors, and instead used smaller plated-through holes spaced at 0.1". That way, you can use a header or just bare wires if needed. From all the pictures I've seen of people's builds, nobody ever seems to use the on-board connectors.
Once the PCB's are done, I'll spend some time getting prices together on each of the kit variants. I would expect the BAL-SE version to be about the same price as before, and the SE-SE version to be a little less. The BAL-BAL version will cost a little more since it uses twice the number of LME49600 buffers, and they aren't cheap!
I'll be bumping up the parts quality across the board, so all resistors will be thin film 0.01%, and all caps will be X7R or NPO where possible.
I'm still up in the air about the power supply, and I need to decide if I really want to force people into more expensive regs when I personally don't feel that it's needed. I'll think about it a little more, and see how it fits in with each board.
As a side note, do people want each board to have dual-mono supplies as an option (e.g. a different supply for both left and right channels)? I will provide a 0R jumper for those looking to run a shunt reg on the front end, and some other supply for the output devices.
Regards,
Owen
i confirm my order:
ONE FULL kit BAL-BAL + PSU
nb: can i order the full kit without opamps and buffers? i already have more than enough LME49600 & LME49990 in stock. if it isn't possible, then i'll just go with the full kit. but again, i will waste my USD50++ opamps and buffers for the same opamps and buffers in the kit
thanks,
Iskandar
ONE FULL kit BAL-BAL + PSU
nb: can i order the full kit without opamps and buffers? i already have more than enough LME49600 & LME49990 in stock. if it isn't possible, then i'll just go with the full kit. but again, i will waste my USD50++ opamps and buffers for the same opamps and buffers in the kit
thanks,
Iskandar
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jdkJake:
Thanks for the excellent write-up and pictures! All feedback is very much appreciated.
You did a great job on the soldering, and it looks like you've got everything up and running as it should be. If you're running SE inputs, then you will be more prone to having noise pickup issues. You'll have to be cautious with your input and output wiring and shielding,and you can always try to BW limit by lifting the BW pin on the LME49600.
There are also some simple mods you could make to the BAL-SE board to bypass the first diff stage and feed your input directly into the second stage op-amp. You'd have to populate a few 0R resistors, and tack your input wires onto one side of an 0805 resistor. I can post the instructions for this if it's of interest.
Thanks again for your feedback, and congrats on another successful SMD build!
Cheers,
Owen
Thanks for the excellent write-up and pictures! All feedback is very much appreciated.
You did a great job on the soldering, and it looks like you've got everything up and running as it should be. If you're running SE inputs, then you will be more prone to having noise pickup issues. You'll have to be cautious with your input and output wiring and shielding,and you can always try to BW limit by lifting the BW pin on the LME49600.
There are also some simple mods you could make to the BAL-SE board to bypass the first diff stage and feed your input directly into the second stage op-amp. You'd have to populate a few 0R resistors, and tack your input wires onto one side of an 0805 resistor. I can post the instructions for this if it's of interest.
Thanks again for your feedback, and congrats on another successful SMD build!
Cheers,
Owen
well Joel, according to wikophonia they are indeed very inefficient orthodynamics!!!, but if you are giving them that much power you are driving them well past their safe max levels. according to the manufacturer they can handle up to 35w amplifier (which they probably dont intend you to crank all the way) and if you are giving them 2/3 of nearly 140w, well..... so either your amps arent as powerful as you think, or you are killing them.
all the same i think you'll be fine, if you put some little cpu heatsinks on the buffers and up the gain to say 4 or 5x, with +/-20v rails you will be able to get maybe 8wpc, or 16w. ever think of getting some new headphones? you might be better off building a mini A for them tbh. i mean this little amp will have some serious kick, but those headphones are what i would term by today's standards, a flawed design.
@opc re the psu chips. most people that mentioned a psu, asked you to upgrade the power supply to a reference design, the addition of using regs that might total in an extra 25 (for dual mono) over using lm317 if the regs are bought in bulk as they will that is (maybe less), is really not a big deal on the greater scheme of things. for a reference class headphone amp this isnt much money and some will spend well over 100 building something to beat it.
whether you believe its worth the money for everyone, to be blunt in this case really isnt the concern, well at least i hope people would speak up? perhaps a show of hands, but i believe we already had that and people seem willing to upgrade it (guys please tell me if i'm talking out of school here). if it helps with the costs of getting 2 options, i would probably buy a number of the psu boards to use in other projects if you use those chips in a bipolar/dual capable design. very handy and small/thin, low noise, fast, reasonable current with no need for additional sinking is a pretty cool thing that can be powered with little overhead and mounted just about anywhere. i suppose you could rerun the old one for people who dont want to spend up, didnt you have a heap of those psu pcbs spare?
agreed on no onboard connectors. input/output that is
definitely a good idea to allow the buffers to be powered separate and dual mono, or not with a jumper. which is a much bigger expense than a couple of chips. you also save money on heatsinks if you use the smd package. that way the psu is scaleable, people can take it as far as they like and can even do it in stages.
all the same i think you'll be fine, if you put some little cpu heatsinks on the buffers and up the gain to say 4 or 5x, with +/-20v rails you will be able to get maybe 8wpc, or 16w. ever think of getting some new headphones? you might be better off building a mini A for them tbh. i mean this little amp will have some serious kick, but those headphones are what i would term by today's standards, a flawed design.
@opc re the psu chips. most people that mentioned a psu, asked you to upgrade the power supply to a reference design, the addition of using regs that might total in an extra 25 (for dual mono) over using lm317 if the regs are bought in bulk as they will that is (maybe less), is really not a big deal on the greater scheme of things. for a reference class headphone amp this isnt much money and some will spend well over 100 building something to beat it.
whether you believe its worth the money for everyone, to be blunt in this case really isnt the concern, well at least i hope people would speak up? perhaps a show of hands, but i believe we already had that and people seem willing to upgrade it (guys please tell me if i'm talking out of school here). if it helps with the costs of getting 2 options, i would probably buy a number of the psu boards to use in other projects if you use those chips in a bipolar/dual capable design. very handy and small/thin, low noise, fast, reasonable current with no need for additional sinking is a pretty cool thing that can be powered with little overhead and mounted just about anywhere. i suppose you could rerun the old one for people who dont want to spend up, didnt you have a heap of those psu pcbs spare?
agreed on no onboard connectors. input/output that is
definitely a good idea to allow the buffers to be powered separate and dual mono, or not with a jumper. which is a much bigger expense than a couple of chips. you also save money on heatsinks if you use the smd package. that way the psu is scaleable, people can take it as far as they like and can even do it in stages.
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qusp:
According to this page:Hifimediy TK2050 Amplifier | Headfonia
they are using a Hifimediy T2 (100@4ohms) to drive Hifiman HE-6's(also orthos I believe), so running Joel running his Wharfdale orthos with LM3886's may be very realistic (they are 68wpc)..
According to this page:Hifimediy TK2050 Amplifier | Headfonia
they are using a Hifimediy T2 (100@4ohms) to drive Hifiman HE-6's(also orthos I believe), so running Joel running his Wharfdale orthos with LM3886's may be very realistic (they are 68wpc)..
Same here, I don't think that the (much too) expensive regulators are necessary in such application.
There are several very good DIY PS out there in different price classes.
If people feel the need to go that way, just take the liberty and go for whatever that fits your need/wallet or that make you feel happier!
Hi Guys,
There seems to be a fundamental misunderstanding about power output and available voltage drive. When you say that you're using a 68W LM3886 based amp to drive the headphones, keep in mind that that the output power is specified for a 4 ohm load and +/- 28V rails. If you then hook a 150 ohm set of headphones up to it, the most you'll ever be able to get is about 2W. You'll voltage clip at about 16.5V RMS while delivering about 110mA RMS of current.
If you use the BAL-BAL version of "The Wire" with 22V rails on the LME49600, you'll be able to swing closer to 26VRMS which would be about 175mA RMS into a 150 ohm load. That means "The Wire" would be able to provide about 4.5 watts for those headphones, over twice what the LM3886 can provide.
It's important to understand that with high impedance loads, the output voltage swing is what will most likely limit the output power. If the LM3886 amp you have now drives them well, then "The Wire" will drive them even louder if needed.
Regards,
Owen
There seems to be a fundamental misunderstanding about power output and available voltage drive. When you say that you're using a 68W LM3886 based amp to drive the headphones, keep in mind that that the output power is specified for a 4 ohm load and +/- 28V rails. If you then hook a 150 ohm set of headphones up to it, the most you'll ever be able to get is about 2W. You'll voltage clip at about 16.5V RMS while delivering about 110mA RMS of current.
If you use the BAL-BAL version of "The Wire" with 22V rails on the LME49600, you'll be able to swing closer to 26VRMS which would be about 175mA RMS into a 150 ohm load. That means "The Wire" would be able to provide about 4.5 watts for those headphones, over twice what the LM3886 can provide.
It's important to understand that with high impedance loads, the output voltage swing is what will most likely limit the output power. If the LM3886 amp you have now drives them well, then "The Wire" will drive them even louder if needed.
Regards,
Owen
