@Bonsai: Can you please check the lead size of the specified 22mF caps in the power supply against the drill size specified for the boards please?
The fit seems tight, but I am only checking with a similar size snap-in cap. At first glance it looks like the hole may be around 60-thou or 1.5mm (a 1/16 bit will not fit w/o force). I think a normal spec for a 10-mm snap in might be 2 mm.
Thanks.
The fit seems tight, but I am only checking with a similar size snap-in cap. At first glance it looks like the hole may be around 60-thou or 1.5mm (a 1/16 bit will not fit w/o force). I think a normal spec for a 10-mm snap in might be 2 mm.
Thanks.
Prototypes & Order Status
The PSU boards are in my hands, and a couple sets have been shipped.
Again, sorry about the delay on the PSU, I ran short of time. To get the boards at a discount, and with no tooling charges, I have to supply some detailed information about each board I order, which means extracting it from the gerbers manually. If I send the gerbers in for a normal quote, the cost per board is much higher.
nx-Amp PCB
---------------------------------------
$10/board, $20/stereo set, + shipping cost + paypal fee (if applicable)
PMI (2 nx-Amp) received
pinnocchio (2nx-Amp) received
fab (2 nx-Amp) received
ivanlukic (2) shipped
evette (2)
potepuh (2)
JethroTull (2)
Cambe (2)
Junie (2)
nx-Amp PSU+Protection PCB
---------------------------------------------------------------------
$10/board, added to the above
PMI (1) received
ivanlukic (1) shipped
pinnocchio (2) shipped
fab (2) shipped
evette (0)
potepuh (1)
JethroTull (2)
Cambe (2)
Junie (1)
The PSU is designed to power BOTH channels, not just one, even though some people are ordering two power supply boards.
Also note that if there is enough interest to reorder, the cost of the PSU board will probably be around $1-2 more than the amp board. Other than that, the cost of a set of three or four boards probably will not change much (up or down), unless the quantity increases quite a bit. (For the moment, we benefit from a business discount on small "Prototype" orders, which the vendor is honoring even though it is pretty obvious what these boards are... )
The PSU boards are in my hands, and a couple sets have been shipped.
Again, sorry about the delay on the PSU, I ran short of time. To get the boards at a discount, and with no tooling charges, I have to supply some detailed information about each board I order, which means extracting it from the gerbers manually. If I send the gerbers in for a normal quote, the cost per board is much higher.
nx-Amp PCB
---------------------------------------
$10/board, $20/stereo set, + shipping cost + paypal fee (if applicable)
PMI (2 nx-Amp) received
pinnocchio (2nx-Amp) received
fab (2 nx-Amp) received
ivanlukic (2) shipped
evette (2)
potepuh (2)
JethroTull (2)
Cambe (2)
Junie (2)
nx-Amp PSU+Protection PCB
---------------------------------------------------------------------
$10/board, added to the above
PMI (1) received
ivanlukic (1) shipped
pinnocchio (2) shipped
fab (2) shipped
evette (0)
potepuh (1)
JethroTull (2)
Cambe (2)
Junie (1)
The PSU is designed to power BOTH channels, not just one, even though some people are ordering two power supply boards.
Also note that if there is enough interest to reorder, the cost of the PSU board will probably be around $1-2 more than the amp board. Other than that, the cost of a set of three or four boards probably will not change much (up or down), unless the quantity increases quite a bit. (For the moment, we benefit from a business discount on small "Prototype" orders, which the vendor is honoring even though it is pretty obvious what these boards are... )
nx-Amp and nx-Amp PSU pcb pics
Better pics of both boards are attached below. Bonsai should be complimented on the clean layout. (fortunately for those of you interested in the boards, I had nothing to do with that part...
)
The color is a bit off, note that the pads are the standard leaded tin, the yellow hue does not mean gold plated.
The boards are double sided, solder mask and silk screen on top and bottom, through-hole & SMD components, SMD pads top and bottom.
Outside Dimensions:
nx-Amp, 107.75 x 96.5 mm
nx-Amp PSU, 115 x 79 mm
Link to the nx-Amp manual on Bonsai's Hifisonix.com web site:
Manual w. specifications and Assembly Instructions
Better pics of both boards are attached below. Bonsai should be complimented on the clean layout. (fortunately for those of you interested in the boards, I had nothing to do with that part...
)The color is a bit off, note that the pads are the standard leaded tin, the yellow hue does not mean gold plated.
The boards are double sided, solder mask and silk screen on top and bottom, through-hole & SMD components, SMD pads top and bottom.
Outside Dimensions:
nx-Amp, 107.75 x 96.5 mm
nx-Amp PSU, 115 x 79 mm
Link to the nx-Amp manual on Bonsai's Hifisonix.com web site:
Manual w. specifications and Assembly Instructions
Attachments
@evette: you are already on the list for the amp boards. As far as I remember, you wanted to wait until I reordered one of my other boards to get them together, and you did not specify whether you wanted the PSU board. Any changes, please pm me...
To anyone else...
I am keeping a list of those who may be interested in a future re-order. Basically nobody is obligated to anything until you decide to send money, aside from the amps Bonsai has built, this is still a prototype. If there is a demand for more than a few boards, I will start a Group Buy thread.
Having said that, you can see examples of his work in the pics thread, as well as the type of chassis I plan to use w. his boards. (do a search for nx-Amp in the pics thread).
More examples his web site, hifisonix.com . It is a very professional design, that would probably cost in the 100's of dollars as a kit, and over $1K as a product. Thanks to his generosity, we are getting it for the price of a few circuit boards (discounted price, at that... )
To anyone else...
I am keeping a list of those who may be interested in a future re-order. Basically nobody is obligated to anything until you decide to send money, aside from the amps Bonsai has built, this is still a prototype. If there is a demand for more than a few boards, I will start a Group Buy thread.
Having said that, you can see examples of his work in the pics thread, as well as the type of chassis I plan to use w. his boards. (do a search for nx-Amp in the pics thread).
More examples his web site, hifisonix.com . It is a very professional design, that would probably cost in the 100's of dollars as a kit, and over $1K as a product. Thanks to his generosity, we are getting it for the price of a few circuit boards (discounted price, at that...
)
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Hello PMI,
I had one spare PSU board on my side and I checked last night. Its a tight fit, but it does fit fine and the big power cap is easily positioned flat on the PSU board. Anyway, just to be on the safe side, I will make the holes on the Gerbers about 0.5mm bigger. Thanks for the feedback.
Ok, thanks for checking. It looks like I can push in Panasonic 35/10 snap-in caps with a bit of effort. CD caps in same configuration, not so well. So, this is probably a matter of tolerances adding up.
PCB Status
The documentation for the nx-Amplifier is available from Bonsai's web site in a PDF document, including BOM and build instructions, here:
The Ovation nx-Amplifier V2.0
A full set of boards as shipped is shown below. Circuit boards are professionally made, double-sided, solder mask and silkscreen top and bottom side, plated through holes. They are made from Gerber plots provided by Bonsai, the OP of this thread.
nx-Amp PCB
$10/board, $20/stereo set, + shipping cost + paypal fee (if applicable)
PMI (2 nx-Amp) received
pinnocchio (2nx-Amp) shipped/received
fab (2 nx-Amp) shipped/received
ivanlukic (2) shipped/received, waiting for FODM3012 optocouplers
potepuh (2)
JethroTull (2)
Cambe (2) shipped/received
Junie (2) shipped, w. FODM3012
nx-Amp PSU+Protection PCB
$10/board, added to the above
PMI (1) received
ivanlukic (1) shipped/received
pinnocchio (2) shipped/received
fab (2) shipped/received
evette (2) 1 shipped & received
potepuh (1)
JethroTull (2)
Cambe (2) shipped/received
Junie (1) shipped
The documentation for the nx-Amplifier is available from Bonsai's web site in a PDF document, including BOM and build instructions, here:
The Ovation nx-Amplifier V2.0
A full set of boards as shipped is shown below. Circuit boards are professionally made, double-sided, solder mask and silkscreen top and bottom side, plated through holes. They are made from Gerber plots provided by Bonsai, the OP of this thread.
nx-Amp PCB
$10/board, $20/stereo set, + shipping cost + paypal fee (if applicable)
PMI (2 nx-Amp) received
pinnocchio (2nx-Amp) shipped/received
fab (2 nx-Amp) shipped/received
ivanlukic (2) shipped/received, waiting for FODM3012 optocouplers
potepuh (2)
JethroTull (2)
Cambe (2) shipped/received
Junie (2) shipped, w. FODM3012
nx-Amp PSU+Protection PCB
$10/board, added to the above
PMI (1) received
ivanlukic (1) shipped/received
pinnocchio (2) shipped/received
fab (2) shipped/received
evette (2) 1 shipped & received
potepuh (1)
JethroTull (2)
Cambe (2) shipped/received
Junie (1) shipped
Attachments
Hi Andrew
Can I ask a few questions here since the discussion of so-called CFAs in the other thread seems a bit futile?
It looks a nice, reasonably simple amp and I expect everyone will enjoy it.
My initial reaction when I look at the schematic is that if the 4 transistors in the front end were reconnected to be a complementary pair of LTPs then the PSRR would be better and the noise a little lower. It would not be a "CFA" of course and you would need a couple of CCS.
Apart from your desire to do a "CFA" what benefit do you see? I haven't analysed this in detail yet, just want to learn your rational.
Best wishes
David
Can I ask a few questions here since the discussion of so-called CFAs in the other thread seems a bit futile?
It looks a nice, reasonably simple amp and I expect everyone will enjoy it.
My initial reaction when I look at the schematic is that if the 4 transistors in the front end were reconnected to be a complementary pair of LTPs then the PSRR would be better and the noise a little lower. It would not be a "CFA" of course and you would need a couple of CCS.
Apart from your desire to do a "CFA" what benefit do you see? I haven't analysed this in detail yet, just want to learn your rational.
Best wishes
David
Last edited:
David,
I did the sx-Amp after reading about Jean Hiraga's 20 Watt class A amp and then JLH's 10 watter, of which much has been written on this site. Keep in mind this was off the back of the e-Amp which is a fairly big (180 Watt), complex VFA design that targets Low distortion. So, the main reason for doing these two amps was to try the CFA topology out, and learn how to design CFA amps. Nothing else and no preconceived ideas about the sound.
As I noted in the write-up, the sound is remarkably good IMV for what is a very simple, low component count design. The nx was a development of the sx-Amp where the output stage was reconfigured for class AB and a buffer/Drver stage added. Again, I was very surprised at the sound.
Of course, these amps don't have the drive capability of the e-Amp or my much older Ovation 250, but they sound very good to my ears.
If you want to target ultra low distortion because you want a challenge, then VFA is probably the way to go ( although I have simmed a 350 Watt CFA that shows < 1 ppm at 50 Watts). But, in most cases, you won't even be able to measure this level of performance- you will need some pretty good test gear.
If its the music you sre interested in, and you have yet to build an amplifier, I'd recommend you start your quest with something simple like one of Nelson Pass's class A amps and take it from there.
I did the sx-Amp after reading about Jean Hiraga's 20 Watt class A amp and then JLH's 10 watter, of which much has been written on this site. Keep in mind this was off the back of the e-Amp which is a fairly big (180 Watt), complex VFA design that targets Low distortion. So, the main reason for doing these two amps was to try the CFA topology out, and learn how to design CFA amps. Nothing else and no preconceived ideas about the sound.
As I noted in the write-up, the sound is remarkably good IMV for what is a very simple, low component count design. The nx was a development of the sx-Amp where the output stage was reconfigured for class AB and a buffer/Drver stage added. Again, I was very surprised at the sound.
Of course, these amps don't have the drive capability of the e-Amp or my much older Ovation 250, but they sound very good to my ears.
If you want to target ultra low distortion because you want a challenge, then VFA is probably the way to go ( although I have simmed a 350 Watt CFA that shows < 1 ppm at 50 Watts). But, in most cases, you won't even be able to measure this level of performance- you will need some pretty good test gear.
If its the music you sre interested in, and you have yet to build an amplifier, I'd recommend you start your quest with something simple like one of Nelson Pass's class A amps and take it from there.
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Appendix 1 – BOM List for 1 off nx-Amplifier Board
Item 10 lists a tab connector from DigiKey while item 12 and 14-17 list the same part number but with Mouser as a source. The part number, A100452CD-ND, is Digikey's format so the Mouser source listing is probably wrong. This is the only part that is sourced from DigiKey and if Mouser has a substitute it would allow all parts to be bought from one place.
Most resistors are listed as 0.5W metal film 1% without a distributor part number. Unfortunately resistor power ratings vary by manufacturer and I can't tell from the entry what the physical size of the resistor is. Is there a particular manufacturer and series you had in mind for the resistors? If some resistors don't really need a 0.5W rating, lower wattage parts may be easier to source or be cheaper.
I'd like to avoid using a preamp by just adding volume controls to the amplifier input. My system is presently configured that way with a 20K Ohm step attenuator and it works with my very limited shelf space. Do you see any problems doing this with the NX amp?
Item 10 lists a tab connector from DigiKey while item 12 and 14-17 list the same part number but with Mouser as a source. The part number, A100452CD-ND, is Digikey's format so the Mouser source listing is probably wrong. This is the only part that is sourced from DigiKey and if Mouser has a substitute it would allow all parts to be bought from one place.
Most resistors are listed as 0.5W metal film 1% without a distributor part number. Unfortunately resistor power ratings vary by manufacturer and I can't tell from the entry what the physical size of the resistor is. Is there a particular manufacturer and series you had in mind for the resistors? If some resistors don't really need a 0.5W rating, lower wattage parts may be easier to source or be cheaper.
I'd like to avoid using a preamp by just adding volume controls to the amplifier input. My system is presently configured that way with a 20K Ohm step attenuator and it works with my very limited shelf space. Do you see any problems doing this with the NX amp?
David,
I did the sx-Amp after reading about Jean Hiraga's 20 Watt class A amp and then JLH's 10 watter, of which much has been written on this site. Keep in mind this was off the back of the e-Amp which is a fairly big (180 Watt), complex VFA design that targets Low distortion. So, the main reason for doing these two amps was to try the CFA topology out, and learn how to design CFA amps. Nothing else and no preconceived ideas about the sound.
As I noted in the write-up, the sound is remarkably good IMV for what is a very simple, low component count design. The nx was a development of the sx-Amp where the output stage was reconfigured for class AB and a buffer/Drver stage added. Again, I was very surprised at the sound.
Of course, these amps don't have the drive capability of the e-Amp or my much older Ovation 250, but they sound very good to my ears.
If you want to target ultra low distortion because you want a challenge, then VFA is probably the way to go ( although I have simmed a 350 Watt CFA that shows < 1 ppm at 50 Watts). But, in most cases, you won't even be able to measure this level of performance- you will need some pretty good test gear.
If its the music you sre interested in, and you have yet to build an amplifier, I'd recommend you start your quest with something simple like one of Nelson Pass's class A amps and take it from there.
Andrew in the 350 watt amp do you make use of Beta enhanced vas ??
PCB Status, Updated
The documentation for the nx-Amplifier is available from Bonsai's web site in a PDF document, including BOM and build instructions, here:
The Ovation nx-Amplifier V2.0
A full set of boards as shipped is shown below. Circuit boards are professionally made, double-sided, solder mask and silkscreen top and bottom side, plated through holes. They are made from Gerber plots provided by Bonsai, the OP of this thread.
nx-Amp PCB
$10 each, $20/stereo set. plus shipping and Paypal fee
PMI (2) received
pinnocchio (2) shipped/received
fab (2) shipped/received
ivanlukic (2) shipped/received
evette (4) 2 shipped/received
potepuh (2)
JethroTull (2)
Cambe (2) shipped/received
Junie (2) shipped
Bill_P (2)
mj777 (2)
nx-Amp PSU+Protection PCB
$10/board, added to the above
PMI (1) received
ivanlukic (1) shipped/received
pinnocchio (2) shipped/received
fab (2) shipped/received
evette (2) 1 shipped/received
potepuh (1)
JethroTull (2)
Cambe (2) shipped/received
Junie (1) shipped
Bill_P (2)
mj777 (2)
I expect the remaining boards to arrive approximately 8/14, and I plan to send out pm's with the exact shipping costs by that time. After that, boards will ship as payment is received. I know some of you have vacations under way or soon to start. There is no deadline
Please review the BOM in the pdf document, and make sure you can source the required components, or suggested alternatives. I will try to supply anything that is easier to get in the US within reason, but this will mean that your boards may be delayed while I am waiting for parts.
The documentation for the nx-Amplifier is available from Bonsai's web site in a PDF document, including BOM and build instructions, here:
The Ovation nx-Amplifier V2.0
A full set of boards as shipped is shown below. Circuit boards are professionally made, double-sided, solder mask and silkscreen top and bottom side, plated through holes. They are made from Gerber plots provided by Bonsai, the OP of this thread.
nx-Amp PCB
$10 each, $20/stereo set. plus shipping and Paypal fee
PMI (2) received
pinnocchio (2) shipped/received
fab (2) shipped/received
ivanlukic (2) shipped/received
evette (4) 2 shipped/received
potepuh (2)
JethroTull (2)
Cambe (2) shipped/received
Junie (2) shipped
Bill_P (2)
mj777 (2)
nx-Amp PSU+Protection PCB
$10/board, added to the above
PMI (1) received
ivanlukic (1) shipped/received
pinnocchio (2) shipped/received
fab (2) shipped/received
evette (2) 1 shipped/received
potepuh (1)
JethroTull (2)
Cambe (2) shipped/received
Junie (1) shipped
Bill_P (2)
mj777 (2)
I expect the remaining boards to arrive approximately 8/14, and I plan to send out pm's with the exact shipping costs by that time. After that, boards will ship as payment is received. I know some of you have vacations under way or soon to start. There is no deadline
Please review the BOM in the pdf document, and make sure you can source the required components, or suggested alternatives. I will try to supply anything that is easier to get in the US within reason, but this will mean that your boards may be delayed while I am waiting for parts.
