So I built my first O2 amp last thursday, and all the checks came up positive and it started up with no issues.
But today I built my second O2 and it failed the first check. Using a Wallwart that supplies 13.5vAC, I measured from the + terminal of BT1 and the – terminal of BT2 and got 13.5v. I've gone over the back and corrected any sketchy-looking solder joints with little success.
Now, from about 30 minutes of part checking, and I'll look back into it tomorrow, all the parts are in the correct positions and orientations. Is there a way I can test for ESD damage/heat damage on the mofsets and on U5/U6, because I had some issues soldering them in and applied more heat than I would've liked, and ESD is always a possibility.
Thanks for your time, I'm really happy with how my working O2 turned out
But today I built my second O2 and it failed the first check. Using a Wallwart that supplies 13.5vAC, I measured from the + terminal of BT1 and the – terminal of BT2 and got 13.5v. I've gone over the back and corrected any sketchy-looking solder joints with little success.
Now, from about 30 minutes of part checking, and I'll look back into it tomorrow, all the parts are in the correct positions and orientations. Is there a way I can test for ESD damage/heat damage on the mofsets and on U5/U6, because I had some issues soldering them in and applied more heat than I would've liked, and ESD is always a possibility.
Thanks for your time, I'm really happy with how my working O2 turned out
And in case anybody still needs parts: The new and improved GB thread is up and running.
It is almost the same as before, just better.
Order batches are limited to 40 kits, after that I will order.
(The idea is to make it continuous, so after the first batch, I will still accept orders for the second batch.)
I will always order some parts with my own money, so I can ship even faster.
The transformers will be available again, manufactured specifically for us.
The cases will also be up for sale, all colors and both heights are good to go.
NEW PCB's will be made, so there will be no more shortage of these (I got tons of mail asking for them).
The "Extras" are back, so people can still order solder/wick/goodness from Mouser & Farnell.
Shipping to all destinations worldwide (customs may apply for non-EU residents).
I upgraded my order processing for this by buying a database software for my computer and my iPad and my iPhone.
-> Less hassle for me and quicker updates for you through the PDF.
Only one limitation: Payments are only accepted via PayPal.
Sorry to the guys that would prefer a wire transfer, but it is fairly time-consuming.
Setting up a PayPal account is not too much work, alternatively, you can always ask friends/family to help you send the funds.
Thanks for everybody that participated in the first round.
May the second round be just as successful in helping this community build excellent equipment!
Best regards,
Jokener
It is almost the same as before, just better.
Order batches are limited to 40 kits, after that I will order.
(The idea is to make it continuous, so after the first batch, I will still accept orders for the second batch.)
I will always order some parts with my own money, so I can ship even faster.
The transformers will be available again, manufactured specifically for us.
The cases will also be up for sale, all colors and both heights are good to go.
NEW PCB's will be made, so there will be no more shortage of these (I got tons of mail asking for them).
The "Extras" are back, so people can still order solder/wick/goodness from Mouser & Farnell.
Shipping to all destinations worldwide (customs may apply for non-EU residents).
I upgraded my order processing for this by buying a database software for my computer and my iPad and my iPhone.
-> Less hassle for me and quicker updates for you through the PDF.
Only one limitation: Payments are only accepted via PayPal.
Sorry to the guys that would prefer a wire transfer, but it is fairly time-consuming.
Setting up a PayPal account is not too much work, alternatively, you can always ask friends/family to help you send the funds.
Thanks for everybody that participated in the first round.
May the second round be just as successful in helping this community build excellent equipment!
Best regards,
Jokener
So I built my first O2 amp last thursday, and all the checks came up positive and it started up with no issues.
But today I built my second O2 and it failed the first check. Using a Wallwart that supplies 13.5vAC, I measured from the + terminal of BT1 and the – terminal of BT2 and got 13.5v. I've gone over the back and corrected any sketchy-looking solder joints with little success.
Now, from about 30 minutes of part checking, and I'll look back into it tomorrow, all the parts are in the correct positions and orientations. Is there a way I can test for ESD damage/heat damage on the mofsets and on U5/U6, because I had some issues soldering them in and applied more heat than I would've liked, and ESD is always a possibility.
Thanks for your time, I'm really happy with how my working O2 turned out
Check again that the diodes D1 - D6 match up with the silkscreens on the PC board, so that the cathode is in the right way. And double check that the regulators are in the right place (7912 negative closest to the edge of the board), turned the right way, and the capacitors C2 - C5 are in the right way.
Then make sure the batteries are not installed and the power switch is off ("out" position). With the power switch "off" the mosfets don't matter - they are downstream from the power switch. Did you make that 13.5Vdc measurement with the batteries installed by chance? If so then 13.5Vdc is just an indication the batteries are out of juice and are charging. Measuring between BT1 and BT2 is *after* the charging resistors so you will get a voltage drop if the batteries are charging a lot.
What DC voltage do you measure between ground (the metal shell of the gain switch) and the BT1 "+" terminal? How about between ground and the BT2 "-" terminal? (batteries not installed of course)
Check again that the diodes D1 - D6 match up with the silkscreens on the PC board, so that the cathode is in the right way. And double check that the regulators are in the right place (7912 negative closest to the edge of the board), turned the right way, and the capacitors C2 - C5 are in the right way.
They are in their correct positions.
Then make sure the batteries are not installed and the power switch is off ("out" position). With the power switch "off" the mosfets don't matter - they are downstream from the power switch. Did you make that 13.5Vdc measurement with the batteries installed by chance? If so then 13.5Vdc is just an indication the batteries are out of juice and are charging. Measuring between BT1 and BT2 is *after* the charging resistors so you will get a voltage drop if the batteries are charging a lot.
No batteries installed.
What DC voltage do you measure between ground (the metal shell of the gain switch) and the BT1 "+" terminal?
5.1 mV
How about between ground and the BT2 "-" terminal? (batteries not installed of course)
11 Volts
I think that narrows it down, huh.
They are in their correct positions.
Then make sure the batteries are not installed and the power switch is off ("out" position). With the power switch "off" the mosfets don't matter - they are downstream from the power switch. Did you make that 13.5Vdc measurement with the batteries installed by chance? If so then 13.5Vdc is just an indication the batteries are out of juice and are charging. Measuring between BT1 and BT2 is *after* the charging resistors so you will get a voltage drop if the batteries are charging a lot.
No batteries installed.
What DC voltage do you measure between ground (the metal shell of the gain switch) and the BT1 "+" terminal?
5.1 mV
How about between ground and the BT2 "-" terminal? (batteries not installed of course)
11 Volts
I think that narrows it down, huh.
Yep.
Try replacing that positive 7812 regulator. It would also be worth removing one end of D3 and checking it with the DMM diode check function.Also - a tip on getting the voltage regulator out. With the board upside down put a piece of solder braid across all three regulator terminals, then lay the soldering iron tip flat on the braid. It spreads the heat to all 3 pins at once and the thing just falls right out of the holes with gravity.
I had to remove a couple of the regulator chips.
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I found a neat trick for soldering those larger pads on the mosfets and regulators without bridging. I apply solder to just one side of the lead and pad, esssentially soldering just the half-oval. Then I solder the other side of the same lead and the other half of the oval. About the time the solder starts to flow on that second half it also flows around the edges of the lead, mates with and re-flows the solder on the first side in about 1/2 second, then I stay on an additional 1/2 second to make sure all the solder on both sides is re-flowed. Then the whole thing cools together.
For some reason the solder seems to be able to make it around the edges of the lead enough to mate up with solder already on the other side, but not enough can get around the edges in the first place, just soldering one side, to get the other side soldered without it "jumping" to an adjacent pad some of the time. I'm using fairly fine 0.022" solder and a small 1/64" conical tip, too.
I bridged two mosfet leads on my first build until I figured this method out. Then no more bridges on 3 additional boards!
I found that tapping the edge of the board lightly on a table right after heating was helpful in clearing the bridges. Would definitely be worth testing those two input rectifiers too, D3 and D5.Also - given that the regulators are cheap compared to shipping I would really recommend getting another negative 7912 to have on hand, too. That negative reading should be closer to -12.0Vdc rather than -11.0Vdc. I was initially thinking the positive regulator would drag the secondary down if shorted and hence the slightly lower negative rail, but it can't do that since both are fed from different half cycles. Would definitely be worth checking those two input rectifiers too, D3 and D4. Once you have the 7812 out you could measure the negative rail again, with the power switch off, and it should be within +/- 0.1Vdc of -12.0Vdc.
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@timjthomas
Getting good sound out of a PC does have a few problems, not least because internally, a PC is a very electronically noisy environment. For this reason, an external sound card that does all the analogue processing outside of the main PC case is recommended - this is the solution adopted by professional recording studios.
I use an Echo Layla, and it sounds as good as anyone could want - probably overkill for most home users, but I got mine, second hand, for a very reasonable price, and it certainly does the job very well - in fact, it was the search for a comparable headphone amp that would give me a similar level and quality of sound - but in a portable version - that initially drew me to the O2 project.
If you are after something simpler and cheaper, and have a sound card with SPDIF output, there's always Browse for Products | CPC
which should make a great input source for an O2.
Getting good sound out of a PC does have a few problems, not least because internally, a PC is a very electronically noisy environment. For this reason, an external sound card that does all the analogue processing outside of the main PC case is recommended - this is the solution adopted by professional recording studios.
I use an Echo Layla, and it sounds as good as anyone could want - probably overkill for most home users, but I got mine, second hand, for a very reasonable price, and it certainly does the job very well - in fact, it was the search for a comparable headphone amp that would give me a similar level and quality of sound - but in a portable version - that initially drew me to the O2 project.
If you are after something simpler and cheaper, and have a sound card with SPDIF output, there's always Browse for Products | CPC
which should make a great input source for an O2.
- Optical/Coaxial to Stereo L/R audio Converter
- Converts digital Coaxial or Optical (TOSLink) to left/right analogue stereo audio (2x Phono) outputs
- Inputs: 1x Phono (Coaxial) & 1x Optical (TOSLink)
- Outputs: 2x Phono (RCA)
- Simple plug & play, no settings required
- 32, 44.1, 48 & 96kHz Sampling rate
- 24bit S/PDIF Incoming bit stream on L/R channels
- Metal body for better EMI elimination & gold plated contacts
- Supplied with power adaptor
- Dimensions (WxHxD): 41x51x26mm
- Weight: 78g
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too much of a generalisation. protools, EMU and RME just to name a few professional solutions that have perfectly good internal cards as well as external. just because its external does not mean its somehow isolated, the USB or firewire bus still connects to ground in the PC, so the same level of care is needed
Also, as RocketScientists blog proves, price is not by definition related to quality or results.
And pretty much any spec is, in and of itself, useless.
I don't say any of the aforementioned products are good or bad, just that you got to be careful whom to trust with their numbers.
I am currently using an (internal) Asus Xonar HDAV 1.3 on my multimedia computer.
The entire computer was designed with EMI shielding in mind (CNCed my own case) and the Xonar passes the signal to second card via I2S.
The second card has its own power supply and sits in an even better shielded box.
-> There is no noise to speak of and signal quality is great.
(This solution may not be the end-all of PC based audio, but it cost 400€ for the computer and another 400€ for the case. You could spend more on a DAC, or even cables ...)
Best regards,
Jokener
And pretty much any spec is, in and of itself, useless.
I don't say any of the aforementioned products are good or bad, just that you got to be careful whom to trust with their numbers.
I am currently using an (internal) Asus Xonar HDAV 1.3 on my multimedia computer.
The entire computer was designed with EMI shielding in mind (CNCed my own case) and the Xonar passes the signal to second card via I2S.
The second card has its own power supply and sits in an even better shielded box.
-> There is no noise to speak of and signal quality is great.
(This solution may not be the end-all of PC based audio, but it cost 400€ for the computer and another 400€ for the case. You could spend more on a DAC, or even cables
...)Best regards,
Jokener
Internal sound cards are a dying breed. They were once upon a time required before the USB audio specification was released about a decade ago. Today there are far more high quality external DACs with USB than high quality internal sound card choices. The same is true for pro-audio interfaces. USB solves the "internal noise" problem and has other advantages as well--like working with laptops, all-in-one PCs, touch PCs, HTPCs, small form factor PCs, home server PCs, "green" low power PCs, etc. Internal slots, especially for anything but video boards, are slowly going away.
I agree on this. To get the parts out of the PC have other benefits as easy access to the ports, easy HW change of input, volume attenuator and so forth. An example might be the new Xonar One. I haven't hear it in person but the specs seems to be promissing.
But still, internal cards can sound amazingly good given their working environment.
Brgds
But still, internal cards can sound amazingly good given their working environment.
Brgds
Transformers
I have noticed that the new GB offered by Jokener includes the option for a custom-made transformer. This seems a bit expensive at 25 Euro, given that one of the main aims of the project is a low build cost - I wonder what other solutions are possible. For example, I am using a ready-made AA-151AD that I got from Ebay, used, for £5.99, which is rated at 1A, 15V AC - as this includes the mains plug, enclosure and power connector it seems like good value, and it certainly does the job. This is the PSU for a Netgear router, so it should be durable. I also saw that RadioSpares have a 230v to 15v PCB-mounted transformer part no 732-0433 that looks suitable for anyone who wants to make their own enclosure - price is £5.50 plus VAT, and I was going to buy one until the Ebay bargain came along.
I have noticed that the new GB offered by Jokener includes the option for a custom-made transformer. This seems a bit expensive at 25 Euro, given that one of the main aims of the project is a low build cost - I wonder what other solutions are possible. For example, I am using a ready-made AA-151AD that I got from Ebay, used, for £5.99, which is rated at 1A, 15V AC - as this includes the mains plug, enclosure and power connector it seems like good value, and it certainly does the job. This is the PSU for a Netgear router, so it should be durable. I also saw that RadioSpares have a 230v to 15v PCB-mounted transformer part no 732-0433 that looks suitable for anyone who wants to make their own enclosure - price is £5.50 plus VAT, and I was going to buy one until the Ebay bargain came along.
Internal soundcards were quite necessary until the USB 3.0 specification came along and no chips I have heard of support 3.0.
Because how else would you send uncompressed 8-channel audio out?
Of course you could try to run and sync two USB-connected soundcards, but you would REALLY rather not do that.
And even 6-channel audio is not uncommon at all anymore and there is no reason a card should NOT support it.
So for everything but headphone (mobile) operation or desktop 2.0 systems, I don't see viable external solutions.
Not even on the horizon. And that sadly includes your upcoming design.
Internal Slots are also not going away at all, quite to the contrary.
For the first time in a long time, almost all connections converge towards a single standard: PCIe.
Even future hard drives (two generations from now) will most likely communicate via PCIe and with ThunderBolt, Intel has taken PCIe external.
There is really no reason why soundcards need to be external (also no reason they need to be internal).
I don't see your claim becoming a reality in the immediate future. Internal sound does offer a valid value proposition.
USB also has the disadvantage that, unless uncommonly powered by an external PSU, it shoves quite an unstable and dirty power down your DACs throat, only moving the "noise issue" from EMI to power noise.
It therefore poses solvable and additionally, as far as I know, unsolvable problems.
I don't know the licensing terms, but I have yet to hear of Blu-Ray compatible USB-soundcards.
And I don't mean playback of the sound, I mean an unaltered bitstream going to the sound-chip like my Asus Xonar offers.
This of course refers to surround sound, for stereo sound there are plenty solutions. All that I have heard of miserable by concept and execution.
I'm really looking forward to your design.
But this time around, its mainly due to the immense educational value of your accompanying articles.
I don't see it solving any of my other challenges/problems and don't see a reason to go for "good enough" if the Xonar offers better performance at a decent price.
(That's of course based on the scarce information you have scattered. I'm fully prepared to turn 180° and claim the contrary if my statements are proven factually wrong.)
And it may represent a good value proposition for most customers, it's just not the same "benchmark" as the O2...
Well... I am genuinely looking forward to your design articles.
Happy hacking away on the rock that is the DAC design in front of you.
@greenalien: Yes, the transformer is on the more expensive side.
But I need to be able to offer it in any quantity that people might ask of me.
There was another possible solution that would be slightly cheaper (slightly under 20€), but it is untested with the O2 as of yet.
Of course nobody is forced to use the offered unit.
But personally, I would always prefer the units I can source to the other solutions that were presented so far.
Because how else would you send uncompressed 8-channel audio out?
Of course you could try to run and sync two USB-connected soundcards, but you would REALLY rather not do that.
And even 6-channel audio is not uncommon at all anymore and there is no reason a card should NOT support it.
So for everything but headphone (mobile) operation or desktop 2.0 systems, I don't see viable external solutions.
Not even on the horizon. And that sadly includes your upcoming design.
Internal Slots are also not going away at all, quite to the contrary.
For the first time in a long time, almost all connections converge towards a single standard: PCIe.
Even future hard drives (two generations from now) will most likely communicate via PCIe and with ThunderBolt, Intel has taken PCIe external.
There is really no reason why soundcards need to be external (also no reason they need to be internal).
I don't see your claim becoming a reality in the immediate future. Internal sound does offer a valid value proposition.
USB also has the disadvantage that, unless uncommonly powered by an external PSU, it shoves quite an unstable and dirty power down your DACs throat, only moving the "noise issue" from EMI to power noise.
It therefore poses solvable and additionally, as far as I know, unsolvable problems.
I don't know the licensing terms, but I have yet to hear of Blu-Ray compatible USB-soundcards.
And I don't mean playback of the sound, I mean an unaltered bitstream going to the sound-chip like my Asus Xonar offers.
This of course refers to surround sound, for stereo sound there are plenty solutions. All that I have heard of miserable by concept and execution.
I'm really looking forward to your design.
But this time around, its mainly due to the immense educational value of your accompanying articles.
I don't see it solving any of my other challenges/problems and don't see a reason to go for "good enough" if the Xonar offers better performance at a decent price.
(That's of course based on the scarce information you have scattered. I'm fully prepared to turn 180° and claim the contrary if my statements are proven factually wrong.)
And it may represent a good value proposition for most customers, it's just not the same "benchmark" as the O2...
Well... I am genuinely looking forward to your design articles.
Happy hacking away on the rock that is the DAC design in front of you.
@greenalien: Yes, the transformer is on the more expensive side.
But I need to be able to offer it in any quantity that people might ask of me.
There was another possible solution that would be slightly cheaper (slightly under 20€), but it is untested with the O2 as of yet.
Of course nobody is forced to use the offered unit.
But personally, I would always prefer the units I can source to the other solutions that were presented so far.
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Jokener - For parts of the soundcard the PC power is quite ok or I might stress perfectly ok, for the analog bits no. But that is the fun part of DIY. Is there something called BR compatible soundcards? If you need multichannel with bells and whistles isn't there an DSP needed taking care of these things. Now, lets talk bits and frequencies instead - you mean you wan't something like 24/96 (at least) on 8 channels?
But then this discussion is quite OT regarding the O2...
Brgds
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sorry mate, but thats simply not true. most truly high bandwidth multichannel professional solutions are still using at the very least the PCIe bus to connect the external hardware because they need direct access to the bus for DSP. if talking prosumer sure where there are not so many channels or not as much bandwidth or low latency needed, but until thunderbolt becomes more mainstream (and even then its still a bottleneck as it doesnt have bandwidth for as many channels as internal PCIe) they arent going away
i have a USB UAC2 usb-i2s card capable of 8x32/192/4 x 32/384 and rigisystems cards will allow 16 x 32/96, 8 x 32/192, 4 x 32/384 and you can gang them together for more channels. you dont need USB3 for sheer transport until you go uber high bandwidth and many channels, or DSP
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As I see it you (i'll change that to we ;-) ) mix to many channels... This would be an companion to the O2 as I see it - plain stereo as good as it can get. For the internal and external cards everything is just fine until the PS decides that something else is of higher priority. As compressing your mailbox or something equally important.
Brgds
Brgds
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oh yeah no problem, i'm not arguing that i think it should suit well, i'm arguing incorrect sweeping statements
just look at UAD this is pretty industry standard stuff
oh and i forgot one you may have heard of it
pro-tools HD
single most universal audio production solution available. sure they have usb solutions in the product line, but anything at the pointy of their lineup end still interfaces via PCI. these things will be the nervous system of major recording studios for years to come, its just too much money to replace when you can simply add another DSP board to add more channels to a current setup. the analogue is external in many cases agreed, but by no means all
no need for more OT, soz guys
just look at UAD this is pretty industry standard stuff
oh and i forgot one
you may have heard of itpro-tools HD
single most universal audio production solution available. sure they have usb solutions in the product line, but anything at the pointy of their lineup end still interfaces via PCI. these things will be the nervous system of major recording studios for years to come, its just too much money to replace when you can simply add another DSP board to add more channels to a current setup. the analogue is external in many cases agreed, but by no means all
no need for more OT, soz guys
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I should have been more clear I'm talking about 2 channel stereo playback when I say "DACS". I'm not talking about multi-channel audio or recording. The context was talking about a CD player vs PC audio. This is the O2 thread. It's a two channel headphone amp for playback only.
As a percentage of all PCs sold, PCIe slots are indeed fading away. For several years now the trend has been away form ancient "tower" form factors and towards laptops, all-in-ones, HTPC models, home servers/appliances, and other small/slim form factors that do not have room for a soundcard inside.
Sure, gamers are still building massive tower systems with six noisy fans, high-end GPUs, multi channel gaming audio, etc. But such PCs are hardly a quiet and/or energy efficient way to play 2 channel audio.
There are now lots of pro audio interfaces that can do a very credible job with 24/96 multi channel recording over USB 2.0 like those from RME, Motu, Roland, etc. USB 3.0 and Thunderbolt will improve things even further.
As a percentage of all PCs sold, PCIe slots are indeed fading away. For several years now the trend has been away form ancient "tower" form factors and towards laptops, all-in-ones, HTPC models, home servers/appliances, and other small/slim form factors that do not have room for a soundcard inside.
Sure, gamers are still building massive tower systems with six noisy fans, high-end GPUs, multi channel gaming audio, etc. But such PCs are hardly a quiet and/or energy efficient way to play 2 channel audio.
There are now lots of pro audio interfaces that can do a very credible job with 24/96 multi channel recording over USB 2.0 like those from RME, Motu, Roland, etc. USB 3.0 and Thunderbolt will improve things even further.