Revised O2 Booster Board BOM posted
I've just posted a revised BOM for this project out on the Google Drive link in the first post in this thread with the rest of the DIY project materials (version 3.6 is the latest).
Just dealing with some part issues at Mouser:
* The two 10V SMD zener diodes in the protection relay circuit, D2 and D5, are being obsoleted by On Semi/Fairchild. I've replaced them with an identical part from Vishay.
* The 499K SMD resistor, R13, is out of stock at Mouser, plus they doubled the price on me. Replaced with an identical Susumu part that costs half as much.
* Mouser is out of stock of the IM26TS relays until next February, but Digikey has them and I also have them. Onlinecomponents.com is another source.
I've run a BOM scan at Mouser and I *think* those are all the significant part/price changes, but if anyone spots anything else please let me know.
Also - just a reminder since some of these are going into commercial O2's from JDS, Mayflower, etc. I would highly recommend keeping the O2 power transformer no higher than 14Vac, with at least 500mA. This goes for just plain old O2's also, without Booster Boards. Someone a few months ago mentioned in an email they had an 18Vac transformer. Definitely not recommended. Remember that NwAvGuy wasn't able to heat sink those voltage regulators in the O2. All that extra voltage just gets burned off as heat in the regulators.
More than 14Vac won't do a thing extra for you with the audio quality in an O2 (with or without a Booster Board), since the regulators limit the rails to +/-12Vdc. After the capacitors 14Vac turns into around 18Vdc unloaded or 16Vdc under full load, more than enough for the 3Vdc drop the regulators need to do their thing. 16Vdc - 3Vdc = 13Vdc, which even leaves an extra volt in case you have low AC wall voltage and takes the regulator tolerance into account.
Mouser doesn't have the AC-AC wall transformers anymore, but Jameco does (www.jameco.com):
* #171408 14Vac 500mA for $8.98
* #2138978 13.5Vac 1A for $4.95
And finally an update on doing more THD testing with the Booster Board, in addition to the QA401 tests already done. I'm waiting for Jens' new tester to ship:
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Sounds like it might be September now. I also haven't had a chance yet to hook the Booster Board up to a Panasonic VP7722A I bought a few months ago. Once I get those done I'll ship a couple off for AP testing.
I don't expect any significant surprises, the QA401 is already pretty good.
I've just posted a revised BOM for this project out on the Google Drive link in the first post in this thread with the rest of the DIY project materials (version 3.6 is the latest).
Just dealing with some part issues at Mouser:
* The two 10V SMD zener diodes in the protection relay circuit, D2 and D5, are being obsoleted by On Semi/Fairchild. I've replaced them with an identical part from Vishay.
* The 499K SMD resistor, R13, is out of stock at Mouser, plus they doubled the price on me. Replaced with an identical Susumu part that costs half as much.
* Mouser is out of stock of the IM26TS relays until next February, but Digikey has them and I also have them. Onlinecomponents.com is another source.
I've run a BOM scan at Mouser and I *think* those are all the significant part/price changes, but if anyone spots anything else please let me know.
Also - just a reminder since some of these are going into commercial O2's from JDS, Mayflower, etc. I would highly recommend keeping the O2 power transformer no higher than 14Vac, with at least 500mA. This goes for just plain old O2's also, without Booster Boards. Someone a few months ago mentioned in an email they had an 18Vac transformer. Definitely not recommended. Remember that NwAvGuy wasn't able to heat sink those voltage regulators in the O2. All that extra voltage just gets burned off as heat in the regulators.
More than 14Vac won't do a thing extra for you with the audio quality in an O2 (with or without a Booster Board), since the regulators limit the rails to +/-12Vdc. After the capacitors 14Vac turns into around 18Vdc unloaded or 16Vdc under full load, more than enough for the 3Vdc drop the regulators need to do their thing. 16Vdc - 3Vdc = 13Vdc, which even leaves an extra volt in case you have low AC wall voltage and takes the regulator tolerance into account.
Mouser doesn't have the AC-AC wall transformers anymore, but Jameco does (www.jameco.com):
* #171408 14Vac 500mA for $8.98
* #2138978 13.5Vac 1A for $4.95
And finally an update on doing more THD testing with the Booster Board, in addition to the QA401 tests already done. I'm waiting for Jens' new tester to ship:
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Sounds like it might be September now. I also haven't had a chance yet to hook the Booster Board up to a Panasonic VP7722A I bought a few months ago. Once I get those done I'll ship a couple off for AP testing.
I don't expect any significant surprises, the QA401 is already pretty good.
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Wrong Jameco part number for 13.5Vac 1A in post above!
I just found a typo in my post above. Wrong Jameco part number for the 13.5Vac 1A wall transformer. The one above is the same thing, but wrong connector on the end. You would want:
* 2202765 13.5Vac 1A for $3.95.
The part number on the 14Vac transformer is OK. I also forgot the http:// in the Jameco link:
http://www.jameco.com
I just found a typo in my post above. Wrong Jameco part number for the 13.5Vac 1A wall transformer. The one above is the same thing, but wrong connector on the end. You would want:
* 2202765 13.5Vac 1A for $3.95.
The part number on the 14Vac transformer is OK. I also forgot the http:// in the Jameco link:
http://www.jameco.com
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Hey Alex! You bet.
I'm (slowly) working on an update to the Booster Board build instructions too. Maybe I'll get that posted this coming week (at the project Google Drive link in the first thread post). Nothing major, just some small additional tips from various questions that have come up over the last couple of years.
I'm (slowly) working on an update to the Booster Board build instructions too. Maybe I'll get that posted this coming week (at the project Google Drive link in the first thread post). Nothing major, just some small additional tips from various questions that have come up over the last couple of years.
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Hi agdr!
Any news on the measurements?
I'm reviving this thread because of an strange issue I've been having lately with one of my O2s equipped with your excellent booster board. In my battery driven O2 I have the booster board with the opa140, as well as your latch board. The issue I am experiencing is that the relay on the booster is more often than not failing to click and connect the output when I turn on the amp.
When I started noticing the problem, I thought it was when the battery were discharged below a certain point. Sure enough, after I left the amp charging for a few hours, it would then turn on correctly on battery power alone. But now it's got to the point where it (the booster) doesn't turn on even with recently charged batteries. I thought maybe my batteries are getting old, but measuring them shows 9,1 and 9,12 respectively.
On AC power, everything turns on fine. I can even plug the AC adapter just to turn on the amp, then disconnect it and continue using the amp. But if I turn it off and back on again (just on batteries) the relay won't click...
Any clues? Heard of anybody else who has experienced something similar?
Any news on the measurements?
I'm reviving this thread because of an strange issue I've been having lately with one of my O2s equipped with your excellent booster board. In my battery driven O2 I have the booster board with the opa140, as well as your latch board. The issue I am experiencing is that the relay on the booster is more often than not failing to click and connect the output when I turn on the amp.
When I started noticing the problem, I thought it was when the battery were discharged below a certain point. Sure enough, after I left the amp charging for a few hours, it would then turn on correctly on battery power alone. But now it's got to the point where it (the booster) doesn't turn on even with recently charged batteries. I thought maybe my batteries are getting old, but measuring them shows 9,1 and 9,12 respectively.
On AC power, everything turns on fine. I can even plug the AC adapter just to turn on the amp, then disconnect it and continue using the amp. But if I turn it off and back on again (just on batteries) the relay won't click...
Any clues? Heard of anybody else who has experienced something similar?
I should add that when doing the above, I do wait at least 10-15 seconds for the PM latch to reset. Even waiting for a minute or so didn't change the behavior. And that was with the batteries measuring at around 9,1 volts each.
Admittedly, I'm on thin ice here, without much knowledge about relay power demands or having studied the 02 booster board schematic. But the behavior you describe sounds just like old batteries. They can still show high volts but without the "umph". Load them with something moderately demanding and see if the voltage drops a lot.
Has anybody heard from him? I haven't gotten a response either. I've never had to have a PCB made, are the png's in the drive document sufficient for doing that?
In the meantime, I just received my panel mount RCAs and power jack to install in the rear. Any advice on how to place them to ensure I can still fit the booster card in later, assuming I still can get one?
No more Booster Board PCBs or assembled units available
Hello everyone! A big thanks to Adydula for letting me know about the questions in this thread. Due to time commits these days I rarely get to stop by here anymore.
Unfortunately I'm no longer selling the O2 Booster Board PCBs or assembled units (and never did sell kits).
I do see 8 PMs right now, I will try to go through those tomorrow. Again, sorry about the delayed replies, just not much time for the audio hobby anymore.
Hello everyone! A big thanks to Adydula for letting me know about the questions in this thread. Due to time commits these days I rarely get to stop by here anymore.
Unfortunately I'm no longer selling the O2 Booster Board PCBs or assembled units (and never did sell kits).
I do see 8 PMs right now, I will try to go through those tomorrow. Again, sorry about the delayed replies, just not much time for the audio hobby anymore.
Hello CHiroshi!
Sorry about the delayed reply, as per above just not much time for audio anymore. Well the good news on the measurements is that I've been slowly collecting equipment. I recently took delivery of one of the new RTX6001 audio analyzers (JensH unit, in the equipment thread on the forum here) and a Panasonic VP7722A analyzer. But the trick is finding the time to learn/use them. Probably not on the horizon, TBH. That is one of the reasons I'm not selling the boards right now. If I ever restart selling them I want them to be measured by more than the current QA401.
On the problem you are having, removing that latch board is a good place to start. It is the one project that never functioned correctly. I stopped selling them a long time ago. Best to unplug it and put the 2903 (I think that is the chip) back in. I know that for a short period I was including those with the Booster Board fully assembled builds. I forget the details now, but it is a state problem. There was one specific combination of on and off where the latch board didn't function as it should.
Sorry about the delayed reply, as per above just not much time for audio anymore. Well the good news on the measurements is that I've been slowly collecting equipment. I recently took delivery of one of the new RTX6001 audio analyzers (JensH unit, in the equipment thread on the forum here) and a Panasonic VP7722A analyzer. But the trick is finding the time to learn/use them.
Probably not on the horizon, TBH. That is one of the reasons I'm not selling the boards right now. If I ever restart selling them I want them to be measured by more than the current QA401.On the problem you are having, removing that latch board is a good place to start. It is the one project that never functioned correctly. I stopped selling them a long time ago. Best to unplug it and put the 2903 (I think that is the chip) back in. I know that for a short period I was including those with the Booster Board fully assembled builds. I forget the details now, but it is a state problem. There was one specific combination of on and off where the latch board didn't function as it should.
Hi agdr!
Any news on the measurements?
with the opa140, as well as your latch board.
Hi agdr!
Thanks for the update, and I guess being kept busy is a good thing, even though we miss your contributions here!
Pity on the booster boards, but I understand your idea of selling products that are fully measured and spec:ed. Although, as my ears tell me, we can safely assume the booster board probably meets its intended objective specs!
I ended up removing the latch board, as that seemed the natural thing to try, and sure enough, everything is back to normal!
Best
Thanks for the update, and I guess being kept busy is a good thing, even though we miss your contributions here!
Pity on the booster boards, but I understand your idea of selling products that are fully measured and spec:ed. Although, as my ears tell me, we can safely assume the booster board probably meets its intended objective specs!
I ended up removing the latch board, as that seemed the natural thing to try, and sure enough, everything is back to normal!
Best
^This. Please post the board design files. Tangent did the very same thing with the PPA and PIMETA projects when time and interest waned.
For anyone in search of the ever elusive Booster Board and/or an Objective2 with AGDR's upgrades, you can get them here either via Head-Fi or eBay:
Objective2 (O2) Extreme Edition Amplifier: Preassembled with V3.1 Booster Board! | eBay
[FS] Objective2 (O2) Extreme Edition Amplifier: Preassembled with V3.1 Booster Board! | Headphone Reviews and Discussion - Head-Fi.org
Objective2 (O2) Extreme Edition Amplifier: Preassembled with V3.1 Booster Board! | eBay
[FS] Objective2 (O2) Extreme Edition Amplifier: Preassembled with V3.1 Booster Board! | Headphone Reviews and Discussion - Head-Fi.org
It is just one set of them, I myself being the source and seller. I used the word “them” in referring to the two items, the O2 and the Booster Board.