Well, I would consider that too risky if I were doing it, unless the headphones involved were $20 throw-away test phones.
If I were not using the power management circuit then I would instead use a headphone protector circuit on the output, like an e12The ε12 Muting / Protect Circuit
or the output relay modification I posted a while back
http://www.diyaudio.com/forums/head...-crc-diode-cap-heatsink-mods.html#post2785867
But... that is just me. Other folks here may have some feedback for you. I just consider it too risky for any headphone amp not to have output protection of some sort.
If you build just amp part, without power management, this is very risky.
If you accidentally disconnect one PS, you got full 9V on phones and burn it in few seconds.
If you want quick amp and building practice, you can build simple CMoy (I know, I know
)If you plan to use only from wall power, get small 12V-0-12v or 15V-015V transformer and build standard regulated PS and O2 amp part on protoboard
Zigis said:
Uh, thank you for the warning! Then I understand the meaning in the O2 details:"The circuit prevents potentially damaging headphones with DC". - This risk is the price for DC-coupling of the headphone, that's my uneducated guess.
The CMoy is not an alternative as it has not near-zero output impedance afaik, which makes the O2 so attractive to me. Thanks for your links to other protection circuits and to show me these options, agdr, it's just with a little more effort I can build the O2 power management circuit. Hm.
Phew. Finally got to the end (started reading back at post one). It's been an interesting read.
I have to say, you guys; adgr, sofaspud, qusp, sgrossklass, nezbleu et al deserve a lot of credit for helping so many people with their builds. I'm sure RS really appreciates you all carrying the ball here while he's obviously very busy. You guys rock.
To anyone in general, what have you folks found to be the optimal gain values with Grado SR80s and AKG Q701s with a 1V source? I don't ask in regards to clipping, but where the best balance of pot travel lies with the 3B taper.
Cheers, everyone.
I have to say, you guys; adgr, sofaspud, qusp, sgrossklass, nezbleu et al deserve a lot of credit for helping so many people with their builds. I'm sure RS really appreciates you all carrying the ball here while he's obviously very busy. You guys rock.
To anyone in general, what have you folks found to be the optimal gain values with Grado SR80s and AKG Q701s with a 1V source? I don't ask in regards to clipping, but where the best balance of pot travel lies with the 3B taper.
Cheers, everyone.
Hey, you're one of the people I forgot to mention in my post above. Here's a belated "you rock". Sorry about that - my memory just ain't what it used to be.
I had been thinking 1.5x and 3.0x, so I wasn't far off for once. I am a quiet listener, but I wondered what people were finding when they tried some really quiet/dynamic recordings with the AKGs. Thanks for chiming in, sir.
I had been thinking 1.5x and 3.0x, so I wasn't far off for once. I am a quiet listener, but I wondered what people were finding when they tried some really quiet/dynamic recordings with the AKGs. Thanks for chiming in, sir.
I use 1x and 3x, but I'm using the 15A taper. The 1x is plenty imo for efficient headphones even with a 1V source.
I use Senn HD 25-1 II, and Brainwaivz HM3 for the most part. Have a pair of Senn 558, but don't use those much at all. Used a friend's k701's for a few days with the amp and 3x was plenty of volume for me. The Brainwavz HM3 I can use with 3x gain but the 15A taper has a lot to do with that.
Hi! I am going to order a set of Beyer DT 990 Premium 250 Ohm headphones very soon and I have been researching all day the best headphone amp for my budget. Around $100-$150, there aren't many good options besides the E9 and the O2 seems to be a much better one.
The O2 seems to be perfect for my situation, and I have decided to go with that one, but I have a few questions first.
How does the O2 operate with my choice of headphones? I have a feeling they will work perfect since the O2 can drive much higher impedance phones and they seem to work great across a wide range of headphone types.
Just looking for some personal experience here.
Secondly I have some questions about the best/cheapest place to get the parts to put this together.
I decided to just order the PCB pre-assembled from JDS labs since I have limited time, experience, and funds (would cost me about $40 just for the soldering kit).
I feel like I could get some better prices on the batteries and power supply since they come to about $30 for the package.
I also don't like the way their enclosure front panel looks. I would definitely prefer something more clean, something like what Fiola has done here would be perfect, the only thing I would like more is black on black with no lettering.
I saw the enclosures at boxenclosures.com but didn't know if that is the best place to order.
Basically what I am looking for is the best place to order power supply, batteries, enclosure, and front plate. I have a feeling Mouser has all of these, but there site is pretty deep and I have a feeling someone more experienced may be able to guide me.
Thanks!
The O2 seems to be perfect for my situation, and I have decided to go with that one, but I have a few questions first.
How does the O2 operate with my choice of headphones? I have a feeling they will work perfect since the O2 can drive much higher impedance phones and they seem to work great across a wide range of headphone types.
Just looking for some personal experience here.
Secondly I have some questions about the best/cheapest place to get the parts to put this together.
I decided to just order the PCB pre-assembled from JDS labs since I have limited time, experience, and funds (would cost me about $40 just for the soldering kit).
I feel like I could get some better prices on the batteries and power supply since they come to about $30 for the package.
I also don't like the way their enclosure front panel looks. I would definitely prefer something more clean, something like what Fiola has done here would be perfect, the only thing I would like more is black on black with no lettering.
I saw the enclosures at boxenclosures.com but didn't know if that is the best place to order.
Basically what I am looking for is the best place to order power supply, batteries, enclosure, and front plate. I have a feeling Mouser has all of these, but there site is pretty deep and I have a feeling someone more experienced may be able to guide me.
Thanks!
I have no personal experience regarding your particular headphones. NwAvGuy lists parts sources in the BOM that are more or less "best." An alternate I'm aware of... you can get a pair of Tenergy 9V 250mAh batteries and a 16VAC 20VA power supply for $26.70 including shipping from All Electronics. The ps is overkill, yes, but it's the smallest they have currently. You could find a 120:12 volt, 500mA transformer for cheap and give it a box and in-out plugs. The enclosure is the "perfect fit" for the O2, but isn't a necessity. I ordered the silver model from Allied and it came with silver panels. I'm not sure, but the black model might come with black panels. Anybody know for certain? Fiola's front panel is from a group buy design ordered through Front Panel Express. I think the official O2 docs include a generic design FPE CAD file that you can use.
Thanks for your response, exactly what I'm looking for.
I'll probably just get the batteries and psu from jds labs since it is around the same price.
I've been away from home for the past couple days so its tough to do research on this. Been studying for a test.
I did read his blog entry fairly thoroughly, I saw the standard enclosures and cad design for the front plate.
Was just wondering if there was anything else different enclosure wise I could throw it into to make it look cooler.
I could potentially edit the cad file to make up the difference.
What specific case did you order from allied.
I am going to be building my desk for my computer in the next two weeks.
Gonna have some spare aluminum, welder, and plasma cutter but I'm not sure how much spare materials I will have.
Panels
@ Grief: There are also the lasercut panels of aerohoff, $6 each + shipping
Thread is over here
Acrylic:
Bamboo:
@ Grief: There are also the lasercut panels of aerohoff, $6 each + shipping
Thread is over here
Acrylic:
An externally hosted image should be here but it was not working when we last tested it.
Bamboo:
An externally hosted image should be here but it was not working when we last tested it.
O2 complete kits, immediate shipping from stock
Following unexpected international interest, I am now prepared to ship my kits worldwide; I am also including a UK to EU mains plug adaptor with kits shipped to Europe - see http://www.diyaudio.com/forums/group-buys/207163-o2-headphone-amp-complete-kits-uk-only.htm
for full details.
http://www.diyaudio.com/forums/group-buys/207163-o2-headphone-amp-complete-kits-uk-only.htm
Following unexpected international interest, I am now prepared to ship my kits worldwide; I am also including a UK to EU mains plug adaptor with kits shipped to Europe - see http://www.diyaudio.com/forums/group-buys/207163-o2-headphone-amp-complete-kits-uk-only.htm
for full details.
http://www.diyaudio.com/forums/group-buys/207163-o2-headphone-amp-complete-kits-uk-only.htm
Got the O2 working like a charm now. It was a bad ground. I sand down the inodize paint properly this time and mount the RCA jack like you recommend and it fixed my hollow sound.
Thanks for the help!
Like you, I had some "issues" with mine not being grounded properly. I didn't build mine, but purchased it assembled. I had to sand down a bit of the paint on the inside of the front cover around the screw hole, so the ground wire would make a solid contact.
... wje from head-fi.org
Great, I've been waiting patiently for news on the ODAC... heading to his blog right away
@Grief, I contacted Allelectronics and asked about the unloaded voltage of the catalog# "ACTX-1620" PSU that sofaspud mentioned, since I'm interested in one or two, myself. I'll let you guys know what they say - it may be useful to others.
Also, aerohoff hasn't been responding to his thread or PMs for several days. Don't know what's up there. Just busy, hopefully.
Also, aerohoff hasn't been responding to his thread or PMs for several days. Don't know what's up there. Just busy, hopefully.
Wicked, thanks for the heads-up.
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