How about a Wire/Beta 22/CK2III/O2 comparison? I'm finishing a 3 channel B22 for a friend, have CK2III and should be able to finish "The Wire" in the next couple of weeks.
I finished soldering all of the components on the board except the ICs, regulators, and MOSFETs. I have a few questions though:
-Has anyone had alignment problems with the battery snaps? I have 3 of them perfectly aligned, but one of them is very slightly leaning back. Would that cause any problems when connecting the batteries?
-Even if I installed all the components in the battery circuit, could I still run the amp off of AC power only?
-Has anyone had alignment problems with the battery snaps? I have 3 of them perfectly aligned, but one of them is very slightly leaning back. Would that cause any problems when connecting the batteries?
-Even if I installed all the components in the battery circuit, could I still run the amp off of AC power only?
My battery prongs aren't exactly aligned, but I did use a dead battery to position them, as long as you can attach a battery and it sticks I'm guessing it should be fine.
you can run the amp off of AC power only even with all the battery components installed, I do this and haven't had any problems.
Almost forgot, what is the advantage of soldering in the vias under C9 like the construction tips say?
I'll have to wait untill I order and get my batteries to see if I didn't screw up lol.
I'll have to wait untill I order and get my batteries to see if I didn't screw up lol.
Nature of analog volume pot. If it's only happening at the very lowest volume level and you can deal with it leave it be. If it's really bugging you, you can buy a few pots and use the one that tracks the best. Analog volume pots will have some imbalance at the lowest volume levels.
I finally got around to installing battery prongs (and wow they're so misaligned), but I soldered them in using a dead battery as a guide, so at least they will fit batteries...crookedly.
The bigger issue is that it seems like the power management circuit is not working correctly. I get a DC offset of like 4 mV with AC power or with battery only power, measured at P2 pads. With battery only power and one battery removed, it goes to 200 mV or so. However, with the other battery removed (and the other one battery put back in), it's more like -2V. Docs say that the offset should be more like 600 mV or under with either battery removed. This is indeed a potential problem, at least if running on batteries?
The bigger issue is that it seems like the power management circuit is not working correctly. I get a DC offset of like 4 mV with AC power or with battery only power, measured at P2 pads. With battery only power and one battery removed, it goes to 200 mV or so. However, with the other battery removed (and the other one battery put back in), it's more like -2V. Docs say that the offset should be more like 600 mV or under with either battery removed. This is indeed a potential problem, at least if running on batteries?
What a lot of guys do is they make an impedance adapter (75ohm is fairly standard). This will make the amp quieter by maybe 70 degrees of volume knob rotation so basically it just offsets your normal listening range toward the middle/upper end of the pot's range.
This all depends on the headphones and gain of course. It's just what I've found trying to amp IEMs.
RS mentioned the it would be good to fill it in since it handles more current than the other vias..
I swear I put a smiley there to indicate I wasn't intentionally being a jerk. I was also surprised to see the size difference between the 2 mosfets, but the part numbers were right, and the data sheet confirmed the package shape and size.
it also depends on the iems, it will sometimes mess with the XO due to the series resistance, so if you can live with less than 75ohms and use multi driver iems i suggest you add as little as possible
Can someone please care to comment on the above? My knowledge of power circuits is somewhat limited. Should I be checking the diodes, the caps, any specific IC's? And if so, what should I be looking for?
Any insight would be greatly appreciated.
I've finished my O2 yesterday and I'm noticing a lot of distortion with the higher gain (6.5x) setting. The low gain (2.5x) setting sounds fine but I notice distortion on very high and low frequency sequences of songs. The first song I noticed on was here if you listen to the bass line from 1:30-2:00 it sounds totally fine on my low gain setting, but then if I switch to high gain and adjust for a similar volume the bass sounds very obviously distorted there.
I'm wondering if anyone is having any similar issues or has any suggestions. I've checked to make sure that the housing of S2 is not shorted with the nearby via. What's interesting is that I did the build with a friend yesterday and his amp also exhibits this same behavior. We are using all the parts from the BOM and opted for the milspec gain resistors. The amp sounds totally fine in low gain, although I do wonder now how it's actually performing.
I'm wondering if anyone is having any similar issues or has any suggestions. I've checked to make sure that the housing of S2 is not shorted with the nearby via. What's interesting is that I did the build with a friend yesterday and his amp also exhibits this same behavior. We are using all the parts from the BOM and opted for the milspec gain resistors. The amp sounds totally fine in low gain, although I do wonder now how it's actually performing.
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