I've got some stranded wire that's super thin which I can strip away and unravel the individual strands which I could oil or tape. I need to track down a micrometer because if these hard to see wires turn out to be something like 42 or 44 AWG then I'd need to mate a few up. That scale that @RS linked shows a steep incline to resistance as gauge shrinks.
@ethanolson, I have to side with qusp on staying away from 40 AWG (if you even find a source for it). I can't see any possible benefit and only downsides (most notably it would be extremely fragile and difficult to work with as qusp suggests). If you want a higher output impedance for some reason, just replace the four 1 ohm resistors with 2 ohm resistors, or add a 0.5 ohm resistor at the jack. There are "well respected gurus" also recommending Sonic Bricks on top of your amp but their recommendations often fail to make any detectable improvement whatsoever. The O2 is all about honest objective performance, not emptying your wallet with snake oil tweaks.
Uninsulated strands would be even worse as an accidental short could have disastrous results to the amp and possibly even your headphones.
Uninsulated strands would be even worse as an accidental short could have disastrous results to the amp and possibly even your headphones.
all good man, i'd forgotten about that. my numbers are taken from the american wire gauge table too, but you are correct i quoted the numbers for external use. i generally er on the side of safety (or overkill,m you choose =)) and use the external ratings anyway, as i see zero point to striving for the thinnest conductor for analogue signalling frequencies or power where skin effect is meaningless and only quoted in jargon to sell cables. no money is saved at these sizes either.
I also generally buy all my wire in bulk and my favourite wire for all but the final tweaker mode builds is solid core milspec 24awg spc as i have it in 8 colours of teflon for colour coding, the rest i use solid 30awg 1.25mm pitch ribbon or belden 50r mini coax. 18 or 16awg of the same milspec for higher current, then neotech upocc in ptfe for final builds of same if i get that far. i prefer solid because it stays where its put
as for the 'guru' recommendation for 40awg, my guess is this was recommended for line level input wiring for power amps driving high impedance, not output wiring for headphone amps driving low impedance.
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The lightbulb just lit, man. I think you're right about where I may have heard it... a different application altogether.
Methinks you might have the case upside down. I just tried it, and there is no way you can use the second slot from the bottom with the stock parts on the BOM...all sorts of things run into the case top. Even accounting for manufacturing tolerances, I still can't imagine there would ever be enough room. However, if you flip the case over and use the second slot from the *top* (upside down), then it will _just_ fit, only touching the batteries, as you mentioned.
Not that there's that much difference in the case bottom and case top, but thought I'd throw it out there in case anyone else wanted to try this method.
There is a Top and a Bottom to the case, and if you use the panel design from RS, and the one from the Group Buy, you have to install the board in the first slot from the Bottom. The top of the case is the side with the extra groves in the panel. The position of the first slots (from top or bottom) is different, so you need to get it right..
Exactly. While the idea of the case holding the batteries in place is a pretty good one, I'm not willing to design a new custom front panel, and can easily hold the batteries with a piece of double-sided foam tape or similar.
Just be sure to double check that you've got the case oriented correctly when installing the PCB and you'll be fine.
Just be sure to double check that you've got the case oriented correctly when installing the PCB and you'll be fine.
Can't imagine who would make a mistake like that, though.
http://www.diyaudio.com/forums/head...-crc-diode-cap-heatsink-mods.html#post2780726
And.. I was planning on posting measurements for the drill holes at the point, but in looking at the pictures it just occurred to me I have the box upside down!
The O2 PDF Documentation Package has finally been updated with the new power management resistor values, as has the BOM spreadsheet. Everything in the Mouser column is now in stock except for the volume pot but they have the first alternate (different taper) and the main part on order. I revised all the prices and incorporated many of agdr's suggestions as well. Both are dated 30 November. The links are in the usual place:
O2 Resources
O2 Resources
Is it ok to stay with the old BOM since I ordered like 100 of everything
-joe
You need to buy some O2 boards and build some for sale
Coming right up.
As soon as my current GB's first round closes, I'll build some units for sale.
Since I also have the cases and everything else, I can offer fully assembled units.
I just need to figure out a way to test them first.
(Testing as in testing them with measuring equipment other than a cheapo-DMM.)
Best regards,
Jokener
As soon as my current GB's first round closes, I'll build some units for sale.
Since I also have the cases and everything else, I can offer fully assembled units.
I just need to figure out a way to test them first.
(Testing as in testing them with measuring equipment other than a cheapo-DMM.)
Best regards,
Jokener
Finished mine last night, sounds really good. With HD600 not to dark but not too light; reminds me of RA1/RS1 combo in some ways but much better and balanced. Wish I still had my grados, they would sound nice with this amp. Im running mine without battery and with a grubdac which fits in case without batteries. Waiting on front panel from the group buy.
You need to buy some O2 boards and build some for sale
I think he is... did you check the Vendor Bazar?
http://www.diyaudio.com/forums/vendors-bazaar/199763-o2-amp-building.html
Yes, no worries. If you want to spend a couple dollars on 100 each 1.2M - 1.5M and 33K 1/8 watt resistors (even 5% are OK) you might want to use those for R25 and R9 but it's not required and doesn't change the audio performance at all (just the low battery shutdown behavior). The other changes were about saving money and/or what's in stock at Mouser.Is it ok to stay with the old BOM since I ordered like 100 of everything