[svyr]

any idea how suitable the amp is to driving fostex t50rp?

 

[Willakan]

They have a sensitivity of 98 db/mw (and a 50ohm impedance), so the O2 should drive them very easily with tonnes of headroom for any ridiculously quiet tracks.

 

[Magedark]

I'm almost done with my O2, except the low gain has a problem where it's playing very softly in the right channel. However, both channels work in high gain, so I know something's off.

 

[limpidglitch]

I'd probably look for a short in the gain stage feedback loop, it could just be that one channel is accidentally set to unity gain.

 

[Magedark]

I'd probably look for a short in the gain stage feedback loop, it could just be that one channel is accidentally set to unity gain.

Thanks for the help, but after I posted my problem, I actually went and bought isopropyl, and did what has fixed, as of now, 100% of my projects: I cleaned the board. Tests are going well, I'm going to run my AKG K501 a bit later.

EDIT: Apparently the switch is broken, so the amp is always in high gain. In low gain, one channel is using the high gain resister, and the other is using the the low gain resister, so volume difference. Or there's something I horribly missed. But messing with the switch apparently triggers the low gain, but doesn't stay that way.

EDIT AGAIN: Ok, it works again. Fully....I hope.

 

[Paul Blythe]

Hi, did the initial build & mods on mine yesterday. A custom built desktop enclosure is next but I'm still waiting on some parts to arrive.
 

 
face plate, as well as back, base and top will be brushed aluminium, the left/right sides will be mahogany (hopfully).

 

[Willakan]

@Magedark:
 
Cleaning the board with the switch on is not a good idea. Gunk gets swept into the switch, which could explain its intermittent behaviour.
 
@Paul:
 
Nice, what did you use for wiring? I cut open an ethernet cable for some 24-gauge copper, but yours looks somewhat better!

 
 

 

[Paul Blythe]

Hi & thanks, I was being quite meticulous with the wiring, which is why it took just under 5 hrs to build & do the initial testing
 
output, ground & power - 16/0.2 equipment wire, <£3 for 10 meters, think it's 22 awg (from Maplin)
left/right input - 16/0.2 single core braided shielded copper wire, £0.99 per meter, again 22 awg (from Maplin)
volume pot - 28/0.1 up-ofc core wire from Van Damme Blue Series studio cable, <£5 per meter, 22/24 awg (from e-bay)

 

[Magedark]

@Magedark:

Cleaning the board with the switch on is not a good idea. Gunk gets swept into the switch, which could explain its intermittent behaviour.

@Paul:

Nice, what did you use for wiring? I cut open an ethernet cable for some 24-gauge copper, but yours looks somewhat better!

It got working after one last pass for some reason.

Anyways, my build just needs a case, so that's probably something to do for this weekend. Paul, which mods have you done to yours?

 

[Paul Blythe]

Nothing major, just off-board input, output, power sockets and volume pot... be nice to see what changes are made to the proper destop O2 once it arrives.
 
Had a good long listening session this evening... Muse, Bring Me the Horizon, The XX, Cinematic Orchestra, Goldfrap, Tchaikovsky's 1812, Coldplay... With my re-cabled HD-650's the amp sounds to be well balanced between low/mid/high frequencies. Nice solid, impactfull bass, clear mid's and upper range, very good levels of detailing... doesn't feel like I'm missing anything from the recordings and everything sounds controlled and well defined. The amp has some warmth thanks to the 650's, but I would like to hear how it sounds with some 702's connected.
 
Very pleased with the O2 after my initial sitting, already hearing new details within much played & loved music, so all's good.
 
Question: with using some wiring on the build, can I expect a small bedding in period? The two CMoy's built prior to this appeared to settle after about 20 - 30 hrs of usage.

 

[limpidglitch]

Quote:

 
Question: with using some wiring on the build, can I expect a small bedding in period? The two CMoy's built prior to this appeared to settle after about 20 - 30 hrs of usage.

Objectively, no.

 

[dogears]

Someone has used it with the t50rp already and its highly recommended... At least that's what I remember. Preordered mine already

any idea how suitable the amp is to driving fostex t50rp?

 

[Willakan]

Quote:

...but I would like to hear how it sounds with some 702's connected.

 
You'll never guess what my O2 is driving!
 
I set the gain at 3.1, which has proved to be incredibly excessive, as I can't get the volume knob past 9 o'clock without blowing my ears off - and this with quietly mastered stuff! As for the amplifier's sound, it balances out my AKG's with the amount of bass they should have when given enough power and an amplifier with a low output impedance. I can't really say much else about liquid mids or airy highs without feeling incredibly stupid, so I'll just say it sounds nice. Like my Clip+, but with more bass and without the soft clipping.
 
 

 

[Paul Blythe]

Quote:

Objectively, no.

lol... thanks.
 
For me the O2 feels transparent, dosen't appear to add or remove anything from the music, plus the tonal signiture is very much that of the headphones.

 

[LizardKing1]

So this could pretty much be used as someone's go-to amp for most hard-to-drive cans? It's just that amps don't have as much appeal to me as headphone - and often cost a lot more than what they're driving, and I wanted to get that out of the way.
 
I especially like how this has no synergy. It's not a warm amp to pair with bright cans, or a relaxed amp to pair with detailed cans. It's an amp, and it just amplifies the god damned signal.