Review: NwAvGuy's O2 DIY Amplifier - Page 22  

Quote:

Originally Posted by jseaber 

Just an FYI: FedEx wiped out two days this week for us with PCB delivery. Nick and I will be working extra this weekend to catch up.

No problem, I can wait. I have seen worst thing done by Fedex myself as they have recently knocked my FiiO E17 sample out of commission (partially anyway) during the shipping.

p/s: Might order the C421 next month or so if I actually have some money left. Hope the final case will be ready by then.
 

Listening to my new O2 and it sounds pretty good.  im very happy for the money i spent on it.  i have it on AC power but have the option of throwing batteries in. i do not plan to. I never planned to use it as a portable. 

my dac is the Muse TDA1543x4 dac coupled with this amp, it makes a very good sounding super budget setup (spent approx 140$ on the pair). tried it with my FX700 and FXT90 last night and liked it with the FXT90 more.  today been listening to it with my T1 and it sounds very very good. kudos to V. 

Quote:

Originally Posted by jseaber 

Good news: FedEx decided to deliver only 1 day late, so we're almost back on schedule 

 

About those c421 enclosures--worst manufacturing I've ever managed. They will finally ship February, and they will look nice!

 

Three O2 customers e-mailed this afternoon describing clicking noises after charging. Twenty minutes on the phone with one kind fellow from CA solved the problem. Please, please note that AC-to-DC adapters are commonly abbreviated "AC Adapters", but they are not AC adapters in an electrical sense! The O2 requires a 14V AC adapter, which is an entirely different beast. You cannot use a laptop power adapter, or the adapter from your Cypher Labs AS! The plug may fit, but those electrons move around quite differently...

Please supply the adapter, at least give the option, it took me 6 days to look for an AC-AC adapter but could not find one, I had to order it on-line  and wait for  6 days to receive it, you should consider this as this is a big let down!!!!!!!!!!!!!!  I got mine from another DIY.............

Quote:

Originally Posted by turokrocks 

Quote:

Originally Posted by jseaber 
Good news: FedEx decided to deliver only 1 day late, so we're almost back on schedule 

 

About those c421 enclosures--worst manufacturing I've ever managed. They will finally ship February, and they will look nice!

 

Three O2 customers e-mailed this afternoon describing clicking noises after charging. Twenty minutes on the phone with one kind fellow from CA solved the problem. Please, please note that AC-to-DC adapters are commonly abbreviated "AC Adapters", but they are not AC adapters in an electrical sense! The O2 requires a 14V AC adapter, which is an entirely different beast. You cannot use a laptop power adapter, or the adapter from your Cypher Labs AS! The plug may fit, but those electrons move around quite differently...

 

Please supply the adapter, at least give the option, it took me 6 days to look for an AC-AC adapter but could not find one, I had to order it on-line  and wait for  6 days to receive it, you should consider this as this is a big let down!!!!!!!!!!!!!!  I got mine from another DIY.............

Isn't that what the option "add North America AC Adapter" is for?

Quote:

Originally Posted by turokrocks 

 

 

Please supply the adapter, at least give the option, it took me 6 days to look for an AC-AC adapter but could not find one, I had to order it on-line  and wait for  6 days to receive it, you should consider this as this is a big let down!!!!!!!!!!!!!!  I got mine from another DIY.............

Where are you located? I ordered my charger off Mouser for $20 shipped and got the good charger. It took them 2 days to get it over here. 

The O2 blog details page has the exact models of the chargers you can use so its really not too hard to just look them up. Plus the charger would drive up prices substantially. $20 shipped and JDSlabs to make any kind of profit including their own shipping is going to cost like $30 minimum with a low profit margin. 

Quote:

Originally Posted by khaos974 

Isn't that what the option "add North America AC Adapter" is for?

 

 

Quote:

Originally Posted by pancakeplease 

Where are you located? I ordered my charger off Mouser for $20 shipped and got the good charger. It took them 2 days to get it over here. 

The O2 blog details page has the exact models of the chargers you can use so its really not too hard to just look them up. Plus the charger would drive up prices substantially. $20 shipped and JDSlabs to make any kind of profit including their own shipping is going to cost like $30 minimum with a low profit margin. 

I had to get 220/230AC so...

This O2 I built is pretty much blowing me away with my Magnums,  amazing detail.

For Grados instead of clipping the gain resistor has anyone thought about bypassing the first stage completely,  I mean if we have the gain set at 1 why do we need U1 and all those ceramic caps in the signal path ?

I love the O2 with my Lcd-2s. Having the O2 amp in hand, I do not miss my previous AMB M3 or Cavalli CTH that much. The O2 sounds like a M3 with AD843 IIRC, and it can fit into my pocket while M3 can not.

I also tried my custom IEMs (Westone ES3Xs) with the O2. Again very very good sound. No hiss, even at high listening volume.

If I have to nitpick, I would say:

1) the O2 may not match very well with bright / cold / aggressive headphones, because O2 seems to be very honest and does not "warm up" the sound like tube amps. I guess it is expected in view of its "objective" nature.

2) Make sure you charge the battery fully, before using it with high impedance headphones such as Beyer DT880s/600 ohm. Without fully charged batteries you will hear distortion at peaks. Not an issue with fully charged batteries. The O2 drives my DT880s/600ohm very well.

Edit: I would like to add that I love how the O2 runs on battery and fits into my pocket. Its size is about the same as Hifiman HM-801.

i clipped the gain and am enjoying it with both my LCD-2's and Westone ES5 Customs

a true world beater amp if you ask me.

What did you change the gain too?  Mine should be here tomorrow. 

I am using the default low gain (2.5X, IIRC) with all my IEMs (Westone ES3Xs) and headphones (DT880/600, Lcd-2s). Perfect for ~80-82db music listening. Good range of volume control.

 it now defaults at 1.  cant remember.. the instructions are HERE

Is there any advantage to using it at the higher gain settings if you can get enough volume on the pot at 1X on low impedance or high impedance headphones?

Is there an advantage to using the AC adapter as far as speed of bass transients or anything?  It's just so low distortion and clean on batteries I haven't even bothered with plugging the adapter in yet.

Quote:

Originally Posted by Reticuli2 

Is there any advantage to using it at the higher gain settings if you can get enough volume on the pot at 1X on low impedance or high impedance headphones?

 

Is there an advantage to using the AC adapter as far as speed of bass transients or anything?  It's just so low distortion and clean on batteries I haven't even bothered with plugging the adapter in yet.

I've been meaning to ask question 1 as well.