[PelPix]

JDSlabs has an ongoing mass order.

 

[Ypoknons]

I'm posting on the off-chance that someone will have heard or has measured and can advise on both the Fubar IV and the Objective 2. I'm an objectivist with amps and I'd love to get a O2 but the Fubar has dealers in my current location (Hong Kong) and hence better support and the Firestone has a better port layout. And what's the Z-out on the Fubar IV, can't find it anywhere; if it's high I might as well go for a E9.
 
I want something to tie me over until or if the Gilmore X2 comes out. (edit: I'm not sure there will be an audible difference but I'd love to try. I want the X2 for reasons other than SQ, wierd talking about it in this thread.) I know it'll be a bit of wait.

 

[Willakan]

Interesting to read the phrase "giant-killer" being bandied around: the point of the O2 is indeed that it is the last word in transparency* (along with many other well-measuring amps) at a very competitive pricepoint. If the O2 becomes a "giant-killer" there are quiet a lot of other amps that will need to be admitted to that category by extension.
 
 
*Into loads that it is designed to drive, ect...

 

[maverickronin]

Quote:

I'm posting on the off-chance that someone will have heard or has measured and can advise on both the Fubar IV and the Objective 2. I'm an objectivist with amps and I'd love to get a O2 but the Fubar has dealers in my current location (Hong Kong) and hence better support and the Firestone has a better port layout. And what's the Z-out on the Fubar IV, can't find it anywhere; if it's high I might as well go for a E9.
 
I want something to tie me over until or if the Gilmore X2 comes out. (edit: I'm not sure there will be an audible difference but I'd love to try. I want the X2 for reasons other than SQ, wierd talking about it in this thread.) I know it'll be a bit of wait.

I don't know much about the Fubar or the schedule on the X2, but if you're concerned about the cramped jacks and/or having a built in DAC you could wait a few months for the Objective Desktop Amp version of the O2 with the optional 24/96 USB DAC.
 
Quote:

Interesting to read the phrase "giant-killer" being bandied around: the point of the O2 is indeed that it is the last word in transparency* (along with many other well-measuring amps) at a very competitive pricepoint. If the O2 becomes a "giant-killer" there are quiet a lot of other amps that will need to be admitted to that category by extension.
 
*Into loads that it is designed to drive, ect...

There are other amps like that but a lot of them are pretty expensive or attached to pretty expensive gear and not sold separately.  I think the O2 is the cheapest of the "sufficiently transparent" amps on the market.
 
Am I wrong on that point?

 

[Willakan]

I suppose if you're going to want to drive a good mix of headphones, the O2 does rather distinguish itself on the price front. If you only want to drive high-impedance headphones, the TPA6120 does pretty well.

 

[estreeter]

Quote:

The measure with or without batteries are available... somewhere online. There are essentially the same except for a slightly higher voltage swing on AC.

I believe that Voldemort states that you can safely hook up 'home' sources to the Objective2 with the AC connected without overpowering the input stage, but he cautions against doing that when running from batteries. I got away with it from a source notorious for the strength of its output signal, at least among USB-powered devices, but I'm sure its advice worth heeding.
 

 

[Reticuli2]

I'm in the process of trying to find a Torx T10 within walking distance of campus.  Having difficulty.  Either my batteries are bad, the AC adapter is bad, or something worse.  I got the clicking sound of drained batteries after just a few hours of use.  I was worried that it might be something more serious, but was reassured by the builder it should be minor once I can get the batteries out to check.

 

[Dixter]

Not sure why your batteries are running out so fast but as to the clicking sound...    the amp has circuits that are there to detect a low voltage condition from your batteries and the way it was designed it should not click..  the clicking is the circuit turning off and then back on again...      the designer made a change to a couple of resistors to correct the clicking...
 
make sure you use the correct WART...   it has to be " AC output "  ... not just plugged into an AC outlet...

 

[zzffnn]

^ my jds o2 made some noise when not fully charged, Especially with 600 ohm Dt880. However, there is no noise at all when fully charged. I bought a charger along with o2 from jds.

 

[mikeaj]

Quote:

I'm in the process of trying to find a Torx T10 within walking distance of campus.  Having difficulty.  Either my batteries are bad, the AC adapter is bad, or something worse.  I got the clicking sound of drained batteries after just a few hours of use.  I was worried that it might be something more serious, but was reassured by the builder it should be minor once I can get the batteries out to check.

You know which batteries you have?  What are you powering when it's on, and how loud?  Depending on the batteries and playback conditions, it could possibly be normal.
 
If the amp works on AC power, then it will charge the batteries with no problem unless the circuit was built wrong.  Even if the AC output voltage is a little low, it will charge the batteries, so most likely you can eliminate the AC adapter from consideration.  Actually, you can just measure the output voltage with a multimeter, if you want.  While you're at it, check the voltage of the batteries after a charge and after you get the low-battery shutdown.

 

[estreeter]

One of the things that this amp could have really used is a circuit to light the LED when it is charging. My uHA-120 starts at cherry red, then orange and green once its charged - handy.

 

[Ypoknons]

It's been a while hasn't maverickronin?

Yes I'm definitely interested in a more refined desktop version of the O2 with all the desktop amp creature comforts down the road but given the particularities in my work schedule I want an amp in the next month or so.

At any rate I checked the Hong Kong forums and there DIYers making them and selling a few but no commercial venture yet (I wouldn't be surprised if Fiio or someone picked it up down the road though). I presume other hobbyists around the world are doing the same thing.

As for the X2, indulge me in my fantasies of having a mini-BHSE will ya? But I do want something that can drive orthos other than he-400 if I ever get a 'nice' headphone amp.

 

[ClieOS]

Received my JDS O2 this morning and haven't spent a lot of time on it yet. First, the overall build quality is really good , kudos to JDS. Out of the limited listening, I still prefer StepDance over it, but it is not to say it isn't quite a good amp for the price. The clean channel separation is the one thing I noticed immediately and it makes it one of the cleanest sounding amp in my collection. Don't really like the size as it is more 'transportable' than it is 'portable', though that is another story of its own. Don't like the fact that it is using AC power-in / charging as these kind of adapter is harder to find in where I live. Good buy overall.

 

[maverickronin]

Quote:

It's been a while hasn't maverickronin?
Yes I'm definitely interested in a more refined desktop version of the O2 with all the desktop amp creature comforts down the road but given the particularities in my work schedule I want an amp in the next month or so.
At any rate I checked the Hong Kong forums and there DIYers making them and selling a few but no commercial venture yet (I wouldn't be surprised if Fiio or someone picked it up down the road though). I presume other hobbyists around the world are doing the same thing.
As for the X2, indulge me in my fantasies of having a mini-BHSE will ya?

But I do want something that can drive orthos other than he-400 if I ever get a 'nice' headphone amp.

Based on the efficiency number at InnerFidelity the O2 should probably be OK with anything but the HE-6.  While they're on the more efficient end for planars/orthos I love my O2 with my modded T50RPs and a few people have reported good results with the LCD-2.  The HE-4, 5, and 5LE could be a little iffy if you prefer rock concert levels or like to add a lot EQ to them.  I don't think there are any first hand reports with those combination yet though.

 

[daigo]

Looking for a medium level DIY project and the desktop version of this amp seems interesting.