[superuser1]

Thanks, I just really want to get this that's all. I seem too eager at times.

 

[CactusPete23]

From what I can gather that amp is rated at 10 ohms output impedance into a 1000 ohm load. This isn't the appropriate way to measure or spec it for a portable device. It should be measured into a 16 or 32 ohms load. I think the z out will measure much lower if that is done, just guessing but likely about 1 ohm. There is a fair amount of info about this amp in head-fi, consensus seems to be it sounds fantastic on high impedance cans, not so much on low impedance, but of course a lot will depend on implementation. Joe, I really would advise your engineers to measure the z out themselves into a load typical of IEM's, 16-32 ohms. I think you're doing yourself a disservice by just quoting the manufacturer spec, because it isn't appropriate for your application. This is similar to the mistake Shanling made when they first reported z out specs for their players.

I hope you are correct, that would be great news!

But still think that most potential buyers would like to see this Output Impedance actually measured with 32 ohm load; and reported officially before placing an order...

@Joe Bloggs This should be easy for one of the HiBy Tech Folks to do, and quickly get verified ?

 

[Joe Bloggs]

I'm inquiring with the engineers on the veracity of @dlayman 's theory.
OT: How the heck do I @ people properly in this new software?

 

[reginalb]

@Joe Bloggs Just type the @, then start typing their user name, a list should populate, and click one of the users. I've manually typed out the full user name, and it doesn't work.

 

[Joe Bloggs]

@reginalb yay that worked I'd actually seen this mechanism at work before but forgotten. Slow network speed here in China making this autosuggestion process less than intuitive.

 

[Joe Bloggs]

Well the indiegogo campaign is live at https://www.indiegogo.com/projects/hiby-r6-worlds-most-advanced-android-hi-fi-player-music#/

Here we go, guys

 

[headwhacker]

This was interesting until the z out was said to be high. I hope this gets clarification. Only thing holding me off from backing it. Actually that and the long wait

 

[goodvibes]

I think the Z will remain higher than we want.

 

[reginalb]

I think the Z will remain higher than we want.

I've been reading up on the amplifier that was selected for this guy and tend to agree. I don't think it's a great choice for what I am looking for. I'd primarily want it for my UM Merlins, and I don't think this amp will handle 12Ω all that well.

Seems that it would be trivial to provide a FR graph with some low-impedance IEMs so that we would know for sure.

 

[reginalb]

For anyone curious, you can read up on the amplifier here:

http://www.ti.com/lit/ds/symlink/tpa6120a2.pdf

Joe indicated that the resistance is from a discrete resistor, which makes sense given the following from that document:

The series output resistor should be between 10Ω and 100Ω. The output series resistance eases the work of the output power stage by increasing the load when low impedance headphones are connected, as well as isolating any capacitance on the following traces and headphone cable.

Also, later in the document:

The series output resistor should be kept at a minimum of 10Ω...

Later in the document, they recommend the 10Ω in the sample layout for "High Fidelity Smartphone Application"

Starting with 1KΩ resistors for input and feedback, and 10Ω output resistance, the feedback resistance was lowered to increase the amount of current in the feedback network. The output resistance was increased to ease the load on the headphone amplifier when low impedance headphones are connected. Both of these additions contribute to the excellent SNR and THD of the TPA6120A2 in such a low voltage application...

...Using such a solution makes the TPA6120A2 transparent in the circuit, even into a low impedance 32Ohm load.

So according to TI, it does just fine with that output resistor in to a 32Ω load.

I happen to have a 32Ω load that I could use to measure its FR with said load to test that claim, but there it is. Hiby, I'd be glad to do those measurements for you

 

[alwass89]

Regarding indiegogo, does anyone know if they charge you right away or once the campaign ends?

 

[Joe Bloggs]

Regarding indiegogo, does anyone know if they charge you right away or once the campaign ends?

Yes, all backers are charged when the campaign ends. The indie does need those funds to go about finishing what they're making

Edit: Actually it's like this--indiegogo backers are charged *the moment they commit*. Unlike Kickstarter, Indiegogo backers are always charged. That's okay--we're always going to make these R6s no matter what the number of backers.

So why don't we all wait until the last day of the campaign to commit? Well, there are the Early Bird perks. You don't see them named as such but all the tiers available in the campaign right now are Super Early Bird tiers. Once these are exhausted they will be replaced by tiers with the same contents but a lesser discount.

The R6 will sell for $649 and $569 respectively for the stainless steel and aluminium alloy-bodied versions after the campaign, these being identical in function apart from the chassis material.

Hope that clears things up.

 

[PapaThrust]

Should our impedance fears be realized, there will be many disappointed potential buyers - my self included. 32 ohm used to be low for IEMs, but not anymore, 12 ohms seems a better target.
Could this have been more thought out?
I'm hoping for flat response with my Andros, yet after reading the paper from the link reginalb provided, I have doubts.
Moving forward, can there be a low impedance version added?

 

[reginalb]

Should our impedance fears be realized, there will be many disappointed potential buyers - my self included. 32 ohm used to be low for IEMs, but not anymore, 12 ohms seems a better target.
Could this have been more thought out?
I'm hoping for flat response with my Andros, yet after reading the paper from the link reginalb provided, I have doubts.
Moving forward, can there be a low impedance version added?

You could bypass the resistor ala the RWA AK100.

 

[mitsu763]

Somehow I missed the high OI spec before pulling the trigger. This is disappointing.

If I'm not mistaken, Fiio is using this amplifier in the K5 which has <1 ohm OI.