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The iBasso D12, dual dacs . images . new Sysconcept optical cable . . Topkit by HiFlight. . - Page 32

post #466 of 601

Do you feel you want more gain or is it something else?

 

I have a D10 and it didn't really push them loudly enough for me to achieve decent headroom.

post #467 of 601
K701's require a lot of current in my opinion so even if they are low impedance they still need good levels of power. Perhaps it is an excuse to try a PB2!
post #468 of 601

Since the Q701's have an impedance of 60 ohms I would guess that the D12 is running out of current.

A higher authority (Top Flight) advised me to try using LMH6643 from the Op Amp rolling kit, this Op Amp can output up to 75 milliAmps.

In addition it has a very low output impedance.

I'll try the LMH6643 Op Amps out when I get some free time and report back..............

post #469 of 601
OK,
I pulled all the op amps out and replaced the buffers with dummy buffers.
First I tried using the LMH6643 in the centre L/R . Waddaya know, D12 has no problem driving my Q701s, good tight punchy bass with an open middle and treble.
Then I replaced the LMH6643 with an AD8532, a bit noisier which was fixed by reducing gain to +3 dB and turning the volume up a bit. So far I'm still trying to figure what the difference is, but the AD8532 does something to the midrange.
My theory is that the Q701s need a lot of current (both the op amps I swapped in can supply a fair amount of current into the load).
More later.
Edited by Chris J - 9/5/11 at 9:55am
post #470 of 601
Quote:
Originally Posted by Chris J View Post

OK,
I pulled all the op amps out and replaced the buffers with dummy buffers.
First I tried using the LMH6643 in the centre L/R . Waddaya know, D12 has no problem driving my Q701s, good tight punchy bass with an open middle and treble.
Then I replaced the LMH6643 with an AD8532, a bit noisier which was fixed by reducing gain to +3 dB and turning the volume up a bit. So far I'm still trying to figure what the difference is, but the AD8532 does something to the midrange.
My theory is that the Q701s need a lot of current ( both the op amps I swapped in can supply a fair amount of current into the load.
More later.


Chris...

 

If you need still more output current from your D12, you might also try the AD8397 in L/R.   As it has built-in buffers, it is best to use it with the bypass (dummy) buffers.   IMO, it does a better job in the L/R position than the AD8532 considering overall tonal balance.   SQ is similar to that of the LMH6643 but with more muscle.  

post #471 of 601
Hi Topflight,
I prefer the LMH6643 sound, but what I am really looking for is more clarity and transparency.
I very rarely turn the volume past 12 o'clock.
regards, Chris
Edited by Chris J - 9/5/11 at 2:42pm
post #472 of 601
Quote:
Originally Posted by Chris J View Post

Hi Topflight,
I prefer the LMH6643 sound, but what I am really looking for is more clarity and transparency.
I very rarely turn the volume past 12 o'clock.
regards, Chris

 

LT1678 will do that.  Quite detailed and transparent.
 

 

post #473 of 601
Quote:
Originally Posted by HiFlight View Post



 

LT1678 will do that.  Quite detailed and transparent.
 

 



Unfortunately they don't source/sink a lot of current, can you recommend a good buffer? Any idea what buffer is shipped with the D12?

 

post #474 of 601
Quote:
Originally Posted by Chris J View Post





Unfortunately they don't source/sink a lot of current, can you recommend a good buffer? Any idea what buffer is shipped with the D12?

 



 

If you seldom go above the 12:00 position with your volume control, I think the LT1678 would still work well with bypassed buffers and give you the SQ that you are looking for.  I can tell very little difference between it and other L/R opamps with buffers as far as driving ability.  I really like the sound of the LT1678 and often use it as the optional opamp for several Topkits.   You might try it with the LMH6643 as buffers.   Should be a very good pairing. 

 

 

 

 


Edited by HiFlight - 9/6/11 at 7:53pm
post #475 of 601

What would you guys recommend as a good starting point configuration for the following headphones

 

Westone 3, Grado, ER4S

 

TIA

post #476 of 601
Quote:
Originally Posted by markkr View Post

What would you guys recommend as a good starting point configuration for the following headphones

 

Westone 3, Grado, ER4S

 

TIA

This was what I got from my HiFlight Topkit For my Grado 325is'.  I can put up the ones for my um3x if you like.  I just have to open my D12 up.

.Photobucket

 

post #477 of 601

For the D12 and D4, do you bypass the DAC if you use a LOD from an iPhone?

post #478 of 601

Using the LOD from the iphone uses the phone's DAC, which then passes the analog signal into the D4/D12 for amplification. The dac in the D4/D12 is not used; you can only use it via usb/optical/coax.

post #479 of 601

Oh I didn't know that, thank you. I always thought the LOD also bypassed the internal DAC.

post #480 of 601
Quote:
Originally Posted by SurfWax View Post

Oh I didn't know that, thank you. I always thought the LOD also bypassed the internal DAC.


I've tried using the LOD on my iPod to D12 Aux In............I wasn't too impressed, I thought the bass was too loose.

I normally use a Wadia 170i with my iPod, I use the digital output on the Wadia to the D12 spdif.

Unfrotunately I can't walk down the street with it, but it's nice for sitting outside on my deck. LOL
 

 

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