[andrew3199]

Is the IBasso D10 the only current Amp / DAC combo that offers all three "USB" "Coax" and "Optical" input, portable or none portable?

 

[jamato8]

Quote:

Originally Posted by HiFlight /img/forum/go_quote.gif Yes, this is the method for modifying a 744 or 5534 for Class A operation. One must remove the #6 pin, connect the #5 pin to the #6 solder pad, then use a 2.2k resistor to bridge #6 to #7 pin. There isn't much room on an adapter for using 1/4 or 1/8 watt resistors, so I use SMD resistors. They are so tiny that they don't interfere with mounting 2 modules onto a 2>1 adapter. I haven't yet found a good (easy) way to modify a dual-channel opamp to Class A operation. Maybe down the road when I get more hacking time.

Wasn't there also a biasing of removing pin 5 and connecting pin 5 to 6 and running a resistor from 5 & 6 to pin 7?

 

[HiFlight]

Quote:

Originally Posted by rhw /img/forum/go_quote.gif WOW class A in the D10 (how does the AD743 classA sound in comparison to your topkit?) once more you are pushing the envelope, attacking my wallet, Ron or can the topkit be modified?

I have not had too much time to compare the 743 standard to the 743 CA, as I have been mostly working at the bench, but my initial impressions are that the basic Class A SQ is very similar but more revealing of small nuances and musical details.

In order to hear these differences, it is imperative to have good recordings, and first-rate upstream components as well as very good phones.

Some recordings might sound better if recording artifacts are not as noticeable, so CA might not always sound best with all recordings.

I have not yet made comparisons for hiss. The different bias might or might not have an effect. Headphone Addict has one of the first prototype AD744 OBCA modules, and will likely post his impressions of how it compares to the standard Topkit.

I am especially interested in whether the AD744s hiss with sensitive IEMs.

My initial impressions are that the 744 has slightly more mid and high frequency detail than the 743. Bass is also tighter.
It really sounds superb with acoustic and vocal music, but, again, I have not had that much time for critical listening.

The AD744 has often been used in high-end audio products, whereas the 743 has most often been used in industrial and military applications. The noise specs are better in the 743, but this doesn't often impact listening to the audio portion of the opamps bandwidth.

In the FWIW department, I have never heard an opamp with specs that showed excellent squarewave response that sounded bad.

 

[HeadphoneAddict]

The AD746 has more his than the AD743 on a 2:1 board. The hiss with the AD743 topkit is mild and less than the ALO Amphora or the Macbook Pro headphone out jack, so I do not use a volume attenuator. I am expecting the Class A AD744 today or tomorrow, and wil report back on that one. I will also spend more time with the OPA2350 and IEM too. Last time it was great with my ES3X but bassy with IE8 (duh) and not as dynamic with HD600 as the AD743 (both with AD8616 buffers).

 

[shredder]

I'm playing with my new D10.... anyone know how to get the USB on a Mac to output the sound from iTunes for the D10s DACs to play for me? Or am i not doing something on the D10?

 

[jamato8]

Now I remember how I did it. I used an adapter board with the DIP opamp leaving the 6 leg out of the hole to the side and I used a wire to tie 5 to 6 and a 2.2K from 6 to 7. That way the dip opamp could still be used as a regular opamp if I wanted to as the leg was still good.

 

[rhw]

Many thanks for your efforts, Ron.
Your day seems to have more hours than mine.

Well, that's the game, to reveil music through sound.
I like acoustic and vocals.

 

[rhw]

Quote:

Originally Posted by shredder /img/forum/go_quote.gif I'm playing with my new D10.... anyone know how to get the USB on a Mac to output the sound from iTunes for the D10s DACs to play for me? Or am i not doing something on the D10?

Open system preferences.
Go to sound preferences - output.
Activate the USB option.
::
better use an optical cable.

(Please someone correct me - I am not on an english system)

 

[rhw]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif I am expecting the Class A AD744 today or tomorrow, and wil report back on that one. .

Will be interesting and surely find many readers.
Also
many I think are awaiting your review of the HF-2.

 

[jamato8]

edit:

The following is while using the opamp with the P3+. I got my amps confused. sorry. :^)


Ok, the AD744 OB and CA very nice. More detail and great presence. Will have to listen more. I can use my adapter now for any dip opamp and of course soic on a Brown Dog etc. I must have made up these adapters 4 years ago or so. I am surprised I have them with me. I used a 1/8 watt resistor on each that is neatly tucked under the adapter so it is out of the way and still works, which it would not if on the side of the adapter.

 

[shredder]

Got it! Thanks!

I take it I will need to pick up an optical connection adapter?

 

[jamato8]

Quote:

Originally Posted by shredder /img/forum/go_quote.gif Got it! Thanks! I take it I will need to pick up an optical connection adapter?

You Mac is a mini optical so you will need a mini to toslink adapter or just buy a mini to toslink from Sysconcept in the length you need for a high quality optical cable.

 

[andrew3199]

Quote:

Originally Posted by andrew3199 /img/forum/go_quote.gif Is the IBasso D10 the only current Amp / DAC combo that offers all three "USB" "Coax" and "Optical" input, portable or none portable?

Anyone?

 

[jamato8]

It's the only one I know of.

 

[shredder]

Quote:

Originally Posted by jamato8 /img/forum/go_quote.gif You Mac is a mini optical so you will need a mini to toslink adapter or just buy a mini to toslink from Sysconcept in the length you need for a high quality optical cable.

Jamato8 - You truely are a Headphoneous Supremus.

I'll get the hang of this head-fi thing yet.