[ztsen]

Quote:

Originally Posted by jamato8 /img/forum/go_quote.gif 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.

does 744 have any hiss on the sensitive iem (um3x, tf10) compare to 743?

 

[qusp]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif Someone at the Colorado head-fi meet summer 2008 told me my Apogee mini-DAC and Blutarsky's Apogee Duet (same table) was better than his RME Fireface.

well; LOL at that, maybe to his ears and with his gear? I know the Duet doesnt have balanced (a muct for me). and yes i've heard both of those apogees. didnt think much of the duet TBH, but the minidac is nice. apogee make some great stuff no doubt; but I favour their errrmm more advanced offerings. I also produce music in Logic studio triggering several hardware synths and a voltage to midi converter to drive an old prophet analogue synth. and record via an ADA8000 into the adat input. neither of those models have enough I/O for me and I cant Justify buying any of their topflight multichannel interfaces; especially since I dont really get enough time anymore to really take advantage of it. she's getting on a bit too these days, had it for a couple of years and bought used. gonna upgrade the power rail at some point. but likely before then i'll be grabbing a buffalo Dac, I mainly bought the fireface for ADC at the time, rather than DAC. the ADC in the FF is very nice, but the main thing I love is the drivers. rock solid. Also love the ability to use it without any computer at all as a hardware mixer, great for parties.

 

[diditmyself]

Quote:

Originally Posted by ztsen /img/forum/go_quote.gif does 744 have any hiss on the sensitive iem (um3x, tf10) compare to 743?

AD744 is one of the noisiest opamps, but I like it's sound when the output stage is by-passed = comp pin out. The noise is clearly audible with IEM's. I have no D10, but I've used it many times in other amps.

 

[GreenLeo]

Can OPA2350 modified into Class A mode?

 

[rhw]

Quoting HiFlight from the iBasso P3+ thread

Quote:

Originally Posted by HiFlight /img/forum/go_quote.gif The NE/SA/SE5534, AD744 and AD829 can be modified to run OB, 5534 and 744 can be run OBCA, 829 can't do both at the same time. Any single-channel opamp can be modified to run CA.

 

[SpudHarris]

To run class A with any single OpAmp is it just a case of putting a 2.2k resistor between pins 6 & 7?

 

[jamato8]

Quote:

Originally Posted by SpudHarris /img/forum/go_quote.gif To run class A with any single OpAmp is it just a case of putting a 2.2k resistor between pins 6 & 7?

Yes. Though it would seem that for different current draws from different opamps and ideal bias might not be obtained. Ron?

 

[rhw]

Quoting Ron once more from the iBasso P3+ thread

Quote:

Originally Posted by HiFlight /img/forum/go_quote.gif The biased 744s were made by cutting off the #6 pin, then bending the #5 pin to fit into the #6 socket hole. I am going to make some up using SOIC case style, as it is much easier to make them up with an adapter. Just cut off a leg and a bit of solder bridging and you are done.

?

 

[SpudHarris]

Thanks to Hiflight and Jamato I managed to put together 2 x adapters for the AD744's to run OBCA and the difference is not subtle. Everything about them is better, resolution, depth, clarity everything!

As everyone knows the further we get down the slippery slope the more we seem to pay for even the smallest of improvements and eventually these improvements against cost become disproportionate. This mod cost next to nothing (although I did melt about 6 adapters to end up with 2 finished modules), but the improvement is quite noticable. Ron said to notice these improvements you must be using a decent source and high bitrate recordings at least and I second this. I'm using these OpAmps with Ibasso buffers + OPA2107 in ground in a P3 with lossless tunes via an ipod LOD and a custom made 12v PSU.

 

[HiFlight]

Quote:

Originally Posted by GreenLeo /img/forum/go_quote.gif Can OPA2350 modified into Class A mode?

No, but the single-channel version, the OPA350 can be biased Class A. I will be making up a set of those for testing very soon.

 

[GreenLeo]

Quote:

Originally Posted by HiFlight /img/forum/go_quote.gif No, but the single-channel version, the OPA350 can be biased Class A. I will be making up a set of those for testing very soon.

Wow, what a news!

I look forward to hearing your impression. Just wish that it can sound better than the OPA2350.

By the way, what is the meaning "single channel" or the difference between the 2350 and 350? Thanks.

 

[jamato8]

Quote:

Originally Posted by GreenLeo /img/forum/go_quote.gif Wow, what a news! I look forward to hearing your impression. Just wish that it can sound better than the OPA2350. By the way, what is the meaning "single channel" or the difference between the 2350 and 350? Thanks.

A single channel is an opamp with one operational amplifier circuit. A dual opamp has two opamps in one chip.

 

[GreenLeo]

Quote:

Originally Posted by jamato8 /img/forum/go_quote.gif A single channel is an opamp with one operational amplifier circuit. A dual opamp has two opamps in one chip.

Thanks John.
So how does a single/dual channel affect the sound?

 

[a_tumiwa]

how to use "DAC only" from D10 and then use other headamp??

 

[rhw]

Quote:

Originally Posted by a_tumiwa /img/forum/go_quote.gif how to use "DAC only" from D10 and then use other headamp??

Connect "Aux out" to any amp.
Switch D10 on.