[FredA]

In audio-gd's gears, thay are only used as servo-control to eliminate the dc offset. The upgrade is minor.

 

[borrego]

A great replacement for OPA2134 are LME49720, LME49860, or LME49170HA metal cans. All 3, especially the metal cans, are a great improvement.

This is not your typical portable amp opamp rolling. All the LME opamps you stated are poor choices as DC Servo opamps for the audio-gd ACSS circuit. For obvious reason of different input impedance and power requirement comparing to the OPA2134.

OPA2134 are actually "disqualified" OPA2132 by BB/TI, they have similar power requirement, just that OPA2132 has better DC aplication spec.

If you replace the OPA2134 with other opamps with different power requirement (lower or higher), you risk upsetting the voltage setting for the other parts in the circuit. What do you think those tiny blue VR pots on the audio-gd circuit board are for?

 

[gLer]

This is not your typical portable amp opamp rolling. All the LME opamps you stated are poor choices as DC Servo opamps for the audio-gd ACSS circuit. For obvious reason of different input impedance and power requirement comparing to the OPA2134.

OPA2134 are actually "disqualified" OPA2132 by BB/TI, they have similar power requirement, just that OPA2132 has better DC aplication spec.

If you replace the OPA2134 with other opamps with different power requirement (lower or higher), you risk upsetting the voltage setting for the other parts in the circuit. What do you think those tiny blue VR pots on the audio-gd circuit board are for?

Well, you know what they say about curiosity...

 

[393699]

I never said I was planning on changing opamps. I was just curious what opamps the NFB1 and C-2 are using.

 

[FredA]

This is not your typical portable amp opamp rolling. All the LME opamps you stated are poor choices as DC Servo opamps for the audio-gd ACSS circuit. For obvious reason of different input impedance and power requirement comparing to the OPA2134.

OPA2134 are actually "disqualified" OPA2132 by BB/TI, they have similar power requirement, just that OPA2132 has better DC aplication spec.

If you replace the OPA2134 with other opamps with different power requirement (lower or higher), you risk upsetting the voltage setting for the other parts in the circuit. What do you think those tiny blue VR pots on the audio-gd circuit board are for?

Thanks for these precisions. I once knew and forgot all that, I ordered the 2132p. Just curious. Maybe i should be less curious...

Have you installed 2132ps yourself? It looks like maybe they are on sockets in my 2014 master-1. I could end up putting them in it.

 

[393699]

I did another full night of burn in last night, followed by all day again today. It must have about 60 hours on it now. This C-2 2017 Edition is just incredible. More people need to get this amp. It is just too good to pass this one up. Audio-GD has done a great job. The slight roll off in the upper treble that was there out of the box is now completely gone. This sound signature is now about as neutral and balanced as you can get. I am just so impressed with this amp.

 

[gLer]

I did another full night of burn in last night, followed by all day again today. It must have about 60 hours on it now. This C-2 2017 Edition is just incredible. More people need to get this amp. It is just too good to pass this one up. Audio-GD has done a great job. The slight roll off in the upper treble that was there out of the box is now completely gone. This sound signature is now about as neutral and balanced as you can get. I am just so impressed with this amp.

Please don’t say it too loud or too many people will start questioning the ‘value’ of their $1500 amps that don’t sound any better or more powerful than the Audio-Gd’s, and then prices will go up!

 

[393699]

Indeed, and so true on the power output of this puppy as well. On new albums, my Amiron Home is very loud on high gain at only 25-28 on the volume. On older discs I am hitting no higher than 35.

 

[FredA]

Indeed, and so true on the power output of this puppy as well. On new albums, my Amiron Home is very loud on high gain at only 25-28 on the volume. On older discs I am hitting no higher than 35.

I love the relay volume control's implementation, one very important reason being it performs evenly/splendidly at any level. No sweet spot or coloration anywhere. Too bad the headphones themselves are not like this.

 

[borrego]

Have you installed 2132ps yourself? It looks like maybe they are on sockets in my 2014 master-1. I could end up putting them in it.

I have OPA2132P on my Reference 5.32 and OPA2132PA on my Master 1.

 

[FredA]

I have OPA2132P on my Reference 5.32 and OPA2132PA on my Master 1.

I have OPA2132P on my Reference 5.32 and OPA2132PA on my Master 1.

Can you describe the benefits with the master-1? That would be much appreciated as i consider trying this mod,

 

[borrego]

Can you describe the benefits with the master-1? That would be much appreciated as i consider trying this mod,

Better dynamic, tighter bass response, much quicker warm-up time.

 

[FredA]

Better dynamic, tighter bass response, much quicker warm-up time.

Looking forward to trying it.

Thanks!

 

[riso1983]

Any good Europe audiogd reseller??

 

[HirschiAUT]

Any good Europe audiogd reseller??

I bought my NFB-1 Amp from Magna Hifi in the netherlands, and can absolutely recommend them!

https://www.magnahifi.com/en/

I have had lengthy Email conversations with Jos, one of the two owners of the Shop, and he even helped me with used Audio-GD gear i bought, like checking serial numbers and such, just top notch customer service!

Oh and they can also officialy repair any Audio-GD gear, even if you did not buy it from them.

I bought a used C-10 SE power amp 2 years ago. If it ever has any problems i will be happy i dont have to send this 40kg monstrosity to China for repair...