[bogginhead]

I finally received my Muses01 and 02 for my E12 DIY and tried installing the 01 last night. Once installed, the amp had no charge and I got the blinking blue light "status". After taking the 01 out and putting the AD797 back in, the amp is back running normally. I went back and tried again, this time making sure the 01 was seated well; I got the same outcome, lol. Any idea on what might be causing this and how to fix it?

 

[CoiL]

You got ripped off? Where did You bought it from?

 

[bagwell359]

I've been trying out different op-amps in tuners made back in the 90's, and am convinced that there is value in optimizing them in equipment under consideration. In this case the Cambridge CXC. Wonder if anyone knows what it is? I've looked. I'd rather just open it once to get the orig out, and get a socket in there to test 2-3 options. Of course not so fast as I'd probably want to upgrade the caps too.

Thanks

 

[bogginhead]

You got ripped off? Where did You bought it from?

If you were meaning me, I'm pretty sure these Muses are legit. I spent quite a bit of time researching sellers, and the op-amps themselves. I also paid what seams to be the current going rate of a genuine Muses ($35 a piece). These very much have the extremely soft legs on them, too

 

[CoiL]

Just finished installing AD8599ARZ into Aune T1 headamp board...

Initial impressions:
1) INSANE DETAILS! Never thought I could get more detail (micro) and separation/layering/transparency out of modified T1 + Siemens E88CC tube.
2) At first little "bright" sided but really very clean sound. I wonder if this chip will "calm down" littlebti after some playtime?
3) My Fidelio X1 hasn`t sounded so balanced with this setup. Just wonderful!

But another note - stock NE5532 is not bad at all. Improvement with AD8599ARZ is not like night-and-day. If not hardcore modder/audiophile, then stock chip is totally OK too (Aune has done NE5532 implementation very well in T1 imo).

Will soon try out 2 more opamps instead NE5532/AD8599 and make socket roll-able.
Any recommendations beside/instead OPA1612AID?

Will add this into list and look more about specs too.
Naah... won`t bother messing with 2x1channel, I decided.

Also... still thinking about changing DAC differential opamp but have to do more research about what will work there as potential upgrade over OPA2134 (btw, haven`t tested V5i-D in that spot yet, so no idea if it will fail to work there too).

Got my OPA1612 installed instead AD8599ARZ and OOTB I seem to prefer OPA1612 straight away. It is back to point as NE5532 where I can hear Siemens E88CC goldpin tube signature - open,airy, holographic without being "thrown in face with detail" like AD8599ARZ.
Will leave it playing for a week and then compare to NE5532.
Also, installed roll-able socket.

 

[SpudHarris]

Is the LME49724MR not a plug and play single OpAmp?

I have soldered them up as such and smoked (literally) 4 off them.

http://www.ti.com/lit/ds/symlink/lme49724.pdf

Any advice appreciated...

 

[ScottFW]

Is the LME49724MR not a plug and play single OpAmp?

LME49724 is not a single opamp as typically used in audio devices. Never used one myself but it's definitely not going to be plug-and-play according to the linked datasheet.
A standard single opamp like a NE5534 has the +V supply on pin 7 and the -V supply on pin 4.
The LME49724MR is a differential opamp with a different pinout. Datasheet shows +V supply on pin 3 and the -V supply on pin 6.
I'm guessing the smoke is let out because you are connecting the 49724 pin 4 (Vout+) straight to the circuit's negative supply, basically creating a dead short.
That opamp is also incompatible with the dual opamp pinout that you're mostly likely to run into, e.g. NE5532.

 

[SpudHarris]

Thanks ScottFW, much appreciated. Do you think there would be a work around or adapter that would enable its use in a normal application?

 

[CoiL]

I have a question about Aune T1 DAC differential opamp (stock is OPA2134) - how do I know if I need 2-channel FET-input opamp or can use AD8599ARZ in that place for example?
Wish to try out changing OPA2134 to V5i-D or AD8599ARZ but have no idea what requirements that circuit needs to test out different opamps in that place.

Also, any other recommendations for headphone amp board opamps?
I`ve tried so far OPA1612, AD8599ARZ and NE5532AP.

 

[Ivan TT]

how do I know if I need 2-channel FET-input opamp

Usually FET input opamps used a term volume control potentiometer as they play well with varying input impedance.
Based on pcb photos it’s a bit hard to tell if that would be the case, I assume you are talking about dip8 opamp next to the gain switch?

 

[CoiL]

Nope, that tiny SOIC-8 left from headphone amp board edge on main PCB:

Spoiler: OPA2134UA SOIC-8

https://eu.mouser.com/ProductDetail/Texas-Instruments/OPA2134UA?qs=7nS3%2bbEUL6vYkwg0jcwJMw==

Also, decided to try out ADA4084-ARZ and OPA2228PA for headphone board.
If those are not good, will probably stay with OPA1612 which is still "burning-in" but when I briefly listened to it after few days playtime, sounded good. Though, NE5532AD seemed to have tinybit more "air" between sounds that instruments/sounds decays/reverbs could "fill in".
Will do more proper listening end of next week.

I`m thinking that if AD8599ARZ would suit spec-wise into DAC differential opamp location to replace OPA2134, then it should give nice result combined with OPA1612 as HP amplifier.
No idea though.

 

[raoultrifan]

I have a question about Aune T1 DAC differential opamp (stock is OPA2134) - how do I know if I need 2-channel FET-input opamp or can use AD8599ARZ in that place for example?
Wish to try out changing OPA2134 to V5i-D or AD8599ARZ but have no idea what requirements that circuit needs to test out different opamps in that place.

Also, any other recommendations for headphone amp board opamps?
I`ve tried so far OPA1612, AD8599ARZ and NE5532AP.

You should be fine with AD8599 or OPA1612 or even MUSES8920 in I/V stage. LME49720 should do as well, but also 2xAD797 if you can DIY a bit. Settle down to those opamps that are delivering the least background noise and least temperature on their shell.

For headphones amp keep the opamps that are delivering lowest background noise, lowest temp on their shell and lowest noise/hiss when moving the volume control/switching gain/powering ON-OFF (thumb noise).

P.S.: It's more important to ensure stability and compatibility between opamps and PCB and surrounding components, this is why I care less for the output sound than background noise. temperature of opamps and no noise-sound when switching power ON/OFF, gain adjust or while volume knob rotation.

 

[CoiL]

You should be fine with AD8599 or OPA1612 or even MUSES8920 in I/V stage. LME49720 should do as well.

By I/V stage You meant that I`m ok to swap OPA2134 with AD8599ARZ ? I`m thinking it will be best by specs for DAC differential opamp and provide OPA1612 with cleaner, more detailed signal and pair up nicely with OPA1612 sound signature.
Just to be sure, are ADA4084-2ARZ and OPA2228PA also compatible to try out in that spot? Don`t wish to buy any more opamps since upgrade isn`t very noticeable so far. I guess upgraded caps are doing their work very well.

For headphones amp keep the opamps that are delivering lowest background noise, lowest temp on their shell and lowest noise/hiss when moving the volume control/switching gain/powering ON-OFF (thumb noise).

So far havent noticed any problems with OPA1612 and AD8599ARZ in that place. No click with gain switch, no noise/hiss with vol control, no power-on pops (audio chain won`t switch on before tube has warmed up, so it isn`t audible anyway).

 

[Rroff]

OPA2228 isn't a drop in replacement if you don't know the circuit - it is optimised for gains of 5 and above and fussy about capacitors around it and load capacitance - pay attention to the section in the datasheet "Using the OPAx228 in Low Gains" as it is also helpful for using it in wider application. Very good opamp when supported properly but I've seen some fairly experienced people dismissive of it with their subjective evaluation of how it "sounds" showing it plainly wasn't stable in their use.

One of my favourites for "easy listening" as it is quite forgiving on the quality i.e. if you are feeding it with a so-so quality MP3 without ever sounding like it is lacking in detail with a nice smooth low fatiguing presentation.

 

[CoiL]

Thanks for info. Won`t try OPA2228PA as DAC differential opamp then. AD8599ARZ first and then ADA4084-2ARZ, maybe OPA1612 too if I find other chip better in HP section.