machinow:
BJT opamps are subject to the same condition, due to their high input bias currents. It is always a good rule of thumb to ensure equal impedances at opamp inputs.
BTW - my current preamp uses a 100K pot input to OPA134 with a discrete SE class-A buffer inside it's feedback loop, and the sound is superb - among the best I've ever had in my system, and I've tried many different variations of opamp and discrete circuits using MOSFET, BJT etc... I'm about to embark on a project to build and test some Borbely preamp circuits, so we'll see how that goes. But, one must not totally discount the possibilities to make opamps sound good! In my case, I needed a quick'n dirty preamp for something different, and so built this circuit in an afternoon, being very surprised to hear it when I powered it up.
BJT opamps are subject to the same condition, due to their high input bias currents. It is always a good rule of thumb to ensure equal impedances at opamp inputs.
BTW - my current preamp uses a 100K pot input to OPA134 with a discrete SE class-A buffer inside it's feedback loop, and the sound is superb - among the best I've ever had in my system, and I've tried many different variations of opamp and discrete circuits using MOSFET, BJT etc... I'm about to embark on a project to build and test some Borbely preamp circuits, so we'll see how that goes. But, one must not totally discount the possibilities to make opamps sound good! In my case, I needed a quick'n dirty preamp for something different, and so built this circuit in an afternoon, being very surprised to hear it when I powered it up.
Erno has some figures for his usual 2SK170, ... discrete FETs in the FET papers on his website.Borbely Audio
NE5532 vs OPA2134
hifiZen,
10-x for the reply. Do you mean in your pre- the OPA just sounds better than the NE5532/AN/ - I also like a lot the OPA134 /probably because I use it in my Power amp, which i believe is some kind of perfect
, but according the theory, the BJT should have better performance there. OPA should have a THD of about 0.005...0.02 % in the worst case at 20kHz, but this may not be audible /again, according the theory!/ Anyway, why should I have these distortion, and at a higher price??
Because I haven't made the pre-amp yet I wonder which op-amp to use. My hearing experience is too limited due to the speakers I've got, so a difference between two quality products can not be caught with them. The parts I'm about to replace are the uPC4570's in an Yamaha integrated amp, the pre- section, where this part is used almost everywhere. /model DSP-A1000/ Generally the bad sound of this pre- /I can hear this difference with my speakers/ should come from the large number of signal electrolytics, and also some electronic switches, but they're correctly designed /the switches - loaded w. over 100kohms, supply +/-15V - LC7523 or some??/
Thank you again!
hifiZen,
10-x for the reply. Do you mean in your pre- the OPA just sounds better than the NE5532/AN/ - I also like a lot the OPA134 /probably because I use it in my Power amp, which i believe is some kind of perfect
, but according the theory, the BJT should have better performance there. OPA should have a THD of about 0.005...0.02 % in the worst case at 20kHz, but this may not be audible /again, according the theory!/ Anyway, why should I have these distortion, and at a higher price?? Because I haven't made the pre-amp yet I wonder which op-amp to use. My hearing experience is too limited due to the speakers I've got, so a difference between two quality products can not be caught with them. The parts I'm about to replace are the uPC4570's in an Yamaha integrated amp, the pre- section, where this part is used almost everywhere. /model DSP-A1000/ Generally the bad sound of this pre- /I can hear this difference with my speakers/ should come from the large number of signal electrolytics, and also some electronic switches, but they're correctly designed /the switches - loaded w. over 100kohms, supply +/-15V - LC7523 or some??/
Thank you again!
Good advices.This isn´t exactly the right thread i believe.
But i wonder why no one ever talks about the AD826 for
dual OPs. I switched a lot OPs into the output buffer
of my DAC (earlier thread somewhere) and ended up
with an AD826. It is the only fast Analog Devices with
the ability of +/- 15V i can buy here. So i had no chance
to compare against the AD8620.
I have to admit that you have to be careful with the
layout cause of its high bandwith. A digital TV
receiver next to it even stopped working when i pulled
the power switch of the DAC
capacitor cross the voltage pins.
It produces a very unspectacular sound with wonderfull
resolution and the touch it needs to sound musically.
Neither synthetic nor agressive or bloated.
Short: I love it
Oh, another thing.
During testing i have collected different 5532s.
LRAY, Philips and Ti
The LRAY sounds harsh and the Ti plugged.
The only good one is the Philips that does everything
right but misses the resolution that faster ones can
archive.
All listening just for my DAC.
Has anybody similar experiences, or should i dung my in-ear
parsley more often?
Differences/wrong ratings within the same type (e. g. NE5532) often arise cause different manufacturers, different factories and even on different years of manufacture; in particular, when the IC is used very often.
Some user's claim, that this is also on the OPA2134 and OPA2604.
Old ones of OPA2604 sounded better, than OPA2134.
in the newer versions, the result is exactly the opposite.
This may not be the case with Analog Devices / Linear Technology types like AD826, ADA8098, LT1358, and LT1469, because the users are offer much higher quality devices than typical home audio devices, and thus much smaller quantities are in demand.
One have to remember that we already have 2018 (almost 2019). With the introduction of the BurrBrown OPA2604 in the early 90s, a bad sound quality would have been claimed immediately. Today, most probably no longer notice when a 709, 741, LF357, or TL082 / TL072 is labeled as OPA2604 (possibly therefore the contradictory observations while listening tests).
Is my estimate right, OP-Amps from Analog Devices are always to prefer,
even if these are usually much more expensive than the ones of TI.
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