I just had a look on the datasheets from STMicroelectronics. Aside from one mention of the TL071 being low noise, everything in the datasheets is the same, including noise figures (15nv/hz) and graphs. 
Are they in fact the very same ICs now ?
A real difference is the price though The TL081 is usually way cheaper
Are they in fact the very same ICs now ?
A real difference is the price though
The TL081 is usually way cheaper
Texas.
TL071 and TL081 have same supply current.
TL061 is the low current version. Which follows not as good data. Slower and higher noise.
For Texas, the only difference I have read is Noise.
TL071, 18/nV and TL081, 25/nV
Now, this 18 or 25 ... they are still at about the same level.
So small difference is nothing, in practical use.
TL071, TL081, TL072, TL082 are good for many audio applications.
And if we take the price into account, they are just great!
They have 13V/uS slewrate
OPA2134 is next step for JFET opamps.
But can not quite compare with TL071 regarding Value for Money.
Has got noise: 8 /nV and Slewrate is 20V/uS
If you need many opamps for filters etc. TL081/TL082 would be a good choice.
If only a couple of opamps, then maybe you will buy the medium priced OPA2134.
It all depends on what is your application.
And if you think anyone can hear the difference. I do not think so.
Even low priced modern opamps can have as low distortion as 0.001 %. No problem.
This will simply drown in Loudspeaker distortions at around 1 %
Make a Recording Mix 2 sounds of two different frequencies.
One at normal level, and the other 1/1000 lower:
For example 1 Vrms 1 kHz + 0.001 Vrms (=1mV) 600 Hertz. This is a 60 dB difference (x1000).
Now part of your recording should only have the 1 kHz
with the 1 mV rms 600 Hz coming in at other parts of your recording.
I bet you can not detect where is One or Two tones
This effect is called 'masking'.
We do not hear a fly/mosquito humming in a Discoteque with Loud Music.
because the stronger sound will mask 'the whisper' ...
The other emperiment would be:
How small would the difference in sound level be for 2 different frequencies
before we can detect the lower level sound.
Where the masking effect is no longer.
TL071 and TL081 have same supply current.
TL061 is the low current version. Which follows not as good data. Slower and higher noise.
For Texas, the only difference I have read is Noise.
TL071, 18/nV and TL081, 25/nV
Now, this 18 or 25 ... they are still at about the same level.
So small difference is nothing, in practical use.
TL071, TL081, TL072, TL082 are good for many audio applications.
And if we take the price into account, they are just great!
They have 13V/uS slewrate
OPA2134 is next step for JFET opamps.
But can not quite compare with TL071 regarding Value for Money.
Has got noise: 8 /nV and Slewrate is 20V/uS
If you need many opamps for filters etc. TL081/TL082 would be a good choice.
If only a couple of opamps, then maybe you will buy the medium priced OPA2134.
It all depends on what is your application.
And if you think anyone can hear the difference. I do not think so.
Even low priced modern opamps can have as low distortion as 0.001 %. No problem.
This will simply drown in Loudspeaker distortions at around 1 %
Make a Recording Mix 2 sounds of two different frequencies.
One at normal level, and the other 1/1000 lower:
For example 1 Vrms 1 kHz + 0.001 Vrms (=1mV) 600 Hertz. This is a 60 dB difference (x1000).
Now part of your recording should only have the 1 kHz
with the 1 mV rms 600 Hz coming in at other parts of your recording.
I bet you can not detect where is One or Two tones
This effect is called 'masking'.
We do not hear a fly/mosquito humming in a Discoteque with Loud Music.
because the stronger sound will mask 'the whisper' ...
The other emperiment would be:
How small would the difference in sound level be for 2 different frequencies
before we can detect the lower level sound.
Where the masking effect is no longer.
Hi Boyofwax,
I see in your sig that you built a pair of Vifa Korrekt. Did you follow Vifa's design exactly? How do you like the sound?
Did you use their crossover design?
I'm slowly acquiring the components to build a pair myself. I have a pair of Polk R30's and am going to put the Vifa components into the R30 enclosures. The volume of the enclosures match within 1% and they're both ported. The only difference is that the R30's have their tweeter on top while the Korrekt's have the tweeter under the woofer.
regards,
Dave
I see in your sig that you built a pair of Vifa Korrekt. Did you follow Vifa's design exactly? How do you like the sound?
Did you use their crossover design?
I'm slowly acquiring the components to build a pair myself. I have a pair of Polk R30's and am going to put the Vifa components into the R30 enclosures. The volume of the enclosures match within 1% and they're both ported. The only difference is that the R30's have their tweeter on top while the Korrekt's have the tweeter under the woofer.
regards,
Dave
Hi Dave,
For my korrekt set I used the original drawing and the original filter. I've listened to these speakers for almost 9 year. I find the price/quality OK, but it lacks bass imo. (I built another set with an active sub) I doubt if the original drivers are still available, as the German developers have changed the box.
I think (I'm more into electronics) this type of box goes lower on the bass instead of having the bass volume of a closed enclosure which does not get as low as these floorstanding ported type's.
I don't know what kind of sound you are looking for. But experimenting is always good
If you are not sure, use the Vifa drivers in a closed box.
In the future I will try a different filter for my Vifa's. I recommend you try a different filter from the original.
Regards.
For my korrekt set I used the original drawing and the original filter. I've listened to these speakers for almost 9 year. I find the price/quality OK, but it lacks bass imo. (I built another set with an active sub) I doubt if the original drivers are still available, as the German developers have changed the box.
I think (I'm more into electronics) this type of box goes lower on the bass instead of having the bass volume of a closed enclosure which does not get as low as these floorstanding ported type's.
I don't know what kind of sound you are looking for. But experimenting is always good
If you are not sure, use the Vifa drivers in a closed box.
In the future I will try a different filter for my Vifa's. I recommend you try a different filter from the original.
Regards.
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