TL074 vers. TL084 ?

[lohk]

Is there a disadvantage to use a TL084 instead of a TL074 ?
What is the difference of those opamps anyway, soundwise ?
(Yes, I know there are better ones, but still...)

Klaus

 

[peranders]

This was like the swedish game "Finn Fem Fel" (Find five errors). I can't see any difference in the datasheets. Am I blind?

The JFET-input operational amplifiers in the TL07_ series are designed as low-noise versions of the TL08_

But the figures are the same....😕

 

[dhaen]

Hi Klaus,

There's always better, but:

The '74 has lower noise figure, so is better for AC signals.
The '84 has lower offset, so is better for DC signals

Cheers,

 

[lohk]

I was looking at the data specs for quite a time and did not find something significant:

So many thanks for the answers. Lower offset vers. higher noise !
I will have to look again...

Any experience soundwise ?
It seems not so important, because the successors are kind of better, but those chips are really cheap, and I just happen to have a lot...

Klaus

 

[dhaen]

Klaus,

IMO the '72 & 74 don't sound too bad, considering the cost.
But please don't tell them in the Tube Forum that I said so!😀

Cheers,

 

[peranders]

I was looking at the data specs for quite a time and did not find something significant:

So many thanks for the answers. Lower offset vers. higher noise !
I will have to look again...

Any experience soundwise ?
It seems not so important, because the successors are kind of better, but those chips are really cheap, and I just happen to have a lot...

If you have them and want to use them I can say that they aren't like µA741. They are like a Volvo 740 GLT in excellent condition. Safe car, OK to drive but not very exciting. Volvo S80 with extra stuff is cooler....

BTW: I have also a bunch of TL0x (plastic and ceramics) for sale....

 

[dhaen]

Hi Per-anders,

Do you have '74 or '84's?
If you have 50 - 500, please e-mail me.😉

Cheers,

 

[Edu Silva]

Hi, all



They are basically the same thing.

The chips come from the same silicon waffer, and selected for lowest noise: the better ones are labeled TL074 (or 72); the others will be TL084 (or 82).

Edu Silva
ES2 Audio

 

[dhaen]

the better ones are labeled TL074 (or 72); the others will be TL084 (or 82).

The "better" ones depends on what you want them for.
'84's are not the unselected ones. They too may be selected
for minimal DC offset.
The opamps that fail both tests probably get remarked and sold to audiophiles.😀

 

[Edu Silva]

The "better" ones depends on what you want them for.

For lowest noise, as I said. More interesting for audio than low DC offset.

(and they aren't good choice for DC servos, anyway...).

 

[djk]

"The chips come from the same silicon waffer, and selected for lowest noise: the better ones are labeled TL074 (or 72); the others will be TL084 (or 82)."

Not only are they the same part, just selected for very minor parameter differences, but you probably cannot tell the difference in a real circuit.

In a real circuit the noise is usually dominated by the resistor values.

 

[peranders]

In a real circuit the noise is usually dominated by the resistor values.

Not quite....TL071 is kind of noisy in a MM RIAA amp but in a high level application I would say that the noise isn't a big problem but the noise can be a problem in a tone control or in an equalizer.

 

[Circlotron]

If you have them and want to use them I can say that they aren't like µA741.

You know, 25 years from now a new generation of diyer's will be using 741's in their audio stuff and and marvelling at how wonderful they imagine they sound simply because they are old, and we will be telling them that they are rubbish, but to no avail. 🙄

 

[halojoy]

You know, 25 years from now a new generation of diyer's will be using 741's in their audio stuff and and marvelling at how wonderful they imagine they sound simply because they are old, and we will be telling them that they are rubbish, but to no avail. 🙄

Like them old vintage tubes are better than newly made

and an old VINYL with scratches sounds "better" than remastered CD-versions

And old Whiskey taste better than last years

And there is nothing like "my old lover woman"
compared to the young "silly" ones
-----------------------------------------------------------

/halo - think them old golden days, back when -
still waits for to be matched by this modern new age

😀 Where guys like Circlotron were not so rarely found 😀

 

[dhaen]

Do be serious...🙂

I don't really think that anyone will revive the TLO's, much less the 741.
In fact, I doubt you will find any working 50 years from now. The'll all have suffered from migration and purple plague, and other such nasties that afflict semiconductors.
Meanwhile, the valves will carry on working.😀

Cheers,

 

[djk]

"Not quite....TL071 is kind of noisy in a MM RIAA amp but in a high level application I would say that the noise isn't a big problem but the noise can be a problem in a tone control or in an equalizer."

In my experience you have it backwards. Because of the low source impedance of a typical MM phono cartridge a quieter opamp is of benefit here, I try and use bipolar types for phono.

I have tried to substitute lower noise opamps for the TL074 in equalizers and found that circuit impedances prevented the 'quieter' opamps from having any lower noise.

As a direct contradiction to your statement I would offer the comment that I have replaced the 4136 with a TL075 and found the circuit to 'sound' quieter even though there was more measurable noise with the TL075 .

Modern high performance opamps are so inexpensive for the small quantities used in DIY that I have hundreds, if not thousands, of TL and LF series opamps that I will never use.

 

[peranders]

In my experience you have it backwards. Because of the low source impedance of a typical MM phono cartridge a quieter opamp is of benefit here, I try and use bipolar types for phono.
...

I'm fully aware of that a AD797, LT1028, etc (very low noise) is not very suitable for high level applications just because they have BJT's input stages with high collector currents. Better to use JFET's when you have rather high signal source impedances, tone controls. equalizers, active filters etc.

But I think we can summerize to the thread starter: Yes, TL0xx can be used and yes there are better ones but still they aren't very bad, kind of average and the differnce between TL074 and TL084 isn't very big if they are used in audio and i normal circuits.

 

[halojoy]

A goos summary, peranders

A good way to sum it up.

We could go on for ages, discussing OP amps
And we wouldn't be much wiser in the end.

It very much depend on the application itself
and what OP-amps you have at home.
Or which ones you can buy around your house
for a price you think you can afford.

There are many good alternatives out there.
We all can NOT agree upon one specific IC
to suit us all in all circumstances.

/halo - have seen this discussion 10 times before
- and this will not be the last .... 😀