OPA134AP vs NE5534?

[3nity]

Im using opa134 in a gssl at the inputs instead of a ne5534 and they work fine but in the vca emulation section it doesnt work at all??
Anyone can comment on this?
Thnaks

 

[john12ax7]

Do you mean driving the outputs? Those are 5532 (dual not 5534 single)

 

[gemini86]

and the side chain is tl074...sooo.


[edit] are you talking about DBX202 emulation circuit?

 

[3nity]

Inputs of the gssl use 5534 and vca section uses 5534...output uses NE5532.
Is it clrear?

Now im using opa134 at inputs and they work, at vca emulation they dont...

 

[abbey road d enfer]

Inputs of the gssl use 5534 and vca section uses 5534...output uses NE5532.
Is it clrear?

Now im using opa134 at inputs and they work, at vca emulation they dont...

What do you mean by "VCA emulation"? Is it the opamp that works as a current-to-voltage converter right at the output of the VCA?
There is no reason for the OPA134 not to work in he position of a 5534. Check the voltages.

 

[3nity]

DBX202 vca emulation sorry...but if i try a 5534 it works so  i doubt its a voltage problem..

 

[john12ax7]

In that part you are buffering a control voltage so it's not in the audio path, so why not just stick with the 5534 then? The feedback resistor and capacitor probably need to be adjusted to use a 134. Also you are attaching a capacitor to one terminal of the 134 offset trim.

 

[abechap024]

Yes, It can sound slightly different depending on what opamp is driving the THAT 2180 control voltage buffer. That is curious the 134 won't work there. Could be unstable in buffer configuration (low gains) and its a fet based opamp....maybe that could have sometihng to do with it. I agree with above poster, thene5534 does a great job here. (but no harm in experimenting )

 

[Kingston]

OPA134 should be unity gain stable. That's how it's usually set up in that VCA CV buffer, or close to unity anyway.

Are you sure it's not some standard error like opamp installed reversed etc?

What size capacitor are you using parallel with the feedback cap? If it's too low the buffer might oscillate. Try 100-220pF to rule out this one.

 

[Harpo]

The NE5534 compensation cap between pins 5/8 might make your OPA134 unhappy.

 

[3nity]

The parts are stock as from Gyraf documents just different op-amp.
Problem is i only have 1 ne5534 and 2 opa134...for the moment maybe a to071??

Thansk

 

[timshel!]

The NE5534 compensation cap between pins 5/8 might make your OPA134 unhappy.

The 134 datasheet shows that pin 5 is NC and pin 8 is for offset... a 5534 uses pin 5 as compensation.

It looks like in this case NC means "Don't" rather than "Not needed". Try pulling the 100pF from between pins 5 and 8 as strictly speaking it's not a pin compatible drop in replacement.