Hi,

I am trying audio circuit which has OPA2134. Can this amplifier be replaced with LF351? I don't know what to look for replacement. I don't have OPA2134 and the market is short of it. I found LF351 which seems closest.

edit: I made mistake in writing OPA1234 instead of OPA2134 in the thread title

 

Hi,

I am trying audio circuit which has OPA2134. Can this amplifier be replaced with LF351? I don't know what to look for replacement. I don't have OPA2134 and the market is short of it. I found LF351 which seems closest.

edit: I made mistake in writing OPA1234 instead of OPA2134 in the thread title

It will work but you will hear some hiss at higher volumes. Also, neither of these OP Amos are intended to drive a pair of headphones (no matter what you see on the internet).

You also need two 9v batteries as power supply or your dynamic range won't be very broad.

Note that these op amps cannot output a signal over the whole power supply range. For an 18 volt power supply (9V virtual ground) your output can only swing over an 8 V range for a 2k ohm load. Not specified how the output can swing for a 16 ohm speaker range.

 

In the US or near mainland US, you can get OPA2134 at Digi-key.

The spec sheet says 35 mA per channel, so this should work alright with higher impedance headphones.

For example, assuming 10 mW per channel and this is to be the result with 10 mA per channel,

R = P/ I^2 = 10 mW/ (10 mA)^2
R = 100 Ohm

In regards to LF351, check the second to last paragraph in the left column of the "Application Notes" on page 7 of the data sheets in the link below. You may understand this better than me, but would seem to suggest that this op amp cannot deliver much more than 5 mA without difficulty.

http://www.alldatasheet.com/datasheet-pdf/pdf/89989/NSC/LF351.html

 

hi,

first thanks.

hi GopherT, actually the opa is being used as LPF/differential to single ended connector in between DAC and actual audio amplifier. So you were right that this amplifier is not actual audio amplifier. by amplifier I meant the designation of this part, it is still an amplifier but not audio amplifier as you have pointed out.

hi PeteHL, I ordered the opa2134. so will be following the given schematic for now.