Upgrade to OPA2134

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
R

ratu

Member
Joined 2004
Few weeks ago, I was here asking about to upgrade an ONKYO receiber model TX DS676, changung the opams NJN 4565 to OPA2134, these are the results:

The music sounds more deeper, and rich, but less lound!!??

I change one of the 15534(5534?) and it runs OK!!


Now i have to put the volume 6..10dB more... It´s strange no?

Ratu
 
Raka

Raka

Member
Joined 2002
mmmm...

It's very strange. The gain is not fixed by the opamp, but by the resistors network, so ... I don't have any at hand, could you please check if the pinout is the same? Which is the voltage applied?
Have you fitted a conector to fast exchanging between opamps?
 
S

sreten

R.I.P.
Joined 2003
A shunt feedback network will act as an attenuator if the
op-amp isn't working, i.e. the signal will still get through
but at a lower level.

(Caught me out once trying to fix a guitar pedal design,
it sounded poor, with not enough output, but I didn't
realise the op-amp had given up the ghost.)

:) sreten.
 
R

ratu

Member
Joined 2004
I only change the opams, the rest of the circuit is the same, the gain of the 2134 is grater than the 4565 and the pinout is the same.

It´s dificult to measure the suply voltage, but i´m gona do it.

Thanx!!..................... any other idea??

Ratu
 
M

mb

Member
Joined 2002
ratu said:
Few weeks ago, I was here asking about to upgrade an ONKYO receiber model TX DS676, changung the opams NJN 4565 to OPA2134, these are the results:

The music sounds more deeper, and rich, but less lound!!??

I change one of the 15534(5534?) and it runs OK!!
Ratu
Click to expand...
The 5534 is a single, and the opa2134 is a dual. If you're saying that the 5534 works, then the answer is that you should be using a opa134.
 
Gasho

Gasho

Member
Joined 2004
soundness.com.hr
NJM4565 is dual OP so you can use OPA2134 or OPA2604 .... the diffrence in topology is input stage of op ,NJM is made with bipolar input , and OPA2134 is FET input op. There must not be any diffrence in gain if you don change resistors ih NFB rail.
If gain is lower somehow , you can simply change values of series resistors in NFB by higher values (50%). Buy that change you will get higher gain , and more better and spacious sound.
Do you think to change something in output stage?:D
 
M

macboy

Member
Joined 2003
It is possible that one (or more) of new opamps are not working at all, and that is why the sound level is attenuated, but still there. You might think that you would get complete silence if if the opamp isn't working but that is not necessarily the case...

Consider what would happen in a basic inverting opamp circuit if the opamp was dead (or was removed). The signal would travel from input to output through the series combination of Ri and Rf. See below for illustration.
 

Attachments

  • no-op-amp.gif
    no-op-amp.gif
    3.4 KB · Views: 530
R

royallin

Member
Joined 2005
thank macboy

Thank macboy for your favor.


I am sure this opa2134 can work ! because the volume level is lower a little than 5218 , not much lower ! If opa2134 was dead, I can only heard very low volume!

I know that gain is not changed by replaceing opamp, In fact , I must adjust more level to get enough volume as 5218 in here , it is so strange!

Sorry ! I forget to mention this case apply to car audio!:smash:

accordong to original circuit design, V+ = 9V, V- = ground , RF = RI = 15K, so the gain value is 2.

now I want to adjust more RF value to get more gain (3 times to 5 times) , Can the way solve the problem ? or you can offer me the better suggestion ! thank you.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom