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Onkyo P-304 Op-amps Replacements

CohibaJoe

CohibaJoe

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Since I am waiting for some caps for Luxman LV-109..

I had recapped the Onkyo P-304 a while back. I would like to replace the Op-amps.

Flat Amp Board has (2) JRC 45558D
EQ Amp has (2) JRC 4558DX

Has anyone Replace these with another type?

OPA2134 or LM4562 or ??

While the Cap Upgrades are Nice...More can be Pushed with P-304
 

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If you use the LM4562, will have to pay attention to PS decoupling to avoid oscillation since it has a very high slew rate (20 V/µs) and GWP (55MHz) as compared to the 4558 (1V/µs and 3MHz). You might have less issues with the OPA2134 although its slew rate is is also high at 20V/µs, its GWP is only 8MHz. Put in a socket and you can try different op amps. If you want to use an better op amp that will very likely not require any circuit changes, you can try the 4580 (5 V/µs and 15MHz). I replaced a couple of 4558s with 4580DD and found it to be quite good, of course, YMMV.
 
Check the power supply voltages on the opamps in the preamp. If it uses +/- 18V supplies you will have to use opamps that can operate at that voltage; check the datasheet.
 
Leestereo said:
If you use the LM4562, will have to pay attention to PS decoupling to avoid oscillation since it has a very high slew rate (20 V/µs) and GWP (55MHz) as compared to the 4558 (1V/µs and 3MHz). You might have less issues with the OPA2134 although its slew rate is is also high at 20V/µs, its GWP is only 8MHz. Put in a socket and you can try different op amps. If you want to use an better op amp that will very likely not require any circuit changes, you can try the 4580 (5 V/µs and 15MHz). I replaced a couple of 4558s with 4580DD and found it to be quite good, of course, YMMV.
Click to expand...
Yes I see this...LME49860 PS:±2.5 to ±22

I have used these in Sony TA-E1000ESD and is Sounds Wonderful. I will also give 4580 a try.

dr*audio said:
Check the power supply voltages on the opamps in the preamp. If it uses +/- 18V supplies you will have to use opamps that can operate at that voltage; check the datasheet.
Click to expand...
Flat Amp: 13.1V
EQ Amp: 22.5V

I do have LME49860 so going to try these 1st since I have then on hand. I will look at some other's in the Volt range.

Thanks...
 
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CohibaJoe--
I'd be very interested in your results with these swaps. I have a couple of Onk P306RS preamps. I seem to recall they have the same 4558's installed. I read a thread about a Kenwood component that used the 4558 op-amps. The info in that thread leads me to believe better ops amps are available. I like the socket idea too. Roll different op amps for testing. Good luck and keep us posted. :lurk:
 
CohibaJoe said:
Yes I see this...LM4562 PS:±2.5 to ±22

I have used these in Sony TA-E1000ESD and is Sounds Wonderful. I will also give 4580 a try.


Flat Amp: 13.1V
EQ Amp: 22.5V

I do have LM4562 so going to try these 1st since I have then on hand. I will look at some other's in the Volt range.

Thanks...
Click to expand...
Can't use the LM4562 for 22.5V, that exceeds the maximum allowable supply voltage.
 
The
LME49860 will work for this application. +/- 23V maximum rail voltage. 20V / uS slew rate, unity gain stable, designed for audio use.
 
dr*audio said:
The
LME49860 will work for this application. +/- 23V maximum rail voltage. 20V / uS slew rate, unity gain stable, designed for audio use.
Click to expand...
You caught my mistake. Going thru my supply and seems LM4562 I was looking at last.

Thanks...
I only have (2) I have put in LME49860 on Flat Amp. Get my Mouser Order Tuesday...I did order some more..
 
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GoRNR said:
CohibaJoe--
I'd be very interested in your results with these swaps. I have a couple of Onk P306RS preamps. I seem to recall they have the same 4558's installed. I read a thread about a Kenwood component that used the 4558 op-amps. The info in that thread leads me to believe better ops amps are available. I like the socket idea too. Roll different op amps for testing. Good luck and keep us posted. :lurk:
Click to expand...
Sockets and LME49860 installed on Flat Amp Board. I will install LME49860 on EQ-Amp Tuesday (getting a order in).
 

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I had a 4558 in the preamp section of my Sony receiver. Replaced it with a 5532 which was better but replaced that with an OP275 which just blew the 5532 away. Not surprising with .0006% distortion.

Bryan
 
Any listening impressions yet for the op-amps you have installed?? About the same or noticeably better?? Your work looks nice. :yes:
 
GoRNR said:
:lurk:
Click to expand...
I checked my Mouser Order and I seem to order a different Op-amp..:yikes:

This is what happens when your working on 3 other Recaps...

In the mean time (placing another Order now)...I will hook this up and let this run for this weekend.

I know...Stay Tuned.
 
GoRNR said:
:lurk:
Click to expand...
Everthing is hooked up...Onkyo M-504.

Need All Day for burn-in...Since I had the M-504 opened I replaced my replaced Caps. Had Nichicon KZ (MUSE) and replaced with Elna SILMIC II.

For Amps...Everthing in the Sound Jumps out with Elna SILMIC II. Low's are Defined to Smooth Highs.
 
Sounds like you are hearing some improvements. So you still want to replace some more of the op amps in the P-304?? I do like the socket installation. I will continue lurking for future details when you have done more work on the Onk pre. :thmbsp:
 
GoRNR said:
Sounds like you are hearing some improvements. So you still want to replace some more of the op amps in the P-304?? I do like the socket installation. I will continue lurking for future details when you have done more work on the Onk pre. :thmbsp:
Click to expand...
I use sockets on All Op-amp upgrades.

Only 4 Op amps in P-304 and I like a Complete job...Order will be in Weds..EQ Amp is last.

Stay Tuned....:banana:
 
onwardjames said:
I have a bone stock P304 and M504.

Watching and waiting...:D
Click to expand...
Here is my Recap Thread on M-504:
http://www.audiokarma.org/forums/showthread.php?t=422094

This shows the LEDS that were used. Not may Caps for the Either P-304 or M-504. The Faceplate on the M-504 needs to be removed to replace the caps. Nichicon FG were used as SPACE is tight as Caps face forward.

P-304 is EASY and I will add the Pic's to this thread.
 
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