Replacement for NE5532

Would like to replace my Denon's DCD-1500AE opamps of the NE5532 type with something better, OPA2604 and AD823 are two candidates with identical pin layouts - which should i choose? i also need a SMD version (is it called SOIC?) for my PCB, are they available in such packaging?

any other suggestion?
 

djk

R.I.P
2001-02-04 4:23 am
USA
Try a pull-down load to the negative supply rail to force the NE5532 into class A, just a few mA will really make it sound better. Use a simple resistor, or a J-fet with the IDSS trimmed to 3mA~5mA.

The OPA2604 and AD823 are both good too, how good are you at soldering SMDs? The AD823 is a bit more neutral, the OPA2604 may be more hi-fi sounding.
 
If you have NE5532 after the volume potentiometer, than exchange it with OPA2134

I'm about to install a transformer into my amplifier to convert balanced from an unbalanced signal (in order to bridge chips)... This transformer uses NE5532 chip which will be fed directly by a passive volume pot.

Can you please explain how this negatively affects the NE5532? Is it due to loss of resolution?
Thanks
 
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Bonsai

Member
Paid Member
2003-07-25 10:44 pm
Europe
www.hifisonix.com
"I'm about to install a transformer into my amplifier to convert balanced from an unbalanced signal (in order to bridge chips)... This transformer uses NE5532 chip which will be fed directly by a passive volume pot.

Can you please explain how this negatively affects the NE5532? Is it due to loss of resolution?"
________________________________________________________________

It has nothing to do with resolution.

The input bias current on the NE5532 is nominally 200nA, 1uA worst case.

If you feed a volume pot directly into this, you will probably get noise ('scratching sound') as you adjust the volume - this is because there is DC appearing across the pot due to the 5532 bias current I mentioned above. The affect gets worse the higher the pot resistance, and is also worst with cheap pots.

This issue has nothing to do with resolution or anything like that.

If your potentiometer is capacitively coupled into the input of the 5532, you will not have this problem, and this is how most designs that use this op-amp deal with the issue.

If you want a DC coupled design, then ideally you want to use a JFET input op-amp, where the bias currents at room temperature are in the pA range. The new LM4562 also has very low input bias currents, and you can safely direct couple low value pots (10k or less) into its input stage. If you go on my website below and look at the X-Altra Mini Preamp, you can see an example.

If you are using a swithed type volume control, then you CAN direct couple into the NE5532 - no problem. You just need a high value bias resistor between ground and the input pin of the op-amp to provide a bias path between the switch break before make periods. The value should be 10 times the value of your pot - so for a 10k pot, use a 100k bias resistor.

That said, the NE5532 is now over 30 years old, but it still is a very fine op-amp for audio. Take a look at Samuel Groners site, or read up in Self's latest book to see just how far ahead of its time this device was (launched in 1978!). I remain a 5532 fan - some things are great, no matter how old.
 
This has been covered in a lot of threads. The 5532 sounds pretty bad but better than most of the opamps which are just plain terrible. Try an NJM2068. Straight drop in and sounding much better.

As a suggestion, you should have searched the forums to find these answers because of the many threads discussing this subject. Search first, ask second.
 
Schematic with NE5532

So here's the schematic - would LM4562 work ok in this circuit? would very much like to get it right from the first attempl, since devices are SMD-type and i don't believe i can do much de-soldering / re-soldering without damaging the pcb...
 

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If you like you must excange all the opamps. Put the JFET's opamps. OPA2134 it is an ideal for you in that configuration. You don't need to modify the power supply, it is possible to be stable without another caps. In that schematic, you have a lot of series resistance , like 820 ohm, and that will rise up the source impedance. It is not good for the input signal currents of the BJT's opamps like 5532's. So, you can exchance it with OPA2134 wich has a huge input impedance. Don't put there a too fast opamp, one with slew-rate of 20V/us it is perfect.
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
How to work on smd without special tools,
http://www.diyaudio.com/forums/parts/127924-working-smd-how-do-without-specialised-tools.html

The LM4562 would work perfectly, so to the OPA2604, both of which are available in SMD. The 2604 remains a personal favourite for me.

Also read post #9 here.
http://www.diyaudio.com/forums/digi...ication-eliminate-distortion.html#post2254391

Replacing of the mute transistors with FET's is something you might consider. These are TR108 and TR109. You can run the player with these disconnected too, to see if you can detect any difference.
 
HELLLPPPPPP

OK I'LL TRY TO POST SCHEMS..
I'M HAVING TO CHANGE SOME INPUT AND FEEDBACK RESISTORS( VENDOR SPEC ECO CHANGE) and I need to get gain structure more in line with preamp.

I need help in 2 areas.. which SMD resistor to buy and ne5532 and tlo74 replacements

1) Resistor SMD work is no problem but there are many type SMD resistors..which ones are the "best" and How do I know between types which one to get esp for signal path resistors.

2) Ne5532 and tl074 are going(i have to cut 2 out to get to other stuff on the board and I'm not going to try to unsolder a $2 chip and wreck a board.

I was thinking 2134 for TL and 4652 for the 5532 or just throw in all 2134?

it seems I would need to decouple the 4562 with some caps but I like the specs on that booger! I can't find much info on sound but it is the main line drive for the amp. I need sumin good here.. 627 on browndog?? thanks I seen more info here than I been able to find elsewhere Digikey and Mouser r my friends!
 

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I was thinking 2134 for TL and 4652 for the 5532 or just throw in all 2134?
no !
don't throw anything in.

Each opamp has a job and a particular specification chosen to suit that purpose. The circuitry around each opamp should have been implemented such that the opamp had a good chance of performing well.

You must consider each opamp and what parameters/characteristics are needed to get that particular opamp to do it's job effectively. Then you must consider what circuitry is needed around that opamp to get adequate performance from it.

After you have done this for all 3 opamps, you may find that different opamps should be used for each stage. Problem !!! how can a dual smd opamp be replaced with a pair of single smd opamps?
 
CLARIFICATION gearhead needs sparky

OOPS.LET ME CLARIFY.. OK I KNOW JFET/BIPOLAR SINGLE AND DUAL..
I'm a gearhead(BSME) and know which end of a solderingis hot. Take a look and maybe help me out. Let me post the updates..... resistors 247,245,271,269 get changed form 4.75K to 4.22K.(not sure why) There is a problem with R240 and R239. I don't know how to do opamp gain calcs but these resistors switch in for balanced/ unbalanced connection and it leaves a gain hole hole in the gain structure< right where my preamp puts out>, so I need to change those also. Since (1) 5532 and (1) Tl074 in the crossover section had to be yanked, to get to some other stuff. I was just going to replace them with something "better" if it would work electrically without too much work. Hence the need for a sparky. I was told that the circuit would support 2132 and 2134 as just a drop in. I think it supplies +-15V for the opamps and I have about 1A to drive them (according to manufacturer). You can replace duals with a browndog SIOP8 single/dual adapter, but the 627 requires bypass caps(from what I have read) and I think the 4562 would too, but have not clue how to figure that out, or where to put them. I know the 4562 looks great on paper like a 5532 on steroids. I do know from reading self, jung, curls and other that noise, slew rate and settling time are big factors in spec sheet performance. that's why I was curious about the 4562. decent slew rate, super low noise, and very fast settling time. Now who knows what it will sound like(omg lets not get into that again) Thanks ya'll for taking the time to read my ramblings.
 
TBH that circuit looks just fine for a '5532. Inverting (which eliminates several major distortion sources), not an awful lot of gain or loading. Measurable improvements, maybe, audible ones, hell no.

I would rather look into installing some bypass caps for the "no_use" parts (C4233 et.al.), and C4226 et.al. seem like a skimpy beancounter's choice as well (10µ / 25V+ bipolars would be more appropriate).