CMoy with other Chips

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I am new to this field. I like to build a CMoy headphone amp but could not find any OPA (BB) chip in my local market (I am from a sounth Asian country). However, I got NE5532 chip. Can i build a CMoy amp with NE5532? Can anyone kindly give me a schematic to build a CMoy amp with NE5532. I will appreciate any help in this regard. Thank You all.
 
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I am new to this field. I like to build a CMoy headphone amp but could not find any OPA (BB) chip in my local market (I am from a sounth Asian country). However, I got NE5532 chip. Can i build a CMoy amp with NE5532? Can anyone kindly give me a schematic to build a CMoy amp with NE5532. I will appreciate any help in this regard. Thank You all.

Yes, you can. But you should use 600 ohm headphone to get distortion low. If you use headphone impedance below 600 ohm, you can add buffer after NE5532.
 
I added a simple op amp headphone driver to a mobile disco setup I used to own.
I put a 100R resistor on each channel output so I could drive 8 ohm headphones.
It wasn't deafening but it was loud enough above the disco to be recognisable.
I used the headphones for setting up the next track to play.

If you dont want to add resistors then a high impedance headphone will be required.
 
It's the nature of the CMoy design - the less-than-optimal loading of the op amps with low-impedance headphones. That sacrifice in return for simplicity and portability. I say give the 5532 a try. The CMoy is, at its core, a textbook op amp circuit. I don't think the schematic needs to be modified.
 
Yes, you can. But you should use 600 ohm headphone to get distortion low. If you use headphone impedance below 600 ohm, you can add buffer after NE5532.

Or just add as many more NE5532s in parallel (with sharing resistors) until you've got enough drive. Look up Doug Self's poweramp design (for Elektor magazine) using NE5532s - that's good for driving 8ohms. Start with that and delete some of the paralleled opamps according to how low an impedance you need to drive.
 
A '5532 should be a good drop-in replacement in a cMoy, actually I would trust its output loading immunity rather more than the original OPA2134's. Maximum current output is about the same.

The amplifier shown here makes use of the JRC NJM4556 opamp, an inexpensive part already designed with headphone use in mind 30 years ago and unsurprisingly still a good performer today - it can basically even do without extra output series resistance, which is not recommended for the '5532. The circuit shown also implements a proper split voltage supply rather than the standard cMoy's rather loose virtual ground (if you use 220 µF buffer capacitors in that one, it's about the equivalent of having 75 µF coupling capacitors on the output).
 
Thank you so much for your comment. As i said, i am a beginner in this field and i have NE5532 chip in my drawer not any OPA chip. Will you please show me a schematic that i can follow blindly with 5532 chip. I am very eager to make a good sounding headphone amp. In my local market there is no OPA chip. Thank you once again.
 
The good thing about the opa2134 in the original cmoy being that it is a jfet opamp... and the Cmoy is made ONLY for JFET opamps. You cannot use the ne5532 as a "drop-in" substitute as it is a bjt input opamp with much larger input bias currents.

You need to adapt the schematic, otherwise you will get massive dc offset and a completely unbalanced rail splitter. A quick run through spice gives me 550mV of offset. With that much offset, you're pushing a lot of current into a low impedance pair of headphones. Which means that you're unbalancing the rail splitter so much it will collapse.

See for basics :
Working with Cranky Op-Amps
Virtual Ground Circuits
 
(if you use 220 µF buffer capacitors in that one, it's about the equivalent of having 75 µF coupling capacitors on the output).

No (unless I misunderstood what you mean). Here's a quick sim. On the right, there are two channels sharing a rail splitter. Worse case since they draw exactly the same current. It's at 20hz. On the left a conventionnal amp with a 75uF coupling cap and perfect supplies. 32R loads for both.

In red, the output of the cmoy. In green, the output of the 75uF coupled amp....
 

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That's not a standard cMoy circuit though. Try the same with the usual 4k7/1k feedback network, referenced to vGnd just like the volume pot. (I'd move the ground node to vGnd and introduce a negative supply instead.) BTW, a 9V @ 45 ohm Vsource seems more realistic for a standard 9V battery.

But yes, DC offset may in fact prove a tad on the high side especially when using a run-of-the-mill TI NE5532 (Ib 500 nA typ would mean ~285 mV @ Gv = 5.7). Nothing terribly unfixable, mind you (things should be a lot more acceptable with a 22k input resistor and a 4556, even more so when going capacitor-coupled for the feedback network's ground leg), but you're right, it's not a drop-in replacement.
 
Oops, you're right, got abused by the simplified sim.

Two things though:
- The problem is highly dependant on feedback values. There's a good case to be made to keep gain as low as possible. With a gain of 2, the classical cmoy is more than competitive capacitance wise vs a single rail setup.
- The problem of the cmoy is highly varying depending on the loading of the two channels. If there aren't sharing the same signal, the rail splitter doesn't get as unbalanced and it's more effective than an output cap.

Btw, a 9V duracell alkaline is 2r fresh, 4r when getting old. So 15V-10R is actually pretty harsh to sim a dual battery setup.

edit: point 2 is a problem too... different signals lead to intermodulation, especially at LF.
 
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- The problem of the cmoy is highly varying depending on the loading of the two channels. If there aren't sharing the same signal, the rail splitter doesn't get as unbalanced and it's more effective than an output cap.
Unfortunately low-frequency content tends to be pretty much equal in L and R, while demanding the highest powers.

This phenomenon would seem to be related to the question of power bandwidth in speaker amplifiers.
Btw, a 9V duracell alkaline is 2r fresh, 4r when getting old. So 15V-10R is actually pretty harsh to sim a dual battery setup.
9 V blocks are better than I thought. I found a datasheet for a Duracell Ultra AAAA cell, says 250 mOhms at 1 kHz - that would be 1.5 ohms for 6 of 'em. I wouldn't be surprised if carbon zinc were an order of magnitude worse though. And who knows about cheapie alkalines...

I had merely estimated things very roughly before - Rsource = Vunloaded (9 V) / Ishort (200 mA). In practice, I guess results will depend not only on charge state, but current draw and frequency as well (since battery chemistry tends to be notoriously slow). Nice mess right there.
 
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