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Can someone give me a better schematic for a headphone amp.

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hobbyguy

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Hi i solder a CMOY amp but it wasn't what i expect it to be, is there a amp that would give me more bass if so can i have the schematic or can you guys direct me to it. Thank you.
 
A CMOY headphones amplifier uses opamps, not power amps to drive Sehnnheiser and AKG very expensive 600 ohms headphones that completely cover your ears for excellent bass.
The input capacitor creates a flat response down to 80Hz which is poor but 16Hz is at -3dB (half power).
The CMOY output is weak when it drives cheap 32 ohm earphones.

If you want bass boost and are using cheap 32 ohm earphones then you need a circuit designed for them.
 
The bass boost circuit in the LM386 datasheet is for tiny little speakers, not headphones. It boosts mid-range frequencies and upper bass frequencies but no boost to deep bass frequencies.
 
Hi,

LM386's dont sound very good. Almost anything is better :)
 
I always thought they sounded ok and were cheap & easy. What would you suggest for a simple amp?
 
Well thanks for all the replies, but how can I find out how many ohm is my headphones.

If you have no documentation with them, or it doesn't say on them, try looking it up online if you can even tell what make & model they are.

Failing that, measure the DC resistance of one side or the other. This will be close to, but not exactly equal to the impedance in ohms. (The actual impedance will be a little bit higher than the DC resistance.)

For instance, if the measured resistance is 27 ohms, then they're probably 32 ohms, which is a common value.
 
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My Kenwood 32 ohm impedance headphones measure 17.1 ohms DC per channel.

An LM386 cheap little amplifier IC has typical distortion of 0.2% when its output is at half the power that causes clipping which is not good.
It also has noticeable hisssss.
There are many headphones circuits using audio opamps driving output transistors so they can drive low impedance 32 ohms headphones. Then the distortion is almost unmeasureable and there is no hiss.
 
So where could i buy the kit or a build one already, the circuit designed that you mention, or could i just build it my self. If so can you provide the schematic. Thank you


A CMOY headphones amplifier uses op amps, not power amps to drive Sennheiser and AKG very expensive 600 ohms headphones that completely cover your ears for excellent bass.
The input capacitor creates a flat response down to 80Hz which is poor but 16Hz is at -3dB (half power).
The CMOY output is weak when it drives cheap 32 ohm earphones.

If you want bass boost and are using cheap 32 ohm earphones then you need a circuit designed for them.
 
(LM386)
I always thought they sounded ok and were cheap & easy. What would you suggest for a simple amp?

Hi there ronv,

I didnt mean to imply they can't be used, but the sound is not very good compared with other amplifiers. I guess if they are not used at the higher power levels they might be ok, but as soon as the volume cranks up a little the distortion kicks in.
It does depend somewhat on the user's interpretation of what is good for audio and what is not, and we all know that means it depends on the user what is acceptable. With this in mind and with the cost being low, it doesnt hurt to try one of these chips and decide for oneself.
 
386 amp

Hmm. Didn't mean to whine.:eek:

It did get me to look into Hissss. So here is a 386 circuit with anti Hissss (R1, C6) and base boost (C2, R5). R2 and R3 in the schematic represent a 10K pot with the wiper going to the amplifier. Hobbyguy, I think all the parts can be had at radio shack if you are in the US. For fun, get it working without C2 & R5 and R1 and C6. Listen to it then add each pair one at a time and share your impression of the performance change.
 

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It did get me to look into Hissss. So here is a 386 circuit with anti Hissss (R1, C6) and base boost (C2, R5).
Hissss is audio from about 2khz to 20kHz. A tiny little 10pf capacitor does nothing at audio frequencies because it is a VHF radio filter (27MHz and higher).
If you reduce high audio frequencies so that everything sounds like your stereo with its treble tone control turned all the way down then you will reduce hissss.
 
That's why I ask him to compare.
If you have google google 386 hiss filter. There are several, several different values, but all above audio frequencies. Maybe you can figure it out, or if you can't we can wait for hobbyguy. If we don't hear back I'll try it out.
 
The ear is the final judge of quality. This isn't a super-expensive project, so my suggestion to the O.P. is to just build the damn thing already! You'll never know how good or bad it is by posting here. Try it and see how it works. If it isn't good enough, then look for something better.
 
If you have google google 386 hiss filter. There are several, several different values, but all above audio frequencies.
They are all used for ham radio that has no high audio frequencies so the hiss filter removes all high audio frequencies.
 
Aw, The one I looked at had a typo. 10 pf s/b 10nf. I think I would put it back at the volume control, then the effect would be kind of like loudness.. What do you think?
 
OK, and it might take a little bit long since I'm not that past on putting together every component from the schematic to a Radio shack circuit board. But thank you so much for this information ronv.

Hmm. Didn't mean to whine.:eek:

It did get me to look into Hissss. So here is a 386 circuit with anti Hissss (R1, C6) and base boost (C2, R5). R2 and R3 in the schematic represent a 10K pot with the wiper going to the amplifier. Hobbyguy, I think all the parts can be had at radio shack if you are in the US. For fun, get it working without C2 & R5 and R1 and C6. Listen to it then add each pair one at a time and share your impression of the performance change.
 
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