My very first headphone amp

[ClieOS]

I got the PCB broad for cmoy2from sgheadphones, so i spent the better half of three day getting all the best part i can find and solder my very first amp.

I replaced the orginal opa2227 with a pair of op270ez, but keep them inside the same case so i can interchange them as i wish

I found the poker case perfact for me...in my opinian...

Sorry about the popup from picture, but i don't really have a place to host picture...

[FallenAngel]

It's a cute case, but there is a section to post pics of your builds where this should go, and guess what, it's called "Post pics of your builds".

[splaz]

Didn't have to be so rude. This is a milestone deserving of it's own post.

A milestone on a long path that you will walk with holes in your pockets.

These holes are just the right size for money to fall out of...

And by holes I mean projects and by fall out of I mean spend on.

[Andrea]

Congrats, it looks good!!


That improved cmoy design should perform very well...

[mrarroyo]

Congratulations!

[mb3k]

Congrats on the build. I've got some CMOY2 PCBs also coming in the mail.. Would you mind PM'ing me your BOM?

[ClieOS]

I decided to change the op270ez to op270gpz as it run a little bit too hot...a mistake when i order the part. The new ic should handle better on larger current. Now i will stick to opa2227.

While using opa2227, it is very difficult for me find any difference it from my Mint but it does drive a wide sound (and Mint is a little muddy). With op270 the mid and bass range stand out more clearly and give a warmer sound, and it seems to be the only one able to drive my philips hp400, much better than Mint and cmoy (very large difference).

Beside op-amp, the only change i made is to increase the gain from 2 to 3.(10k resistor on R2 and R6 to 20k)


Here is the part i got from Farnell online(part#, quantity,Manufacter#,item des.), got my switch and socket locally.

9341145 50 MF25 10R RESISTOR, 0.25W 1% 10R; RoHS Compliant:YES; Resistor element type:Metal Film; Resistance:10R; Case style:Axial; Power rating:0.25W; Tolerance, +:1%; Tolerance, -:1%; Temperature, operating max:155°C; Temperature, operati

9497994 10 RC55C-10K0DI RESISTOR, 0.25W 0.5% 10K0; RoHS Compliant:YES; Resistor element type:Metal Film; Resistance:10.0kR; Case style:Axial; Power rating:0.25W; Tolerance, +:0.5%; Tolerance, -:0.5%; Temperature, operating max:155°C; Temperatur2

9501061 4 RC55Y 20K 0.1% RESISTOR, 0.25W 0.1% 20K; RoHS Compliant:YES; Resistor element type:Metal Film; Resistance:20kR; Case style:Axial; Power rating:0.25W; Tolerance, +:0.1%; Tolerance, -:0.1%; Temperature, operating max:155°C; Temperature,

919639 1 290070 POTENTIOMETER, 50KA; Resistor element type:Variable Rotary Carbon; Resistance, track:50kR; Power rating:0.05W; Angle, rotation mechanical:300°; Diameter, shaft:6mm; Depth, external:11.35mm; Length / Height, external:9.55

3323791 2 OPA2227PA. IC, OP-AMP DUAL LOW NOISE; Amplifier IC type:Operational; Amplifiers, number of:2; Voltage, supply +nom:15V; Bandwidth:8MHz; Voltage, input offset max:200µV; Slew rate:2.3; Temperature, operating max:85°C; Temperature, o

9493611 1 LM6171BIN IC, OP-AMP LOW POWER; RoHS Compliant:YES; Amplifier IC type:Operational; Amplifiers, number of:1; Voltage, supply +nom:15V; Bandwidth:100MHz; Voltage, input offset max:8mV; Slew rate:3600; Temperature, operating max:85°C

1006040 5 MKS2 1UF +/-10% 63V CAPACITOR, 1UF 63V; RoHS Compliant:YES; Capacitance:1µF; Voltage rating, AC:40V; Voltage rating, DC:63V; Capacitor dielectric type:Polyester; Tolerance, +:10%; Tolerance, -:10%; Temperature, operating max:100°C; Temperat

9691855 3 EEUFC0J102 CAPACITOR, 1000UF 6.3V; RoHS Compliant:YES; Capacitance:1000µF; Voltage rating, DC:6.3V; Capacitor dielectric type:Aluminium Electrolytic; Temperature, operating max:105°C; Temperature, operating min:-55°C; Tolerance, +:

1057120 1 NSPB500S LED, 5MM R 15DEG BLUE; RoHS Compliant:YES; Colour, LED:Blue; LED / lamp size:5mm/T1.3/4; Luminous intensity, typ:3000mCd; Wavelength, typ:470nm; Angle, viewing:15°; Current, forward If:30mA; Voltage, Vf typ:3.6V; Case

9475443 10 PR02-680R 5% RESISTOR, PRO2 5% 680R; RoHS Compliant:YES; Resistor element type:Metal Film; Resistance:680R; Case style:Axial; Power rating:2W; Tolerance, +:5%; Tolerance, -:5%; Temperature, operating max:155°C; Temperature, operating

9502734 2 RC55Y 715R 0.1% RESISTOR, 0.25W 0.1% 715R; RoHS Compliant:YES; Resistor element type:Metal Film; Resistance:715R; Case style:Axial; Power rating:0.25W; Tolerance, +:0.1%; Tolerance, -:0.1%; Temperature, operating max:155°C; Temperature,

662320 1 16H-2D-A KNOB ALUMINIUM 16MM; Colour:Natural; Depth, external:14mm; Diameter, knob:16mm; Diameter, shaft:0.25"; Material:Aluminium

[ClieOS]

After more testing, i figure out the problem is not on the op27ez heat, but ruther it power consumption. it took so much power to drive, a 9v battery die in a few (<10) hours ... (compare to opa2227's 20+ hrs). i think i will keep op270ez for now , and switch it when i dont need to drive bigger headphone.

[kramer5150]

Wow, Nice job.

definitely worthy of your own thread. From my recollection the 2227 is a major energy - miser. At least in my govibe that was the case.

[spraggih]

Congratulations. Less than 10 posts and you already have an amp! At this rate, I would expect by your 100th post you will have an Orpheus set-up.