So recently I bought a pair of cheap open back headphones, since I never experienced the "open design that allows ambient noise to seep into the ear cups. This typically creates a more immersive sound."- Open-back vs Closed-Back Headphones: Which one is best for you? - RTINGS.com
The headphones are the Superlux® HD668B Superlux HD668B Professional Studio Standard Monitoring Headphones - Newegg.com
Superlux HD 668B Review - RTINGS.com
The issue I'm having comes from using the headphones with the headphone output of my amplifier . Which is quite unbalanced for the 56Ωx2 drivers. While playing music,games,movies,etc... I have to turn the volume up past 40 on the amplifier to even get sound to come out of the headphones, and for a thrilling experience I need to turn it almost to max. I cant help but feel this is doing a number on the poor preamp section of my amplifier.
So my question is can someone please help me design a low noise, ultra linear stereo headphone amplifier that is matched to the impedance of my new headphones. I don't have any experience with designing IC amplifiers but I have soldered kits for them before. For this project I have a variable split regulated DC power supply rated at ±15v 1a. and I will be using a 1/4" TRS for the signal out. the input impedance needs to be around 50k for my sound card.
I'm really sorry if it is rude or against TOS to ask for help like this on here, if it is please just ignore my post. like I said though my IC amp circuit design leaves alot to be desired, and I hope I can find some help here.
(TL,DR) i need a headphone amplifier design that will power 56ohmx2 headphones at 300mv
The headphones are the Superlux® HD668B Superlux HD668B Professional Studio Standard Monitoring Headphones - Newegg.com
Superlux HD 668B Review - RTINGS.com
The issue I'm having comes from using the headphones with the headphone output of my amplifier . Which is quite unbalanced for the 56Ωx2 drivers. While playing music,games,movies,etc... I have to turn the volume up past 40 on the amplifier to even get sound to come out of the headphones, and for a thrilling experience I need to turn it almost to max. I cant help but feel this is doing a number on the poor preamp section of my amplifier.
So my question is can someone please help me design a low noise, ultra linear stereo headphone amplifier that is matched to the impedance of my new headphones. I don't have any experience with designing IC amplifiers but I have soldered kits for them before. For this project I have a variable split regulated DC power supply rated at ±15v 1a. and I will be using a 1/4" TRS for the signal out. the input impedance needs to be around 50k for my sound card.
I'm really sorry if it is rude or against TOS to ask for help like this on here, if it is please just ignore my post. like I said though my IC amp circuit design leaves alot to be desired, and I hope I can find some help here.
(TL,DR) i need a headphone amplifier design that will power 56ohmx2 headphones at 300mv
Use LME49720/LM4562 opamps and LME49600 buffers
https://www.ti.com/lit/ds/symlink/lme49600.pdf?HQS=TI-null-null-mousermode-df-pf-null-wwe&ts=1595067702980&ref_url=https%253A%252F%252Fwww.mouser.com%252F
Check page 10
The OPA551/OPA552 is also a good option
https://www.ti.com/lit/ds/symlink/opa551.pdf?ts=1595068200880&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FOPA551
https://www.ti.com/lit/ds/symlink/lme49600.pdf?HQS=TI-null-null-mousermode-df-pf-null-wwe&ts=1595067702980&ref_url=https%253A%252F%252Fwww.mouser.com%252F
Check page 10
The OPA551/OPA552 is also a good option
https://www.ti.com/lit/ds/symlink/opa551.pdf?ts=1595068200880&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FOPA551
Last edited:
+1 for LME49720+LME49600. The OPA1622 is good too.
You can also check out my HP-2 headphone amp: HP-2 – Neurochrome
Tom
You can also check out my HP-2 headphone amp: HP-2 – Neurochrome
Tom
Good tip on the TPA6120, they are around $8 on AliExpress 😱
The real question is: is the TPA6120 used in those amps a genuine TI part?
I've become really distrustful of buying any semiconductor from eBay or AliExpress Chineese suppliers, there are a lot of fake parts and many times you find out after you soldered it and your equipment is not working properly. The TPA6120 is around $3 in single quantities and $1.5 for 1000 units from Digikey/Mouser. I am amazed that they managed to make a PCB, add capacitors, connectors, resistors, etc... sell it for $8 and still make a profit.
The real question is: is the TPA6120 used in those amps a genuine TI part?
I've become really distrustful of buying any semiconductor from eBay or AliExpress Chineese suppliers, there are a lot of fake parts and many times you find out after you soldered it and your equipment is not working properly. The TPA6120 is around $3 in single quantities and $1.5 for 1000 units from Digikey/Mouser. I am amazed that they managed to make a PCB, add capacitors, connectors, resistors, etc... sell it for $8 and still make a profit.
Last edited:
I think you're onto the right track. Even if you buy 1k of them at TI, you'll end up paying $1.37/each just for the TPA6120. As you said, building the rest of the board and turning a profit seems doubtful at best.
You could buy the TPA6120A2 EVM from TI, though. $99. At least you get a genuine chip. https://www.ti.com/tool/TPA6120A2RGYEVM
Tom
Attachments
I just bought one, I'll report back on my findings, I forgot to mention that the $8 price includes shipping 😀 if you want it assembled just add 1 more dolar. Jeez
It would cost me more than $9 to send an empty envelope across town. 🙂 At least if the envelope contains a product (i.e. is considered a package).
Tom
Tom