Go Back   Home > Forums > >

Headphone Systems Everything to do with Headphones

How to get the best out from a (or 2) TPA6120A2
How to get the best out from a (or 2) TPA6120A2
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools
Old 25th October 2020, 09:09 PM   #1
Giordano is offline Giordano  Hungary
diyAudio Member
 
Join Date: May 2005
Location: Hungary
Default How to get the best out from a (or 2) TPA6120A2

Hello,
I made several headphone amp with quite high expectation. I have one I like, it is a single ended class A tube one, but it is a monster.

Solid state ones, I did built a few and also listened a few very famous and with good reputation.
Most solid states I just did not like. Like beta22 is extremely well detailed, but also makes me tired after 10-20min. I also tested tube amp which was not my taste, easy listening, but lacks details somewhat.

I was surprised to see the Sennheiser's HDV-820 use TPA6120's. In balanced config. I did built a normal 'inbalanced' one before and I kind of liked it, but it was very depending on the PSU, (I found most headphone amp does.), tried with batteries also, the best PSU was some scrapped Agilent 6627A, which is a monster too, but I just could not make a better PSU. That time I did not hear the "superreg's".

Now I checked the HDV-820 with my source and my headphone and I have to say I was surprised and liked it. I found it very detailing while it is still not made me tired. That is the balance what my normal, 2A3 PSE amp does and fills the room and this is eaxctly what I was looking for in headphone amps + some portability, at least less than 10kg.

So now, I want to bring the best out of the TPA6120A2, with superreg and with the old monster HP6627A. I've just ordered some PCB's, it is coming.

Do you guys know more of this chip? What voltage level is the best to use (for 300 Ohm headphones)? What feedback resistor? What else, to get the best out of it?

Thanks,
JG
Attached Files
File Type: pdf TPA6120bal.pdf (261.0 KB, 123 views)
  Reply With Quote
Old 28th October 2020, 10:14 PM   #2
Andersonix is offline Andersonix  Sweden
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Marin County, California
How to get the best out from a (or 2) TPA6120A2
I bought a couple of these Chinese boards with Pavouk's layout to try, but still haven't gotten around to connecting them (sidetracked by O2 and ACP+ preamp). Plan to run one on +/-12V (maybe using Murata SR7812) and one on +/-15V using cheap TPS7A type vregs.

If you poke around there are a couple of versions using TPA6120 plus an input buffer....

But yes, at least you are on the right track about the PS being critical, and generally very expensive (10:1) relative to the actual audio circuit.
Attached Images
File Type: jpg TPA6120 chip on pcb w Pavouk schema.jpg (386.1 KB, 505 views)

Last edited by Andersonix; 28th October 2020 at 10:21 PM. Reason: meant input buffer
  Reply With Quote
Old 30th October 2020, 01:02 PM   #3
Giordano is offline Giordano  Hungary
diyAudio Member
 
Join Date: May 2005
Location: Hungary
Hello, I agree mostly, but not fully. I did tested expensive power supplies, like the beta22's "original" psu, also some fancy new super low noise regulator IC, but without success. I found the cheap old LM317/337 brings a very decent result, also a zener shunt regulator better for low power circuits.
I've also played with transformers and found it is important to under utilze the core, I mean B is about 0.8 * Bmax. Sometime I found big transformer is the best choice, but than I found, small, but under utilized (not sure what is B in English, basically more far from saturation on peaks) transformer can be even better.
Anyway, another thing, I never tried with LiPo batteries, now I will. Straight 2+2 cells without regulation. I did used others with SLA batteries, it was not bad, but the big HP lab psu was still better.
  Reply With Quote
Old 1st November 2020, 01:47 PM   #4
kn0ppers is offline kn0ppers  Germany
diyAudio Member
 
Join Date: Mar 2019
Read the Datasheets of TPA6120A2 and THS6012. They are high-speed current feedback amplifiers and the feedback resistance value plays a role in setting their bandwidth (incorrect values can cause peaking and other trouble). If you check the datasheets, the reasonable range of feedback resistor values starts somewhere around 750 or 820 Ohms with 1kOhm being the general recommendation from application examples if I remember correctly. The THS6012 datasheet is more detailed in some aspects, although the TPA6120A2 datasheet has at least one graph regarding this as well. I also don't know if the devices are 100% identical or if they have any slight differences in internal compensation.

I also might add that what Andersonix described as an Input buffer might really be the VFA part of a VFA-CFA Composite amplifier. This is probably also the way to get the most out of this chip, BUT I would strongly suggest you only follow this approach if you have access to a reasonably fast scope so you can check for oscillation. Look at datasheets, evaluation boards as well as other commercial or noncommercial implementations and strive for a compact but clean layout, no matter what approach you end up choosing.

Last edited by kn0ppers; 1st November 2020 at 01:49 PM.
  Reply With Quote
Old 2nd November 2020, 01:46 PM   #5
sgrossklass is offline sgrossklass  Germany
diyAudio Member
 
sgrossklass's Avatar
 
Join Date: Nov 2004
Location: Germany
This chip also depends on the power pad being attached to a good amount of copper for power dissipation, and if you have trouble soldering it like that you may want to turn it upside down and attach a heatsink like that instead.
  Reply With Quote
Old 2nd November 2020, 04:59 PM   #6
Andersonix is offline Andersonix  Sweden
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Marin County, California
How to get the best out from a (or 2) TPA6120A2
Quote:
Originally Posted by kn0ppers View Post
I also might add that what Andersonix described as an Input buffer might really be the VFA part of a VFA-CFA Composite amplifier. This is probably also the way to get the most out of this chip, BUT I would strongly suggest you only follow this approach if you have access to a reasonably fast scope so you can check for oscillation.
I attached the two schematics using input buffers that I've seen here at Diyaudio.
Also attached a photo of the Rubert Neve RNHP which appears to use an input buffer, along with output caps.
Attached Images
File Type: jpg TPA6120 hpa w buffer FauxFrench.jpg (177.8 KB, 443 views)
File Type: png TPA6120 amp w buffer by DontHertzMe.png (101.7 KB, 436 views)
File Type: jpg Rupert Neve RNHP inside1.JPG (146.1 KB, 434 views)
  Reply With Quote
Old 2nd November 2020, 07:42 PM   #7
bogdan_borko is offline bogdan_borko  Serbia
diyAudio Member
 
bogdan_borko's Avatar
 
Join Date: Nov 2005
I made stereo head amp in se mode with this chip and have a problem, it has 1K5 feedback resistors and 10k pot on the input, no buffer or servo. On one channel I get 250mV offset when pot is at zero and goes to 2V at input pot to max, I know the chip have high input current and offset problems but this is odd. It happens only on one part of the chip, another half have about 10x less offset. The power supply is properly decoupled like as datasheet recommends.. Any ideas?
__________________
As Below So Above
  Reply With Quote
Old 2nd November 2020, 07:53 PM   #8
BamboszeK is offline BamboszeK  Poland
diyAudio Member
 
BamboszeK's Avatar
 
Join Date: Jun 2012
Hello,
You can take a look at my composite TPA6120A2 headphone amplifier.
High performance OPA1602 + TPA6120A2 Composite Headphone Amplifier
  Reply With Quote
Old 2nd November 2020, 08:06 PM   #9
DontHertzMe is offline DontHertzMe  South Africa
diyAudio Member
 
DontHertzMe's Avatar
 
Join Date: Jul 2013
Quote:
Originally Posted by Andersonix View Post
I attached the two schematics using input buffers that I've seen here at Diyaudio.
I recognise one of those ! That amp is in daily use. Composite TPA6120 with servo HPA

Be sure to pay attention to the layout guidelines in the data sheet, especially the part about not having ground pour under the input pins.
  Reply With Quote
Old 2nd November 2020, 09:49 PM   #10
Andersonix is offline Andersonix  Sweden
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Marin County, California
How to get the best out from a (or 2) TPA6120A2
Your projects are works of art, Donthertzme!
Attached Images
File Type: jpg TPA6120 HPA donthertzme.jpg (645.1 KB, 413 views)
  Reply With Quote

Reply


How to get the best out from a (or 2) TPA6120A2Hide this!Advertise here!
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
TPA6120A2 Headphone amp or better? mark31385 Chip Amps 35 22nd April 2016 01:15 PM
Optimizing a TPA6120a2 layout 00940 Headphone Systems 9 8th May 2014 10:27 AM
TPA6120A2 with balanced crossfeed? vcelkamaja Headphone Systems 5 4th August 2012 07:16 PM
tpa6120a2 headphone amplifier steeve Headphone Systems 29 19th March 2009 07:21 AM
Looking for TPA6120A2 Odysei Swap Meet 1 2nd June 2007 08:49 PM


New To Site? Need Help?

All times are GMT. The time now is 12:42 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki