[lordearl]

Does anyone have much experience with this chip?

I'm comparing a headamp with this chip (MGL mini DACPre) and the discrete circuit which ships with the Audio-GD Compass. Would a cheap discrete circuit like this compete with the TPA6120?

 

[peranders]

I have. The TPA6120 is ultrafast and have ultralow distortion and is very current capable. If you google qrv07 you can find much info.

Please notice that the IC is a current feedback opamp which means that it's quite different than plain voltage feedback ones. The bandwidth is controlled by the feedback resistor value, not the gain and you can't apply the same theories for feedback as for voltage controlled devices. What you have to do is to study the subject in order to succeed. An another thing is the 12 uA input bias current which can cause real troubles if you don't are aware of them.

 

[peranders]

Samuel Groner has tested lot's of opamps and also some discrete ones.

http://www.sg-acoustics.ch/analogue_...distortion.pdf 374 pages!

 

[peranders]

Quote:

Originally Posted by lordearl /img/forum/go_quote.gif Would a cheap discrete circuit like this compete with the TPA6120?

It depends what you are after. If we talk electrical performance ans size it has probably zero chance to compete but if you count in other parameters it's possible such as "it a discrete solution" (discrete solutions sounds better than integrated ones). Personally I'll doubt very much if a cheap solution can compete at all with a high class opamp.

 

[FallenAngel]

I have heard good things "of" it, but not anything designed around this chip itself. It does look like it measures wonderfully though basically needs an opamp input stage to feed it and because of the FOTM status, the LM4562 (aka LME49720) seem to have been decided as a nice input stage.

I would love to hear a design based on this, just haven't had a chance to yet.

 

[peranders]

You are right about the input conditions. The TPA will have problems working properly if the input isn't driven with low impedance. I have tested OPA627, AD8610 and OPA134, all three sounding very good with or without my class A option on the board.
Details from my design where the PowerPad has 18 vias in order to get good cooling. You can also the that the groundplane is removed under the input in order to reduce stray capacitance.

 

[lordearl]

Well I probably should have posted this in the amp discussions section as I'm certainly no DIY guy. I tried to build some AIKIDO boards and ended up scorching most parts of my house and ruining the boards.....

What I'm looking to compare are two amps, one with discrete opamps which has been reviewed extensively (Audio-GD Compass) and the MGL Laboratories Mini DACPre, which is not been reviewed at all but uses the TPA6120.

The TPA6120 is my favourite opamp (based on a limited exposure and which I have primarily compared with the OPA627) for use with K701s, and so on one hand I'd like to stay with familiar territory. But the Compass is cheaper, and uses discrete circuitry which might sound better but could also be more unreliable.

If anyone is aware of technical reasons as to which would be better, would be great to hear.....

 

[peranders]

The TPA is fast, you could call it extremely fast and this requires a good pcb in order for the TPA to work at it's best. Other opamps are not so demanding in this repsect. The TPA runs also rather hot unloaded so cooling is necessary in many cases.