Infineon MA12070 Class D

[torgeirs]

My Purifi have 88.7dB and it's just to little for MA12070 I just heard when I bought the new TPA3255.
So maybe 90dB could be a good start.

Don`t know the volume played here. But the actual voltage into the speaker is quite easy to measure with a volt meter. I often get suprised how low it is.
An extra check with SPL meter often confirm the results.
70 watts into a 6 inch speaker is quite a lot stress for such a small voicecoil.
guesstimated the diameter from the dB number

 

[Solve]

70 watts into a 6 inch speaker is quite a lot stress for such a small voicecoil.
guesstimated the diameter from the dB number

Don't think so.
https://ptt.purifi-audio.com/shop/p...,5210,5211,5212,5213,5214,5215,5216,5217,7591

Sorry for that stupid long link numbers...

Linear excursion, Xlin	±9.8mm
Maximum mechanical excursion, Xmax	±14.5mm

Long term maximum power

250W

 

[mamocel]

Don't think so.

Xmax

±14.5mm

impressive for a 6.5 inch! Better than Tang Bang HP...

 

[Solve]

impressive for a 6.5 inch! Better than Tang Bang HP...

Yes you can very easy EQ the low bass without bottom out.
Just love this element!

 

[mamocel]

Indeed the MA12070 should really be limited to exploit this type of hp

 

[Solve]

Indeed the MA12070 should really be limited to exploit this type of hp

Yes it couldn't take care of it high volume but the new 3e TPA3255 is nice.
But still love MA12070 at HF as I have!

 

[mamocel]

Perhaps you should have tried the MA5332MS KSD (integrated power supply), It packs a punch and sounds better than the Pillor MA5332 card that I tried first, The treble is excellent and the bass is well controlled.

 

[Solve]

No sorry it's not same and not differential input.
I don't like the measurements I seen on those chips.

 

[torgeirs]

My Purifi have 88.7dB and it's just to little for MA12070 I just heard when I bought the new TPA3255.
So maybe 90dB could be a good start.

Think maybe you held back some important information like 15 mm xmax.

 

[ValoWaking]

My ears are my main test instrument, so you can't rely on my results. But I will get the analog one tested once I'm done with my new DAC.

Have you already measured your board? Already assembled the analog version?

 

[ValoWaking]

Looks like it has implemented a LC filter, but the 10uH inductors are more than what's recommended by Infineon.

There are no recommendation for coil induction, only says that the minimal induction must be 0.5 uH. And measuring test goes on 22uH inductors

 

[Radian]

Depending on the impedance of your speakers and cable length the sweet spot is roughly between 2uH and 5uH.
Many amp chip manufacturers got calculators or spread sheets on there sites.

 

[jmansion]

Think maybe you held back some important information like 15 mm xmax.

As far as I can see, Purifi use different terminology - and maybe you've fallen for it.

From https://ptt.purifi-audio.com/shop/ptt6-5x04-nfa-01-ptt6-5x04-nfa-01-283

Maximum mechanical excursion, Xmax	±14.5mm
Linear excursion, Xlin ±9.8m

I would expect Xmax to mean what they call Xlin, and Xmech to be what they call Xmax.
Having said that, +-9.8mm linear is not to be sneezed at.

 

[MrHifiTunes]

2 and 9 millVolt or 0.002 and 0.009 Volt can be ignored as it can be called zero offset. Probably will be even less with better filtering. I wouldn't even worry till about 20 mV just for the sake of desired "perfection" as even 50 mV won't harm a loudspeaker.

Speak0A and Speak1A should both be + AFAIK. I have the 1.3 so judgement from your 1.5 picture.

Balanced inputs are nice but less so without balanced volume control. Only if you are truly faithful you can connect a power amplifier directly to a device with software volume control. It can go well for some time, many did it ...and burned woofers. I am curious how most balanced people (I see what I did here) do this as 4 channel potentiometers are not the best. Probably relay based stepped attenuators are about the best one can build. Gustard does this in some DACs.

Unbalanced to balanced active conversion with unbalanced volume control in front of it is way easier and cheaper to realize. Better than the single cap to GND ChiFi way of doing it.

Can you explain a bit more clear please (rephrase) or even beter a picture how you connect unbalanced inputs the best way? Just to be sure I don't make any mistake. I want to do 2 unbalanced in and 4 out

 

[MrHifiTunes]

According to the manual gain can be low 19db or high 25db. How can you change/adapt the setting?

 

[poigen]

Hello all ! My CD player with 2Vpp output and MA12070 distorts the sound a little. What can be changed in the scheme?

 

[xrk971]

If the amp is set to 25dB gain, then 2Vpp in makes 35vpp output for BTL configuration. To be able to do that will require the amp’s PSU to provide 35v/2+4v for dropout on the MOSFET. So is your PSU at least 22v?

Another thing to consider is what it the speaker impedance and how many amps does the PSU provide. You could also be current clipping if driving a difficult low impedance load.

If the PSU is either voltage or current limiting the amp, you will get clipping and distortion when driving near max output.

 

[mamocel]

Hello all ! My CD player with 2Vpp output and MA12070 distorts the sound a little

If you have 8 ohm speakers with an output lower than 90db, there will be no miracle...24 volt power supply recommended.

 

[poigen]

to mamocel
power supply 19 v
speakers 4 Om

 

[mamocel]

Ok ! Try 24v !