I would be quite interested to hear how your upgrades go. I’m not going to attempt the resistor mod suggested by Aiyima, those resistors are just too small for my eyesight. I don’t listen at high levels so the reduced output will probably be OK for me.
I did try to swap the NE5532 opamps for LM4562NA but on power up the amp went into error mode (flashing power light, no sound). Swapped back to NE5532 and all was fine again. The LM4562NA could have been defective, though I sourced them from from a well established UK Ebay trader with good feedback. I don’t have any way to test them.
After buying & returning 3 other amps which all had far too much hiss for my new TABAQ Box with 91dB 4FE35 at my computer desk, the A04 is perfect! Mine appears to be the rev 3.1 from what I can just about see under the heatsink, so combined with the relatively low output of my UMC404HD the total available volume is a bit on the low side... however until I move out of this apartment I don't need any more 🙃
Dropped in some OPA1656 from James, did a fresh REW calibration & I'm very happy!
Dropped in some OPA1656 from James, did a fresh REW calibration & I'm very happy!
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Nice speakers
Do you know if I can power Aiyima 04 with 12v 2A adapter? I m thinking to get this one over 07. Im going to pair with some small 4" maybe 5" speakers and i listen quiet i think . I had an active speakers and once I measured how much power they draw on Digital power meter (10$) it shows around 1-1,5W usual and when i cranked it up it peaked at 5-6W max and that was enough for me Afaik 12v is the lowest acceptable voltage for the TPA3251 chip itself, so in theory it would work... however I can't speak for any sort of low voltage protection that the Aiyima may have that could lead to issues if the adapter's voltage sagged?
It doesn't seem to raise the price by that much to buy the amp bundled with a 32v adapter.
It doesn't seem to raise the price by that much to buy the amp bundled with a 32v adapter.
Nice speakers
TPA3251 performance is correlated to voltage. Seems a shame to buy a TPA3251 and then pair it with a 12v power supply. I think the typical 19v laptop power supply would be more suitable.
What performance criteria are you referring to ? I never tested (and will probably never) : does changing the input voltage affect the max output sound volume ?
Regarding sound quality, I did quick comparative tests between 24 and 28v and did not percieve any difference. I finally stayed at 24v.
Some of you have probably done more extensive testing on this topic, would be interesting to share your findings ?
Enjoy music !
Gilles.
Regarding sound quality, I did quick comparative tests between 24 and 28v and did not percieve any difference. I finally stayed at 24v.
Some of you have probably done more extensive testing on this topic, would be interesting to share your findings ?
Enjoy music !
Gilles.
Yep, 12V means you are really running low and 8R speakers will struggle, 4R less so, but obviously in both cases your max power will be limited.
Further, per spec the chip doesn't want to see less than 12V... using 12V PS means you are likely to have a bit less at the chip pins and possibly problems.
It is just me of course, but I don't see the point of using a 12V PS, eventhough you need very few power. Especialy given the low price of SMPS, you really want a bit more voltage (and a few amperes). Not saying it wouldn't work at all, biut obviously no ideal conditions
All IMHO
Claude
Further, per spec the chip doesn't want to see less than 12V... using 12V PS means you are likely to have a bit less at the chip pins and possibly problems.
It is just me of course, but I don't see the point of using a 12V PS, eventhough you need very few power. Especialy given the low price of SMPS, you really want a bit more voltage (and a few amperes). Not saying it wouldn't work at all, biut obviously no ideal conditions
All IMHO
Claude
From TPA3251 datasheet https://www.ti.com/lit/ds/symlink/tpa3251.pdf
Wide 12-V to 36-V Supply Voltage Operation
Undervoltage protection limit, GVDD_x and
VDD 9.5 V
And i dont know if it the same for Aiyima 04 but thats the numbers i found
I just found 12V 4,17A power adapter and thats 50W of power and I will see in couple of days if this is enough to run 6ohms speakers.
Wide 12-V to 36-V Supply Voltage Operation
Undervoltage protection limit, GVDD_x and
VDD 9.5 V
And i dont know if it the same for Aiyima 04 but thats the numbers i found
I just found 12V 4,17A power adapter and thats 50W of power and I will see in couple of days if this is enough to run 6ohms speakers.
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Lower supply voltage not only limits the overall output power, but also increases THD+N at the same output power.
Looking at the graphs on page 10 of the datasheet, a 36V power supply gives around 80W into an 8Ω load at 1% THD+N, while a 12V power supply barely gives 10W into the same 8Ω load but also at 1% THD+N.
The two takeaway messages from this;
- It doesn't matter how much current your 12V power supply can produce, the amp won't produce much more than ~10W per channel into 8Ω.
- The amp will sound noticeably better outputting 10W per channel into 8Ω with a 36V power supply than with a 12V power supply, because THD+N will be <0.01% instead of 1%.
The overwhelming majority of my listening is probably <5W per channel, but I would still shy away from using a 12V power supply even if it 'worked' (which it probably will).
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