Which power supply should I pair with AIYIMA A07 TPA3255 amp?

[daftcombo]

a DAC's noise is there whether it's at full blast or not.

I meant: at full blast of the amp. You wrote yourself that the noise was worse when you turn the amp knob, right?

I mean might as well delete this forum then since nothing means anything to you.

What does it mean for you that something is "twice as loud" as something else? Is it +6dB or tell me?

 

[abdo123]

What does it mean for you that something is "twice as loud" as something else? Is it +6dB or tell me?

it takes 10 dB for something to be twice as loud, a doubling of voltage is 6 dB increase, with a 29dB gain you have 28 times the input voltage so that's around 24dB to 30dB reduction in S/N of a DAC once it's amplified by the amplifier. this means that something like Topping D90SE has 100 S/N in this case. and that's the best performing DAC on this site.

The run of the mill DAC starts hissing way faster.

I meant: at full blast of the amp. You wrote yourself that the noise was worse when you turn the amp knob, right?

the noise is there whether the music is playing or not. it doesn't matter if it's 'full blast' or no blast.

 

[daftcombo]

it takes 10 dB for something to be twice as loud, a doubling of voltage is 6 dB increase, with a 29dB gain you have 28 times the input voltage so that's around 24dB to 30dB reduction in S/N of a DAC once it's amplified by amplifier. this means that something like Topping D90SE has 100 S/N in this case. and that's the best performing DAC on this site.

The run of the mill DAC starts hissing way faster.

Then you will explain why, with the same DAC, some amps can produce barely no hiss in the speakers and some a lot of hiss. I have tried the Topping D10 with the Aiyima A07 and with the Audiophonics Hypex S500NS and those were completely different stories.

the noise is there whether the music is playing or not. it doesn't matter if it's 'full blast' or no blast.

Tell me why noise increases when you turn the knob of your amp clockwise, no music playing, then.

 

[nerone]

Well, I am also searching for an amp that:
- is small like my Aiyima A07
- doesn't hiss in my speakers, like my AD18 or my Hypex S500NC
- is cheap.

my drMordor amp is small and superior to the Aiymas, I have tried it on JBl L112, Tannoy Benkerley and other speakers without hearing any sibylline.

 

[abdo123]

Then you will explain why, with the same DAC, some amps can produce barely no hiss in the speakers and some a lot of hiss. I have tried the Topping D10 with the Aiyima A07 and with the Audiophonics Hypex S500NS and those were completely different stories.

Both the DAC and the Amplifier has their own noise contribution. However, the DAC is the biggest perpetrator because its noise is amplified by the amplifier.

Tell me why noise increases when you turn the knob of your amp clockwise, no music playing, then.

because the gain of the amplifier increases, increasing the amplification means the DAC's noise is getting more amplified.

 

[Raindog123]

the noise is there whether the music is playing or not. it doesn't matter if it's 'full blast' or no blast.

In all fairness, we need to distinguish between the sources of noise. Multiple components of the system contribute to the overall output noise level (lowering total SNR). The “full blast” [of an amplifier] would not [usually] affect the internal noise of this amplifier, but will amplify (increase) the input noise — eg internal noise output by the DAC or picked up by the interconnect.

Here, simple but clear, toward the bottom.

 

[daftcombo]

because the gain of the amplifier increases, increasing the amplification means the DAC's noise is getting more amplified.

That's what I meant by "at full blast".
My concern is getting noise even when the amplifier gain is minimal, as I showed on the Aiyima A07 and Loxjie graphs: -68dB and -60dB around 100 mW respectively.

 

[abdo123]

That's what I meant by "at full blast".
My concern is getting noise even when the amplifier gain is minimal, as I showed on the Aiyima A07 and Loxjie graphs: -68dB and -60dB around 100 mW respectively.

what about quiet passages in a movie? in fact what about the noise while you're listening to anything and you have to keep the amplifier's volume knob raised?

you can't possibly play DJ while listening.

 

[Raindog123]

ecause the gain of the amplifier increases, increasing the amplification means the DAC's noise is getting more amplified

An amplifier does not know a difference between the two and equally amplifies both the useful “signal” and [input] “noise”. So, a “perfect” amplifier - the one not adding its own internal noise (whose noise figure is 0) - does not affect the system SNR. Ie, the input and output SNRs are the same, as both signal and noise are amplified equally and their ratio remains the same. The SNR is affected (lowered) when internal amplifier noise is added (amplifier noise figure is >0 [or noise factor >1]).

https://en.wikipedia.org/wiki/Noise_figure

 

[daftcombo]

what about quiet passages in a movie? in fact what about the noise while you're listening to anything and you have to keep the amplifier's volume knob raised?

You are right that DAC noise is also an issue. But in my experience, far less concerning at low volume than amp noise.
Here it is a thread about an amp, not a DAC.

 

[abdo123]

An amplifier does not know a difference between the two and equally amplifies both the useful “signal” and [input] “noise”. So, a “perfect” amplifier - the one not adding its own internal noise (whose noise figure is 0) - does not affect the system SNR. Ie, the input and output SNRs are the same, as both signal and noise are amplified equally and their ratio remains the same. The SNR is affected (lowered) when internal amplifier noise is added (amplifier noise figure is >0 [or noise factor >1]).

https://en.wikipedia.org/wiki/Noise_figure

yes but when the signal is gone ( music over , no body talking .etc ) the amplified noise jumps at you like a dog’s balls.

most people aren’t concerned by the hiss when something is playing.

 

[VanO]

Does anyone know a good affordable power supply for AIYIMA A07 amp?

I use a Drok 48v 10 amp power supply:
https://www.amazon.com/DROK-110V-220V-Converter-Adjustable-Transformer/dp/B08GFQZFC1/

 

[Raindog123]

yes but when the signal is gone ( music over , no body talking .etc ) the amplified noise jumps at you like a dog’s balls.

most people aren’t concerned by the hiss when something is playing

FYI, Just tried, again. On my two large setups, and with headphones. After the music is over, nothing jumps at me. Stays dead silent, neither at my listening spot nor ear-to-the-speaker. That’s why we are after equipment with those SNRs… And I might have some trouble with 15kHz, but I would hear 60-Hz hum and it’s harmonics fine!

(And don’t get me started about dog’s balls )

 

[VanO]

My A07 on the 48v 10 amp PS runs dead silent. I've got another one I'm setting up with the 32v 5amp brick. Im only running tweeters off of it so I don't really need the extra power. I'll post if I hear any noise from it though.

 

[daftcombo]

I use a Drok 48v 10 amp power supply:
https://www.amazon.com/DROK-110V-220V-Converter-Adjustable-Transformer/dp/B08GFQZFC1/

View attachment 148134

Don't let what's in your AC/DC mug drop on it though. It is dangerous.

 

[Deleted member 9685]

From the graph I already showed, the Loxjie will probably hiss more than the Aiyima A07.
I'm waiting to see here a test with a cheap powerful amp having -80dB noise at 100mW before pulling the trigger.

AIYIMA D03 might not hiss. I used HiFiBerry Amp2 which produced very very little hiss with Eltax Monitor 1. HiFiBerry Amp2 uses TAS amp chip.
AIYIMA D03 also uses TAS amp chip.

 

[Deleted member 9685]

That the source of noise is the amplifier, not something else.

https://www.audiosciencereview.com/...s-and-review-lm4562-and-opa2134-option.19155/ made me realize that a clean linear power supply may not necessarily increase SNR of AIYIMA A07.

But, a clean SMPS is still good to have for reasons other than noise floor.

Noise measurements – all with 30V regulated linear power supply

Noise with NE5532 was -73.4 dBV linear 24kHz BW (with the 40kHz lowpass filter as in all further measurements). This would make S/N 86.4 dB re 5W/4ohm and 101.2 dB re maximum power, which I estimated at 150W/4ohm (later).

 

[Deleted member 9685]

I'm thinking of pairing AIYIMA A07 with Mean Well LRS-350-36.

I don't know how to connect this safely to an amplifier. Does anyone have some tips on making this safe?

 

[Deleted member 9685]

I use a Drok 48v 10 amp power supply:
https://www.amazon.com/DROK-110V-220V-Converter-Adjustable-Transformer/dp/B08GFQZFC1/

View attachment 148134

If the sound source was grounded, wouldn't it be better to not ground the SMPS?

Ground loop can ruin audio signal.

 

[VanO]

I have everything that is connected to my system (including a Mac Pro, printer, etc.) going through a Furman PL-8C power conditioner and that is the only thing plugged into the wall outlet I use. I have zero noise or ground loop issues. I'm running two A07s now, one with OPA1656 op amps, the other with OPA2134s. The amps and chips are great. I'm using the 32v 5 amp brick on the other A07 to run some tweeters. I'm running Spektor 2s with Drok PS. Last night I checked for noise at high volume on the whole system and couldn't detect any.