Budget power/stepped amplifiers?

[Sokel]

Bypassed Purifi + ADI-2.
Go for it,peace of mind has no price.

 

[CDMC]

I suppose OP is still hung up on SINAD and noise... as well.

Based on their posts in this thread hangups about SINAD and noise are probably the least of the OP’s hangups.

 

[Deleted member 58865]

Based on their posts in this thread

You mean my posts?

 

[Deleted member 58865]

It is not needed at all.
He just needs an amplifier with a decent volume control and possibly a balance control.
OP just had a bad experience with the volpot on his cheap Aiyima.

Technically, yes. I'm just entertaining the idea of stepped amplifiers for fun. In practice, a schiit power amp is good enough.

I'm just thinking that stepped amplifier design should be common and cheap.

 

[Deleted member 58865]

I suppose OP is still hung up on SINAD and noise... as well.

I don't yet know how much dynamic range is good enough. Maybe, SINAD above 80dB is fine?

 

[solderdude]

Technically, yes. I'm just entertaining the idea of stepped amplifiers for fun. In practice, a schiit power amp is good enough.

I'm just thinking that stepped amplifier design should be common and cheap.

It isn't needed at all for speaker amps. A connected amp only needs to have a decent to good volume control.
The one on your Aiyima is not a typical one but it is cheap.

I don't yet know how much dynamic range is good enough. Maybe, SINAD above 80dB is fine?

Most amps and DACs will have a dynamic range that exceeds your hearing by far. It really is nothing to worry about.
SINAD is not the same as dynamic range b.t.w.
As long as you cannot hear noise from the speakers when no music is playing the dynamic range already exceeds that of your hearing.
Besides the dynamic range of most pop recordings is very limited anyway.

 

[Deleted member 58865]

Most amps and DACs will have a dynamic range that exceeds your hearing by far. It really is nothing to worry about.

As long as you cannot hear noise from the speakers when no music is playing the dynamic range already exceeds that of your hearing.

I don't want to find out that my speakers have hiss and distortions after spending hundreds of dollars. I want to know in advance by looking at some numbers before pulling the trigger.
For example, with efficient speakers in a dead quiet room, even 80dB SINAD may not be enough. When 80dB SINAD amp is not enough, I guess you can look into Schiit Rekkr for near-field listening.

As you wrote, in most cases, it is nothing to worry about. In some cases, it is. I don't want to rely on blind luck and hope that my new setup doesn't bother me with noise and distortion.

So, what I really need is some knowledge to "quickly" predict whether noise and distortion will be audible without spending hundreds of dollars.

There are actually cases where people hear noise and distortions. I used to live with extreme amounts of noise and distortions. That's why I'm still a little bit obsessed with measurement numbers.

 

[solderdude]

Your speakers do not hiss.

For example, with efficient speakers in a dead quiet room, even 80dB SINAD may not be enough.

It will be more than enough. SINAD is NOT the same as S/N ratio and it says nothing about the audibility of distortion, harmonic spectrum, noise levels and how much distortion there is at any given output level.

So... even a SINAD of 60 can be noise free and sound fantastic. It literally says NOTHING about the sound quality.
SINAD can be an indication for 'technical signal fidelity excellence' if the numbers are high. That's really all that it is good for. It merely shows THD + noise with a 1kHz stimulus to a specific level. Nothing more, nothing less.

You need an amp with a good S/N ratio, capable of driving the rated impedance of your speakers and has a good volume control.

 

[Deleted member 58865]

So... even a SINAD of 60 can be noise free and sound fantastic. It literally says NOTHING about the sound quality.

Distortions are inaudible because the speakers are inefficient? Or, my ears are insensitive? Or, what?

Maybe, SINAD was measured at low volume levels? That's why SINAD is low?

I'm open to the idea of euphoric distortions as many people like the sound of tube amps. But, I don't want to study what kinds of distortions sound good. I don't want to go that deep. For simplicity, I would just aim for clean transparent sound. Higher SINAD and SNR mean simplicity. Figuring out whether a 60dB SINAD amp sounds good requires some study if I don't have enough money to experiment with various products.

 

[Deleted member 58865]

You need an amp with a good S/N ratio, capable of driving the rated impedance of your speakers and has a good volume control.

SINAD is not going to be higher than SNR. So, if SINAD is high, SNR is going to be high, too.

How much SNR is good enough? Ideally, 96dB. But, I can live with lower if it is good enough.

 

[solderdude]

Distortions are inaudible because the speakers are inefficient? Or, my ears are insensitive? Or, what?

Ears cannot detect distortion that well. There are plenty of online tests where you can test your hearing.
Distortion limits using music can lie between 1% (-40dB) and 0.03% (-70dB) depending on the type of distortion and recording.

Maybe, SINAD was measured at low volume levels? That's why SINAD is low?

Forget SINAD. It is just a metric with a limited 'value'.

I'm open to the idea of euphoric distortions as many people like the sound of tube amps.

Audible amounts of 'euphonic' distortion always go together with InterModulation distortion which can be anything but euphonic.

But, I don't want to study what kinds of distortions sound good. I don't want to go that deep. For simplicity, I would just aim for clean transparent sound. Higher SINAD and SNR mean simplicity. Figuring out whether a 60dB SINAD amp sounds good requires some study if I don't have enough money to experiment with various products.

SINAD is not going to tell you anything. The only thing it can tell you is what distortion at 1kHz is present opposite a specific level.
The higher the number the lower the distortion (and/or noise) but it does not tell you anything about IM distortion at high frequencies nor about frequency response.
A low S/N ratio is always desirable but the spectrum of the noise is even more important.

SINAD is not going to be higher than SNR. So, if SINAD is high, SNR is going to be high, too.

No... you can have a S/N ratio of -120dB and a SINAD of 60 and it will sound just fine and noise free.
You can have distortion as low as -100dB and a terrible amount of noise at -60dB and SINAD will be 60. It will sound noisy as f#k. Distortion products will be drowned in noise.

 

[Deleted member 58865]

So, SINAD measures a specific kind of distortion at 1kHz. It doesn't measure all kinds of distortions across all frequencies.

Then, what measurements do I want? SNR number and a distortion graph? What numbers should I consider good enough?

 

[Deleted member 58865]

Audible amounts of 'euphonic' distortion

Yes, euphonic. My english still needs working.

 

[Deleted member 58865]

I turned the aiyima a07 volume pot to the max position and set DAC volume to -90dB. I could still hear something when I play audio.

It seems SNR is higher than amir's measurement? Or, my AC power is cleaner than amir's AC power? By the way, I try to keep my house wires as free from noise as possible.

At -96dB of DAC volume, audio is barely audible, but I can feel something from speakers.

Maybe, I have to add amplifier's gain to the DAC volume?

 

[solderdude]

So, SINAD measures a specific kind of distortion at 1kHz. It doesn't measure all kinds of distortions across all frequencies.

Yes, only harmonic distortion (not IM) at 1kHz and at a specified level. That could be near 'max. power' or a specific voltage.
Distortion could be different and the distortion spectrum (how high each harmonic is) and IM distortion is not reported in SINAD and matter a lot.

Then, what measurements do I want? SNR number and a distortion graph?

You need to understand all measurements in a review and understand the possible consequences when combined with the speaker/headphone you own/use and your listening habits. This requires knowledge about measurements, hearing thresholds and maybe even some basic psycho-acoustics.

What numbers should I consider good enough?

start here: https://www.audiosciencereview.com/...-thresholds-of-amp-and-dac-measurements.5734/

Or, my AC power is cleaner than amir's AC power?

AC power 'quality' should not matter one little bit on your gear.

It seems SNR is higher than amir's measurement?

S/N ratio is opposite a specified signal level.
There is a difference between hearing 'something' and listening to music.
When you 'test' this late in the evening or when coming in from a working day or from a busy street you hearing limits can differ a lot.

By the way, I try to keep my house wires as free from noise as possible.

How would you do such a thing ?
Mains filter each and every device in the home ?

 

[Zek]

It seems SNR is higher than amir's measurement?

How can you know that when you don't have the measuring equipment to measure it?

Maybe, I have to add amplifier's gain to the DAC volume?

What does this mean?

 

[Deleted member 58865]

How would you do such a thing ?
Mains filter each and every device in the home ?

I replaced active PFC computer power supply with a passive PFC one. Active PFC in most computer power supplies creates a lot of differential-mode noise in the entire house. I also replaced a monitor that has a DC jack with a monitor that has an AC inlet which grounds its own noise through the AC cable instead of HDMI cable. Grounding monitor's noise through HDMI cable injects a lot of EMF noise into the entire computer system. I could just buy an actually grounded DC power supply, but I could not find a grounded 19V DC power supply easily.

I also replaced all fluorescent lights with LED lights and removed smart devices in my home.

Passive PFC power supply and LED lights decreased differential-mode noise a lot. But, I don't have a way to measure common-mode noise other than a portable AM radio. Maybe, I should attach a common-mode choker somewhere in the main breaker panel.

I may purchase a whole-house dirty electricity filter that I can attach to the main breaker panel if I have more money.

 

[solderdude]

The cheaper LED lighting can give much higher 'mains pollution' than FL.

Differential noise is NOT an issue because all AC is converted to DC for all AV gear. That removes any differential noise anyway.

The whole 'clean mains power' thing is highly over rated. Audio equipment should be immune to that anyway when somewhat decently designed.

I have NO extra filters anywhere in the house nor any audio equipment. It might only be needed for really problematic mains (far away from the street transformer) and depending who and what else is connected to any wiring connected to that street transformer.
The last few meter after the breaker box is not going to change much.

 

[Deleted member 58865]

How can you know that when you don't have the measuring equipment to measure it?

I have my ears?

What does this mean?

AIYIMA A07's gain is reportedly 21.5dB. If I set DAC volume to -21.5dB, net gain would be 0dB. If I set DAC voulme to -91.5dB, the net gain would be -70dB.

The cheaper LED lighting can give much higher 'mains pollution' than FL.

At least, my LED lights reduced differential-mode noise by a ten~hundred fold, compared to compact fluorescent lights.
Are audio gears affected a lot by common-mode noise if they are almost immune to differential-mode noise?

 

[Deleted member 58865]

I have NO extra filters anywhere in the house nor any audio equipment.

Neither do I. I just have passive PFC power supply and LED lights and a monitor with an AC inlet. I think it's just good to reduce a lot of electrical noise if I can do so without spending a lot of money, energy, and time.

The best way to reduce noise is to eliminate a lot of it at the source without any filter. I implemented the source solution.