Chasing SINAD: 33 ohm at 5mW

[jasonhanjk]

This morning I'm thinking, let's say I need a good amp that can produce good results at a low power of 5mW; with my low impedance ear phone.

So I dig thru the reviews and come out with this table:

Interestingly, the Schiit Heresy and EL AMP II perform quite well in the low impedance HP. Let me sort out with a new ranking.

Interestingly, the top 4 still retain their seat. However the biggest surprise is rank 13 JDS Labs EL AMP II jump from 13 to 6.
The Atom also able to squeeze into top 10 in this category.

 

[Pdxwayne]

I bought a 30 ohm headphones recently. Bought L30 yesterday. I guess I got the #1 amp choice for my headphones. : )

 

[pozz]

This morning I'm thinking, let's say I need a good amp that can produce good results at a low power of 5mW; with my low impedance ear phone.

So I dig thru the reviews and come out with this table:

View attachment 93445

Interestingly, the Schiit Heresy and EL AMP II perform quite well in the low impedance HP. Let me sort out with a new ranking.



View attachment 93446

Interestingly, the top 4 still retain their seat. However the biggest surprise is rank 13 JDS Labs EL AMP II jump from 13 to 6.
The Atom also able to squeeze into top 10 in this category.

Did you use a tool to extract data from the plots?

 

[jasonhanjk]

Did you use a tool to extract data from the plots?

You mean my eyes.

Some older data are in % so have to convert them to dB.

 

[pozz]

You mean my eyes.

Some older data are in % so have to convert them to dB.

If you want to do it with a high level of accuracy there's this tool: https://automeris.io/WebPlotDigitizer/

Nice to see the good old Atom rank so well.

 

[jasonhanjk]

If you want to do it with a high level of accuracy there's this tool: https://automeris.io/WebPlotDigitizer/

Nice to see the good old Atom rank so well.

Wow, thanks! Let me try 'em out.

 

[solderdude]

This morning I'm thinking, let's say I need a good amp that can produce good results at a low power of 5mW; with my low impedance ear phone.

So I dig thru the reviews and come out with this table:

View attachment 93445

Interestingly, the Schiit Heresy and EL AMP II perform quite well in the low impedance HP. Let me sort out with a new ranking.



View attachment 93446

Interestingly, the top 4 still retain their seat. However the biggest surprise is rank 13 JDS Labs EL AMP II jump from 13 to 6.
The Atom also able to squeeze into top 10 in this category.

Consider that very high efficiency IEM's usually have a very low power rating and a low impedance.
Many of the amps above can do 1W or so.
Power rating is just a few mW and when these IEM's are not in your ear (yet) or accidentally the power is turned up your IEMs may be blown up.
Consider, for these types of headphones a passive attenuator of say -20dB.

This will...
A: Increase the noise part of SINAD by 20dB !
B: Get your amp in a 'better' functioning range.
C: Protect your IEM from accidentally blowing it up.
D: Get you a more usable volume control range.

 

[pozz]

a passive attenuator

For example: https://www.audiosciencereview.com/...asurements-of-ifi-ear-buddy-and-iematch.4707/

 

[jasonhanjk]

Update on 15th Nov 2020.

 

[raistlin65]

Wonder which dongles fit in the list?

 

[jasonhanjk]

Wonder which dongles fit in the list?

I just checked this morning, sinad too low for top 15.

 

[raistlin65]

I just checked this morning, sinad too low for top 15.

I know the HIDISZ S8 has impedance auto sensing. So I'm wondering if Amir's equipment was measuring it in high gain or low gain when doing his 33 ohm measurements?

 

[jasonhanjk]

I know the HIDISZ S8 has impedance auto sensing. So I'm wondering if Amir's equipment was measuring it in high gain or low gain when doing his 33 ohm measurements?

https://www.audiosciencereview.com/...dizs-s8-usb-c-headphone-adapter-review.10823/

He did mention truncated to 16 bits. I will update the spec if there's new data for the low power Sinad.

 

[jasonhanjk]

Consider that very high efficiency IEM's usually have a very low power rating and a low impedance.
Many of the amps above can do 1W or so.
Power rating is just a few mW and when these IEM's are not in your ear (yet) or accidentally the power is turned up your IEMs may be blown up.
Consider, for these types of headphones a passive attenuator of say -20dB.

This will...
A: Increase the noise part of SINAD by 20dB !
B: Get your amp in a 'better' functioning range.
C: Protect your IEM from accidentally blowing it up.
D: Get you a more usable volume control range.

The new rank now must pass the pot test, it must exceed 5 seconds between the -20dB and -40dB range.
The Topping is out of the race.

 

[Paul Take]

What is this 5 secs pot test and why is it a factor?

 

[okok]

snr more important for amps

sorry

 

[jasonhanjk]

What is this 5 secs pot test and why is it a factor?

All data are taken from Amir's potentiometer left right unbalanced graph. He will slowly rotate from max to min and capture using AP.

For low impedance HP, the lower level of the pot is where we normally listen to. So when Amir is turning the knob, how much time does it take to travel from -20dB to -40dB. If the time is more than 5 seconds, it means I have better resolution at the low level. If it's less than 5, IEM users better don't get this.

snr more important for amps

sorry

SNR is not important for low impedance HP. A 100dB SNR base on 1V looks good on spec but it's very noisy for IEM. Good HP amp for low impedance HP should look out for -114dVB or below; 2uV.

 

[wasnotwasnotwas]

If you want to do it with a high level of accuracy there's this tool: https://automeris.io/WebPlotDigitizer/

Nice to see the good old Atom rank so well.

Interestingly, I got a second hand Atom, it does exactly as expected. Except for when I plug in sensitive IEMs- I hear the noise audibly. Not so on the L30 in lowest gain.

So I am not sure how to square this "5 second" metric with my real world experience . Unless the noise comes from elsewhere- but I doubt it- SMSL SU8 DAC

 

[wasnotwasnotwas]

All data are taken from Amir's potentiometer left right unbalanced graph. He will slowly rotate from max to min and capture using AP.

For low impedance HP, the lower level of the pot is where we normally listen to. So when Amir is turning the knob, how much time does it take to travel from -20dB to -40dB. If the time is more than 5 seconds, it means I have better resolution at the low level. If it's less than 5, IEM users better don't get this.





SNR is not important for low impedance HP. A 100dB SNR base on 1V looks good on spec but it's very noisy for IEM. Good HP amp for low impedance HP should look out for -114dVB or below; 2uV.

I get that the time taken to get from -20 to -40 indicates how much "room" you have on the pot - but I dont get how I have more resolution at , say -30 (as a fixed point on any knob) on amp A vs amp B just because it takes longer to get there. But I'm not great at understanding such things

 

[pozz]

Interestingly, I got a second hand Atom, it does exactly as expected. Except for when I plug in sensitive IEMs- I hear the noise audibly. Not so on the L30 in lowest gain.

So I am not sure how to square this "5 second" metric with my real world experience . Unless the noise comes from elsewhere- but I doubt it- SMSL SU8 DAC

I used Final Audio E3000 IEMs with the Atom without problems.

What kind of IEMs do you have?