Driving low impedance, 9 ohm iem's with DAC/AMP recommended minimum of 16 ohm's
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reg66

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Quick question guys, sorry for being a noob. I have on order a Lotoo PAW S1 DAC/AMP that is yet to arrive. I have just taken delivery of my Audiosense T800's (9 ohm) and have a Cyrus Soundkey (minimum of 16 ohm) to tide me over for the mean time. Question is;
1. I just want to check I won't damage anything trying the combo (I think if anything, if there's not enough power they'll just sound pants, right?)
2. The Soundkey has 2 x 138mW into 16 Ohms at 1% THD+N, do you think that'll be enough for my 9 ohm iem's or shall I just try it and see what the pairing sounds like, assuming (1) it won't damage anything.
3. Do any experts know if the output is 2 x 138mW into 16 Ohms at 1% THD+N, what sort of mW am I looking at with 9 ohms? I have seen online calculators but I don't really get them without further reading and I wan't to try these iem's pronto!!!
The T800's have sensitivity of 90dB if that helps...
Thanks
 
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Quick question guys, sorry for being a noob. I have on order a Lotoo PAW S1 DAC/AMP that is yet to arrive. I have just taken delivery of my Audiosense T800's (9 ohm) and have a Cyrus Soundkey (minimum of 16 ohm) to tide me over for the mean time. Question is;
1. I just want to check I won't damage anything trying the combo (I think if anything, if there's not enough power they'll just sound pants, right?)
2. The Soundkey has 2 x 138mW into 16 Ohms at 1% THD+N, do you think that'll be enough for my 9 ohm iem's or shall I just try it and see what the pairing sounds like, assuming (1) it won't damage anything.
3. Do any experts know if the output is 2 x 138mW into 16 Ohms at 1% THD+N, what sort of mW am I looking at with 9 ohms? I have seen online calculators but I don't really get them without further reading and I wan't to try these iem's pronto!!!
The T800's have sensitivity of 90dB if that helps...
Thanks
The Audiosense T800 is a very easy set to drive, you will likely damage your ears if you put the volume too loud before you damage the drivers. The issue is that the T800 is a very source picky set due to the low output impedance of 9.2 ohms, so it needs a source with as lowest output impedance as possible to sound good.

Do read this article, I've learnt a lot about source matching here: https://www.headphonesty.com/2019/04/headphone-impedance-demystified/#:~:text=Pairing a headphone with an,driver control (damping factor).

The "rules of eights" in this article is a rough guide for source and headphone/IEM matching. This rule advises that the headphone/IEM impedance be divided by 8, and that is the maximum source output impedance that should be paired. Ie if you have a 32 ohm IEM, if this is divided by 8, then ideally a maximum 4 ohm output impedance for the source is the highest that you should be accepting for output impedance, so as not to affect sound quality. This is just a guide of course, exceptions exist, sometimes there are different driver types such as planars that behave differently and as usual YMMV.

For our friend the Audiosense T800, the reported output impedance is 9.2 ohms, so 9.2 divided by 8 means a 1.15 ohm (let's round this down to 1 ohm) is the max source output impedance you should accept.

So this article states: " “…if an amplifier's output impedance is significantly more than an eighth of the headphone’s impedance, the frequency response and sound of the headphone can change. This results in bigger mismatches and creates more variation from the headphone’s default sound signature. The way that a headphone responds to an amplifier with output impedance higher than one eighth of the headphone can be entirely erratic – different headphones will respond in different ways, but generally the results will be negative.” – RHA Audio "

Indeed the Audiosense T800 doesn't sound as good in high output impedance gear, but sounds very good in < 1 ohm output impedance gear. I use the Tempotec Sonata HD Pro dongle (it has very low output impedance) with a smartphone to drive it, no hiss and very good sound with the Audiosense T800.
 
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Quick question guys, sorry for being a noob. I have on order a Lotoo PAW S1 DAC/AMP that is yet to arrive. I have just taken delivery of my Audiosense T800's (9 ohm) and have a Cyrus Soundkey (minimum of 16 ohm) to tide me over for the mean time. Question is;
1. I just want to check I won't damage anything trying the combo (I think if anything, if there's not enough power they'll just sound pants, right?)
2. The Soundkey has 2 x 138mW into 16 Ohms at 1% THD+N, do you think that'll be enough for my 9 ohm iem's or shall I just try it and see what the pairing sounds like, assuming (1) it won't damage anything.
3. Do any experts know if the output is 2 x 138mW into 16 Ohms at 1% THD+N, what sort of mW am I looking at with 9 ohms? I have seen online calculators but I don't really get them without further reading and I wan't to try these iem's pronto!!!
The T800's have sensitivity of 90dB if that helps...
Thanks
It probably won't damage anything. You probably won't be putting anywhere near 138mW into the T800 unless you like listening at maximum volume. You ought to worry more about the output impedance of your amp because ideally, you want an amp with an output impedance that is at least 1/8 the impedance of the IEMs you wish to use with it.
 
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Thanks so much for the assistance guys (or gals!). I'm getting a little overwhelmed with all the technical data stuff. @baskingshark thanks again for the very detailed reply (as always). I know I have read on these forums that the Lotoo PAW S1 pairs well with T800's, especially - according to that user - on 'dental' mode. However, I still can't find any data on what the actual minimum impedance is, I'm hoping it's 1, like you guys say is best.

The S1 specs are;

Supported Format: PCM 32K-384KHz DSD64/DSD128

Weight: 27.10g

Size: 66mm*22mm*13mm

Max Output: 3.5mm:70mW/ch @32Ω

4.4mm:120mW/ch @32Ω

HP Port: 3.5mm Unbalanced

4.4mm Balanced

Freq. range: 3.5mm: 20-20KHz..+0/-0.017dB

4.4mm: 20-20KHz..+0/-0.016dB

USB Port: USB Type C

Noise Level: 3.5mm: -118dBu

4.4mm: -114dBu

Screen: OLED 128×32

THD+N.. Low gain: -106dB(0.0005%)

High gain: -108dB(0.0004%)

OS.. LTOS

S/N: 3.5mm: 123dB

4.4mm: 122dB

Firmware Update: Supported

But this still leaves me pretty in the dark as to what the lowest impedance is.... Can you guys help? I don't even know what to enter on calc :O

For dental mode, when the S1 arrives, I have invested in decent toothbrush, too. (joke!)

EDIT: @baskingshark do you think the Sonata HD PRO would have been the better choice? Or perhaps sell the PAW S1 and get Hidizs S9? Hmmm.... Do bear in mind, I don't want any or minimal 'colouration' or signature (if that be the better word?) to the sound.

Really sorry for being such a beginner.

Cheers guys
 
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Thanks so much for the assistance guys (or gals!). I'm getting a little overwhelmed with all the technical data stuff. @baskingshark thanks again for the very detailed reply (as always). I know I have read on these forums that the Lotoo PAW S1 pairs well with T800's, especially - according to that user - on 'dental' mode. However, I still can't find any data on what the actual minimum impedance is, I'm hoping it's 1, like you guys say is best.

The S1 specs are;

Supported Format: PCM 32K-384KHz DSD64/DSD128

Weight: 27.10g

Size: 66mm*22mm*13mm

Max Output: 3.5mm:70mW/ch @32Ω

4.4mm:120mW/ch @32Ω

HP Port: 3.5mm Unbalanced

4.4mm Balanced

Freq. range: 3.5mm: 20-20KHz..+0/-0.017dB

4.4mm: 20-20KHz..+0/-0.016dB

USB Port: USB Type C

Noise Level: 3.5mm: -118dBu

4.4mm: -114dBu

Screen: OLED 128×32

THD+N.. Low gain: -106dB(0.0005%)

High gain: -108dB(0.0004%)

OS.. LTOS

S/N: 3.5mm: 123dB

4.4mm: 122dB

Firmware Update: Supported

But this still leaves me pretty in the dark as to what the lowest impedance is.... Can you guys help? I don't even know what to enter on calc :O

For dental mode, when the S1 arrives, I have invested in decent toothbrush, too. (joke!)

EDIT: @baskingshark do you think the Sonata HD PRO would have been the better choice? Or perhaps sell the PAW S1 and get Hidizs S9? Hmmm.... Do bear in mind, I don't want any or minimal 'colouration' or signature (if that be the better word?) to the sound.

Really sorry for being such a beginner.

Cheers guys
None of that information lists the output impedance and my quick Google search didn't turn up anything either. Looks like Lotoo is reticent about disclosing that figure, as is Sony, which is a slight annoyance with some of these equipment manufacturers.

Honestly - don't worry too much. Once you have the S1 in hand, try it with the T800 and find out whether it sounds good to you. Technically, that's all that matters. You can also see if your impressions line up with other reports (there are many in the Audiosense thread). If all else fails, then get the Sonata HD Pro. Frankly that little thing is all anyone really needs if they're just starting out. The Hidizs just looks like useless frippery to me (I mean, colour changing LEDs, really?)
 
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Thanks so much for the assistance guys (or gals!). I'm getting a little overwhelmed with all the technical data stuff. @baskingshark thanks again for the very detailed reply (as always). I know I have read on these forums that the Lotoo PAW S1 pairs well with T800's, especially - according to that user - on 'dental' mode. However, I still can't find any data on what the actual minimum impedance is, I'm hoping it's 1, like you guys say is best.

The S1 specs are;

Supported Format: PCM 32K-384KHz DSD64/DSD128

Weight: 27.10g

Size: 66mm*22mm*13mm

Max Output: 3.5mm:70mW/ch @32Ω

4.4mm:120mW/ch @32Ω

HP Port: 3.5mm Unbalanced

4.4mm Balanced

Freq. range: 3.5mm: 20-20KHz..+0/-0.017dB

4.4mm: 20-20KHz..+0/-0.016dB

USB Port: USB Type C

Noise Level: 3.5mm: -118dBu

4.4mm: -114dBu

Screen: OLED 128×32

THD+N.. Low gain: -106dB(0.0005%)

High gain: -108dB(0.0004%)

OS.. LTOS

S/N: 3.5mm: 123dB

4.4mm: 122dB

Firmware Update: Supported

But this still leaves me pretty in the dark as to what the lowest impedance is.... Can you guys help? I don't even know what to enter on calc :O

For dental mode, when the S1 arrives, I have invested in decent toothbrush, too. (joke!)

EDIT: @baskingshark do you think the Sonata HD PRO would have been the better choice? Or perhaps sell the PAW S1 and get Hidizs S9? Hmmm.... Do bear in mind, I don't want any or minimal 'colouration' or signature (if that be the better word?) to the sound.

Really sorry for being such a beginner.

Cheers guys
Yep, I can't find any data online for the Lotoo PAW S1's output impedance. Dunno why they are so secretive about it LOL. As @unifutomaki says, just try the T800 on your PAW S1 first and see if u like the sound.

Anyways Sonata HD Pro definitely is a good pairing with the T800. It can go for even sub $30 USD during sales (like the current black friday sale). It is quite neutral with a tinge of warmth, very transparent, no hiss, dark background. Also it doesn't get warm and has very low output impedance and excellent measurements (I know measurements aren't everything). It's one of my best purchases this year. Only thing is Sonata HD Pro cannot drive more demanding headphones or stuff like planars.
 
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RikudouGoku

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Yep, I can't find any data online for the Lotoo PAW S1's output impedance. Dunno why they are so secretive about it LOL. As @unifutomaki says, just try the T800 on your PAW S1 first and see if u like the sound.

Anyways Sonata HD Pro definitely is a good pairing with the T800. It can go for even sub $30 USD during sales (like the current black friday sale). It is quite neutral with a tinge of warmth, very transparent, no hiss, dark background. Also it doesn't get warm and has very low output impedance and excellent measurements (I know measurements aren't everything). It's one of my best purchases this year. Only thing is Sonata HD Pro cannot drive more demanding headphones or stuff like planars.
I usually just assume that if they dont list a spec (and they list everything else), it is because it isnt good. Like why else would they hide it lol. :joy:
 
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Brilliant, thanks guys. Will compare to the Soundkey which I'm currently running. Sounds great, no distortion thus far - which I half, perhaps naively, expected becuase they only go to 16 ohm. All seems well! Tried a few classical first, just listened to Lindsey Stirling - Crystallize subs sound grand to me (FLAC, not youtube!). I read reports of all BA not reproducing sub bass well, but also read T800's break the mould. I'm for sure not dissapointed :) Happy days. Bring on the PAW S1 (currently lost in transport!) for comparison.

I may just give the HD Pro a try too, as it's on offer. Ta

Cheers so much guys
 
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I can answer the question on PAW S1's output impedance: both 3.5mm and 4.4mm output has output impedance of < 1 ohm, measured myself.

Also an extra note: source manufacturers often make a claim on 'minimum' or 'recommended' range of headphone impedance to use, but 90% of the time those number are just rubbish / made-up number that carry no technical reasoning / information to the user. They are there only to serve as a comforting element for the uninformed because a lot of people expect to see some number of recommendation but completely have no knowledge of how these things work. The take home message is that: don't put too much stock into what you read in the spec.
 
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I can answer the question on PAW S1's output impedance: both 3.5mm and 4.4mm output has output impedance of < 1 ohm, measured myself.

Also an extra note: source manufacturers often make a claim on 'minimum' or 'recommended' range of headphone impedance to use, but 90% of the time those number are just rubbish / made-up number that carry no technical reasoning / information to the user. They are there only to serve as a comforting element for the uninformed because a lot of people expect to see some number of recommendation but completely have no knowledge of how these things work. The take home message is that: don't put too much stock into what you read in the spec.
Ahhh, perfect. Many thanks indeed!! And to others too for input. Having a whale of a time with them. Good times :)
 
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81BC7D53-AF30-425A-8AAD-1DE497E4FE05.jpeg

What is happening here?

my iphone 6s 3.5mm out with 4.5Ω output impedance everything sounds normal and with the lightening adapter with 0.37Ω, treble spikes up suddenly.


0EBC4EC1-63A8-4DEA-879A-759B4BAB8CA6.jpeg
 
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81BC7D53-AF30-425A-8AAD-1DE497E4FE05.jpeg
What is happening here?

my iphone 6s 3.5mm out with 4.5Ω output impedance everything sounds normal and with the lightening adapter with 0.37Ω, treble spikes up suddenly.


0EBC4EC1-63A8-4DEA-879A-759B4BAB8CA6.jpeg
1606341218505.png

15 (even 27...) ohms with 4.5 OI is going to change the FR a lot.
 
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Brilliant, thanks guys. Will compare to the Soundkey which I'm currently running. Sounds great, no distortion thus far - which I half, perhaps naively, expected becuase they only go to 16 ohm. All seems well! Tried a few classical first, just listened to Lindsey Stirling - Crystallize subs sound grand to me (FLAC, not youtube!). I read reports of all BA not reproducing sub bass well, but also read T800's break the mould. I'm for sure not dissapointed :) Happy days. Bring on the PAW S1 (currently lost in transport!) for comparison.

I may just give the HD Pro a try too, as it's on offer. Ta

Cheers so much guys
Cheers, Enjoy your set!

The T800 has been my daily driver for the past 1.5 years for stage monitoring and transit use. I'm generally not a fan of BA bass but the T800 is pretty unique in that the BA subwoofers are vented, so they sound quite close to DD bass in terms of extension and decay.
 
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What is happening here?

my iphone 6s 3.5mm out with 4.5Ω output impedance everything sounds normal and with the lightening adapter with 0.37Ω, treble spikes up suddenly.
I think it is just a case of you calling an over-dampened sound as 'normal' while calling the actual manufacturer intended normal sound as 'spike'. It is like having too much salty food for too long and suddenly finding everything else bland.
 
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