Fosi DS1 Portable DAC & Headphone Amp Review

[staticV3]

so there is no point in 32 bit?

For consumer audio, absolutely not.

Even the value of 24bit is debatable given typical limitations in recording and playback dynamic range.

 

[Zoide]

How would the DS1 compare to the E1DA PowerDAC v2.1 when it comes to driving the DCA E3 (27 ohms, -90 dB/mW)?

I use the latter to drive my DCA E3 due to its amazing specs and solid manufacturer reputation, but it chews through my phone's battery and heats up a lot.

Thanks

 

[Jimster480]

How would the DS1 compare to the E1DA PowerDAC v2.1 when it comes to driving the DCA E3 (27 ohms, -90 dB/mW)?

I use the latter to drive my DCA E3 due to its amazing specs and solid manufacturer reputation, but it chews through my phone's battery and heats up a lot.

Thanks

I think both would work fine, this one might save some battery. However if you want something with potentially less power output; the Hiby FC3 that I sent in for review really saves power vs some of these bigger ones. I have that and the FiiO KA13 and the FC3 really saves power, but it also has much less output power.

 

[Zoide]

I think both would work fine, this one might save some battery. However if you want something with potentially less power output; the Hiby FC3 that I sent in for review really saves power vs some of these bigger ones. I have that and the FiiO KA13 and the FC3 really saves power, but it also has much less output power.

Thanks, I just took a look at the FC3 review but it might be too little power for the DCA E3 at only 62 mW with a 33 ohm load: https://audiosciencereview.com/forum/index.php?threads/hiby-fc3-portable-dac-hp-amp-review.55429/

Meanwhile, the DS1 outputs 261 mW.

 

[johny_2000]

How would the DS1 compare to the E1DA PowerDAC v2.1 when it comes to driving the DCA E3 (27 ohms, -90 dB/mW)?
I use the latter to drive my DCA E3 due to its amazing specs and solid manufacturer reputation, but it chews through my phone's battery and heats up a lot.

This is pure physics. More output power (for demanding headphones) = more power consumption from the battery + losses due to heat dissipation (efficiency of electronic components). I use FiiO KA17 (650mW max) and E1DA #9039S (710mW max) dongles with balanced connection to FiiO FT1 Pro headphones (20 ohms, 95 dB/mW), and both are more than loud enough, and are able to deliver this continuously without overheating. I'm not sure about the total power consumption of both dongles (I estimate around 5V/1A each) since I'm using them with a laptop which has a relatively large battery capacity compared to smartphones.

 

[Earwax]

Does anyone know the operating temperature of these encapsulated DAC`s ?

My DS1 has always run hot from the 1st time I used it after about 10 minutes it was hot to the touch using the stock set up with supplied cable to just my cellphone.

Today I measured the temp reading using infrared thermometer with no music playing so not even any current flowing through it or headphones plugged in it`s 37.4 C after 10 minutes.

It was even hotter with playing music but it`s now not working, one channel is dead other side only has very distorted scratchy low volume audio so no point in measuring that way now.

I contacted with Fosi Audio customer service yesterday, Today they sated the temp varies from 15 to 25 C so mine was way over that.

I been using this DAC for 2 months now, at times for 3 hours straight so maybe the heat was to much ?

Why I didn't measure the temp when I 1st noticed it was hot is beyond me.

I did see another review of the same design encapsulated DAC made by ASUS that had the same failure after just 2 months so I`m curios do we need to take this into consideration when using these tiny heat sink DAC`s ?

 

[johny_2000]

I contacted with Fosi Audio customer service yesterday, Today they sated the temp varies from 15 to 25 C so mine was way over that.

They probably mean a temperature of 15–25°C above ambient temperature.

 

[Earwax]

They probably mean a temperature of 15–25°C above ambient temperature.

Here is the temp reading of DS1 just plugged into cellphone with no music playing no headphones attached nothing plugged into aux port.

 

[johny_2000]

Here is the temp reading of DS1 just plugged into cellphone with no music playing no headphones attached nothing plugged into aux port.

So if your ambient temperature is 24°C, then it is on the lower side (+13°C) of the manufacturer's specifications.

 

[Earwax]

I sent them the same picture, they said nothing about air temperature only stated their engineer`s explained the unit body can safely be at 37C.

Of course it was overlooked that was the temp when only plugged into my cellphone NOT playing music and no headphone plugged into aux port.

The body appears to have been much hotter after playing music as when I changed my listening position and touched the metal I was always thinking that feels too hot but never remembered to do further research after the fact.

They do keep repeating the same question asking me to test it again and again but that is fare enough.

I`ll update when I get a final response.

Should have bought the extended warranty offered on Amazon by Asurion it`s only $9.99 Canadian covers 2 years with free shipping.

 

[mc.god]

Here is the temp reading of DS1 just plugged into cellphone with no music playing no headphones attached nothing plugged into aux port.

It could mean nothing since they have different chip inside, but my Sonata BHD, similar form factor and balanced architecture, connected to my pc and with iems plugged, measures 23.8C in a rom at 22C, via an infrared thermometer like the one you used.

 

[DSJR]

My DS2 is often run with no music through it while its connected PC is running, often for hours and, powered by this computer's USB output, it's stone-cold as used as a dac to feed an amplifier's 50k Aux input. Same with music playing through it. Apologies if this pollutes the thread, but thought I'd post anyway

 

[MRC01]

Multitone amplitude for each tone is lower so less distortion.

I'd like to understand this better. I would expect total distortion with multitone to be higher than with a single tone, since each of the tones comprising the multitone has its own distortion harmonics, which all add up, and also create intermodulation tones between them, which further add up.

Yes it is true that each individual tone in a multitone is quieter, because they sum to the multitone. For example, a multitone consisting of 1/3 octave tones from 20 Hz to 20 kHz (30 tones) each at equal levels, is about 8-9 dB louder than any of the individual tones. Put differently, if the multitone peaks just below full scale / 0 dB, each of the individual tones is around -8 to -9 dB. Some devices do show increasing distortion near full scale, so reducing from 0 to -9 dB can improve (lower) relative distortion.

However, that multitone is a complex wave whose amplitude varies over time. All the individual tones are superimposed, so the high frequency waves ride on top of the slower moving low frequency waves. This means that the peak amplitude of each of the high frequency tones is constantly changing in absolute terms. Suppose wave W1 is a high frequency wave. Sometimes a W1 peak occurs while the lower frequency overall wave it's riding on is in a trough so that W1 peak may be, say, -12 dBFS. A moment later in time another W1 peak occurs at the same time as the lower frequency wave peaks, so the W1 peak is close to 0 dBFS.

A picture's worth 1000 words. Here's a multitone with frequencies, low and high (equal amplitude):

So while this W1 wave is itself at a constant -9 dB, this is only evident in the frequency domain. In the time domain, the waveform of the complete multitone signal, wave W1 peaks anywhere from -9 to 0 dBFS because the overall wave it's riding on pushes it up or down the scale.

It seems that even though the individual waves in a multitone are attenuated, their amplitudes in absolute terms will still peak near full scale. If so, why would we expect distortion to be lower?

 

[wwenze]

Because the cause of distortion due to transistor transfer function curve has a nonlinear time-based aspect, due to parasitic (or designed in) capacitance.

So when you play a 1kHz wave full swing, it's going to eat up that capacitance during one half-cycle and change the circuit characteristics.

If you play the 1kHz wave at -6dB and a 10kHz at -6dB, the capacitance gets filled up less, since it is the area under the graph. You may even mathematically argue that the 10kHz wave does not affect the 1kHz at all if there is enough headroom. But in practice it does, and hence why there is IMD.

Altho the individual distortion components can be lower, you should still look out for the total sum, which can still be higher than simple THD test.

And to address the most important question, "why would we expect", the answer is we don't. We don't know what will be the outcome. There are indeed amplifiers with IMD frequency peaks that are identical to and obviously caused by HD, like what you described as expected to happen. I suppose if you build an amp with zero feedback that's probably what will happen. Point is, we see the output first, we hypothesis what is the root cause, and then we test for it and try to improve it.

 

[MRC01]

Because the cause of distortion due to transistor transfer function curve has a nonlinear time-based aspect, due to parasitic (or designed in) capacitance.

So when you play a 1kHz wave full swing, it's going to eat up that capacitance during one half-cycle and change the circuit characteristics.

If you play the 1kHz wave at -6dB and a 10kHz at -6dB, the capacitance gets filled up less, since it is the area under the graph. You may even mathematically argue that the 10kHz wave does not affect the 1kHz at all if there is enough headroom. But in practice it does, and hence why there is IMD.

If it's the area under the curve, then it depends on frequency and amplitude. Big low frequency waves eat it up the most? If so, then that it makes sense that a 1 kHz wave eats less at -6 dB than it does at 0 dB. But if that 1 kHz wave at -6 dB rides with a 100 Hz wave also at -6 dB, then when the 100 Hz wave rises, pushing the 1 kHz peaks to 0 dB, that would eat more capacitance and you should get more distortion?

Obviously, it's the same question rephrased in terms of the capacitance you mentioned.

 

[wwenze]

C

If it's the area under the curve, then it depends on frequency and amplitude. Big low frequency waves eat it up the most? If so, then that it makes sense that a 1 kHz wave eats less at -6 dB than it does at 0 dB. But if that 1 kHz wave at -6 dB rides with a 100 Hz wave also at -6 dB, then when the 100 Hz wave rises, pushing the 1 kHz peaks to 0 dB, that would eat more capacitance and you should get more distortion?

Obviously, it's the same question rephrased in terms of the capacitance you mentioned.

Counterexample: If you have an infinity high frequency wave it will eat up zero capacitance.

 

[MRC01]

... Altho the individual distortion components can be lower, you should still look out for the total sum, which can still be higher than simple THD test.

Yes, this is what I was asking.

And to address the most important question, "why would we expect", the answer is we don't. We don't know what will be the outcome.

So compared to a single tone, the multitone test can go either way: the device can produce higher distortion or lower distortion (or the same). Interesting.

So this Fossi looks like it's "the same" or close to that. Single tone shows about -100 dB and multitone around -110. But that -110 is the overall level of the peaks of the "grass". You need to add (roughly) 9 dB to that to get the overall level of their sum, which is about the same as the -100 dB of the single tone.

 

[MRC01]

PS: this also suggests that a pink noise multi-tone may show higher distortion than white noise, because it has more low frequency energy - or relatively speaking, less high frequency energy.

Or, if we don't have expectations, we could say that pink noise may show a different level of distortion than white noise. And pink noise is more representative of music.

 

[danadam]

Yes it is true that each individual tone in a multitone is quieter, because they sum to the multitone. For example, a multitone consisting of 1/3 octave tones from 20 Hz to 20 kHz (30 tones) each at equal levels, is about 8-9 dB louder than any of the individual tones. Put differently, if the multitone peaks just below full scale / 0 dB, each of the individual tones is around -8 to -9 dB.

When I generate such multitone in REW then it's 31 tones and each tone is at around -24 dBFS.

 

[MRC01]

When I generate such multitone in REW then it's 31 tones and each tone is at around -24 dBFS.

When I do the same in REW, (1/3 octave from 20 to 20 k), I can set the level as high as about -8.7 dBV before it clips.

Here, -8.79 dBFS does not clip and shows peak levels at 0 dBFS:

Going to -8.78 dBFS clips: