It does not work anymore :-(Thank Amir for the great, detailed review
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Fosi DS3 Portable DAC & HP Amp
- Thread starter amirm
- Start date
Worked for me just now
Such self promotion is now allowed around here ? Serious question.Thank Amir for the great, detailed review
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Robbo99999
Master Contributor
Yep, same here, I've got the DS2!
I do really like the fact the DS3 has EQ though, and the web interface looks useful/good. I guess the balanced out issues are a bit of a stain, and Amir in the listening tests hearing static in bass heavy tracks above 50 percent volume seems quite a let down. I think I can't give it the highest vote.
So do I. Pity, since the rest is excellent.
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A lot to like in the Fosi Audio DS3 and a little bit not so much...
I hope Fosi Audio considers addressing the issues seen in the sample measured by Amir and offers a revised model for review.
I hope Fosi Audio considers addressing the issues seen in the sample measured by Amir and offers a revised model for review.
Based on the FOSI DS3 page, it states that there is a 2 year warranty: Would your DS2 be similarly covered w/a 2year warranty that may allow you for a refund/replacement/upgrade?
None of the 3 FOSI "portable" DAC offerings provide any information regarding the power-consumption from which, each is drawing power from. My deep search has failed within the reviews here at ASR, or at FOSI website and/or FOSI forum pages for the DS3.
I estimate roughly 150-400mA at 5Vdc under typical listening levels, more at max balanced output or into low impedance. Absence of such specifications (and obviously NO need for them, from buyers)…
Such 'portable' power needs may equate to somewhere around 10-15% of say an iPhone15-level battery' hourly consumption.
I have been noticing lately that FOSI has been quite lax with providing needed specifications for few other of their product offerings: Their DC power filter and their LPS are other examples.
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I'm considering one for the car and sometimes laptop use.. but my cheap Apple dongle does the job just fine for now. Cool product though - I have multiple Fosi products and so far haven't had one problem with them.
Excellent review @amirm . Was the IMD graph done at low gain (it says "Log Gain" in the graph)? If you still have the DS3 can you measure it at high gain?
I've had my DS3 for a while now and found a few things with it, particularly:
1. DC offset at the 3.5mm output when no audio is playing
When no audio is playing the 3.5mm output has quite a large DC offset depending on the load impedance. Here's an annotated picture of a measurement with my Rigol DS1054Z oscilloscope. The DS3 was measured in high gain mode with volume at max.
I also measured it with my Fluke 189 multimeter with lower load impedances:
If connected to a DC-coupled amplifier that has a high input impedance this may trigger DC protection circuitry or even worse send it right through to the load. In practice I don't think there are many amps that don't have AC coupling capacitors on their unbalanced inputs or some sort of DC protection so it's probably not an issue for the vast majority of users.
@Sensi I sent this issue to Fosi Support back on April 7th and they replied that they had forwarded it to your engineering team. I've since updated to the 1.6.5 firmware that was briefly available and the DC offset is still there. I believe this may have to do with power saving features? Since the DC offset is 0V when silence is playing, perhaps this can be fixed by setting the XMOS streaming mode to "Always On" in firmware (so that it's fixed with all host devices), or expose the Streaming option in the Windows driver (so that it can at least be toggled on Windows machines), or if possible even have it as a "Power Saving" toggle on the Fosi Audio Audio Control Center web UI.
2. 3.5mm output inverts polarity
The 3.5mm output appears to invert polarity. Whether this is audible is up for debate but I believe preserving polarity is preferred.
@Sensi I reported this to Fosi Support on March 11th and received acknowledgement but wasn't told if it was sent to engineering. The ES9039Q2M has a DAC_INVERT register that should be able to fix this:
If inverting the 3.5mm output to correct polarity unintentionally inverts the balanced output (i.e. the balanced and unbalanced outputs have opposite polarity at the hardware level), perhaps a toggle on the web UI to invert the DAC output would be a good idea. This would give the user flexibility based on the output they use most.
3. Non-flat frequency response when upsampling is enabled
When upsampling is enabled on the web UI the frequency response of the DS3 drops about -3 dB at 20 kHz:
44.1 kHz sample rate
48 kHz sample rate
@Sensi I sent this to Fosi Support on May 11th but didn't receive acknowledgement. I tested it again with the 1.6.5 firmware and the issue still remains.
Other than these issues/quirks the DS3 sounds damn good with my Truthear Zero REDs. It's definitely an upgrade over the Apple dongle I was using previously.
I've had my DS3 for a while now and found a few things with it, particularly:
1. DC offset at the 3.5mm output when no audio is playing
When no audio is playing the 3.5mm output has quite a large DC offset depending on the load impedance. Here's an annotated picture of a measurement with my Rigol DS1054Z oscilloscope. The DS3 was measured in high gain mode with volume at max.
I also measured it with my Fluke 189 multimeter with lower load impedances:
| Load impedance | Left (volts DC) | Right (volts DC) |
| 10k | 0.0386 | 0.0356 |
| 47k | 0.1275 | 0.1163 |
| 100k | 0.2425 | 0.2221 |
| Unloaded with Rigol 1054Z (1M) | ~1.8 | ~1.6 |
| Unloaded with Fluke 189 (10M) | 5.1440 | 4.6214 |
If connected to a DC-coupled amplifier that has a high input impedance this may trigger DC protection circuitry or even worse send it right through to the load. In practice I don't think there are many amps that don't have AC coupling capacitors on their unbalanced inputs or some sort of DC protection so it's probably not an issue for the vast majority of users.
@Sensi I sent this issue to Fosi Support back on April 7th and they replied that they had forwarded it to your engineering team. I've since updated to the 1.6.5 firmware that was briefly available and the DC offset is still there. I believe this may have to do with power saving features? Since the DC offset is 0V when silence is playing, perhaps this can be fixed by setting the XMOS streaming mode to "Always On" in firmware (so that it's fixed with all host devices), or expose the Streaming option in the Windows driver (so that it can at least be toggled on Windows machines), or if possible even have it as a "Power Saving" toggle on the Fosi Audio Audio Control Center web UI.
2. 3.5mm output inverts polarity
The 3.5mm output appears to invert polarity. Whether this is audible is up for debate but I believe preserving polarity is preferred.
@Sensi I reported this to Fosi Support on March 11th and received acknowledgement but wasn't told if it was sent to engineering. The ES9039Q2M has a DAC_INVERT register that should be able to fix this:
If inverting the 3.5mm output to correct polarity unintentionally inverts the balanced output (i.e. the balanced and unbalanced outputs have opposite polarity at the hardware level), perhaps a toggle on the web UI to invert the DAC output would be a good idea. This would give the user flexibility based on the output they use most.
3. Non-flat frequency response when upsampling is enabled
When upsampling is enabled on the web UI the frequency response of the DS3 drops about -3 dB at 20 kHz:
44.1 kHz sample rate
48 kHz sample rate
@Sensi I sent this to Fosi Support on May 11th but didn't receive acknowledgement. I tested it again with the 1.6.5 firmware and the issue still remains.
Other than these issues/quirks the DS3 sounds damn good with my Truthear Zero REDs. It's definitely an upgrade over the Apple dongle I was using previously.
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I wonder what happens with the real music when you pass those high noise and instability regions?
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Thank you for your reminder. I'm studying in it.
Nabooh
Member
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Am I the only one surprised that the Fosi DS3 received a golfing Panther despite the rather absurd amount of distortion on the balanced output? I’ve seen products get completely trashed in reviews here for way less than that.
Now, I understand the appeal of the Fosi DS3 and the brand in general, which has often offered great value for money on its products and is globally appreciated by Hi-Fi enthusiasts. But in this specific case, I find this measurement hard to forgive, and the product's low price doesn't excuse it either. At its core, I buy a quality DAC/Amp for accurate signal reproduction. Despite the attractive features and the very complete overall package of the Fosi DS3—especially a tempting PEQ—if I end up with a less clean signal on a 300 ohm load in balanced mode compared to 3.5mm...
Now, I understand the appeal of the Fosi DS3 and the brand in general, which has often offered great value for money on its products and is globally appreciated by Hi-Fi enthusiasts. But in this specific case, I find this measurement hard to forgive, and the product's low price doesn't excuse it either. At its core, I buy a quality DAC/Amp for accurate signal reproduction. Despite the attractive features and the very complete overall package of the Fosi DS3—especially a tempting PEQ—if I end up with a less clean signal on a 300 ohm load in balanced mode compared to 3.5mm...
Guilty as charged...
I took some steps to redemption, by downgrading my original vote.
10q!
No, I agree. I think happy panther would be more fitting.
What does upsampling even do? If anything, that looks like a NOS frequency response to me...
phoenixdogfan
Major Contributor
Just bought an Iphone 13 and I need to know if I can power this and run digital signal for something like TIDAL with a lightning to usb 3 adapter? Moreover could I use the android app to set up the dongle and then just run it on the I13 with maybe some parametric presets for my individual IEMs?iOS version is still on its way. I'll push our software engineer to get it done ASAP. I'd like to share the Android app that some members may need. (Special thanks to our fan herefishiyfishfish who made it for us)
fosi-ds3-app.apk
drive.google.com
Any feedback on the app will be welcome and appreciated.
Finally, I'm seeing set frequencies associated with each individual band on Amir's picture of the PEQ. Are those frequencies really set or can each band frequency be set to whatever the user desires?
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