SMSL RAW-MDA 1 DAC & Headphone Amp Review

[Nezil]

Are you sure the 4,4mm is single ended and not balanced? Some say it's balanced and claim they can hear a difference? I haven't tried it yet

I was planning on checking if there is continuity between the L- and R- (or L+ and L-) on the balanced headphone connector. If the 4.4 and 6.35 are linked internally, there is no way that these could be separate because there are only three connections going to the 6.35.

It should be a simple test if you have a 4.4 balanced connector / cable. I don't have one currently, but will probably buy one because my headphones (Oppo PM-3) are balanced 'ready' with the appropriate cable.

 

[Roland68]

Thank you for your response.

I’m primarily interested in using it with a balanced output and at low gain, in pursuit of maximum precision. As I listen exclusively to classical music, I favor an analytical reproduction—one that is as faithful and nuanced as possible.

If the SMSL RAW-MDA1 is truly capable of driving the HD 660S2 under these conditions, it would allow me to avoid turning to the FiiO K9 Pro ESS. While it features an excellent ESS chip—which I was initially drawn to for its neutrality and surgical approach to signal processing—its price, and more importantly, its age (nearly four years now!), have given me some pause.

If anyone has tried the SMSL with the HD 660S2, I’d be very interested to hear their impressions.

Are you sure the 4,4mm is single ended and not balanced? Some say it's balanced and claim they can hear a difference? I haven't tried it yet

I was planning on checking if there is continuity between the L- and R- (or L+ and L-) on the balanced headphone connector. If the 4.4 and 6.35 are linked internally, there is no way that these could be separate because there are only three connections going to the 6.35.

It should be a simple test if you have a 4.4 balanced connector / cable. I don't have one currently, but will probably buy one because my headphones (Oppo PM-3) are balanced 'ready' with the appropriate cable.

As @JIW writes, only an SE headphone amplifier is installed, not a balanced one.
They only have a dual op amp driving the HPA, so only 2 channels.
The discrete HPA only has 4 large SMD transistors, and 2 are required per channel.
There are only 2 relays for the HPA outputs, with only 2 normally open contacts per relay. So, only 2 channels here.

Each of these criteria only allows for one SE HPA, so a balanced HPA is not possible.
The measured power of 167 milliwatts at 300 ohms and 1.4 watts at 33 ohms is completely oversized for most HPs and more than sufficient, even for the HD 660S2.

 

[Nezil]

As @JIW writes, only an SE headphone amplifier is installed, not a balanced one.
They only have a dual op amp driving the HPA, so only 2 channels.
The discrete HPA only has 4 large SMD transistors, and 2 are required per channel.
There are only 2 relays for the HPA outputs, with only 2 normally open contacts per relay. So, only 2 channels here.

Each of these criteria only allows for one SE HPA, so a balanced HPA is not possible.
The measured power of 167 milliwatts at 300 ohms and 1.4 watts at 33 ohms is completely oversized for most HPs and more than sufficient, even for the HD 660S2.

Thanks for the clarification; I was actually writing my response while @JIW posted the image video. Good to know that the 4.4 is not truly a balanced output once and for all.

Is there any benefit at all in using a balanced cable with a single ended output? There was a school of thought a few months back that Bi-wiring was worthwhile with a single ended amp output, even when using the same amp channel for both the woofer and tweeter of speakers. I think the rationale for that was that the resistance of a longer cable run might affect the passive crossover in the speaker.

 

[JIW]

Thanks for the clarification; I was actually writing my response while @JIW posted the image video. Good to know that the 4.4 is not truly a balanced output once and for all.

Is there any benefit at all in using a balanced cable with a single ended output? There was a school of thought a few months back that Bi-wiring was worthwhile with a single ended amp output, even when using the same amp channel for both the woofer and tweeter of speakers. I think the rationale for that was that the resistance of a longer cable run might affect the passive crossover in the speaker.

There is a benefit to only combining the cable's ground connections in the connector or the jack since this reduces crosstalk. The single ended Sennheiser cables for the HD600 type series already do have separate grounds all the way to the connector so there is very little to be gained by using a balanced cable with a single ended amplifier for those.

 

[Von Nassau]

The amplifier is only single ended regardless of connection and the only apparent difference between gains is the noise level.

Are you sure the 4,4mm is single ended and not balanced? Some say it's balanced and claim they can hear a difference? I haven't tried it ye

It is certainly single ended. Here is the board.

Awesome thanks. Can you point me to how I can see it? I am a Machine designer and not used to look at boards loke this.

 

[Nezil]

There is a benefit to only combining the cable's ground connections in the connector or the jack since this reduces crosstalk. The single ended Sennheiser cables for the HD600 type series already do have separate grounds all the way to the connector so there is very little to be gained by using a balanced cable with a single ended amplifier for those.

But there might be for my Oppo PM-3s...

 

[JIW]

Are you sure the 4,4mm is single ended and not balanced? Some say it's balanced and claim they can hear a difference? I haven't tried it ye

Awesome thanks. Can you point me to how I can see it? I am a Machine designer and not used to look at boards loke this.

@Roland68 pointed it out in post #622 above. I just saw identical two rows and L and R besides them.

 

[JIW]

But there might be for my Oppo PM-3s...

In terms of the cabling only, really.

 

[JIW]

But if anyone can tell me whether the SMSL RAW MDA1 works perfectly in balanced mode with the HD660S2, that would be amazing.

It will work just as well as any other transparent amplifier. The power is most likely sufficient as well. No idea what you mean by perfect if not that.

 

[JIW]

I’m afraid that listening to classical music might be limited due to the balanced output and low gain…

Is this really a technical problem? Where is the difference between low and high gain other than noise for the RAW-MDA1?

 

[staticV3]

I’m afraid that listening to classical music might be limited due to the balanced output and low gain…

The RAW-MDA1 can drive the quite sensitive 660S2 to 122dB SPL Peak.

You will destroy your ears and your headphone, before you can reach the SMSL's limit.

 

[Roland68]

Aber wenn mir jemand sagen könnte, ob der SMSL RAW MDA1 im symmetrischen Modus mit dem HD660S2 perfekt funktioniert, wäre das großartig.

Ich befürchte, dass das Hören klassischer Musik aufgrund des symmetrischen Ausgangs und der geringen Verstärkung eingeschränkt sein könnte …

Ich frage mich, ob der SMSL RAW MDA-1 leistungsstark genug ist, um meinen Sennheiser HD 660S2 bei geringer Verstärkung über den symmetrischen 4,4-mm-Ausgang voll anzutreiben.

Für meine Ohren klingt der 4.4-Ausgang (symmetrisch) präziser, sauberer und neutraler, was genau meinen Ansprüchen entspricht – vor allem, weil ich ein großer Fan klassischer Musik bin. Ich möchte das volle Potenzial meines HD 660S2 auch bei geringer Verstärkung ausschöpfen können.

Wenn das nicht möglich ist, ziehe ich den FiiO K9 Pro ESS in Betracht, auch wenn sein Alter (jetzt etwa 4 Jahre alt!) mich etwas zögern lässt.

Es wurde mehrfach gesagt, dass der SMSL RAW-MDA 1 nur ein SE-Kopfhörerverstärker ist und der 4,4-mm-Anschluss nur ein SE-Ausgang ist.
Und egal, wie oft Sie es schreiben, das Ergebnis ist nicht ausgeglichen.
Auch symmetrische Anschlüsse (z. B. 4-poliger XLR, 4,4 mm, 2,5 mm) werden in SE HPAs häufig verwendet; dies dient lediglich der Anschlussfreundlichkeit und stellt kein Problem dar.

Es gibt absolut keinen Grund, warum der HD660S2 nicht perfekt mit dem SMSL RAW-MDA 1 zusammenarbeiten sollte. Ob für den HD660S2 ein SE- oder ein symmetrisches Anschlusskabel verwendet wird, spielt dabei keine Rolle.
Wenn Sie befürchten, dass die Leistung (gemessen 167 mW bei 300 Ohm) für Ihre Anwendung zu gering ist, können Sie dies mithilfe eines Computers selbst überprüfen oder einen anderen DAC mit einem leistungsstärkeren HPA oder separaten HPA in Betracht ziehen.

Niemand kann diese Entscheidung für Sie treffen.

DACs mit leistungsstärkerem HPA, zB:
RME ADI-2-DAC FS
SMSL DO400
Loxjie D40 Pro
Topping DX9

HPA, zB: Topping L30 (SE), L50 (SE), L70, A30 Pro (SE), A70 Pro
Alle sind mehr als ausreichend, auch mit EQ.

Zwei der günstigsten und leistungsstärksten Kombinationen sind:
SMSL SU-1/C100 und Topping L70 (RCA-Verkabelung)
Topping D50 III und Topping L70 (TRS/XLR-Verkabelung)
Symmetrische Leistung 1 Watt bei 300 Ohm und 7 Watt bei 32 Ohm.

 

[staticV3]

I’m wondering if the SMSL RAW MDA-1 is powerful enough to fully drive my Sennheiser HD 660S2 on low gain, using the 4.4 mm balanced output.

On Low gain, the RAW-MDA1 will drive the 660S2 to 113dB SPL Peak.
Still way louder than I could comfortably listen to.

To my ears, the 4.4 (balanced) output sounds more precise, clean, and neutral

More precise, clean, and neutral than the 1/4" output?

Then I'll have to disappoint as both outputs are connected to exactly the same Amp output internally.

All perceived sound differences are caused by expectation bias. They exist only in your head.

 

[RHO]

But what do you think about the FiiO K9 Pro ESS? I honestly prefer the ESS DAC chip—I find it more neutral and analytical.

Test it blind and you'll not be able to differentiate between ESS or AKM or whatever decently implemented DAC-chip.
As mentioned before, it's all expectation bias/placebo.

 

[Crook]

Hi, I like the look of this unit, so I can move my existing DAC/HPA (El Dac II+ / L30ii) upstairs to the desk.

I am though somewhat concerned about the clicking and popping posts. No issues with a little pop on start up or shut down, but absolutely unacceptable whilst listening to music or through sample rate changes in a play list. It will be driven by Wiim for music only (no PC, no YT, no USB).

Does this issue only occur over USB, as I will be using optical / coax?

Any guidance is appreciated, as if it pops even once, it is going back to Amazon as faulty and I'd prefer to save the hassle if known issue over optical/coax too.

Thank you.

 

[ArthurStein13]

DACs mit leistungsstärkerem HPA, zB:
RME ADI-2-DAC FS
SMSL DO400
Loxjie D40 Pro
Topping DX9

Is the SMSL DO400 capable of driving my HD 660S2 efficiently in balanced mode and low gain !?

 

[JIW]

Is the SMSL DO400 capable of driving my HD 660S2 efficiently in balanced mode and low gain !?

It will just be 6 dB louder than the RAW-MDA1. What kind of DAC and headphone amp and what headphones do you have currently?

 

[JIW]

I exclusively listen to classical music with my Sennheiser HD660S2 headphones. As a student at the Paris Conservatory, I have a dream CD collection and use a Marantz CD60. In a year, I plan to add a high-quality streamer to my setup, as well as treat myself to the Sennheiser HD800S.

Do you use the headphone output of the CD60? If so, how high is the volume setting typically and do you ever need more volume than is available?

 

[JIW]

A week ago, I purchased the Marantz CD60 along with the Sennheiser HD660S II headphones, but I quickly realized that the built-in headphone amplifier in the Marantz doesn’t meet my expectations. I am now considering the SMSL RAW MDA1, the SMSL DO400, the FiiO K9 Pro ESS, and the Loxjie D40 Pro.

Okay, but does it get loud enough or not?

 

[ArthurStein13]

Okay, but does it get loud enough or not?

The sound from the Marantz CD60 headphone amplifier is poor, with noticeable distortion and insufficient volume.