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Beyerdynamic DT 770 pro (250Ohm) paired with SMSL M500 MKIII

swimnbird

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I'm using this [TBA] setup for mixing/mastering so I have had one pair of Beyerdynamic DT 770's at 250 Ohms for that reason. I've been using them through the UAD Apollo Twin built in amp (which isn't giving them what they need I sense). I'm here because I want a DAC/AMP for Mixing & Mastering purposes that I don't have to later upgrade-- I want to get it right the first time and forget about it. My first choice would have been the RME ADI-2 because it is tried-and-true industry standard. My budget didn't allow for me to purchase that so instead I got the S.M.S.L. M500 MK3 on the official site at a discounted price (450$). I considered some other options like: the Topping L30 & (Topping D10 or E30) stack, or some AIO's like: the DX3Pro+ or DX7Pro+.

The DX7Pro+ was a bit pricey (699$)
I also heard the SMSL MK500 had a better DAC than the DX7Pro+ (so assumedly better than the DX3Pro+ also)
The Topping L30 & (Topping D10 or E30) had no XLR/TSR outputs and I preferred how the M500 looks.

I have sense been considering the Topping L50 ( 2.8 watts at 32 Ohms ) & SMSL C200 (450$ + whatever cables they don't include) or maybe just the DX5Pro+
However I do have hope as the reviewer here @ 8:00 mins says the M500 has no issue with a 300ohm headphone. Not sure how situational that is though.

I have other pairs of headphones at 32ohms so I wasn't necessarily purchasing the Mk500 MkIII with the Beyerdynamic DT's in mind... initially. However I became curious and started to see how they fair with the amp built into it-- I can not for the life of me understand the specs given on the website here.


Screen Shot 2022-10-15 at 10.15.21 PM.png


The Beyerdynamic DT 770's [Link]:
REQUIRED POWER: 64mw
REQUIRED VOLTAGE: 4.01RMS (V)
REQUIRED CURRENT: 16.0RMS (mA)
HEADPHONE SENSITIVITY: 98 db(1mw)
HEADPHONE IMPEDANCE: 251 Ω (Ohms)

HEADPHONE LOUDNESS: 110dB

My question is this:
1. Can someone explain what "2Wx2(16Ω)" & "1Wx2(32Ω)" even means in relation to this-- it's a different format than even some other amps I have seen the specs of.
2. If these are not compatible, what is a better option for both DAC/AMP within the 0 - 450$ price range.
 
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Dunring

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I've had the DT770 250's many times and 1 watt into 32 ohm is plenty to power them. If you do equalizing with a preamp reduction, use replaygain, or prevolume war recordings, high gain would likely be needed. If you need more power, the L50 is a terrific amp, and with the Topping D10b DAC and doesn't cost a mint. Also the SMSL SP200 and M300 DAC is excellent (I have that combo as a daily driver). If the M500 gets you to the volume levels you want, stick with it. The L50 and SP200 both have same power out the single ended connector as the XLR one, so it's really nice for Beyerdynamic headphones with are usually single ended with a non removable cable. My daily driver is the Beyerdynamic T90, but I like the 250 ohm DT770 too, best value in closed back headphones.
 

twsecrest

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I would just get a pair of Sony MDR-V6 headphones (60-Ohm).
They sell used, for under $100, on eBay.
I think their more boring sound, is better for audio production work.
 
OP
swimnbird

swimnbird

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I've had the DT770 250's many times and 1 watt into 32 ohm is plenty to power them. If you do equalizing with a preamp reduction, use replaygain, or prevolume war recordings, high gain would likely be needed. If you need more power, the L50 is a terrific amp, and with the Topping D10b DAC and doesn't cost a mint. Also the SMSL SP200 and M300 DAC is excellent (I have that combo as a daily driver). If the M500 gets you to the volume levels you want, stick with it. The L50 and SP200 both have same power out the single ended connector as the XLR one, so it's really nice for Beyerdynamic headphones with are usually single ended with a non removable cable. My daily driver is the Beyerdynamic T90, but I like the 250 ohm DT770 too, best value in closed back headphones.
Thankyou for that, that was really helpful Dunring
 

djtetei

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@swimnbird
Beyerdynamic DT-770 Pro 250 ohms headphones have a power capacity of 100 mW an efficiency of 96 dB SPL / mW and a sensitivity of 102 dB SPL / V.
In order to drive the headphones to their rated power the amplifier has to deliver 100 mW, 5V and 20 mA at 250 ohms for a maximum loudness level of 116 dB SPL.
With an input signa level of 2V RMS and a gain setting of 9 dB (high), the SMSL M500 MK3 amplifier would deliver 5.63 V RMS, and 127 mW. This means a headroom of only 1 dB.
 

staticV3

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1. Can someone explain what "2Wx2(16Ω)" & "1Wx2(32Ω)" even means in relation to this-- it's a different format than even some other amps I have seen the specs of.
It's the power that the SMSL can output at a certain load impedance, before some threshold is exceeded. The most stringent threshold, which Amir uses is "at the knee". That's the point at which distortion shoots up suddenly. Other more lenient thresholds are at 1% THD+N, at 10% THD+N.

You can convert power into voltage with this formula:
Voltage[Vrms] = sqrt(Power[W] * Impedance[Ω])

Do the math and you'll see that SMSL claim the M500III can output a little over 5.5Vrms into both 16 and 32Ω loads.

As you decrease the load (=increase the impedance), the maximum voltage that an Amp can output increases.
Here's what that looks like for the M500III (source):
1662829346-THDN-Ratio-vs-Measured-Level.jpg

At the knee, about 4.7Vrms at 16Ω, 6Vrms at 32Ω, and about 6.3Vrms into 300Ω (that's the relevant info for your DT770)

Your DT770 has a maximum allowed input voltage of 5Vrms, so the M500III can saturate that and then some.

2. If these are not compatible, what is a better option
They are compatible.
 

solderdude

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Acc. to Amirs measurements 6.3V in 250 ohm so almost 160mW so 117dB SPL in the mids, 122dB SPL in the bass and 125dB SPL at 7kHz (not really nice).

The 100mW rating is continuous and to reach an average of 100mW with music (short) peaks of 0.5W to 1W are allowed but will be VERY uncomfortable to the ears and the drivers will be compressing/clipping.
You will probably not drive those headphones above 100mW anyway.
 
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