This is a review and detailed measurements of the Topping Professional E2x2 audio interface (ADC, DAC, Headphone Amp). It was sent to me by the company and costs US $159.
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As the British would say, the E2x2 definitely "looks the part" as far as fitting in the general offering of interfaces in the market. And that extends to control app which seems a lot fancier than I expected from a company just getting into this market:
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The company must have staffed up on the software side of things. You can power the unit exclusively via USB-C if your host supports its level of power (mine did), or with auxiliary USB-C power:
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Note an interesting feature that if you use TRS in line In, you get a different gain than when using XLR. One is used for microphone and the other for line in/instrument.
We have three subsystems to test so let's get on with it.
Topping E2x2 DAC Measurements
Treating the unit strictly as a DAC, we have this for our dashboard:
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I am so used to chart topping measurements from Topping DACs that this seems decisively less performant:
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We do beat the spec so that is good.
Noise performance is better:
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As is multitone:
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Linearity is near perfect:
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As is jitter:
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IMD noise and distortion is along the same lines as the dashboard SINAD:
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One filter is provided:
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Wideband THD+N again is similar to what we saw in dashboard:
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Topping E2x2 ADC Measurements
The E2x2 starts to show the strength of the brand in this department:
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Noise performance is nice:
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As is frequency response:
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Measuring the IMD level was a bit tricky in that the gain impacted that initial hump. This measurement is also not ideal as it shows the generator level on X axis, not the output:
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Still what is there seems pretty nice especially if you use the right gain structure. Testing against measured level, I had an older THD sweep which I resurrected:
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As you see, it matched the reference pretty well.
Performance is essentially frequency independent:
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Topping E2x2 Headphone Amplifier Measurement
Let's see if Topping brought its "A game" in this department:
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Seems to be the case seeing how this is USB powered. Many competitors just have a checklist headphone amp with low power and high noise and distortion. Not here. We have good bit of power in high gain mode and excellent noise and distortion in low gain. Same is true of 32 ohm:
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I was impressed by the noise level as represented in our 50 mv test:
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Many stand-alone headphone amps struggle to achieve this level of quietness:
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Conclusions
Topping gives us a "good" DAC in E2x2. But then surprises us with very good performance of its ADC and excellent response of the headphone amplifier. I suspect the cost constraints here kept it from delivering better DAC performance. For some reason I thought if Topping entered the interface market, they would top of the chart performance with costs to go with it. Thinking about it, they may have been wise to go after the entry level market first. This way, they pick up customers who are not wedded to long established brands.
I am impressed by the completeness of the product especially when considering the control app and such. You would think the company has been in market for many years.
I am going to recommend the Topping E2x2 audio interface as an entry level product.
E2x2 Specifications@24bits/96kitz)
1. Microphone Inputs:
Equivalent Input Noise@A-wt,150 Ohm | -130.5dBu
THD+N@A-wt | -110dB (0.0003%)
Dynamic Range @A-wt | 115dB
SNR | 115dB
Crosstalk@1kHz | -140dB
Frequency Response | 20Hz-40kHz (#0.2dB)
Maximum Input Level | 8.6dBu
Input Impedance | 1.5k Ohms
Available Gain | 58dB + 20dB (20dB digital gain)
Phantom Power | 48V
Phantom Power | XLR connector of the combo socket:
2. Line Inputs:
THD+N@A-wt | -107dB0.00045%)
Dynamic Range @A-wt | 115dB
SNR @A-wt | 115dB
Crosstalk@1kHz | -140dB
Frequency Response | 20Hz-40kHz (#0.1dB)
Maximum Input Level | 23.9dBu
Input Impedance | 6k Ohms
Available Gain | 58B + 20dB (20dB digital gain)
Connector Type | TRS connector of the combo socket:
Tip (Hot), Ring (Cold) & Sleeve (Shield)
3. Instrument Inputs:
THD+N@A-wt | -108dB (0.0004%)
Dynamic Range @A-wt | 115dB
SNR @A-wt | 115dB
Crosstalk@1kHz | -140dB
Frequency Response | 20Hz-40kHz (#0.3dB)
Maximum Input Level | 14.8dBu
Input Impedance | 1M Ohms
Available Gain | 58dB + 20dB (20dB digital gain)
Connector Type | TS connector of the combo socket:
Tip (Hot) & Sleeve (Shield)
4. Line Outputs:
THD+N@A-wt | -100dB (0.001%)
Dynamic Range @A-wt | 115dB
Analogue Dynamic Range@A-wt, -40B attenuation | 127dB
SNR @A-wt | 115dB
Crosstalk@1kHz | -128dB
Frequency Response | 20Hz-40kHz (#0.3dB)
Maximum Input Level | 14dBu
Noise @A-wt | 1.8uVrms
Output Impedance | 100 Ohms
Connector Type | 6.35mm TRS balanced jack:
Tip (Hot), Ring (Cold) & Sleeve (Shield)
5. Headphone Outputs:
THD+N @A-wt | -100dB (0.001%)
Dynamic Range @A-wt | 115dB
Analogue Dynamic Range @A-wt, -40dB attenuation | 132dB
SNR @A-wt | 115dB
Crosstalk@1kHz | -120dB
Frequency Response | 20Hz-40kHz (£0.3dB)
Maximum Input Level | OdBu@ Gain=L, 17dBu@ Gain=H
Noise @A-wt | 1 uVrms
Output Impedance | 1 Ohms
Connector Type | 6.35mm stereo headphone jack:
Tip(Left), Ring (Right) & Sleeve (Shield)
6.35mm stereo headphone jack | 580mWx2@320 THD+N<1%
380mW x 2@64Q THD+N<1%
198mW x 2 @1500 THD+N<1%
105mW x 2@3000 THD+N<1%
55mW x 2@6000 THD+N<1%
*Note: The above data is the result of the test in TOPPING laboratory.
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