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The Dayton DTA3116 is a small class D amplfier that came in two models, a basic one and one that added a built-in headphone amplifier. I received the version with the headphone amp (DTA3116HP) as a door prize at a DIY speaker event shortly after it was released for production. If I recall correctly, these retailed for $30-$35 initially. Layout is pretty simple with a front panel headphone output and 3.5mm stereo line input. On the rear, there are standard RCA inputs and light duty 5 way binding posts for the speaker outputs. Overall, build quality feels like a step up from the budget amps tested here (Lepy, Kinter, Lepai). When amplifier boards using the TI TPA3116 amplifier chip were first introduced, the maximum operating voltage was reported as 24V and many recommended using an old computer power supply to operate them at approximately 19V. The DTA3116 models came with a 14.5 V power supply. With that supply, Parts Express published the following specs.
Power output: 2 x 15 watts RMS into 4 ohms, 2 x 8 watts RMS into 8 ohms
• Frequency response: 20-20,000 Hz
• Total Harmonic Distortion (THD): <0.4% @ 1W per channel
• Minimum impedance: 4 ohms
• Signal-to-Noise Ratio (SNR): 103 dB, A weighted
• Minimum input impedance: 10K ohms
• Input sensitivity: 680 mV
• Channel separation: 95 dB
• Efficiency: >90%
• Dynamic range: >100 dB
• Headphone power output: 150 mW into 16 ohms
• Case dimensions: 3-13/16" W x 1-1/4" H x 4-3/4" D
• Overall dimensions: 1.44" H x 3.82" W x 5.16" D.
With that, let's check out the dashboard. At 5W, 4 Ohms, the distortion comfortably meets the spec, it will probably be better at 1W. This is generally comparable to the Lepy. Signal to Noise ratio is much lower than spec due to a 60 Hz peak coming from the power supply and some higher order harmonics of that leaking through. If one looks at the noise floor (not considering the peaks), the spec might be plausible. I also didn't apply A-weighting for this test.
Next, let's look at the frequency response. Like the Class D Lepy, the frequency response does depend on the load impedance. Into 4 ohms, the response is down a little more than 1 dB at both 20 Hz and 20 kHz, but very smooth in between. Into 8 ohms, there is some a high frequency peak, but we're only up about 0.5 dB at 20 kHz, so this shouldn't pose any major issues from a sound quality perspective.
Next, let's take a look at distortion vs. power output at the standard 1 kHz. First, let's see how this amplifier does vs. the published specs of 2 x 8W RMS into 8 ohms and 2 x 15W RMS into 4 ohms with <0.4% THD at 1W RMS. At 8 ohms, this actually hits 0.4% at around 8W. At 1W, we are actually around 0.07%-0.08% THD. Into 4 ohms, this amplifier produces 15W x 2 with about 0.5% THD. The Lepy offered similar performance, but this is a smoother, more predictable curve and there is more power available, as we run out of power at about 10 WPC into 8 ohms and 20 WPC into 4 ohms.
With class D amplifiers, distortion can rise with high frequencies and can have complex behavior. We see some of that here. Distortion rises considerably by 5 kHz and by 10 kHz, we are approaching 1% THD at 1W and above. One should keep in mind that the Kinter and Lepai budget amps tested had higher distortion than this at all frequencies under the same test conditions. The Lepy measured a little cleaner at high frequencies up to about 4W, but quickly fell apart above that.
Overall, I would say this represents a step up from the budget amps, like the Lepy LP-2020A, as well as the Kinter and the Lepai amps. Frequency response doesn't have any major issues, distortion is not extremely low, but seems under control and predictable. There is enough power to usable for many situations. For a small, low-cost amplifier, there is value here. It would be interesting to see what a TPA3116-based amplifier could do with a higher drive voltage, but I haven't wanted to do that with this amplifier, as there may be other aspects of the design that are limited to the lower voltage. This type of amplifier should work will for portable systems and I have frequently thrown mine into a travel bag to power various speakers while on the road.
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