Introduction

TOPPING is an audio brand popular for its various audio sources used to drive headphones, earphones, and even speakers now. It has made a name for itself by offering competitive DACs and amplifiers at various price points such as the E30 II/L30 II, E50/L50, and E70/L70 stacks we saw already. TOPPING also sells a few portable DAC/amps and desktop-class DAC/amp combo units but it would be safe to say individual DACs and amplifiers are its bread and butter even to this day. The amplifiers use solid-state amplifier topologies that allow a scalable product portfolio split into different product lines too. The various amplifiers all use solid-state topologies and are designed with more standard transducers in mind—IEMs, dynamic driver headphones, and planar magnetic headphones. The new TOPPING EHA5 changes this and is one of the more important releases this year in my opinion.

I’ve covered three different electrostatic headphones by the time this article goes live, including a recent review of the impressive Dan Clark Audio CORINA. E-stats differ from dynamic or planar magnetic headphones in requiring a different type of amplifier altogether with most e-stats on the market opting to be compatible with the STAX 580 V Pro Bias connection to drive the high capacitive load in electrostatic transducers. This creates a vicious cycle of few headphones owing to few amplifiers on the market which in turn means there isn’t a strong incentive to develop more e-stat amps, all contributing to a scenario where we have very few affordable e-stat amps and nothing really that breaks the price barrier to get a newcomer to justify going down the e-stat route from scratch. So when TOPPING started teasing an e-stat amplifier, I was extremely interested to see how this would perform and be priced at. All initial photos showed an acrylic chassis with what looked like an orange glow from tubes insides, as seen in my own photo above. Let me clarify right now that the TOPPING EHA5 is a solid-state amplifier too and there’s plenty to talk about in this quick look article so let’s thank TOPPING, via SHENZHENAUDIO, for providing a review sample to TechPowerUp and begin with a look at the product specifications below. Be sure to click the image twice to fully open it and go through all the details.

Packaging and Accessories

If you end up purchasing the TOPPING EHA5 then note that the product box is the shipping box itself. It’s plain cardboard with branding on the sides and a sticker to let you know the amplifier is inside in the specific configuration chosen. Interestingly, it mentions the amp is black in color suggesting there may be other color options as with most other TOPPING amplifiers. However, black is all you get at this time. Open the box to reveal the various accessories placed in cutouts around the EHA5 itself.

TOPPING provides a user manual (online copy here) that goes over the basic set up and use of the EHA5. It comes alongside a warranty card and an AC power supply for the region of your choice. This is where the EHA5 differentiates itself from most e-stat amplifiers that have a bespoke power supply unit inside or separated from the amplifier unit as with my Headamp BHSE. The provided linear power supply is rated to provide a max of 30 W to the amplifier itself, meaning this is the maximum power it can provide to the headphones assuming no losses. The EHA5 itself comes placed between two thick foam pieces with machined cutouts to snugly hold and protect it during transit.

Closer Look and User Experience

At ~23 x 17.5 x 9.5 cm and weighing approximately 2.5 kg, the EHA5 is the largest TOPPING product I have reviewed to date. This is still quite small compared to the vast majority of electrostatic headphone amplifiers though and I agree with the brand’s marketing assessment that this can be a space-saving source on your desk. The form factor is a standard box and the design language reminds me of the various TOPPING DACs and amps I’ve tested too. There’s the usual CNC machined aluminium chassis given a sandblasted matte finish that is quite resistant to fingerprints and the black color also helps hide dust and other scratches over time. The front panel is slightly larger than the rest of the body and has a bottom metal section in contrast to an acrylic top section that gives a sneak peek at the internals. Branding comes in the form of a TOPPING logo at the top left corner and the product name at the bottom. We see two switches on the left with one controlling the input mode (single-ended, balanced, off) and the other allowing you to choose between low and high gain (+14 dB). In the middle is the expected 5-pin STAX Pro Bias-style e-stat headphones output and rounding off the front is a volume knob on the right with a marker to help indicate the current level. The wheel is smooth in use and feels recycled from other TOPPING amplifiers—not a bad thing.

There isn’t much to see on the top or sides with the use of solid aluminium panels. The lack of any ventilation means the amplifier design inside isn’t likely to be power hungry and running hot. On the bottom we see certification information and a set of four screwed-in feet with rubber pads to help prevent scratches to the EHA5 while also preventing it from sliding around on your desk. There are aesthetic covers around the feet in addition to a lot more screws that are used to assemble the amplifier and it’s chassis.

On the back we see the various analog inputs on offer—balanced via dual 3-PIN XLR or 1/4″ TRS combo connectors and single-ended RCA—in addition to analog outputs too via balanced dual 3-pin XLR and single-ended RCA. This is where the “off” state on the switch in the front comes in since the TOPPING EHA5 has a pass-through mode allowing you to use it with DACs and a more standard headphone amplifier. If your DAC supports a preamp output mode, for example, you could then have the EHA5 be in the middle of the DAC and other amplifier and thus choose to have e-stat or DD/planar headphones running depending on what you want to listen to. Next up is the 12 V trigger section with its own dedicated on/off switch. If you have a source with a 12 V trigger out connected to the EHA5, such as the TOPPING E70/E70 Velvet DACs we saw before, you can have the EHA5 be turned on or enter standby mode in conjunction with this other device that may come with its own remote control, thus allowing the absence of an EHA5 remote to be less egregious. Finally, we have a USB Type-C port for any future firmware updates to the device as well as the power input from the power supply included in the box.

After all testing was completed, I decided to take a look inside the TOPPING EHA5. I was admittedly curious because I had seen some discussion elsewhere about the construction of the device and many had concerns too. Given this is a quick look article, I’ll keep things simple and say that the TOPPING EHA5 shares the NFCA-based amplifier circuitry from its popular A90D flagship headphone amplifier that is then fed to transformers for the higher output bias. There are no tubes anywhere to be seen and the orange glow seen in the various photos comes in the form of two LEDs which shine upward into plastic diffuser sheets. It can potentially create a placebo effect of warmth from the amplifier, among other things. Either way, one of the concerns people had was the lack of protection in various stages of the design. While I can see several venues of improvement, it would no doubt cost more—Lundahl transformers fed from the TOPPING LA90 power amplifier design, for example, would likely run north of $1000. The transformers also inherently block DC in the first place and TOPPING provided the following comments to help alleviate things:

There are multiple levels of protections applied in the EHA5 to protect the headphones. A bit more insights. The caps are rated at least 1000 V. The suggested output protection is not necessary. For two reasons, the transformer has certain output impedance to limit current. When for some reason the diaphragm is hitting the plate, the other side of it is the resistance in the bias circuit, 3.3M ohm will definitely limit current. And various tests with headphones are performed, including full sine wave with max volume at high gain into different headphones this shows no issues to the amp and the headphones. And when diaphragm hits the plate continuously, there’s still not damage seen. There are bias voltage detection and protection, amplifier DC protection, power supply voltage detection, over current protection in EHA5 to ensure the safety of the headphones.

The takeaway then is that the TOPPING EHA5 won’t kill your headphones even if it’s not the most elegant design by any means. So with that taken care of, it was time to set up the device for use and here the basic minimum comes in the form of the analog input connection—I went with balanced XLR inputs—and the power supply itself. When you turn on the amplifier from the front, you will notice the LEDs turn on immediately and illuminate the inside in orange. Given the right side has daughter PCBs which stop the light immediately past the LED, you will notice the left side ends up less bright and more spread out by comparison. If the lights bother you for whatever reason, you can disassemble the amp—you will void warranty—and then simply place opaque tape over the LEDs.

Here is a look at the TOPPING EHA5 connected to the TOPPING E70 Velvet. I paired the amp with a few different DACs at my disposal and ultimately found the AKM4499EX-based E70V to be a good pairing in both cost and synergy. Note how the EHA5 is larger than the DAC and thus I had it placed underneath rather than above the DAC as I usually do with stacks. The black colors work nicely together and the red accent on the volume knob of the E70V somewhat matches the orange lighting in the EHA5 I suppose. The 12 V trigger with the remote control for the E70V also helps, as does the preamp functionality for reasons discussed above. I was then ready to test the EHA5 with a variety of different e-stat headphones at my disposal and I chose two in particular for most of my review period in the form of the flagship Dan Clark Audio CORINA and the more budget-friendly Nectar HiveX.

The TOPPING EHA5 is rated to provide 700 Vrms with as much as 2000 V peak-to-peak swing. This is higher than the vast majority of e-stat amps on the market, especially those from STAX. TOPPING also says the output current is ~20 mA, which is also on par with many respectable e-stat amps. This can help overcome diaphragm inertia in e-stat headphones as it first experiences a bias differential or even if it is stuck to a stator perhaps. These numbers are also backed by a high SNR and low THD although note that TOPPING measures these by adding a load in front and then removing it in the calculations. What it comes down to is whether the EHA5 can drive e-stats properly or not. I’d say it gets most of the way there. With some harder-to-drive headphones such as the Audeze CRBN and Nectar HiveX, I had to switch to high gain and turn the volume wheel most of the way (~3 o’clock on the wheel) to get to my usual listening volumes and have enough room for transient spikes. Low gain is deliberately set quite low to account for more sensitive headphones such as the STAX L300. The side effect is, if you have a set of headphones that is especially prone to diaphragm sticking to stators, the high voltage supplied can increase the odds of this happening. The HiveX was especially notorious here with the EHA5—bass notes made it worse. So it can be annoying if you have this experience wherein you will have to frequently disconnect and discharge the headphones before hoping it doesn’t happen again. With headphones such as the DCA CORINA and the HIFIMAN Jade II/Shangri-La Jr, I had no such issues. I will also mention I did not experience clipping here unlike with some STAX amps that started to clip at ~12 o’clock on the volume wheel.

Seen above is the average frequency response of the TOPPING EHA5 obtained via acoustic measurements of two headphones—DCA CORINA and Nectar HiveX—and three measurements each relative to the same headphones at the same SPL driven off the Headamp BHSE. The acoustic measurements done result in some noise as seen in the “wiggles” in the lower frequencies. Objectively there isn’t much to complain, although perhaps subjectively I did find some bass extension lacking. It could be that I was simply not wanting to up the volume more lest I had the same issues as mentioned above, but my time with the EHA5 led me to believe it’s best paired with a more neutral-tuned set such as the CORINA rather than brighter-leaning sets as with most e-stats on the market. The EHA5 is somewhat lean and clinical and I personally preferred tube amps with the likes of the HIFIMAN Shangri-La duo—probably also many of the STAX offerings, too. The TOPPING E70V helps add some body to the mids with the EHA5 though so that’s one of the reasons I preferred it as a DAC compared to, say, the TOPPING E70 with the ESS9038PRO that is more of the same EHA5 experience.