Part I: 3e Audio - A5 Stereo and A7 Mono Class D + PFFB, TI TPA3251/3255 Amplifiers - Features and initial measurements.

Every once awhile, a manufacturer will connect to see if I might be interested in testing out one of their upcoming products. Recently, 3e Audio (their mission being to Enhanced, Exceed, Enjoy) based in Shenzhen reached out for an honest, independent, evaluation of their new amplifiers. As usual, most of my hardware discussions are based on objective results which I believe significantly reduces personal subjective biases and advertising hype - no YouTube videos where reviewers make silly facial expressions to draw attention to the thumbnail image here folks. 🙄

You probably haven't heard of this brand, but the engineering-focused company has been around for a number of years selling boards to the DIY market with DSP, power supply, and Class D amplifiers. In August, they announced the release of their line of five fully-assembled "A5x A7x Series Next-Gen PFFB Amplifiers". In the picture above, we see the pre-release A7 Mono (260W into 4Ω 1% THD+N, single TPA3255, PBTL) and A5 (150W x 2 into 4Ω 1% THD+N, dual-TPA3251, PBTL) models sent here for evaluation.

As you might know, in this blog over the years I've been covering a number of these very reasonably priced TI TPA chip amps from the early generation TI TPA3116, to the early TPA3255 models (like the AOSHIDA A7), to the very high performance Topping PA5 MkII+ (TPA3251), to the recent inexpensive and higher powered Fosi Audio V3 Mono (TPA3255) with Post-Filter Feedback (PFFB). The inclusion of PFFB to 3e Audio's amplifiers is not new for this company as this feature has been available in their DIY boards since at least 2022. 3e Audio is aiming to exceed the performance of others that have come before; of course, we'll see about that on the testbench!

I'm not sure exactly what date 3e Audio will make these amps available or the prices. At the time of these tests, I was told that they will be taking orders on their AliExpress store in early December 2024. Final prices might change, but I was told that the amps will range from US$199 for the A5se (140W x 2 into 4Ω, 1% THD+N, single-TPA3251, BTL), to US$300 A7 models with power supply.

MUSINGS: The need for full-range sound (likely with subwoofers) in audiophile systems. [And Ojas New Ageism?]

"As an audiophile with an eclectic taste in music, I feel that life is too short not to enjoy the full audible frequency range."

That statement above is just an audiophile's (my) opinion. While I know some audiophiles debate about the need for the use of subwoofers, it has always been a "must" for my reference systems over the decades. Obviously, it's not really my business what anyone else buys or enjoys for themselves. My only intent in this post is to remind audiophiles that most of our passive speaker systems, including relatively large floor-standers, are frequency bandwidth limited (for human hearing).

I know that there are some audiophiles and well-known reviewers out there who have expressed aversion towards the need for full-frequency reproduction - basically flat frequency response down to 20Hz - as a priority. Since robust low-frequency reproduction below 40-50Hz commonly requires an adequate subwoofer, it's surprising to me that the idea of having one isn't more universal among audiophiles, and there are often comments like this warning of issues that come across as dissuasive.

Dirac Live 3: A look & listen with the Integra DRX-8.4 - the process, microphone placement suggestion, tweaking, and multichannel/Atmos results.

As discussed years ago with my sound room set-up, I believe room correction DSP is very important and has become part of my routine whenever I make significant changes in room layout or when I incorporate new equipment. I would argue that an audiophile who has not seriously spent time trying this likely has not heard the best sound in their room from their system. Simply put, you'll notice a level of control and audible difference way more than just swapping hi-fi DACs, amps, etc. hardware.

With the arrival of the Integra DRX-8.4 receiver recently, I started using the included Dirac Live Full Bandwidth license embedded in the hardware. As I had done in the recent past with Acourate and Audiolense XO, let's dive into the steps I used to get Dirac running and the results I achieved. Hopefully this discussion could be useful for those of you thinking of trying out Dirac.

I'll document the steps I followed, issues I ran into, and tips to overcome problems.

Integra DRX-8.4 Multichannel Receiver: Overview, features, build, a few pre-out measurements...

Obviously, value is an important consideration for consumers when it comes to buying and enjoying products. As discussed over the years, I'm not an audiophile who's particularly interested in the luxury aspect of these machines. To me, the ideal of achieving "high fidelity" sound does not care about MSRP or some other determinant of whether a product is artificially exotic/elite, thus "High End Audio" (a.k.a. High Priced Audio) is meaningless to me unless there is evidence of improved sonic performance (whether from plain increased objective fidelity or incorporating technical features) correlating with higher asking price. As such, I believe audiophiles should seriously think about the value of modern AV receivers which over time have also incrementally shown improved sound quality by incorporating higher quality DACs, newer DSP room correction technologies, and potential benefits like balanced connections.

In my opinion, this also means the divide between "home theater" enthusiasts and "audiophiles" is largely artificial when it comes to sonic performance. Subjectively, we're all aiming for an excellent audio experience with high-fidelity to the source with utmost clarity (including time-domain coherence), low distortion, high dynamic range, excellent reproduction of nuances, while achieving realistic/intended soundstage. Objectively, a high quality AV receiver these days should not have difficulty providing hi-fi performance compared to many very expensive products (like the Dan D'Agostino Momentum monoblocks US$80k/pr as an obvious example - other than high power, there's nothing particularly good), plus typically these AV companies provide way more features and modern amenities. The R&D firepower behind these companies are substantial compared to the small-business shops that typically make products for the esoteric 2-channel audiophile niche. Over time, as I hope audiophiles increasingly consider enjoying the new multichannel recordings and remixes, moving into "immersive" audio, these multichannel receivers should be seen as serious options.

The only utilitarian difference between home theater enthusiasts and audiophiles is whether video playback is needed.

In this post, let's start with having a look at the item pictured above, the Integra DRX-8.4 multichannel receiver. (Discussions and measurements of AV receivers are not new on this blog with previous posts on the Yamaha RX-V781 and Onkyo TX-NR1009.)

Despite being the current flagship receiver from Integra, the price is "only" US$3,200 or about CAD$4,000. I bought this item through standard retail channels online because I was interested in it; no company incentives.