Does this amp distort? [Aiyima T9 Pro]

Summary

In this video, the reviewer explores the importance of providing accurate, detailed reviews, specifically focusing on measurement and distortion in audio equipment. The reviewer critiques the lack of transparency in some reviews where products are given for free without proper disclosure. They delve into the design of the IMA T9 Pro amplifier, highlighting its features, such as tube amplification for added warmth, and its low distortion levels. A series of measurements are presented, showing the distortion levels at under 0.1%, emphasizing how low distortion is inaudible in real-world use, but inviting discussion on whether 'warmth' equals distortion.

Takeaways

• 😀 The importance of including measurements in reviews, as without them, the review might be perceived as biased or a paid promotion.
• 😀 Reviewers must declare if they have received anything of value in exchange for their review, as per YouTube's terms and conditions.
• 😀 The script discusses the idea of measuring products, especially audio equipment, and the costs associated with accurate measurements.
• 😀 A second-hand audio precision APX 525 costs around 10,500 GBP, highlighting the expensive nature of professional-grade test equipment.
• 😀 The speaker plans to measure the IMA T9 Pro Power Amplifier, and the review will include a discussion of its power output, frequency response, noise, and distortion.
• 😀 Distortion in amplifiers should ideally be inaudible, but tube amplifiers can introduce pleasant distortion that some audiophiles enjoy.
• 😀 Tubes in amplifiers, such as the T9 Pro, are used to add warmth to the sound, but the actual output is driven by a class D amplifier chip.
• 😀 The speaker uses a spectrograph to measure distortion and harmonics in the T9 Pro, noting the second harmonic is at -72 dB (around 0.1% distortion).
• 😀 The script contrasts the subjective perception of distortion, noting that while some people might find 0.1% distortion inaudible, others might hear it.
• 😀 The T9 Pro has a Vu meter that displays how hard the amplifier is working, which is both visually appealing and practical for maintaining consistent volume levels.
• 😀 The amplifier has various inputs (Bluetooth, RCA, USB, etc.) and features like a subwoofer output, but the speaker prefers the old USB over USB-C.
• 😀 The speaker concludes that despite the T9 Pro's low distortion, the warmth provided by the tubes should not be mistaken for distortion, but opinions on this vary.

Q & A

What is the importance of declaring paid promotions in product reviews on YouTube?

It is important for YouTube reviewers to declare paid promotions to maintain transparency. If a reviewer receives anything of value, YouTube requires a banner or card to notify viewers that the review might not be entirely unbiased.

How does the speaker feel about reviewing products without performing detailed measurements?

The speaker believes that a review without measurements is not a true review but rather a 'puff piece' paid for by the manufacturer. They stress that providing accurate, reliable measurements adds credibility to the review.

Why doesn't the speaker just rely on reviews from others when considering a product?

The speaker appreciates the variety of reviews available on YouTube for any given product. They value that different reviewers might approach the review from unique perspectives, making it unnecessary for one review to cover every detail.

What are some of the key challenges in performing detailed measurements for audio products?

Accurate and reliable measurements can be expensive. For instance, obtaining professional test equipment like an Audio Precision system can cost over £10,000, making it unaffordable for casual reviewers.

What does the speaker plan to measure in the IMA T9 Pro Power Amplifier?

The speaker intends to measure various aspects of the amplifier, including power output, frequency response, noise, and distortion. However, they focus on measuring distortion in this review.

What is the significance of the tubes in the IMA T9 Pro, and how do they affect the sound?

The tubes in the T9 Pro do not drive the output directly; instead, they are used to color the sound, adding warmth. The actual amplification is done by a class D amplifier chip. The tubes are included to enhance the audio with pleasant distortion, which some listeners might find desirable.

What was the result of the speaker's distortion test on the IMA T9 Pro?

The speaker ran a test with a 100 Hz sine wave and measured the distortion. They found the second harmonic distortion to be at -62 dB, which translates to approximately 0.1%, a level that is considered inaudible to most listeners.

How does the speaker describe the 'warmth' in tube amplifiers, and how does it relate to distortion?

The speaker acknowledges that tube amplifiers often produce warmth, which some listeners associate with distortion. While scientifically, warmth may not be equivalent to distortion, the speaker leaves room for subjective opinions, acknowledging that some may enjoy this 'warmth.'

What role does the VU meter play in the T9 Pro amplifier?

The VU meter on the T9 Pro is a visual indicator of the amplifier's working status. It shows how hard the amplifier is working, and the movement of the needle is visually appealing, adding a retro aesthetic to the device.

What does the speaker think about the general features of the IMA T9 Pro's design?

The speaker appreciates the well-designed features of the T9 Pro, such as its variety of inputs (Bluetooth, RCA, coaxial, digital, USB) and the aesthetic addition of the VU meter. They also note the practical and separate on/off and input selector switches as a user-friendly design choice.