Can I Bench Test an Integrated Amp with Just the FNIRSI 2D15P? | Review Part 2 ~ Real World Testing

FNIRSI sent me this 2D15P free of charge in return for an honest assessment. Patreon - Learn Audio Repair Differently: https://novaluxstereophonic.com/join-... As an Amazon Associate, I earn from qualifying purchases at no additional cost to you. The affiliate links below may include products featured in Amazon promotional campaigns. 🛒 FNIRSI 2D15P Oscilloscope / DMM https://amzn.to/4dA43hj 🛒 Related tools and accessories: https://amzn.to/4ftmV41 If you are interested in load testing amplifiers, consider building this simple 8 ohm stereo dummy load. Build Video:    • Build This Simple 8 Ohm Audio Dummy Load f...   Make sure to check the build video description for additional upgrade videos. Real World Tutorial:    • How to Bench Test Amplifiers the Right Way...   In Part 1, I covered the technical features, interface, and limitations of the FNIRSI 2D15P. Part 1 Video Link:    • This One Tool Can Start Your Audio Repair ...   In this follow-up video, I put the 2D15P to work in a real bench-testing scenario to see how far a beginner can realistically go using just this one device. For Part 2, I attempt to fully bench test a vintage Sansui AU-20000 integrated amplifier using only the FNIRSI 2D15P, a dummy load, and basic cables — no full bench of test gear. The goal is to answer a simple question: Can a beginner meaningfully troubleshoot and evaluate an audio amplifier with this tool alone? What’s covered in this video: Initial inspection and safe power-up of an unknown amplifier Separating and testing the preamp and power amp sections Using the 2D15P to: Inject test signals, compare left/right channel behavior, Identify dirty controls and switching issues Square-wave testing of tone controls and filters Phono stage verification using low-level square waves Use of an inverse RIAA network to validate phono stage frequency response Power amplifier testing into dummy loads Output voltage measurement and power calculations Identifying the limitations of the built-in sine wave generator Verifying results with a standalone bench signal generator Key takeaways: The FNIRSI 2D15P performs very well for preamp and phono stage testing, especially when using square waves. It makes it easy to: Compare channels Spot control issues Verify overall signal flow Perform meaningful diagnostic work as a beginner Where the device falls short is standalone power amplifier testing. The internal sine wave generator lacks the cleanliness and fine amplitude control needed to accurately detect clipping and channel balance at rated output power. In this case, a dedicated signal generator is still required for precise power amplifier evaluation. Final thoughts: While I wasn’t able to perform a complete amplifier bench test using only the 2D15P, I came surprisingly close. For someone just starting out in audio repair, this device covers a lot of ground at a reasonable price, with an intuitive interface, solid oscilloscope and DMM functionality, and excellent usability. As long as you understand the limitations of the signal generator — and plan to add a standalone generator later — the 2D15P remains a strong beginner tool. Chapters: 00:00 Introduction 00:32 Visual Inspection of the AU-20000 01:29 Setting Up the 2D15P For Audio Testing 03:20 Separating the Preamp & Power Amp for Isolated Testing 04:29 Preamplifier Testing 09:09 Affiliate Link Call Out 09:24 Phono Stage Testing 13:01 Power Amplifier Testing 29:07 Does the D215P Pass the Test? Summary of Results 32:29 Closing Thoughts YTL086