Coupling caps - changing them can make a big difference. I've only once bought into the expensive audiophile thing and regretted it almost immediately - silver foil caps. They were good but the next week bought some cheap as chips Russian K73-16 PEPT ones, slagged off by some old American 'gurus'.
There's a big thread from some years ago on diyaudio 'pept capacitors-One Of The Best.
In a word 'transparent', Like a lot of others on that thread, didn't want to accept what the OP wrote but he was right. He had spent a lot of money on audiophile/fool caps - well worth reading what he wrote.
Of course the real 'true believers' came steaming in with insults as they always do - had never used them, didn't need to - they were right and everyone else was wrong/deluded/stupid. The audiofools believe that to be good caps must be big -the K73-16 aren't. There other PEPT caps that are said to be as good. I've used 10 and 22uF caps in speaker x/overs. One American speaker maker daren't tell his American clients he uses them, they would go crazy - everything COMMIE is bad LOL.
I don't know if I have values that would work in this amp or if it would benefit.
The word transparent is maybe insufficient to describe these caps, it's that other caps colour the sound, these don't. I can only think of one other component that has the same effect - Z foil resistors.
O/A if you can't hear a difference in sound from different caps I think you have a real hearing problem.
When discussing the impact of capacitors on audio systems, it's essential to consider the science behind electronic components and their influence on sound quality. The argument you've presented can be addressed from a technical perspective that clarifies why different capacitors might seem to have varying effects on sound.
1. Capacitor Functionality in Audio Circuits
Capacitors in audio circuits primarily function as filters, coupling elements, or part of crossover networks in speakers. Their role is to manage the signal path, preventing DC from passing through while allowing AC signals (audio signals) to flow. The fundamental purpose is to ensure the signal is as unaltered as possible, maintaining fidelity.
2. Material and Construction Impact
The material and construction of a capacitor (e.g., dielectric type, foil, or film material) can influence its performance characteristics, such as Equivalent Series Resistance (ESR), capacitance stability, and dielectric absorption. However, in many audio applications, particularly in the audible frequency range (20 Hz to 20 kHz), the impact of these factors is often negligible if the capacitors are within the appropriate specifications.
- ESR and Inductance: While ESR and inductance can affect high-frequency performance, in audio circuits, the impact is minimal unless the components are severely mismatched or defective.
- Dielectric Absorption: Different dielectrics have varying levels of absorption, which can theoretically influence audio quality. However, many of these effects are outside the range of human hearing or are so subtle that they require extremely controlled conditions to be noticeable.
3. Perception vs. Measurement
Human hearing is highly subjective, and psychological factors like expectation bias can significantly influence perceived audio quality. This is why double-blind tests are essential when evaluating audio components. Scientific studies have repeatedly shown that when listeners are unaware of the component being used, they often cannot reliably distinguish between different capacitors if the technical specifications are equivalent.
- Expectation Bias: If a listener believes that a particular capacitor, especially an expensive or "audiophile" one, will sound better, they are more likely to report an improvement, even if there is no measurable difference in the output signal.
- Placebo Effect: This is well-documented in audio, where belief in the quality of a component can create a perceived improvement in sound.
4. Capacitor "Transparency" and "Coloration"
The term "transparent" often refers to a component's ability to not alter the sound. Scientifically, if a capacitor is truly transparent, it means it is not adding any coloration or distortion to the signal. In well-designed audio systems, with capacitors that meet the required specifications, there should be minimal to no audible difference between different types of capacitors.
5. Objective Testing
The most reliable way to determine if a capacitor changes the sound is through objective testing using equipment like Audio Precision analyzers that can measure Total THD and SNR, and other key audio performance metrics. If two capacitors measure identically in these tests, the difference in sound quality is either nonexistent or beyond the threshold of human hearing. There is no magic going on here.
Conclusion:
While different capacitors may have variations in their construction and materials, their impact on audio quality in well-designed systems is often minimal when objective criteria are applied. The subjective differences reported by users can frequently be attributed to psychological factors rather than measurable changes in the audio signal.
Regarding your suggestion that those who don't hear a difference in capacitors might have hearing problems, it's important to remember that hearing acuity varies from person to person and diminishes naturally with age. However, claiming that those who don't share your perception are suffering from hearing loss is both scientifically unfounded and overly aggressive. Discussions about audio quality should be grounded in mutual respect and objective analysis rather than dismissing others' experiences or knowledge with such claims.
,
