Amplifier manufacturers always strive to keep circuit path lengths as short as possible; recording engineers may prefer coaxial over twisted pair cable designs or simple pot small faders versus larger VCA (voltage controlled amplifiers) ones: and customers get excited enough to send me emails describing how something familiar now sounds amazing. I especially enjoy the "what did you do" reaction when I switch out a power cable or digital cable during a demo.
Cables are electro mechanical by nature. They convey complex signals spanning many wavelength octaves over a massive power range. We detect differences due to our extraordinary hearing ability: detectable power range using the logarithmic dB measure is from 1dB to 120dB(pain threshold) - a power ratio of 1,000,000,000,000 to 1. Even if we consider a useable 80dB dynamic range from 30dB to 100dB the power ratio is still 100,000,000 (amplitude ratio is 10,000 still a big number) The wavelength ratio over the 20 Hz to 20kHz eleven octave range is about 1000:1 versus visible light spectrun range of less than 2:1 in wich our eyes operate.
For good transient response and to avoid phase shifts, good power amplifers generally operate between 5Hz and 80 kHz - a couple of extra octaves outside of the accepted 'music' range. Speaker cables control what passes from the amplifier to the speakers and what passes to the amplifier from the speakers. Speaker cables are also good Radio Frequency antennas and allow RF interference to enter and intermodulate with the amplifiers negative feedback loop
Compared with using a flashlight to send an "on and off" morse code, considering all the possible signals that could be described and passed by cables it's unlikely no degradation occurs. Furthermore cables generate additional signals just from the mechanics of triboelectric effects and vibrations transfered from speakers.
High quality cables take longer to manufacture under much more tighly controlled conditions using more expensive materials and more sophisticated manufacturing methods. Higher level cables are made in much smaller batches.
There is no hard rule but generally the cable budget allowance should be in proportion to the performance capability of the components. A $500 consumer grade receiver is likely tuned to sound best with the performance characteristics of low cost cables and high resolution cables may reveal the limitations of the equipment. The converse is also true, using $50 speaker cables on $5,000 is unlikely to make the speakers sound their best.
With the potential permutations of analog/digital interconnects, speaker, and power cables available from many manufacturers, on-line research as a means to pick cables is a bit of a hit or miss affair. Just because a cable works well in one situation doesn't mean it will neccessarily work well in another. Not just because cables interact with the complex reactive impedance of components but because room acoustics are involved.
At kemela we regularly use cables from two American and two European brands across a range of equipment in preparation for auditions and have become intimately acquainted with cable sonics and interactions. We also regularly consult with the cable manufacturer's compatibility knowledge base.
Let us take the guess work out of cable selection for you. We will work with local customers to loan some broken in cables to try.