High quality in-wall UL-C2 rated 10-gauge A/C wiring ?
This is the same thing that happens inside larger power cords.No it's not. Even if R were the same, L&C are vastly different. In the 'test' did you also have the heavier ga single wire connected to the same side of the transformer and routed closely so you could listen to each with minimal delay? If not, there innumerable changes possible on the A/C |
Yup, I totally know that it's not to code. My point was that 14awg is really not enough to supply good current to audio equipment. The on-demand current draws are just restricted by the small 14awg wire along with the high dielectric insulation (this is not anything like foamed polyethelyne or teflon found on many good power cords). While ieales seems to think that 14awg is perfectly okay for 20 amps of current (and it may be for general purposes, but highly not recommended!!!), is it definitely not acceptable for the fast current draws required by audio equipment for good sound. You guys can laugh at me all you want, I really don't care because I know what works and what doesn't. |
Headroom loss for 14ga vs 10ga is less than ¼db @ ≈14A / ≈1600W See http://ielogical.com/Audio/CableSnakeOil.php#ACWiring |
Voltage drop calculator. http://www.windsun.com/Hardware/Voltage_Calc.htm Distance or Conductor Size: .... (Distance) Single or Three phase: ........... (Single) Conductor Type: .... (Copper) Installation: ............. (Conduit) .... Same for Romex Voltage: .................... (120V) Maximum Voltage Drop: ... (Already set for 3%. You can change the percentage to what ever you want.) 3% of 120V = 3.6V VD 2% of 120V = 2.4V VD Conductor size: ...... (14 gauge) Current: ...................(12 amps) Max length of branch circuit for a 3% VD (Voltage Drop) 55.97ft. Max length of branch circuit for a 2% VD 37.32ft Remember, up, down, and all around when figuring the entire length. Dynamic Headroom: https://forum.audiogon.com/discussions/dynamic-headroom Here’s a quote from a Pro Audio web site, old post. Around 1984 when I bought my first QSC power amp I called QSC after reading that it has 3db of headroom. I was told that the 300 watt rms rated amp could produce 600 watts of peak power when needed.https://forums.prosoundweb.com/index.php?topic=139460.10 . I guess if all you listen to is elevator music at a moderate listening level #14 wire is all you need. . Note: When a load is known the NEC says the wire shall be sized at 125% of the connected load. Again when the load is known. Using #14awg copper wire, #14 has an ampacity rating of 15 amps. 80% of 15 = 12 amps. (For a continuous load. Continuous load is defined by the NEC for a load lasting 3 hours or more.) (ieales there’s your reserve you are looking for. ) That does not mean you can’t load a convenience receptacle outlet circuit to the 15 amp max until the 15 amp breaker trips..... If it trips..... With a receptacle convenience outlet circuit the loads are not known. The limiting factor is the circuit breaker. In a dwelling unit there is no limit on the number of receptacle outlets that can be installed on a 15 or 20 amp branch circuit. . |
Other than Class A, HiFi is not a continuous load. A ’typical’ tube amp is about 1A per 70W sum of both channels. Peak power can be a numbers game. The 1974 FTC rule mandated an amplifier provide 1/3 rated power for 1 hour @ rated distortion without shutting down. Peak power is the greater of power supply or protection circuit voltage and current. Into a complex load, i.e. loudspeaker and cables, rated power maybe a fantasy. Most every home over 1500ft² in America fails the 3% rule in some area, being wired with 14/2. Obviously if one has a very heavy continuous draw, a heavier circuit should be installed. However, for the vast majority of systems, the load is neither heavy or continuous. I guess if all you listen to is elevator music at a moderate listening level #14 wire is all you need.and if you listen to Def Leppard @100db, your hearing is so screwed as to make HiFi irrelevant ~<;-P For nearly ½ century, I’ve used an oscilloscope to determine undistorted power at the load. Musical peaks of 100db are handled easily. Said oscilloscope also determines that line voltage is always more than sufficient to keep the power supplies at full charge! As mentioned previously: A large transient at line zero crossing depends 100% on amplifier power supply. 4/0 cable will not make one iota difference. And 3% drop is only about -¼db |
