Amp to speakers cable length? How long is too long?

Do you have a choice? Oh NO you don't. So just do it. I'd get 12AWG from Blue Jeans or Monoprice and don't worry about it. If you want to play with exotic expensive stuff, buy the cheapo first, then purchase the exotic only with a money back guarantee.

 

I use 10 gauge. The lower the gauge the better if the number of stranding goes up too.

 

I try to keep them under a foot...active speakers for the win!!!

 

You want to keep your speaker cabled short, to keep the controll over your speakers. I'm in the position to have mono-amps, so the cables are as short as 60cm. And they are solid wires 1,2mm² (silvered copper) so they are close to 0 when talking about influencing the signal, like flexible cables do with their capacity.

They used to be abour 2m each when I had a stereo power-amp.

And interconnect cables (like between pre- and power-amp) can be much longer, as long as they have a low capacity. I heard a cable once, wounded, more then 10m and you clould not tell the difference with a 1m cable. This was on a very musical, refined, uncoloured set of around €20.000,-.

 

With speaker cable, though there are other issues, the big, critical factor is cable resistance. A longer cable of the same wire thickness is going to have more resistance than a shorter cable of the same wire thickness. However, if you increase the conductor thickness, you lower the resistance, that's why people say go up to 12 gauge cable if you're going with longer runs. In most set ups, 15-20 feet of 12 awg cable (or maybe even 14 awg) won't be a problem at all -- at places like nightclubs and sports stadiums and concert venues, people run longer speaker cables runs than 15 or 20 feet all the time. The only challenges could be if you have certain situations -- like a tube amp with a highish output impedance (all have much higher output impedances than solid state amps, and some have pretty high output impedances relative to speaker nominal impedance), or some kind of esoteric speaker cables of unusually high inductance or capacitance, etc. Application matters. But, if you're running a low impedance solid state amp to common dynamic speakers with common geometry speaker cable, you're not going to have a problem running 15-20 feet of speaker cable if the cable is of sufficient gauge.

With interconnects, the big issue is not resistance but capacitance. Capacitance and shielding. The output impedance of a device in the signal chain is going to form a low pass filter with the capacitance of the cable, a cable of a certain capacitance per foot with have more total capacitance at 10 feet in length than it will have at 3 feet in length, obviously. So you can choose either shorter interconnect, or interconnects of lower capacitance per foot. In most modern solid state applications between active electronics, you're not going to have any problems with signal loss or high frequency roll off because of cable capacitance, because the output impedances of these devices is low. But if you component with a high output impedance -- like some unbuffered tube components have or like a passive preamp -- you could run into frequency response modification problems with long interconnects.

Interconnects between these higher impedance connections (vs speaker cable) mean they're more susceptible to picking up induced hum from environmental sources. And when you're doing long runs, often that means routing them close to and parallel to power cables or power wires in the walls or near other electronic equipment with transformers or near switch mode power supplies, etc. These are all opportunities for those interconnects to function as antennas for induced noise. So you can go longer with interconnects if you go low capacitance, and if your cables are very well shielded with, as near as possible to 100% shield coverage, taken right up to the terminations on both ends of the cable and you take care with the routing of the interconnects away from sources of induced noise.

Actually, while I said resistance wasn't the thing to focus on with interconnects, that's not entirely true. In unbalanced set ups, the resistance of the ground/shield connection, is going to have an impact on noise levels in the presence of AC leakage. So another reason to keep interconnects shorter with low resistance shielding is not just lowering levels of environmentally induced hum but also lowering noise levels in the presence of AC leakage.

Different rule apply for an interconnect that connects a turntable to the input of a phono preamp. That cables is actually part of the passive tone generating circuit together with the phono cart itself and modifies the phono cart's frequency response. It also carries a very low voltage signal into a high gain circuit and is very susceptible to induced noise. It should be kept very short and low capacitance and very well shielded. A cable between a solid state preamp with a low impedance buffered output and a high input impedance power amp, could be much longer without any problem.

 

How does this change if the electronics are connected with balanced audio cables?

Thank you for the great information

 

15' to 18' is not too long, I ran 20 footers for years. Quality cable's at this length will make a big improvement.

 

If you have a differential input and output and balanced connections it should reject common mode noise and have higher signal voltage and long runs will be much less of a problem.

 

Thanks for posting - this is the rule of thumb. Which makes 11AWG for my 10 foot cables total overkill! Gotta keep that resistance down

 

I’m using QED Silver Anniversary XT cable and was looking at rearranging the room, which would require going from 4 meter length cable to 16 meter length cable for each speaker. Would this have any discernible affect on playback?

This is the spec from their website:

Silver plated 99.999% OFC conductors
Provides a low frequency path for the audio signal and delivers stunning high frequency detail

Specifications
Wire gauge - 16 AWG
Unique SPOFC triple braid 5 x 16 x 0.1 mm
X-Tube™ technology
Jacket OD - 3.90 mm
Cross-sectional area - 1.50 mm²
Loop resistance - 0.021 Ω/m
Capacitance - 50 pF/m
Inductance - 0.47 µH/m
Dissipation factor - 0.0006

 

If you've transposed the cable specs correctly, they're not very good. Unfortunately too, they're also only 16 gauge cables. For 16 meter runs, 12 gauge is highly recommended to avoid any significant insertion loss. 10 gauge is better still and you'll then be ready for any speaker and amplification combo you can think of.

You'll be far better off with large gauge cable from Blue Jeans (their Belden 10 gauge is excellent quality and also measures extremely well) or the Kimber 8TC or 12TC from Kimber Kable which is also excellent quality and evens slightly edges the Blue Jeans/Belden 10 gauge in the measurements department. No insertion losses with either one. No effect on sound therefore. Both cables are terminated extremely well at the factory.

 

Absolutely not.

 

Your speaker cable length is no issue. Use #12 gauge, not #18 gauge.

 

Thanks for the response, I’ll look into those. I’m a bit confused about the gauge though, the guide someone else posted about from PSB recommends 16 gauge up to 15m and 14 gauge for 14m. If I stick with the QED what kind of loss of sound could I expect to experience?

 

You want to lower the resistance of the speaker cable as much as possible as you go longer. Yeah, depending on the output impedance profile of the amp -- like a very low impedance SS amp vs. a tube amp -- and the impedance profile of the speakers you might have no audible effects at that length with higher resistance cable like 16 awg cable. Personally I take a belt and suspenders approach and just use 12 awg (actually 11.5 awg Cardas litz cable) at any length. You know, why not? A basic 12 awg cable like the Belden 5000UE will have like half the loop resistance per meter of your current cable at less than a dollar a foot in price.

 

I am not familiar with Knuconcpts, but I have BJC 12 gauge with bananas and do not find it too stiff to work with or any such. It just seems to me like a "sweet spot" for home use, and bananas are just so easy to use and provide such a nice solid connection.

 

I've been using 10' Anticables 2.1 speaker cables with no issues. Just order 1 meter shielded IC's for the turntable to the preamp. I want to keep those short.