Tube Monoblock location? - Rack or near speakers?

Thanks for the question Cooljazzcat (nice name). The general rule in electronics is to minimize the cable length if you are concerned about losses (power) and phase shifts due to the reactive impedence caused by the inductance and capacitance of the cables. The inductance caused reactive impedance is 1/jwl and the capacitance caused impedance is jwc. where c=capacitance of the cable, w=2(phi)f and f is frequency and phi is 3.14157...... for inductance l=inductance. These values change depending on the length of the cable and the frequency of the signal. As you can see, the simple impedence is R+1/jwl+jwc. Basically, real+reactive impedance. One is fixed (resistance) and the other varies over frequency. A nightmare if your equipment is not really designed to handle variations in impedance. They are designed for a particular imput impedance that it will see and for a particular output impedence that it will see. But a good designer must account for real and reactive impedance variations. So, the shorter the cables, the better. The rediculously expensive cables with internal networks are built to try to reach a point of resonance where the inductive reactance and the capacitive reactance over a certain frequency range basically cancel themselves out and you are left with only resistive load on the wires. That resistive load causes losses in the form of real power (IxIxR) losses. Current squared times resistance of the wire. This is why electrical transmission lines are of much higer voltages, 230kV, 500kV, etc. The higher the voltages, the less the impact of the losses on the line will be. I hope I didn't put you all to sleep. But, this is not magic. It is science and everything else is basically creative nonsense. But, if the equipment isn't designed very well, then yes, you have to play with the cables to get good sound. Not really because the cables are better, but because the equipment was designed poorly. It is really hard to design an amp or pre-amp that will handle all the really desired design characteristics with load over frequency and impedance, voltage, current, phase, and power ratings and not oscillate like crazy. Really? this is why the best equipment cost a lot of money. But, a one foot pair of Mogami 10 gauge speaker cable would really sound the same or better than a five foot $2,000 cable if the equipment was designed property.

enjoy

Minorl, thanks for your reply. So what is the maximum length of speaker cable before you start to have issues? I was told 10ft is typical.

Thanks for the question Cooljazzcat (great name). There really isn't a quick and dirty answer or correct or wrong answer to your question about maximum cable length. it depends on 1) how well the electronics were designed and built, 2) quality of the cables, 3) impedance and phase interaction between cables and equipment. However, if you can, check out the specifications of your equipment, eg, input impedance, output impedance, loading that the equipment can handle over frequency, etc. Also, look at the specs of the cables, particularly, the capacitance, resistance and inductance per unit lenght, and if they list it (probably wont), the capacitance and inductance impedance variations over frequency for the cable. That will tell you volumes. But, here is the best way. Have a good relationship with a Stereo store and ask them if you can take sample cables home for a week to audition them with your equipment. They don't have to be the perfect length for your equipment, but that will tell you what you want to know. Also, and this is important. Purchase the equipment that you are auditioning from that store. If you show them that you are serious and will buy from them, they will let you audition the equipment. Especially in this market today. Give them a credit card and they won't charge to it until you either don't return the equipment or when you purchase it. My favorite store is far from me, in San Diego, CA (Stereo Design). I have purchased most of my equipment from them over the years. They allow me to take equipment home (to Los Angeles) and listen for a week or so. Cables and electronic both. I trust my ears first, but their recommendations are valuable to me also.

So, ask to audition equipment (leave the credit card info.) and see for yourself. If your store won't do that, go to one that will. As you know, equipment sounds much different in the store than in your home and purchasing blind doesn't work for me. But, once I use their expertise and consideration, I buy from them, not elsewhere. I want to keep this Dealer in business. So, if I am going to purchase, I typically go to them first.

Enjoy.

I am in the same boat set-up wise.

However my question is a little equipment specific, sorry OP for hijacking the thread.

I am running the ARC Ref5 preamp to CAT's JL3 Mk.2 monoblocs. My dealer says single-ended sounds better but I am concerned that the 5meter length of ICs will degrade the sound. (I will use Nordost Freys)

What do you guys think?

5 meters is a long way to run single-ended cables.

FWIW your dealer must not know what balanced lines can do. His statement is preposturous.

But since the CAT has a single-ended input, and because the ARC does not support the balanced standard (which includes the ability to drive 600 ohms- you'll find it looses bass and output when trying to drive such a load) you are probably better off running the long single-ended cables. I know that the preamp has a 600 ohm output impedance but that is not the same as saying it can **drive** 600 ohms, and for balanced operation, that is important.

If the ARC did support the standard, you could run balanced lines to a set of transformers that could convert balanced to single ended right at the input of the amps. That way the length of the cable would not be a source of degradation. Jensen makes a nice set of transformers for that purpose that are 600 ohm to 600 ohm- now you see why I mentioned that part of the balanced line standard.