Tube Monoblock location? - Rack or near speakers?


Mike for quicksilver recommends that I place the mini mite monoblocks close to the speakers to minimize the speaker cable length. This will mean rca runs of 10 to 15 ft! This is contrary to everything that I've heard. I assumed that speaker cable runs can be much longer than rca and are less prone to interference and capacitance + resistance?

Any opinions would be appreciated.
cooljazzcat
Minorl, what would you consider as an acceptable run of speaker cable (length?) thanks
For 4 ohms, 1 meter, for 8 ohms, 2 meters and 4 meters if 16 ohms. Hifitime, I have never heard what you are saying about balanced lines and it is simply untrue. You might tell whoever told you that that they are full of beans. I have yet to see RF problems in a balanced cable- the assertion is absurd!

Balanced lines were developed originally by the phone company decades ago and made trans-continental phone calls possible. A few years later they were in common use in the recording industry- most of your records and CDs were recorded with them, in some cases the cables were over 150 feet long.

In the home they solve the issue of speaker cable length quite elegantly. **If** the preamp supports the balanced line standard, then the length and the cost of the cable is not important in the overall sound. I have seen my 30 foot $85 pair of Mogami Neglex be indistinguishable from a $24,000 set of balanced cables 24 feet long. (The system was mbl101e speakers, with mbl power amps driven balanced by our MP-1)

I've done numerous PA setups over the years. One might interest you. It was in a concert hall- we needed a PA for the singers. The speakers were mounted in the ceiling so we set up amps and ran 40 feet of speaker cable to the speakers. You could not make out the words they were singing! Then we moved the amps to the speakers and ran the same cable, shortened to 1 meter long. We set up a transformer system that allowed us to run a balanced line between the mixer and the amps- the instant increase in clarity was startling!

I've done the same thing in my home, and BTW have a set of SRA stands for our amps as well. They do help (they are some of the best), but by far the bigger difference is seen in keeping the speaker cables short as possible. Since we can run a balanced line of any length with our preamps this is a very easy test to perform.
Hifitime, true, if the noise is in the signal. False, if the noise is common-mode (for example, impinged on the cable itself). Of course, you need a balanced input at the amp to take advantage of that.
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