shabtek said:
Is that the only reason to call the cables junk?
Might under-heating be desirable?
I know the connectors are likely a compromise...don't know about general durability and screen/shield,
Might be useful for different project or power supply:
either parallel conductors for less V-drop or make adjustable power supply
No, that is not the only reason to call it junk! The first, and most glaring, problem is the undersized FIL conductors. The MAIN problem, regardless of conductor function, is flat out low quality conductors. Feed some various voltages through the cable and read. Low and behold, they are all low. I can not remember all of the voltages I tested but, the PSU FIL voltage was higher than 6.3V, more like 6.7V. So, with that said, that is a one volt or a 15% loss! YOW! A 15% loss through the mic cable has to be generating some kind of heat not to mention possible noise. Now, start throwing 200V plus through it and one could run into a potentially dangerous situation not to mention noise(again).
As for adjusting the voltages to read correct at the mic: Yes, this could be beneficial. But, again, the problem is not the PSU, it is the stock cable! Adjustments made to the PSU voltages are merely a "Bandaid" to the real problem. As for running FIL at lower power, this is a terrible practice that has gone on for years because Neumann did it for years in their U47. Yes, FILs can be ran at +/- 10% of their rated voltage(in most cases!) but, it is not a good idea to do so. Running the FIL at a lower than rated voltage CAN extend the life of the tube but, not always. Plus, the sound/tone of a tube/valve FIL being ran at a lower voltage can start to sound "mushy" IF the voltage drop starts to get too low. On the other hand, running a tube/valve FIL at a higher voltage results in that valve's life to be shortened by as much as 50%(!) and it does not sound that good. Hard to describe really. It makes the sound/tone a little "hard" in the midrange. That is the best way I can describe it. I have done extensive testing on an Epiphone Valve Junior which comes with it's FIL jacked way up. I measured 6.8V on mine and it had a terrible tone even after some mods. After I soldered a resistor in there, the FIL voltage lowered and the tone improved. Not night and day but, markedly better (in the mids mainly).
On the other hand, some tubes FIL have a wider voltage range namely compactron tubes. This allows an 11V FIL to be ran at 9V, an 8V to ran at 6V ect. One can increase the life of a tube by slightly lowering it's voltage. By lower I mean 6V for a 6.3V tube/valve, 12V for a 12.6V and so on. Notice that it is a 5% drop not 10% plus! The slightly lower voltage will not effect the tone/sound.
Before any of you start with your "defaming" of what I said, go out and buy Merlin Blencoe's books on tube amps. Yes, it is not microphone book but, loads of valuable tube info that applies to ALL tubes not just amp circuits. So please, DO NOT take what I say as truth, go find and read for yourselves!