For point-to-point internal wiring I use 18g silver-plated with 600vdc breakdown. There’s a guy on eBay who sells MILSPEC teflon-coated (not the cheap PVC stuff that melt/shrinks while you solder it) by the foot. Not cheap, but very high quality stuff.

Thank you, Stephe. Better views: Like I’d said, I got the wrong OPT’s, the 507S models. Correct size ones H-20-7U (5k/7k) OPTs are en route. These I’ll sell on ePay. Still sound awesoime though.

When I was young(er) my brother, a former NASA aerospace engineer who went into audio equipment repair, showed me how to build a current-limiting light bulb gadget. It’s worked for me for many decades (arithmetic is pretty simple,, VA=W so a 100W light bulb will pull a steady-state 0.85A on a 120 VAC circuit and blow if inrush current exceeds… I forget it’s been so long) but it’s only been the past ten or so years I’ve started using a variac upon advice of many in the field. Seems like a reasonable precaution given the time/money invested, I just don’t know how necessary it is, really.

For over 100 years, USA, European electronic industry powerhouses then Japan, Inc., and now Chicom, Inc. (also encompassing all of greater Asiatic prosperity sphere countries like Taiwan, Malaysia, etc.) have been cranking out radios, audio gear like amps/preamps/crossovers and (but not limited to) medical equipment jam-packed full of electrolytic capacitors. I can’t, for the life of me, believe that every single factory takes such great care exercising due diligence in ensuring each and every capacitor is exposed SLOWLY to increasing amounts of current until full power is reached. Transformers are chokes. Chokes are chokes and, while I don’t know the actual math (any more, calculus and physics is 40 years behind me now), the moment the electrical connection is completed, so too is the magnetic field which “energizes” the circuit. I find it difficult to believe out of the hundreds of millions of pieces of future landfill electronics that, each and every piece was first turned on the way you show OR as I do too and have had recommended to me by IEEE technogeeks and hobbyists since I was doing this stuff in Jr. High School circa 1970. I too use a variac both a 20 amp unit about fifty years old for powering up newly assembled (or discharged for reworking/recapping) gear and another 15A model to limit our wall voltage to 118V (this goes into a sine wave regenerator/UPS unit for my HiFi stack) for older gear built for 115V which was standard US outlet voltage way back when as our local power company - BGE - very frequently cranks up the voltage to 125 and higher. In years past it’s been as high as 127 peaking at 132 (I ran a monitor with memory for over a week one time) which burned out several pieces of audio and video equipment including several high-value UPS units and we had a bear of a time going through our homeowner’s insurance to recoup the costs. I think of this practice as good insurance but, is it really necessary? BTW, how’d it turn out?

Question; when is Ohm's law just a suggestion? Power supply is wired, powered it up and I'm getting 478 +VDC at B+ on either feed. Same voltage out of the rectifier tube + out. In SOME schematics I've seen a 100 Ohm 10 watt resistor there (prior to any capacitors), so I ran some numbers and came up with a dropping resistor value of 240 ohms (478 to 430) at a nominal 0.201 Amps (what Hammond advertises the output as at the HV red leads). Took a pair of 470 ohm resistors (close enough) in parallel and clipped one side to B+ for one channel to compare. Nothing. No difference, same voltage output. It's been 40 years since physics, algebra, trig, calculus but this is simple arithmetic, not complicated derivitives or something, but NOTHING? Should I put the resistor UPstream (at the filament B+ side of the rectifier) FIRST? How/why should that make any difference? Thanks in advance.

Definitely NOT point "C." That's AC voltage at that point. Point B will STILL have an enormous amount of ripple when the idea is to get the 6.3 VAC heater voltage riding atop a 50 VDC "offset" exactly why I'm not entirely sure, so it HAS to be Point A. But which line? And how to compensate for the current draw from that side's anode? Meaning, 50 VDC tapped off 430 + VDC leave 380 + VDC for the other circuit. There's "magic" in that circuit somewhere, I tell ya.

I'm betting Stephe shows where to make the connection in the videos. I found a burner for my Linux laptop and put them all on my android and my iPad for further review. Waiting for an input selector switch or I'd probably be done by now.

I watched that a few months back. Mesmerizing. But how is she going to do any tube-rolling?🤣

I went ahead and blew a few bucks a while back and bought 600V teflon silver-plated solid copper 18g wire in several colors from a guy in California who sells on ePay. I wasted money on a box of multi-colored PVC-coated wiring from the global jungle sales site and the melting point of the PVC is so low as to make it nearly useless. I recycled it all. Teflon doesn't melt, shrink or offgas at normal soldering temps/times and the silver coating conducts heat/electricity really well.

And THAT made all the difference. That "extra" 50 VAC violet line and the arrow pointing TOWARDS B+ (not towards the CT at 6.3 lines for the heaters) really mixed me up. I'm obviously less than a novice (been troubleshooting, fixing SS and tube amps - and a handful of old Heathkit HF ham radio linear amps - by reading manuals and instinct mostly since the early 70's but I lack a fundamental grounding in circuit design and function. I can read schematics to a degree but it's not second nature figuring out the what and the whys). There's another person here asking a question I still have in mind and figured I'd glean from your videos and that is exactly from what point in the circuit is the "COnnect to B+" connected? He drew a picture showing takeoff before the 10H choke, at the takeoff of the two 1.5H chokes, or one of the B+ lines into one of the 300b tubes. Pulling down 50VDC from ONE tube will offset power output, won't it?

I have this from this website. It's the 374bx wiring which is just different enough that it's confused me.

I've been wrong before but this is going to take some time to really wrap my head around. Thank you for taking the time to straighten me out here. Back to the bench...