VSi60 Tube Amp Startup Power Needs

Gosh. That's an excellent response, Bifwynne. I appreciate you taking the time to respond. That clinches it for me to skip the online/double conversion UPS for the VSi60. Kal didn't actively discourage me from using it, but he did mention that inrush current could well exceed the manufacturer's recommendations for the Eaton EX1000 UPS. I talked to Eaton's tech support and they said the EX1000 could take no more than 7.5 amps, at which point the UPS would overload and the load would drop. Not sure if that's entirely a bad thing. What didn't make sense to me about using a separate breaker for the amp (per the VSi60 manual and per Kal's recommendation), is that it really isn't isolating the amp from the rest of the house because everything is tied together at the breaker box and into the same ground stake outside. The only way to truly isolate a circuit is to ground it separately with its own ground stake at least 10 feet away from another ground stake. I do have some new questions after making several calls to Kal and to Eaton, and after reading your comments. First, if inrush currents are high at startup, doesn't it make sense to limit them with an external device like the Ameritron ICP-120? Any thoughts on this to save on tube life? Second, although I only saw a 5 mVDC drop due to the dryer, I'm assuming that when the AC is on in the summer, the fridge compressor is running, and the garbage disposal kicks on, this 5mVDC could end up being more like a 15 or 20 mVDC drop. Top this off with one of my kids vacuuming their room upstairs, and it could have a detrimental effect on the VSi60, I assume. I'm not that concerned about sound quality at this point because with all that noise, it won't matter. I'm more concerned about amplifier integrity. Third, we had our lights go dim and flicker several times on New Year's eve due to a winter storm. I had music playing. When I checked the bias voltage a few days after that, it had drifted up to 80mVDC on one tube and down to 50mVDC on another. I'm not sure if the flickering did this, but the last time it had been set to 60mVDC was three weeks before that. So, I have a concern about bias drifting long term (not just momentarily due to surges in the house) and I'm still in search of a clean AC source without having to get a new breaker box with a separate ground stake just for the amplifier (unless this is the least expensive option, which I doubt). Fourth, in my conversation with Eaton I asked whether their UPS could keep up with transients, and they said that its response was instantaneous and possibly better than the house receptacle. Their tech said the house outlets will have more time delay since they are tied in with other breakers at the circuit box, and these are supplying the instantaneous demands of the rest of the house. So, I'm not exactly sure if other people's experience with acoustic quality degradation with UPS's is due to overload of their particular unit or due to psychoacoustics. Regardless, a UPS battery backup for a power amplifier isn't the right tool for the job for no other reason than (that) an amplifier doesn't need a battery backup, plus the fact that it could overload a UPS at startup. So, I'm still looking for an economical clean AC solution that won't break the bank. Thanks. -Stuart

OK. The high end audio store in Indianapolis swears by Kal too. And, if your experience is that their amps are robustly built, then I'll go with that. I'll run a separate outlet to the breaker, as Kal recommended. I've only had the amp for a few months and got it used from someone here on Audiogon who just had the tubes and bias resistor replaced at the factory (had receipt of work done). The amp uses KT-120's. Kal didn't have an answer for the drifting in two different directions, but he said to keep an eye on it and call if it happened again. I should probably back up another step here. The entire reason I even checked bias voltage in the first place and found the drift was that the right channel volume was very low after I had made adjustments to the speaker wires and reattached them. I loosened a spade connector behind the amp and the right channel came back. This was after I had switched speakers, switched inputs, and switched interconnects to eliminate all the other possibilities. I've been able to repeat the issue when I tighten that connector too tight, so now I just keep it tight enough and not too snug. The post doesn't move like its loose or anything. Anyway, this is an issue that may or may not have affected bias. At this point, I'm going to reconnect the amp and let it do its thing. If an issue makes itself known, I'll make sure it's repeatable, call Kal, send it in if for repair. I just love how this amp sounds. It really rocks my ML's.