That doesn't make much sense to me. Granted, toroidal transformers can pull a lot of inrush current we they turn on but a 20A circuit should be able to provide that without browning out. I'm beginning to wonder if the Monster isn't the choke point and is causing the brownout when hit with the big inrush.

Take it out. See if #4 breaks

I wish he would give the full amp list. At one time the front right and left were tri-amped and it did not stop there.

Put a voltmeter with a save feature on the power strip and turn on all your equipment to see how low it goes. All my music equipment is powered by the APC-15 and it doesn't dip more than a volt when the amp and sub turns on.

He did this right after he and I started talking about the problem at another forum. There was a radical drop that at times would be out of even the wide spec for voltage leveling listed in the manual for the APC-15 you use. Nice unit by the way and I have been looking at them closely for my own system.

EEman mentioned the inrush current a toroidal transformer can be capable of pulling. Now imagine there are eight or nine of them all trying to power up at the same time.

I would replace the breaker that feeds the circuit. Years ago I had a breaker to a dryer circuit that showed good voltage right up until the dryer stared then the dryer wouldn't run. Circuit City replaced three dryers before I finally replaced the breaker. If he is trying to fire up 8 amps at the same time he is overloading the circuit. Has he tried starting them manually one at a time?

Why does it take a forum member to suggest the obvious?! Big thnx EEman for your input.

When I called about the third failure, the person hesitantly, seemingly reluctantly, suggested a conditioner - but didn't HINT Outlaw sold them!

I'll look at them tomorrow PM.

first two unit failures were before I learned of the damaged neutral. The third failed after power neutral repair and install of dedicated 20A line.

Noooo, they didn't say, shame on me didn't ask. SteveB volunteered the answer - thnx dude!

I hope what follows will answer most of y'all's questions though it may cause new head scratchin'. For brevity BNR = before neutral repair; ANR = after neutral repair

BNR, in various places, line voltage would go up & down like the stock market has lately, 5-10VAC. When the electric dryer would turn on, it would drop to 67-70VAC(!) in my family room/home theater.

ANR w/electric dryer still in the mix, I measured 1-1.5VAC. Under a volt on the dedicated 20A line. BTW: BEFORE reinstalling the 975 we switched to a gas dryer.

The 20A line voltage steady @ 119.9-120.1. When the amps & sub kick on, momentarily drops to 116 then quickly recovers to 119. Anyone want to guess why it pooped the third time? I can't even begin!


For you, Steve, my man! Please pardon the correction below - you ARE, however, speaking the truth in advance! The ANR configuration has just one change: the Furman Miniport 20 feeds power to the Belles amps, the MC strip handles everything else

A quick preface: LR speakers come w/4 binding posts (bi-wire) I modded for active bi-amping, using an active XO for the curious. Mid/tweet the "tops," the "bottoms" a pair of what Polk call subs; a 7" sub(?) Yup. Well...maybe...they're rated to 35hz
The amps:
Rotel RB-985* rated @100***&160**WPC/8&4 ohms, powers the CC & the L&R tops
Separate L & R Belles Series 1 rated @ 100WPC powering LR bottoms
Hafler XL-280 145/WPC powering rears
Audio Pro B1.35 powered sub
* using 3 of the 5 channels; toroidal in PS
** tested exceeding power rating all channels driven, while meeting distortion specs

I so appreciate everyone's time, interest, & help in the search for "no more returns to repair!"
Tony

thanks for the welcome Steve and you're likely more right* than you know*. I'll call you some time this weekend. I want the next $pent on this (problem**) to be the last.

I'm dyin' to finish the work to tri-amp my LCR but I hafta get past this distraction** first. I have IC cables to make, binding post upgrades & additions to do before I can rip out the last of the passive filtering.

While the Surgex SA line that we carry has filtering for EMI/RFI and transients, it does not have AC regulation in order to protect against voltage sag or brownouts. As such, it would not solve 975 destroyer's problem. It does appear the Tripp Lite unit has AC regulation though. Unfortunately as voltage drops, current rises and voltage sag or brownout like conditions could blow internal fuses and damage internal circuitry.

I agree with Ben (sort of). I don't think the problem is transients and brownouts coming from outside as much as I think the transient and brownouts are generated by the system and back-feeding the 975. I'm concerned that the number of amps on the one circuit are causing high inrush currents (transients) and POSSIBLY low power factor (a potential source of brownouts) although I need to think about this some more. Adding protection to the input power is unlikely to solve the problem UNLESS it also isolates the individual loads from each other

BTW, It does makes sense to me that a floating neutral on a 240 volt feed to a dryer would cause a lot of problems with voltage levels on individual circuits as the input to your house is a center tapped transformer. Doesn't explain the third unit failure though.