[MediaSeth]

I just moved into this place.

First, my NAD C350 went into a coma. It won't come out of protection mode whether it's connected to speakers or not. This happened right on powerup.

Second, my NAD 7140 works as well as ever. I don't think it has any kind of fancy shmancy protection mode?

Third step, I order a Cambridge Audio 650aV2. I connect it in the living room. After about 10 minutes, it goes into "three flashes" for overload protection.
     -I check my speakers cables. Good. I check interconnects. Good. Still, there's the problem.
     -Swapped out speakers and speaker cables. It works about 15 minutes, then goes into overload protection.
     - Audio Advisor techs and Cambridge Audio techs are ready for me to return the thing, but neither think
       the problem is the amp. Remember, my trusty C350 died the moment I plugged it in here.

Fourthly, I test the voltage. It's nominally 125. I plug in a Panamax power condition with voltage readings. I get 125. The funny thing is, the Cambridge Audio goes into overload protection RIGHT AWAY when plugged into the Panamax, but will work 10-15 minutes plugged straight into the wall!?!!? I'm confounded.

I'm really confounded. About the only conclusion I can come to is that I want a constant 120 and not 125 voltage, but I thouht that should be within safe operating range. It is also pretty safe to say that equipment I'm using is not faulty. Remember, I tried different speakers and cables and checked all connections.

I've run out of options. I'm frustrated. I can't even enjoy music in my new home.. well..unless I turn up the "vintage" NAD in the bedroom.


Any sort of advice or direction would be welcomed.

[TomS]

I have a Belkin PF-60 power center on my HT and it regularly reads about 124v with no problems on my Arcam gear.

[MediaSeth]

ok -- so if 125v is normal, does anyone have any idea what could be giving my newer amps a hard time while my NAD 7140 and hey, even my Sonic T work just fine?

It's something to do with overload protection on the outputs.. yet two different sets of speakers and cables yield the same results. That's why this is a mystery!

[SET Man]

Hey!

   Well, that is strange. At 125V it should pose no problem with any equipments, especially with SS stuffs.

   Have you checked the wiring of your place to see if they are wired correctly? Grounded? There is an inexpensive checker that you could pick up at your local hardware store. I'm not sure if this is going to tell anything but it is a good thing to know.

   BTW... I'm in Queens, NY. And my V is range around 119-125V and mostly at 123V... not bad. But of cause it is another story during hot Summer days.

    I'm using tubed pre and SET amps.... but I have a PS Audio P600 so I'm not really worry much now

Take care,
Buddy

[MediaSeth]

hm. but none of this explains why I get 10-15 minutes of usage with it plugged straight into the wall, but with my panamax OR my furman it goes into overload protection right away.

I just wanted to throw another wrench into this problem.  It's true, though. No April fools. This is driving my crazy.

[lonewolfny42]

Got a friend with a system nearby ? Take you amps there and check them in his system....see what happens.

[shep]

sounds like an over-sensitive protection circuit. There might be a way to disable it (then again there might not )

[Wayner]

Do you have a dimmer that could be wired on the same circuit?

W

[JimJ]

Heck, the voltage meter on my Monster power conditioner reads 128V almost all the time, and I've double checked that with a DMM...haven't had problems with any of my gear.

[Wayner]

I don't think voltage is the problem. I think the frequency is amuck by some upstream device.

[MediaSeth]

Do you have a dimmer that could be wired on the same circuit?

W

No dimmers at all in this place, but I was planning on installing them. Should I not?

[MediaSeth]

I don't think voltage is the problem. I think the frequency is amuck by some upstream device.

That's an interesting theory. I should point out that I have the same issue whether it's the turntable, CD, or tuner. 

[Wayner]

What I think should be done next requires some investigation. Go to the breaker box and try to determine which circuit breaker the outlet is hooked up to. With that breaker off, find out what other outlets or lights are now dead. After that find out what is hooked up to those outlets or lights and give us a little report.

w

[slbender]

Back 45 years ago when they wired my room, I didn't live here. There are five outlets in this room, four are miswired. Yes, its pretty common.  And Yes, it can wreck havoc with some 3 prong equipments.  And its not my job to rewire their mistakes.  So, on the one outlet that is properly wired, I have a 1 to 6 outlet box plugged in, and my air conditioner connected, and maybe one Reel to Reel and a little Tripath based Home Theater Amp.  From the first outlet box, I have a second 1 to 6 outlet box wired to connect some Reel to Reel decks and CD Players, and from there it goes to a third 1 to 6 outlet box and a surge protector box for the modem, then to a 1200VA UPS for my Pee Cee and Mac computers/modems/scanner, LCD Monitor, and an older 240VA UPS for the Preamp and SET Power Amp; then to a fourth 1 to 6 outlet box which powers my phone machine, phone, laser printer, and a couple of sockets free for me to plug in a soldering iron, shaver, battery charger for my camera... stuff I'm testing, whatever. 

The only time I ever had a problem was with the Tube Preamp, the Stereo SET Amp, the AC, the PC, and the Laser printer on all at the same time, that would blow the 15 Amp breaker, but that was only with the old laser printer which drew about 950 Watts.  My newer Laser draws at most 550 Watts so this is no longer a problem.  My line for the past ten years has been about 122 Volts day, 125 Volts nights.  On one of the other (miswired) outlets, I have a single light bulb in the closet, and on another miswired outlet I have the digital clock I built 30 years ago. 

Check your AC outlets for improper wiring with one of those little three neon lamp AC outlet checkers; it just might be that they are OK, in which case I don't have any answer for you, except... Your amps may have developed problems, independently of the wiring.  Or you may have inadvertantly wired the left channel speaker outputs to the right channel speaker outlets and the Left Speaker to the Right Speaker or something like that   And if the outlets ARE miswired... well there ya go! 

Also many expensive speaker cables, like the thick as your wrist, $100. per foot stuff, especially long runs of it, have way too high a capacitance and cause many amps to go ballistic, especially older transistor stuff, whose power supply capacitors may be failing or falling below spec.  In that case, try some cheapie speaker zip-cord cables and then see if those sets suddenly work.  Ya gotta love those high-end pricey cables, don't ya ?


Steven L. Bender, Designer of Vintage Audio Equipment.

ok -- so if 125v is normal, does anyone have any idea what could be giving my newer amps a hard time while my NAD 7140 and hey, even my Sonic T work just fine?

It's something to do with overload protection on the outputs.. yet two different sets of speakers and cables yield the same results. That's why this is a mystery!

[mjosef]

Mhnnn...this sounds familiar... I once diagnosed a similar problem, power for a short while then no power. I thought it must be a defective outlet and since they were pretty old...changed them both and measured for voltage and it was good. Then the next day I got a call back for the same outlets... no power. Then of course it was a matter of checking the breaker, and the breakers were old PE (defunct Co. with bad rep.), changed that particular one...but still, no power, but I do get a 120V reading, but just no sustainable juice to even power a lamp.
Tracing the circuit from the panel to the outlets was easy because the basement was not finished, found the problem in a junction box...loose wire under the wire nut. Maybe you have an intermittent
connection problem somewhere between the outlet and the panel. Check the outlet first then the panel, extending to the circuit run.
Good luck.

[MediaSeth]

Mhnnn...this sounds familiar... I once diagnosed a similar problem, power for a short while then no power. I thought it must be a defective outlet and since they were pretty old...changed them both and measured for voltage and it was good. Then the next day I got a call back for the same outlets... no power. Then of course it was a matter of checking the breaker, and the breakers were old PE (defunct Co. with bad rep.), changed that particular one...but still, no power, but I do get a 120V reading, but just no sustainable juice to even power a lamp.
Tracing the circuit from the panel to the outlets was easy because the basement was not finished, found the problem in a junction box...loose wire under the wire nut. Maybe you have an intermittent
connection problem somewhere between the outlet and the panel. Check the outlet first then the panel, extending to the circuit run.
Good luck.

Nope. It's not even that. Through the same outlet connected to a Panamax Power Conditioner I have a Rotel RCD1070, TT, Proton Tuner.. nothing is actually losing power here. The amp is going into overload protection. This is an amp with four protection modes. It always goes into the third mode, which is overload but not shorting. The NAD amp just went DEAD, by comparison. The older NAD doesn't have any problem. Neither does the tri-path amp.

I'd say for sure it was the Cambridge Audio amp if it didn't also happen with an NAD.

Today, I'm going to hook up an Alesis RA100 pro amp to the pre-outs of the Cambridge and see if the pro amp complains. I already know the Cambridge will not go into protection mode when it's not driving speakers. (and just in case - yes I tried two different pairs of speakers/speaker cables).

I'm willing to replace the Cambridge Audio amp because I obviously can't use it anyway, but then I have to figure out an amp that's not so complain-y about overload.

[Dan Driscoll]

The voltage is probably not the problem. Someone mentioned frequency variations, there could also be spikes or transients on the line, high frequency noise riding the AC, etc. You would not be able to see any of those or many other potential problems with a DMM. I'm not familiar with your Panamax, so I don't know if it would fix those problems or not. The only way to check it positively would be with an oscilloscope or a chart recorder.