Voltage Regulation

[Guest " "]

I wonder what kind of outfit would put this under their trade name

"While you're visiting, check out some of the funky old tubes, books, meters, & stuff, we dug out of the Radio-TV Lab and put on our Ebay Auctions"

Whats the tube number?

[Speedball]

do you believe the same applies to solid state gear?[8-|]

[NOSValves]

While for the most part I agree completely with what Mark has stated in most homes some cases do exist where wall voltage can be a problem.

Case #1 would be Dean where his wall voltage was hitting a high of 131 VAC at night and he was biasing the amps earlier in the day when the wall voltage was at 124 VAC then leaving the on over night. This makes a huge difference on the plate dissipation the output tubes are experiencing in his case exceeding the max by a pretty good margin so he was burning up output tubes. I tested this not long ago with my variac and at that wall voltage the plate voltage was up to near 560V and the bias would get up over .80 at 131 VAC ouch!! Dean has had problem with just about every tube amp he has ever owned until he installed this new regulation device.

Case #2 I had a customer write me the other day and say that when his frig kicks on he actually gets a breif second of zero sound out of his system from a huge power drop. I bet it was his CD player shutting off since the power would have to go out for at least a full minute before the amps would shut down. I'd say that situation needs some attention for sure most likely the compressor in his fridge is about to give up.

All in all who knows what Lisa's problem is since no one else is experiencing what she has and she purchased the amps second hand. I've been asking her to send them in now for maybe a year or more? I'm done guessing at what her problem may or may not be.

No one needs to be constantly adjusting the bias you simply need to set it when the wall voltage at its highest point and forget it. The actual bias number means very little as long as it does not exceed the max. The important part is that they all stay relatively close to each other whether its .65 or .70 means very little if anything to the sound. People get way to overly anal about bias once they learn how to do it! I bet I check my own amps once every 3 or 4 months this with them right in front of my face and the multi meter right on hand most of the day.

The simple fix for folks with high wall voltage of say 125 and up is to lower your bias to .60 to .65 with VRD's.... fairly simple. But in reality the amps were deisgned for 120 VAC and will sound the best with that voltage.

Craig

[Speedball]

......interesting.[8-|]

[Deang]

Mark, with all due respect I have to disagree with you, and I hate disagreeing with you because I don't know the first thing about tube amps. All I can do is relate it from practical experience. I really enjoy the sound of tube amplifiers, but using them was wearing me out until I got the Furman. Like Lisa, I was going through fuses and rectifiers constantly. As long as I left the amps on, I didn't have a problem -- but it was still impossible to maintain a steady bias. Once I put the unit in all problems stopped. When I had both the Canary 300B push-pull and QUAD forties I was literally sitting in the chair anticipating watching them start to smoke -- and neither failed to disappoint. I found myself soldering in new bias resistors at the same rate other people were changing out CD's. Obviously some gear is more tolerant than others to this kind of thing, but I personally think it's a bad idea to take your advice. Sags, surges, brownouts, and blackouts are not things expensive and precious gear should be left unprotected from.

http://www.kerchner.com/electrical/powerline.htm

[meagain]

Hmmm... Interesting. Mark makes sense as well. I guess Dean has a goofy electrical situation. I can see where 131+ can be a problem technically for an amp that wants to be at 120? For me, looking at my numbers.....

10:15am 124.7
12:08pm 121.6
12:20pm 121.2, 120.1,
123.1 VRD at .645-.650 (I biased them to .718ish last night. I
have to bias each time I sit down to listen to music.)
12:22pm 123.4, 121.5
1:03pm 123.3 VRD .722-.725

On this day, I didn't get to 125 so it sounds like I'm 'in the realm' of being OK. (I think). But looking at the bias, I can see if I biased to .720 at 12:20pm, it would be pretty hot at 1:03pm. That makes me nervous and I can see where this could affect tube life. Mostly, I have VERY sketchy electrical in this section of the house. Daisy-chained like crazy. Not kosher. We still have old-style fuses. I have a little ornamental koi pond who's air pump died which created a freeze-over. I stuck a pond deicer in there and in 20 minutes - poof. This whole section of the house blew due to overload. All audio/video dead. It makes me real nervous to have this gear straight into the wall. At least with this current sketchy electrical situation. The Peach and Jolida haven't blown any tubes, but I think the little tubes deal with things better. If the amps check out ok, I still might consider buying a gadget at least to hold me over till a remodel/electrical redo. I might be barking up the wrong tree with this as we really don't have electrical problems other than the recent fuse blow.

The Belkin PureAV offerings seem very cheap and perhaps I can snag one off Ebay for $120 or so. I only fear, at that price point, a sound quality decrease. If anyone can chime in on the PureAVs, I'm listening.

[Deang]

How many instruction manuals warn people about damage from SSB&B? I'm sure there is some, but I haven't noticed any manufacturers giving such instructions about their gear. If you can cite examples, I'd be interested.

I have no idea, but every manual I've ever read says to operate the given unit within the rated voltages -- typically 110-120. They also have nice disclaimers that say if you run the unit outside of the parameters stated by the manufacturer then they aren't liable for any damage, including damage to equipment attached to it. They expect the purchaser to follow the recommendations.

"...how exactly did a million Dynaco tube amps survive for 40 or so years before anyone even HEARD the words "surge suppressor?"

I don't see how you can speak for the thousands upon thousands of units used all over the country over the last 40 years. You make it sound unlikely any of them ever had a problem due to any of the issues under discussion, which seems unlikely. As for what people did before surge protectors -- they usually shut off and unplugged their gear before thunderstorms and during brownout and blackout conditions -- and hoped everything worked right when the power came back on. Don't you guys get thunderstorms on the West Coast? When they roll through here during the summer the lightening strikes put enough static in the air that your hair starts to stand up. BTW, after a brown out last year I lost the fuse and rectifier in the Peach -- remember when I called you for a new one? We also have older homes (like ours), where a single circuit supports half the receptacles on a floor along with the several appliances. I just think every situation is different, and your personal experience doesn't offer much comfort to someone like me who has had a host of problems vanish after putting one of these units into my system.

Various sources: None of them from power correction vendors.

Do not plug your amp into an A.C. outlet where heavy appliances or industrial equipment are also plugged in, such as refrigerators, freezers, heaters. Their off and on transients may cause severe voltage spikes on the power line which could take out weak components. Your amp will not like the brownout condition a 15 amp heater will cause if plugged in together.

A ten volt voltage spike from your AC outlet is equal to a forty to a fifty volt spike in your tube amplifiers power supply which can destroy your power supplys capacitors. The turn on surge can also stress your power supply capacitors. It appears that power supply capacitors are one of the weakest links in every tube amplifier which is why they should be of the highest quality and be conservative rated with at least an extra 100 volt safety margin. It seems an oddity of progress that tube rectifiers are much kinder to tube circuits when it comes to these spikes.

A two year study by IEEE members Martzloff and Hahn completed in 1970 shows that surges and impulse voltage spikes can occur as frequently as twice per hour in a typical residence with peak values of 1500V to 2500V. Spikes in industrial environments are even more frequent and severe. Spikes as high as 5600V were recorded during lightning storms.

A study by IBM in 29 different locations throughout the U.S. showed that an average of 50.7 voltage spikes occur per month which in their study was 39.5% of the total disturbances.

A two year study by Bell Laboratories showed that most locations will experience approximately 25 power line disturbances per year 87% of which they found to be sags below 96 volts. Voltages below 96V can cause the power supply in most equipment to malfunction and thus lead to equipment failure.

[meagain]

Dean - Sorry if I already asked somewhere, but - you didn't notice any sound quality degradation, noise, decrease in dynamics, etc. with the addition of this Furman... right? Do you have 'everything' plugged into it? You have a TV between the khorns I think so I assume DVD players, etc? Or do you just have the stereo pre, amps in it?

[Deang]

I didn't notice anything different with the sound. The Furman isn't a "power conditioner", it uses autoformers to help regulate voltage. I have everything plugged into it except the Television. This is because I unplug it when I listen to music and roll it to the other end of the room.

Has Craig taught you how to retension your tube sockets? Loose connections with your tube pins can cause arcing which will take out output tubes and rectifiers. Uh, yeah, I know all about that too.

[meagain]

Yes, I tensioned them. They were pretty snug to begin with though. Hopefully I did it ok. I'll triple-check that. Both amps do this at an equal rate so it's not just one causing problems. Voltage is at 121.7 at 2:38am so I think I might be good with that.

Dean - Why do you move your TV out of the way when you listen to music? Does the TV affect room acoustics?

[DrWho]

Cuz, isn't 124 high?

All the power filtering we do in the labs at school is designed around a 126V wall voltage, which is the voltage we measure on the wall. A good filter will be able to handle voltage swings as low as 110V and as high as 140V with less than 0.5% variation from 126V on the output.

I've been wondering what the actual standard is supposed to be though, because I've seen a lot of equipment rated for 115/120V and sometimes 110V, but never 126V...sounds like a good question to ask the profs. Maybe the voltage at school is slightly different for some reason?

All that to say, a good power supply should have no problem dealing with the voltage swings. The profs tell us the bigger issue is the power factor which is crap due to all the inductance put on the line from transformers and electrical motors (the majority of the applications for electricity). So the biggest advantage to power filtering is the ability to correct the power factor - I don't quite understand the issue completely, but I've heard it mentioned elsewhere too. I'm not sure what all the furman power conditioners do, but I've heard dramatic improvements in more than one situation...seems I'm not the only one either.

Another way to look at it - good power conditioning isn't going to have any detrimental effects and the extra layer of protection never hurts.

[mas]

I find myself in the middle of the various camps. All have raised some good points.

I agree wholeheartedly with Mark that most of the worry about voltage, above and beyond basic surge protection, is hysteria. Not so much in the notion that there is no trash on the lines, but rather that a well designed power supply will address the vast majority of it.

On the other hand, I have witnessed first hand, individual site specific issues where turn on transients and other fed back line noise have caused significant problems (usually solved by isolating the offending technology on an independent circuit). I have also encountered site issues where power factor and brown out conditions were a real problem, which required assistance from both the utility company to correct (in terms of a new transformer) and additional site based isolation and conditioning equipment.

So I know that both conditions can and do exist.

But that being said, in the average household which is not located in an industrially zoned area, the majority of your attention should be focused on whole house and local surge protection, especially in the often overlooked sources such as the antenna, cable, and network feeds! It is amazing how often folks worry only about the AC and ignore these more frequent sources of damaging surges!

Additionally, rather than spend exorbitant sums for some magic box, simply isolating the AC feeds to the equipment and providing a common ground for all of the equipment will do more for your site related issues than anything else I can recommend - short of a $60K+ Sola UPS - and yup, I have played with plenty of them as well. (No! Not at my home! ;-)

The other comment I have is in regards to losing a bias resister on a tube amp. On the smaller amps (Fischer), and MI amps such as Mesa-Boogie, Traynor, Ampeg, Fender, Marshall, Orange, HiWatt, etc., I have never had a problem with this (knock on wood). But then, when you consider how the MI amps were normally driven and the distortion levels that were intentionally created, one wonders how one could tell when they were working correctly and when they weren't!!! In fact, I actually suspect that there would have been more complaints if they were operating solely in their linear range and not audibly distorting! ;-)

But with the larger (90-125W/ch) push-pull tube amps (Audio Research, Conrad Johnson and McIntosh), when I have lost a drive tube, the blown bias resistor has NEVER failed to act like an ice fishing tip-up to tell me exactly which tube has shorted! I am actually glad that something as small and insignificant as the bias resistor is acting as a fuse in this case - almost to the degree that I wish these resistors were socketed instead of mounted directly to the motherboard!

But, please, continue. I just hope that more listen to the discussion and understand the balance and qualifications that several have posted here - if only to cause more to focus on specifically identified real problems and to cease chasing imagined gremlins many automatically assume live under the bed (or in this case on the AC feeds) all because they have read some exaggerated horror story somewhere else - and most likely in some marketing brochure! And think about it...how often have you ever read a marketing brochure that told you that this or that product (edit: referring to themselves) is most likely not necessary in your particular application? (Edit: Rare indeed. And one that does is generally a superior product not afraid to disqualify itself from inappropriate use.) 'Nough said.

Thanks fellows...

[Parrot]

And think about it...how often have you ever

read a marketing brochure that told you that this or that product is

most likely not necessary in your particular application? 'Nough said.

Not often. But there is Rega, who tells buyers of its turntables not to use record cleaning machines.

[rcarlton]

The Belkin PureAV offerings seem very cheap and perhaps I can snag one off Ebay for $120 or so. I only fear, at that price point, a sound quality decrease. If anyone can chime in on the PureAVs, I'm listening.

Meagain,

I have the Belkin PureAV PF60. Got it for less than $200. I noticed a difference initially, seems everything sounded better. Really subjective.

The nicest feature is it allows me to turn my components on in a set sequence. For example turn on DVD player, Preamp, TV, BFD, amplifiers in that order. Nice blue meter. Huge power cord.

You can see it near the bottom of my Avatar near Mr. Waddles head.

[jackpod]

Another perspective...

Something I didn't see mentioned but will proceed with a big warning message " Don't do it unless you are sure you know what you are doing, and please be careful" For those with the large voltage swings, have you ever gone to your main breaker panel and checked to make sure all the screw terminals are tight? the connections on breakers do loosen in time, constant expansion and contraction from not only the outside temperatures but from the conductors themselves will loosen the conections causing noise, voltage swings and on demand current deprivation. Another place to look is the actual recepticle that the equipment is plugged into. Many track homes, the electrical contractor not only uses the cheapest materials but to save time using the recepticles that you just push the wire in the little hole in the back, very poor connection. Replace that recepticle wih a good backwire unit, where the screw actually tightens the wire against a solid surface. I see a lot of talk about voltage, but nothing of current, remember if the voltage goes up the current goes down and if the voltage goes down the current goes up. Another option would be to take some comparison voltage checks at your main panel, do you see the same swings as you do at the end point?

[meagain]

Meagain, I have the Belkin PureAV PF60. Got it for less than $200. I noticed a difference initially, seems everything sounded better. Really subjective. The nicest feature is it allows me to turn my components on in a set sequence. For example turn on DVD player, Preamp, TV, BFD, amplifiers in that order. Nice blue meter. Huge power cord.

You can see it near the bottom of my Avatar near Mr. Waddles head.

"Mr. Waddles"!?! Are you saying you can program/set this PureAV up to where you can push one button to have everything turn off in a set sequence? If so, that's interesting.

Dean - I just had a nice reprieve from fuse/tube blowing for the last 2? months or so. I can't figure out why, but I was holding off turning them off till I can send them in, then I ordered new Rectifier tubes so I can. I was able to shut them off each night as the problem went away. Till the party ended 2 days ago. I hope what you're experiencing isn't just plain luck.. I guess if your bias is holding so steady as you report - then it must be doing something good.

[Guest " "]

"The nicest feature is it allows me to turn my components on in a set sequence"

This feature (on switch cold starting) used to be very popular with home and office PC users....until it be came apparent that cold starting electronics was contributing to early componet falure. Bypassing the on and off switches on the componets themselves circumnavigates the warming circuts most home electronics have ......there is usally a circut of some type across the poles of the on and off switch...this is obvious when you consider you can use your rmote control to turn the unit on....if it truely was off line with no power....you would not be able to do this.

[rcarlton]

My amps are 30 years old and draw no power when off. The programmable outlet banks allows me to set switched and delay functionality for each outlet bank. This means I can have some outlet banks always on (say for components that need to retain memory or other settings). I can also have outlet banks switched on with no delay or switched on after a delay (great to avoid loud "thump" when amplifier voltage is stabilizing). Setup this way I use one remote to start the system (Harmony 880).

[meagain]

RCarlton - I've been reading up on that Belkin. It seems that it doesn't regulate the voltage to 120 or 124, etc. but shuts everything off if the voltage isn't in a certain range as a way to deal with it? If I'm right on that, I could see this as being annoying at best. Listening to music and having the whole system shut off? If I have this right, then I guess that's the difference in the price point between it and Dean's Furman?

Can anyone confirm this re the Belkin?

[rcarlton]

That's my understanding as well. Not sure what the cutoff is. Never had it cut out on me at all.