house voltage

[M Fowler]

Well I am concerned because I have a new build which is going to be shipped to Nashville very soon and if they have that high of voltage it could be a problem I should address now.

I decided I was going to run the 5U4 rather then the GZ34 to lower the voltages. I might send both types of rectifier tubes with the amp.

Mark

[Cliff Schecht]

My house voltage hovers around 124vac +/- 3vac. It puts my filaments at 7vac on some of my vintage amps. ?Dangerous??
D

That depends, does the B+ ever reach levels above that which the electrolytics can handle (i.e. with all tubes pulled B+ is higher than rated capacitor voltage). It's only really dangerous then as the electros will eventually fail or perhaps the output tubes display fireworks (rare case!). Running at 7V is a hair on the high side for heaters, but isn't the end of the world. We've been running them high unknowingly for years and for the most part, it just kills the tubes a bit quicker. I've even plugged the wrong tubes into sockets and applied hundreds of volts to heaters. Didn't kill any of the NOS tubes I was using thank goodness, but it was only for a moment.

I posted a rant and questions about high filament voltage on AX84 after I built a P1 w/ the spec'd hammond and had 7.1 on the filamnts. I got a lot of very informed replies and a long white paper from the 1950s detailing tube life with respect to filament V - it matters a lot, and 7V and over is really bad. Funny, at AX84 everyone was, "big deal, just use resistors" but to me that's more space, more parts, more heat, more stuff to fail and not a proper solution. Solution is get the right PT and that Hammond wasn't it.

I was under the impression (apparently wrong) that low filament voltage is harder on tubes than a high filament voltage.
This may be worth looking into more in depth.

rd

They are both hard on tubes. Too low and you can't get a reasonable electron cloud to form. In some tubes this causes the heater to strip of its coating, but AFAIK this only affects directly heated thoriated tungsten filaments when you try to operate them under warm-up conditions. Too high and you'll literally cook the innards and eventually reduce the cathode efficiency. I don't remember who posted it but there is a bell shaped curve essentially showing that tube life drops dramatically if you run the tubes even a few percent outside of their rated voltage. The further you go out, the shorter your tube life.

[azatplayer]

Im in Melbourne, Australia, i have big issues with the power on my house. Had guys out to check it out, they replaced the cable from the pole, but made no diff. Mine swings from 237 max to 225, and it really sux. My neighbour gets 240V bang on always, but as the 3 phases run along the street, hes getting a different phase to me. Mine must be in the house somewhere tho.
I just ordered a 500VA trannie from Heyboer with a low primary and 5 taps at 4V apart, which im gonna build with some kinda dial on it so i can switch in to get my 240V, probably an easier way to do it, but the trannie was the cost of a normal PT for an amp, and i only need to put it in a box and add a switch and dial. Of course i put my house on the market a couple weeks ago, so it might become redundant..

[overtone]

There is a house in England that I have been working on where the electrician has been getting spikes of 288V, the usual supply is supposed to be 240V. It has a three phase supply and sometimes one phase only comes in at 115V or so. That is one big fun palace.

Here in Germany I have been trying get the voltages right on a 1954 Gibson GA-40. We have 230V and I have several step downs, but it ends up either too low or too high on the heaters. I am going to try out a couple of options:
a) accept the higher voltage and fit the usual dropping resistors in series with the heater circuit
b) as the HT voltages in the amp seem to be low, I am going to try a separate filament transformer giving the original '54 PT a lighter job to do. Is my thinking right on this one?
I really don't like messing with this old beauty but it needs a couple of things fixing anyway. The work will be discrete and reversible, but I see no other way as I would like to use it England too, but not in that particular house mentioned above!

[Reeltarded]

Not what I would call empirical evidence by any means, but I have been running variacs as volume controls for around 25 years.

I haven't had any failures caused by super-under volting the whole thing. I even run lil amps in the high 30v range for extended periods for days in a row. I guess I am asking 'where is the cathode stripping?'.

I expected it a million times. Look for it.. nothing. Where is it?

[MCK]

Wow. Never knew it was this bad. At this rate in a few years perhaps all US will run on 220V. Not such a bad thing. Wish we could have 1 voltage around the world. Life would be so much easier for people who make things for other people.

[bb5000]

Here in Sweden I'm getting 220V at my house 15 km from the city center, at most other locations the voltage is 230-235 V..So I have a variac at home that can transform my 220V to 230 and I've verified that the amp can handle all voltages...I have to use the 220V winding on the PT since the heater voltage is a bit low with 230V on the 240 V winding

[Reeltarded]

Wow. Never knew it was this bad. At this rate in a few years perhaps all US will run on 220V. Not such a bad thing. Wish we could have 1 voltage around the world. Life would be so much easier for people who make things for other people.

Not for people who make trouble!

I like the way it is. I'd hate to have to finance the burials.

[Aurora]

All power companies have a tolerance for the supplied norm voltage, usually in the order of +/- 10%, so variations must be expected.
This usually results in subscribers close to a HV transformer substation having higher than normal voltage, and those at the end of the line usually somewhat lower, but today variations close to max tolerance is not very common, except maybe for very rural areas.
Most of Europe have a 230V norm voltage ( as stated by EU regulations) and Norway subsequently changed from 220 to 230 some years ago, to harmonize to a common european system. I live on the far end of an island, where the main supply lines ( HV supply of course) are well over 100 km, but still normal variations are fairly low, ususally in the order of just a few percent, and mostly above spec....

[Structo]

There is a house in England that I have been working on where the electrician has been getting spikes of 288V, the usual supply is supposed to be 240V. It has a three phase supply and sometimes one phase only comes in at 115V or so. That is one big fun palace.

Man, 48 volts over spec?

I would think that is an anomoly.

When I have measured my wall voltage it has never been below 119 or more than 124.

I wonder how the powers that be decided what voltage each country would use?

With 120vac you have to supply more current than at 220vac.

I'm curious as to what amperage the breaker is in a normal lighting branch in a European home, like in England (or any other country for that matter).
Here in America it is 15 amps for a normal branch in a house or 20 amps in the kitchen where you use higher current appliances.

Must be hell on electronics manufacturers to build for two or three different world wide voltages.

[C Moore]

This is an older thread, but very interesting. I am in;
USA CA 94585
I have never seen the wall voltage at 120. It consistently hits between 121-124. Pretty close to 120.
My DMM is an Amprobe 35XP.
It would be interesting to check it with a few different meters, just to see what the numbers are.......

[Cliff Schecht]

124 is not close to 120, it puts the heaters almost 10% too high for your typically loaded 117V transformer. Just because we don't make a big fuss about it doesn't mean it isn't a problem. I'll post a thread on the bucking transformer box I built, it's relatively compact and works like an extension cord. Most 50W amps only need a 6.3V, 2A transformer wired up to get voltages closer to spec.

With a 124V line on a 117V transformer, everything is about 6% too high (probably worse if your transformer isn't loaded to its full rating ala Trainwrecks) which will definitely have an audible difference vs. running the amp at its proper voltage. I think the modern Heyboer stuff is all wound for 120V but even then the heaters end up too high with 125V and up. I guess there isn't much we can do though because it's all so inconsistent nowadays. I've never measured bar voltages but I suspect they are lower than house numbers.

[martin manning]

Poking around on this subject I came across an interesting way to reduce voltages: If your PT has an unused filament winding, for a tube rectifier, say, you can use it to buck down the primary voltage. This might just be the kind of transformer where the secondary runs a bit high on modern line voltages, eh?
https://tubeamparchive.com/viewtopic.ph ... ng+voltage

[Dr-Joned]

As I stated before, if you are worried about a particular amplifier ( ie, old Fender Bassman), you could use one of the the power conditioner/regulators such as:
http://www.tripplite.com/en/products/mo ... delID=2010
I'm sure they also offer a 220/240 for our friends across the pond. I have even seen a programmable unit that was slightly adjustable on the output side.

If you are concerned about future builds, then maybe specifying 120/125/130 volt primary taps. (On the US builds of course)

[C Moore]

As I stated before, if you are worried about a particular amplifier ( ie, old Fender Bassman), you could use one of the the power conditioner/regulators such as:
http://www.tripplite.com/en/products/mo ... delID=2010
I'm sure they also offer a 220/240 for our friends across the pond. I have even seen a programmable unit that was slightly adjustable on the output side.

If you are concerned about future builds, then maybe specifying 120/125/130 volt primary taps. (On the US builds of course)

Hey Doctor.....
That is a pretty good price on that Tripp-Lite. All those things seem to be heavy....20 lbs. Are the Furman rack-mount units that weight? Guess I need to just take a peek......
Thanks For The Info

Well, something similar, and it weighs in at 12 lbs. Not sure if one is any better than the other. They sure seem like a useful piece of gear......don't they..?
http://accessories.musiciansfriend.com/ ... sku=500823