power conditioning

by rymi Sat Jun 10, 2017 7:40 am

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Join date : 2017-05-20

Post n°1

power conditioning

by rymi Sat Jun 10, 2017 7:40 am

Vta st70 & 120 users-

I was wondering if any of you are using power conditioning with your amplifier?

Are you using a UPS to prevent hot switching of the amp in the event of quick power outages and other line abnormalities?

How concerned should i be about that?

Thanks.

by **Bob Latino** Sat Jun 10, 2017 8:36 am

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Post n°2

Re: power conditioning

by Bob Latino Sat Jun 10, 2017 8:36 am

rymi wrote:Vta st70 & 120 users-

I was wondering if any of you are using power conditioning with your amplifier?

Are you using a UPS to prevent hot switching of the amp in the event of quick power outages and other line abnormalities?

How concerned should i be about that?

Thanks.

Be careful using power conditioners with tube amps. SOME less expensive power conditioners do not put out AC in the form of a true sine wave. Many tube amps will choke on power sent out by an inexpensive power conditioner. The best thing to do is check with the manufacturer of the power conditioner that their conditioner in fact DOES put out a true sine wave.

For power outages the Shockshield GFCI plug is recommended. See link below. If you lose power, the Shockshield must be manually reset. It also will trip if you get a power surge ..

Shockshield GFCI

Bob

by deepee99 Sat Jun 10, 2017 2:48 pm

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Post n°3

Re: power conditioning

by deepee99 Sat Jun 10, 2017 2:48 pm

Bob Latino wrote:

rymi wrote:Vta st70 & 120 users-

I was wondering if any of you are using power conditioning with your amplifier?

Are you using a UPS to prevent hot switching of the amp in the event of quick power outages and other line abnormalities?

How concerned should i be about that?

Thanks.

Be careful using power conditioners with tube amps. SOME less expensive power conditioners do not put out AC in the form of a true sine wave. Many tube amps will choke on power sent out by an inexpensive power conditioner. The best thing to do is check with the manufacturer of the power conditioner that their conditioner in fact DOES put out a true sine wave.

For power outages the Shockshield GFCI plug is recommended. See link below. If you lose power, the Shockshield must be manually reset. It also will trip if you get a power surge ..

Shockshield GFCI

Bob

That's the one I've got; it has saved us from a train wreck several times. That, and the time-delay relays.
You're probably looking at close to a kilobuck (or more) for a Furman or equivalent power conditioner that puts out a pure sine wave and clamps output voltage to +1/-1 VAC of 121 pretty much regardless of what it's fed. Output comes from various taps on a toroidal xformer. Spendy, and heavier than a pair of M-125s, though.

by rymi Sat Jun 10, 2017 3:28 pm

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Post n°4

Re: power conditioning

by rymi Sat Jun 10, 2017 3:28 pm

Do you get a lot of nuisance tripping with that gfci plug?

gfci's aren't the most forgiving devices, I know they don't particularly like motors... I wonder about the transformers.

Does it induce noise?

by wildiowa Tue Jun 13, 2017 11:46 am

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Post n°5

Re: power conditioning

by wildiowa Tue Jun 13, 2017 11:46 am

Variac. Set at 117-119vac and forget it. Variac!

by corndog71 Tue Jun 13, 2017 1:11 pm

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Post n°6

Re: power conditioning

by corndog71 Tue Jun 13, 2017 1:11 pm

On my tube gear I use a Blue Circle PLC Thingy and DC Offset blocker and for just the amps a PS Audio Duet and Variac.

by Corona Tue Jun 13, 2017 2:46 pm

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Post n°7

Re: power conditioning

by Corona Tue Jun 13, 2017 2:46 pm

I generally keep my audio stuff on APC UPS systems to prevent those quick 'power flickers' which can blow your rectifier tubes or cause other damage. I also use a furman power station 8 with my main system.

by deepee99 Thu Jun 15, 2017 9:10 am

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Post n°8

Re: power conditioning

by deepee99 Thu Jun 15, 2017 9:10 am

What is this obsession with variacs? They ride up and down with the incoming power fed to them. Great on the bench if you're powering up old gear and want to start at 60-70 VAC to form-up caps and see what the tubes can handle & etc., but as a steady-state power source, I don't think so. Perhaps my negative opinion is biased by the fact that both brand-new variacs I bought quickly developed ground faults, and it wasn't the fault of the VTA equipment they were upstream of.
I haven't had any nuisance GFCI tripping (at least not with the model Bob L. described, which is what I use.) And I do like the steady-state sine-wave output from the better Furmans. Line voltage from 108-130 VAC will come out of the Furman at 121, give or take one volt. But again, they are spendy.
As far as power "conditioning" goes, a dedicated circuit for the cost of a 15- or 20-amp breaker and a few yards of Romex will get rid of 99 percent of line racket. Just don't be plugging the vacuum cleaner or a fluorescent light into the outlet when you gear is running.

Last edited by deepee99 on Thu Jun 15, 2017 9:12 am; edited 1 time in total (Reason for editing : typo)

by corndog71 Thu Jun 15, 2017 3:09 pm

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Post n°9

Re: power conditioning

by corndog71 Thu Jun 15, 2017 3:09 pm

deepee99 wrote:What is this obsession with variacs? They ride up and down with the incoming power fed to them. Great on the bench if you're powering up old gear and want to start at 60-70 VAC to form-up caps and see what the tubes can handle & etc., but as a steady-state power source, I don't think so. Perhaps my negative opinion is biased by the fact that both brand-new variacs I bought quickly developed ground faults, and it wasn't the fault of the VTA equipment they were upstream of.
I haven't had any nuisance GFCI tripping (at least not with the model Bob L. described, which is what I use.) And I do like the steady-state sine-wave output from the better Furmans. Line voltage from 108-130 VAC will come out of the Furman at 121, give or take one volt. But again, they are spendy.
As far as power "conditioning" goes, a dedicated circuit for the cost of a 15- or 20-amp breaker and a few yards of Romex will get rid of 99 percent of line racket. Just don't be plugging the vacuum cleaner or a fluorescent light into the outlet when you gear is running.

For me it's kind of needed as the AC in my apartment in Chicago runs 120-125VAC and I don't use a tube rectifier in my amps which leads to higher B+. Haven't had any problems with my variac in 3 years and my amps are happier with 116VAC which I confirm with a Kill-A-Watt.

by Peter W. Thu Jun 15, 2017 3:32 pm

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Post n°10

Re: power conditioning

by Peter W. Thu Jun 15, 2017 3:32 pm

For me it's kind of needed as the AC in my apartment in Chicago runs 120-125VAC and I don't use a tube rectifier in my amps which leads to higher B+. Haven't had any problems with my variac in 3 years and my amps are happier with 116VAC which I confirm with a Kill-A-Watt.[/quote]

Not to be snarky at all, as I have, essentially, the same issue with variacs as DP99. But.

a) If your wallplate voltage runs from 120 - 125 VAC (agreed, the latter is too high for most tube equipment) and,
b) You have set your variac to 116 V at 125 VAC,

Then, it will float between ~116V and ~110V in actual output. I know that my vintage tube equipment is perfectly happy at 110 V, and many of my vintage radios actually prefer it. But not everything.

Or, if you have set it for 116V at 120V, it will vary between ~116V and ~121V. Despite Bob's assurances that 121 VAC is fine. I am unhappy at anything above 120 VAC going into my 'stuff'.

Bare variacs are good for dimming lights. Full Stop.

Were I in that situation (and, thankfully I am not at this time), I would invest in a true-sine-wave 1,500+ watt PC and adjust to 117 VAC-out for all incoming voltages. Against the cost of even one piece of equipment, it is a quite reasonable cost for peace-of-mind.

by **Bob Latino** Thu Jun 15, 2017 5:38 pm

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Post n°11

Re: power conditioning

by Bob Latino Thu Jun 15, 2017 5:38 pm

deepee99 wrote:What is this obsession with variacs? They ride up and down with the incoming power fed to them.

Yes - they do ride up and down as the line voltage fluctuates but variacs are relatively inexpensive. The one at the link below (as of today) is only $55 with free shipping and will handle any VTA ST-70 or ST-120.

5 amp variac from Circuit Specialists

The more heavy duty 20 amp unit below will handle two VTA M-125's and costs a little over $100 with free shipping.

20 amp variac at Circuit Specialists

Yes - Both are made in China but reports from customers tell me that they work as advertised. I am lucky here in Massachusetts. My line voltage has never gone above 120.4 VAC. I had one customer in Texas tell me that he measured up to 126.7 VAC at the AC outlets in his home. Every user of a tube amp should measure his AC line voltage. Anything above about 122 VAC will cause shorter tube life especially the rectifier tube. A variac will always put out a true sine wave and is relatively inexpensive considering the $$$ you have put into your music system.

Deepee does make a good point though. A GOOD power conditioner will adjust the voltage UP and DOWN slightly to compensate for line voltage changes. The problem with inexpensive power conditioners is that some of them do not put out a true sine wave. A tube amp will choke if not fed AC current in the form of a true sine wave. If you like power conditioners, check with the manufacture to be sure that it puts out a true sine wave before connecting up your tube amp.

Bob

by bluemeanies Sat Jun 17, 2017 7:41 am

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Post n°12

Re: power conditioning

by bluemeanies Sat Jun 17, 2017 7:41 am

My m125's are connected into a kill-o-watt, the kill-a-watt is connected to a VARIAC and the Variac is connected to a fault line detector purchased at the HOME DEPOT.
Variations of line voltage in my house are crazy at ALL times of the day. Lows of 117 and highs of 125.
I also have a Furman Elite line conditioner where all other equipment is connected except my Outlaw 7700 amplifier which is connected to another fault line detector.

by arledgsc Sat Jun 17, 2017 9:06 am

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Post n°13

Re: power conditioning

by arledgsc Sat Jun 17, 2017 9:06 am

For years I have been using a Furman P-1800 PF. It's a 1-U rack mount unit designed for electronic musical instruments. Has overvoltage/ surge protection, filtering in the audio band including ground, plus a special power factor corrected output specifically designed for tube amps. And has a nice voltmeter on the front displaying the incoming line voltage. Built like a tank as I have my ST-120 sitting on top of it.

by aguaazul Sat Jan 11, 2020 6:59 pm

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Post n°14

Re: power conditioning

by aguaazul Sat Jan 11, 2020 6:59 pm

Is it necessary to have the Manual Reset GFCI in front of the Furman SPR-20i Power Conditioner?

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