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    VTA-70 Tube Amplifier?

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    music

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    Post by music on Sun Sep 06, 2020 3:17 pm

    Since I have numerous issues with my two year old VTA-120, such as blowing rectifier tubes, and Variac fuses because of high voltage spikes of 118 to 128, a friend told me to buy a new VTA-70, of which I should have no issues, is this a true statement?
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    Post by Bob Latino on Sun Sep 06, 2020 4:12 pm

    music wrote:Since I have numerous issues with my two year old VTA-120, such as blowing rectifier tubes, and Variac fuses because of high voltage spikes of 118 to 128, a friend told me to buy a new VTA-70, of which I should have no issues, is this a true statement?

    The VTA ST-120 is somewhat more sensitive to higher line voltages than the VTA ST-70 because the ST-120 has higher internal voltages. You have line voltages that spikes to 128 VAC ?  Wow ! I would be on the phone to my power company and find out why ? That said, if you get yourself a power conditioner that will put out a true sine wave and also control the voltage to 120 VAC, your ST-120 will work fine. Check out the Furman at the link below ..

    Furman 215A power conditioner

    Bob

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    music

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    Post by music on Sun Sep 06, 2020 8:37 pm

    [quote="Bob Latino"]
    music wrote:Since I have numerous issues with my two year old VTA-120, such as blowing rectifier tubes, and Variac fuses because of high voltage spikes of 118 to 128, a friend told me to buy a new VTA-70, of which I should have no issues, is this a true statement?

    The VTA ST-120 is somewhat more sensitive to higher line voltages than the VTA ST-70 because the ST-120 has higher internal voltages. You have line voltages that spikes to 128 VAC ?  Wow ! I would be on the phone to my power company and find out why ? That said, if you get yourself a power conditioner that will put out a true sine wave and also control the voltage to 120 VAC, your ST-120 will work fine. Check out the Furman at the link below ..

    Furman 215A power conditioner

    Bob
    [/quote I was told by some people that I would have to spend over $2,000 for a good power conditioner. I had the Utility Company come to my house and check my line, he said I have a transformer 2 houses away, and a power plant nearby, he said I was better with more voltage then less.
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    Post by peterh on Mon Sep 07, 2020 3:01 am

    music wrote:
    Bob Latino wrote:
    music wrote:Since I have numerous issues with my two year old VTA-120, such as blowing rectifier tubes, and Variac fuses because of high voltage spikes of 118 to 128, a friend told me to buy a new VTA-70, of which I should have no issues, is this a true statement?

    The VTA ST-120 is somewhat more sensitive to higher line voltages than the VTA ST-70 because the ST-120 has higher internal voltages. You have line voltages that spikes to 128 VAC ?  Wow ! I would be on the phone to my power company and find out why ? That said, if you get yourself a power conditioner that will put out a true sine wave and also control the voltage to 120 VAC, your ST-120 will work fine. Check out the Furman at the link below ..

    Furman 215A power conditioner

    Bob
    [/quote I was told by some people that  I would have to spend over $2,000 for a good power conditioner.  I  had the Utility  Company come to my house and check my line, he said I have a transformer 2 houses away, and a power plant nearby, he said I was better with more voltage then less.

    The furman mentioned is quoted at $229  and seems to be a good choice.
    Alternativly an APC sinewave UPS will cost about the same and protect the amp
    for glitches in delivery + you will have emergency power for a while at power interruptions.
    This unit cost $284 and has the capacity of 1500 watts ( a 1000 watt would do
    and is cheaper)
    https://www.apc.com/shop/us/en/products/Back-UPS-PRO-BR-1500VA-SineWave-10-Outlets-2-USB-Charging-Ports-AVR-LCD-interface/P-BR1500MS

    In addition you could demand that the utility company pays this as they deliver
    damaged goods.


    Last edited by peterh on Mon Sep 07, 2020 3:15 am; edited 1 time in total (Reason for editing : Added link to APC)
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    Post by mijohn on Mon Sep 07, 2020 6:03 am

    Despite what your utility company have told you at up 128V your supply is clearly outside the standard required.
    In the United States and Canada, national standards specify that the nominal voltage at the source should be 120 V and allow a range of 114 V to 126 V (RMS) (−5% to +5%)
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    Post by music on Tue Sep 08, 2020 7:28 am

    music wrote:Since I have numerous issues with my two year old VTA-120, such as blowing rectifier tubes, and Variac fuses because of high voltage spikes of 118 to 128, a friend told me to buy a new VTA-70, of which I should have no issues, is this a true statement?
    Since I have two pairs of speakers, I was looking into getting one more tube amp, called Rogue, asked about their Atlas Magnum 111, and told him about my voltage spikes, he said no problem. Why is it that that amp has no issues with voltage spikes?
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    Post by Bob Latino on Tue Sep 08, 2020 8:01 am

    music wrote:
    music wrote:Since I have numerous issues with my two year old VTA-120, such as blowing rectifier tubes, and Variac fuses because of high voltage spikes of 118 to 128, a friend told me to buy a new VTA-70, of which I should have no issues, is this a true statement?
    Since I have two pairs of speakers, I was looking into getting one more tube amp, called Rogue, asked about their Atlas Magnum 111, and told him about my voltage spikes, he said no problem. Why is it that that amp has no issues with voltage spikes?

    Your VTA ST-120 amp kit with all tubes is $1200. The Rogue Atlas Magnum III is a $3000 amp. At that price they can put in relays to shut the amp down on your 128 VAC voltage spikes. They can also add voltage regulation circuits to protect the tubes on start up. The 128 VAC spike that you mentioned is the highest voltage ever reported to me by a customer in the last 14 years. Most people in the USA/Canada have AC line voltages in the 118 - 122 range. All VTA amps can deal with this range of voltages with no problems. You have what I would call "a unique situation". If you add in a $230 true sine wave power conditioner like the Furman mentioned above, you can probably run your amp with no issues. You could also sell your VTA ST-120 amp and buy the $3000 Rogue Atlas III ?

    Bob
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    Post by PeterCapo on Tue Sep 08, 2020 8:45 am

    128VAC from the wall is too high. Not long ago I had an issue with our mains that I reported to the power company. Their tech came by but wasn't interested in addressing it. I had to really beat the bushes to finally get in touch with the field service manager. I also obtained the assistance of the State Department of Public Utilities. They finally made an adjustment and now my mains is at a more reasonable level.
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    Post by monkuboy on Tue Sep 08, 2020 10:55 am

    I have a question about the Furman 215A that was recommended. The product page says it shuts down if the voltage reaches 138. Prior to that, does it regulate the voltage output to keep it in a safe range? I'm not familiar with these devices and am not clear exactly how they protect equipment if it allows the voltage to hit 138 before shutting down. Does that mean it maintains a 120V output up until the voltage gets too high to regulate?
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    Post by music on Tue Sep 08, 2020 11:37 am

    monkuboy wrote:I have a question about the Furman 215A that was recommended. The product page says it shuts down if the voltage reaches 138. Prior to that, does it regulate the voltage output to keep it in a safe range?  I'm not familiar with these devices and am not clear exactly how they protect equipment if it allows the voltage to hit 138 before shutting down. Does that mean it maintains a 120V output up until the voltage gets too high to regulate?
    I would prefer not to spend over $230 for the Furman, to see if it will probably work, I already spent over $100 for a variac that blows fuses. I have been checking my voltage all week, so far its ranging- 118-122.
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    Post by peterh on Tue Sep 08, 2020 11:59 am

    monkuboy wrote:I have a question about the Furman 215A that was recommended. The product page says it shuts down if the voltage reaches 138. Prior to that, does it regulate the voltage output to keep it in a safe range?  I'm not familiar with these devices and am not clear exactly how they protect equipment if it allows the voltage to hit 138 before shutting down. Does that mean it maintains a 120V output up until the voltage gets too high to regulate?
    It seems from the sparse documentation that is the case.

    The APC UPS i linked to will "buck or boost" if voltage is outside
    a configurable limit. And it will continue to deliver for a while when power
    fails. All at a price comparable with the furman.

    Ask APC about the limits, as they now are owned by schneider electric it has
    been an enormous improving of their support, then answer the phone
    and i can speak to a knowledgeable person ( at least in europe)

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    Post by PeterCapo on Tue Sep 08, 2020 1:13 pm

    Definitely do research in advance of buying something like this. Power conditioners are not necessarily AC mains regulators. AC mains regulators, at least in the audiophile sphere, tend to be pricey. I'd inquire with the manufacturer about any device that supposedly regulates the AC mains and what the regulation tolerance is. For instance, I looked at a Furman AC mains regulator, and the specified range of regulation fell outside of the usual fluctuations of my mains from the wall, which would render that particular Furman useless.

    The variac and blown fuses - do you mean the fuse in the variac or in the amplifier? The variac fuse should not blow simply becasue your mains went up to 128 VAC or even higher. The variac does not regulate the AC mains, by the way, and you cannot rely upon the scale or meter on the variac itself. The scale or meter on the variac is calibrated for a single assumed value of AC mains coming from your wall. The only dependable way to set the variac's output is with the use of a separate handheld meter.
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    Post by Hops on Tue Sep 08, 2020 7:38 pm

    When I first assembled my 120, the Chinese rectifier kept blowing my Variac Fuse. Once I got a Weber Copper Cap, all was good. My Variac Fuse also blew when a bad 6550 red plated. I suspect blowing the Variac fuse has saved me from other damage. Variac Fuses are cheap.

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    Post by Hops on Tue Sep 08, 2020 8:23 pm

    I plug a Killawatt into my Variac, and adjust the Variac based on the display on the killawatt

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    Post by music on Tue Sep 08, 2020 8:50 pm

    Hops wrote:When I first assembled my 120,  the Chinese rectifier kept blowing my Variac Fuse.  Once I got a Weber Copper Cap, all was good.   My Variac Fuse also blew when a bad 6550 red plated.   I suspect blowing the Variac fuse has saved me from other damage.  Variac Fuses are cheap.
    How long ago was your last incident.
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    Post by Hops on Wed Sep 09, 2020 5:12 am

    About a month ago. I had the bad rectifier tube, and the bad 6550.
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    Post by music on Wed Sep 09, 2020 9:19 am

    Hops wrote:About a month ago.   I had the bad rectifier tube,  and the bad 6550.
    Did you ever check the wall voltage?
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    Post by PeterCapo on Wed Sep 09, 2020 9:40 am

    Wall voltage, BTW, should be monitored 24/7 with a Kill-a-Watt or similar device, placed in convenient line of sight http://www.p3international.com/products/p4400.html

    Spot checks may not be sufficient.  It wasn't until I installed a 24/7 monitor did I realize the true range of variation in my mains.

    Once you establish the range of your AC mains, you could also install one or more appropriately rated NTC thermistors in series with the power transformer primary.  NTC thermsitors ease startup and drop the value of AC mains that the amplifier sees.  Finding appropriate ratings for the thermistor might be a problem, however, but it's worth looking into, IMO.
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    Post by Hops on Wed Sep 09, 2020 5:45 pm

    [quote="PeterCapo"]Wall voltage, BTW, should be monitored 24/7 with a Kill-a-Watt or similar device, placed in convenient line of sight http://www.p3international.com/products/p4400.html
    "  It wasn't until I installed a 24/7 monitor did I realize the true range of variation in my mains."

    Anyone have an idea for an affordable 24/7 recording monitor? I could get by with just the High and the Low of the last 24 hrs, or since the last reset. I will have to check to see if my kill -a - Watt does that..... currently I just look at it when I power up the amp
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    Post by PeterCapo on Wed Sep 09, 2020 5:48 pm

    I think the Kill A Watt sells in the vicinity of $25? I don't think it records, though. I believe it's just a real time display. But if you can look at it often enough, hence the convenient line of sight, it should be sufficient.
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    Post by peterh on Thu Sep 10, 2020 2:41 am

    Hops wrote:
    PeterCapo wrote:Wall voltage, BTW, should be monitored 24/7 with a Kill-a-Watt or similar device, placed in convenient line of sight http://www.p3international.com/products/p4400.html
    "  It wasn't until I installed a 24/7 monitor did I realize the true range of variation in my mains."

    Anyone have an idea for an affordable  24/7 recording monitor?   I could get by with just the High and the Low of the last 24 hrs, or since the last reset.   I will have to check to see if my kill -a - Watt does that..... currently I just look at it when I power up the amp
    Funny you mention this : on my APC UPS i am supervising it from a server
    using "nut" software, giving me graphs for a year.
    The APC itself keeps a log which can be downloaded with a computer.VTA-70 Tube Amplifier?  Rrd-ups_daily

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    Post by peterh on Thu Sep 10, 2020 5:14 pm

    VTA-70 Tube Amplifier?  Rrd-ups_daily
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    Post by MechEngVic on Sat Sep 19, 2020 2:04 am

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    Post by peterh on Sat Sep 19, 2020 2:48 am

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    Post by PeterCapo on Sat Sep 19, 2020 8:14 am

    That's what I'M looking for, too!

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