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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peterh
Bob Latino
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VTA-70 Tube Amplifier?
Bob Latino- Admin
- Posts : 3276
Join date : 2008-11-26
Location : Massachusetts
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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[quote="Bob Latino"]
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.
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.
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
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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mijohn- Posts : 119
Join date : 2013-06-19
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%)
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%)
Guest- Guest
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?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?
Bob Latino- Admin
- Posts : 3276
Join date : 2008-11-26
Location : Massachusetts
music wrote: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?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?
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
monkuboy- Posts : 46
Join date : 2016-03-23
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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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.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?
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
It seems from the sparse documentation that is the case.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?
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)
Hops- Posts : 87
Join date : 2019-09-21
Location : South Detroit, Michigan
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.
Hops- Posts : 87
Join date : 2019-09-21
Location : South Detroit, Michigan
I plug a Killawatt into my Variac, and adjust the Variac based on the display on the killawatt
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How long ago was your last incident.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.
Hops- Posts : 87
Join date : 2019-09-21
Location : South Detroit, Michigan
About a month ago. I had the bad rectifier tube, and the bad 6550.
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Did you ever check the wall voltage?Hops wrote:About a month ago. I had the bad rectifier tube, and the bad 6550.
Hops- Posts : 87
Join date : 2019-09-21
Location : South Detroit, Michigan
[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
" 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
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
Funny you mention this : on my APC UPS i am supervising it from a serverHops 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
using "nut" software, giving me graphs for a year.
The APC itself keeps a log which can be downloaded with a computer.
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
MechEngVic- Posts : 107
Join date : 2019-01-16
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
Seems to be what you are looking for !