VT-50

CDLehner

CDLehner

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Nov 9, 2013
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Eastern Shore, MD
Guys...I've been looking for an amp, to pair with my Wyred STP that has been sitting on the sidelines for some time now.

When I got it...it was supposed to be, to feed a completely neutral signal; to the warm-ish Pass XA-30.8. But then the Pass didn't seem like a good match for the KEF Ref 1s (also sitting on the sidelines now...waiting for custom stands :()...so I sold it; and then didn't care for the STP, into Wyred mAMPS.

So I just picked up, this VT-50. Nothing exciting; I know it's an old model...but I'm a sucker for ARC kit, liked the fact that it didn't have 16 tubes to replace, and the price was right...lol.

Anyone familiar with this model, think it could handle 120s?
 
The VT-50 is a good sounding amp and unlike the rest of the bigger brothers in the VT series, it's not a nightmare to bias the output tubes. The best way to find out if it's safe to run KT-120 tubes is to contact ARC.
 
As for 6550s...I know it's hard, to find genuine Winged-Cs anymore (and I had a bad experience, so I'm gun-shy).

What's my next, best bet...for some fresh 6550s?
 
Did you have a bad experience with an SED 6550 from Kevin or just a bad experience in general? If you are going to stick with the 6550 tube, I still think the SED tubes are the best of that breed. I'm pretty sure the VT-50 will run the KT-88 tubes (check with ARC to be sure). If so, the Gold Lion reissue tubes sound very good.
 
mep said:
Did you have a bad experience with an SED 6550 from Kevin or just a bad experience in general? If you are going to stick with the 6550 tube, I still think the SED tubes are the best of that breed. I'm pretty sure the VT-50 will run the KT-88 tubes (check with ARC to be sure). If so, the Gold Lion reissue tubes sound very good.
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Mep, they were from Kevin...through a trusted 3rd-party; but i don't want to discredit Upscale. It could have been an issue with the unit, or a biasing mishap.

Point is...I just hear these tubes, are a real dice-roll these days; even from a reputable dealer like Kevin. He also recommends the Sovtek 6550WE and Tung Sol reissue, for ARC amps. Yes, I was curious about KT88s...and need to call ARC, and see if 90s or 120s are an option.
 
CDLehner said:
Mep, they were from Kevin...through a trusted 3rd-party; but i don't want to discredit Upscale. It could have been an issue with the unit, or a biasing mishap.

Point is...I just hear these tubes, are a real dice-roll these days; even from a reputable dealer like Kevin. He also recommends the Sovtek 6550WE and Tung Sol reissue, for ARC amps. Yes, I was curious about KT88s...and need to call ARC, and see if 90s or 120s are an option.
Click to expand...

Is that like a third cousin twice removed? :rolleyes: Seriously, I don't understand what you mean when you say "they were from Kevin... through a trusted 3rd-party." If you didn't buy them directly from Kevin, how do you know what you bought? Were these used tubes? Why was there a third party after Kevin? How many people owned them from the time they were purchased from Kevin? If you were buying new tubes, why wouldn't you buy them directly from Kevin instead of your third cousin twice removed?

As for KT-90s, to my knowledge, they are long out of production and can't be bought unless you are going for used tubes or somebody who claims to have matched pairs of NOS tubes. It would be great if ARC told you that you could safely run KT-120 tubes in the VT-50. If not, I personally would go for the GL KT-88 reissues.
 
mep said:
Is that like a third cousin twice removed? :rolleyes: Seriously, I don't understand what you mean when you say "they were from Kevin... through a trusted 3rd-party." If you didn't buy them directly from Kevin, how do you know what you bought? Were these used tubes? Why was there a third party after Kevin? How many people owned them from the time they were purchased from Kevin? If you were buying new tubes, why wouldn't you buy them directly from Kevin instead of your third cousin twice removed?
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Mep, take it easy bro. I bought them from someone...who had bought them brand-new from Upscale; and hadn't used them yet.
 
CDLehner said:
Mep, take it easy bro. I bought them from someone...who had bought them brand-new from Upscale; and hadn't used them yet.
Click to expand...

Chris-It just sounded funny to me so I had to try and put some humor in it. Seriously, if the VT-50 can't run KT-120 tubes safely but can run KT-88 tubes, I would go with the GL KT-88 reissue tubes. I have used them and they are very good sounding tubes.
 
For the record...I reached out to Upscale; explaining how I was leery of the SEDs...and asking for a reco, between Sovteks and Tung Sols. Per Upscale...

"I don't blame you about your hesitation regarding the SEDs. We won't even sell them into ARC amps anymore, as the last batches to come from the SED factory before they shut down exhibit a soft vacuum, which causes them to fail prematurely when they are pushed hard."

He recommended the Sovteks, as he says that's what ARC suggests now.
 
UPDATE-

So...I have not had a chance, to try out my VT-50 yet; because shortly after I got it...I blew it up :blush: :( :mad: :S

I'm not experienced with "manual" biasing; so I brought the amp into my office...and had some of the "techs" help me with it. We fired it up, waited 15 minutes...and tested the voltage. Left side was stable and spot-on; right side was a little wobbly. So we waited another 45 minutes or so (per manual...you should measure at 15 minutes and 1 hour).

At the 15 minute mark, I had the "techs" do it...so I could watch, and make sure there wasn't much to it. At 1 hour...I decide to give it a try. I swear...it seems all I did, was touch the 2 voltmeter leads to the test points; just as I had seen the other guy do it. But I must have shaky hands, and I got a pop that nearly made me shite me pants!

So I shut it down right away, and packed it right back up to be repaired at ARC. It looked to me...the untrained eye...that the damage was minimum; some noticeable burn, down on the tracer circuit...where things arced from the test point. And I talked to the owner, and he said he's arced a tracer board before (not necessarily on the same unit); so I didn't feel like a total idiot.

Of course, I was hopeful and optimistic...repair, and therefore cost, would be minimal. After all: I had just bought this piece used, to "try out"; and now was having to shell-out for a repair bill...before I even had a chance to hear it, and/or flip it.

Hadn't heard from ARC in a spell; so I just dropped them a polite line, to see if they had an update for me. Word back today "technician says unit has extensive PC board damage and will need a tube set. Don is in the process of working up an estimate. Should have more info later in the week”.

Yikes; not, at all, wanted I wanted to hear. I'm especially surprised...by the need for a new tube set? Describing the incident that occurred; is it really possible, I could have blown all 8 tubes!!?? I guess what I'm really asking is: (and I think I know the answer) is ARC pretty reputable, for giving it to you straight?

Thanks
 
UPDATE-

So...I have not had a chance, to try out my VT-50 yet; because shortly after I got it...I blew it up :blush: :( :mad: :S

I'm not experienced with "manual" biasing; so I brought the amp into my office...and had some of the "techs" help me with it. We fired it up, waited 15 minutes...and tested the voltage. Left side was stable and spot-on; right side was a little wobbly. So we waited another 45 minutes or so (per manual...you should measure at 15 minutes and 1 hour).

At the 15 minute mark, I had the "techs" do it...so I could watch, and make sure there wasn't much to it. At 1 hour...I decided to give it a try. I swear...it seems all I did, was touch the 2 voltmeter leads to the test points; just as I had seen the other guy do it. But I must have shaky hands, and I got a pop that nearly made me shite me pants!

So I shut it down right away, and packed it right back up to be repaired at ARC. It looked to me...the untrained eye...that the damage was minimum; some noticeable burn, down on the tracer circuit...where things arced from the test point. And I talked to the owner, and he said he's arced a tracer board before (not necessarily on the same unit); so I didn't feel like a total idiot.

Of course, I was hopeful and optimistic...repair, and therefore cost, would be minimal. After all: I had just bought this piece used, to "try out"; and now was having to shell-out for a repair bill...before I even had a chance to hear it, and/or flip it.

Hadn't heard from ARC in a spell; so I just dropped them a polite line, to see if they had an update for me. Word back today "technician says unit has extensive PC board damage and will need a tube set. Don is in the process of working up an estimate. Should have more info later in the week”.

Yikes; not, at all, wanted I wanted to hear. I'm especially surprised...by the need for a new tube set? Describing the incident that occurred; is it really possible, I could have blown all 8 tubes!!?? I guess what I'm really asking is: (and I think I know the answer) is ARC pretty reputable, for giving it to you straight?

Thanks
 
Man...I don't know what's happening, when I try to post from work. Every time I go to edit post...it's blank. So this time, I went back a step...and it looked like I was able to edit. Now I see...it was just re-posting several times!

I'd ask one of the mods to delete the extras; but last time we tried that...it disappeared altogether. So...I guess you just really get the point driven home ;)
 
Yes ARC will give you the straight honest truth. No shenanigans. They are not cheap but will thoroughly go through the unit and let you know what's what. Good luck.
 
It's been a long time since I have seen the inside of an ARC VT-50 amp, but I believe there is a resistor at the top of the board of each channel (between the output tubes) that you are measuring across for the bias. Were you on the resistor or did you touch your meter probes to two different places on the board?
 
mep said:
It's been a long time since I have seen the inside of an ARC VT-50 amp, but I believe there is a resistor at the top of the board of each channel (between the output tubes) that you are measuring across for the bias. Were you on the resistor or did you touch your meter probes to two different places on the board?
Click to expand...

On the resistor test-leads. Here's a pic I took after; I don't know HOW I could have messed it up???



The tech guy (after he picked himself up off the floor. It was loud...like a firecracker), said I must have "slipped" and hit something else. IDK; I'd like to think, I'd be cognizant of a "slip"...but, the damage she is done.
 
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