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VTL 450 mystery - please help


Hello Folks:

I am now the very proud owner of the VTL MB-450 monoblock. They were built in 1998 and upgraded with every available option in 2003. The seller has an impeccable reputation and I trust him. With that said, something very very upsetting is happening that I could use some advice on.

The first night that I used them, I brought them over to a friends home who has a new PS Audio Premier power conditioner and we plugged both of the amps in and listed for a few hours with no problems. Late that night, after I left, one of the amps B+ fuses blew out.

When I went over to run some tests, we found that both amps tube bias readings are about dead-on and while we were working on one of them with no signal, the other fuse in the other monoblock also blew and I thought I observed one of the tubes near the front of the unit glow unusually bright just before that happened.

The preamp that my friend has is passive, built by Creek and was not muted. The home also has one dedicated power line and one older power line that the other unit was running through.

Bea at VTL told me that sometimes power conditioners inhibit the amount of current that these amp's need to function. She also recommended that I buy a new set of tubes.

Can anyone help?!!

Thanks.

D.H.
danhirsh

Showing 3 responses by nrostov

nrostov's avatar
nrostov
199 posts
 
Just for the record if you call PS Audio they will tell you that their power conditioner's can't handle the VTL 450's. Too much power for them. I don't know if this would cause a tube to go bad but it will restrict the dynamics. I use the hydra 8 because a. it's passive b. it can handle my amps.

Usually when the B+ fuses blow it is a bad tube. The easiest way I found to test for a bad tube was to remove all the tubes, put in a new B+ fuse, and put one tube in at a time, until the fuse blows again.
nrostov's avatar
nrostov
199 posts
 
Hey Oz/JC51373,

I have to respectfully disagree with you. I plug both my VTL's into my Shunyata Hydra 8 and have dramatically better sound than when I plug them into the wall. Now I have to say that plugging them into a Shunyata is like going straight to the wall except you get surge protection and noise free power.

Justin
nrostov's avatar
nrostov
199 posts
 
No I don't. When I got my Shunyata I a/b'ed with the wall outlet. There was a dramatic(and I am talking night and day difference here) increase in dynamics when I plugged my amps into the Shunyata Hydra 8.
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