NOS tubes causing Tranny hum?
cbl117
Posts: 285
Is it possible for "new" NOS tubes to cause transformer hum? I put a matched pair of mullard 12at7 and a matched pair of sovtek 12ax7 lps into my pre and now there is a very faint hum coming from the transformer.
2 Channel
Vandersteen 3a Sigs
Music Reference RM-200
Hovland HP-100
VPI Scout w/ Benz Ace
Rotel RCD-1072
Cardas Golden Reference Speaker Cables
Cardas Golden Reference Interconnects
Cardas Golden Power Cords
PS Audio UPC-200HB
Black Diamond Racing Isolation
Vandersteen 3a Sigs
Music Reference RM-200
Hovland HP-100
VPI Scout w/ Benz Ace
Rotel RCD-1072
Cardas Golden Reference Speaker Cables
Cardas Golden Reference Interconnects
Cardas Golden Power Cords
PS Audio UPC-200HB
Black Diamond Racing Isolation
Post edited by cbl117 on
Comments
-
I don't know if it's possible but you could take the nos tubes out and put the previous tubes back in to see if the hum goes away.
-
I should do that, but I'm lazy and wanted to see if anyone had some ideas.
2 Channel
Vandersteen 3a Sigs
Music Reference RM-200
Hovland HP-100
VPI Scout w/ Benz Ace
Rotel RCD-1072
Cardas Golden Reference Speaker Cables
Cardas Golden Reference Interconnects
Cardas Golden Power Cords
PS Audio UPC-200HB
Black Diamond Racing Isolation -
Bad tube(s) cause all kinds of noise issues. Swap the known good tubes back in one at a time to determine which are bad.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
I tried plugging the preamp into a different outlet and the mechanical transformer hum is gone. The new outlet I tried is on a different circuit. I'm in an apt, so maybe there is some DC in my AC causing the coils in the transformer to get polarized.
After this experiment, I'm assuming its not the tubes. But can someone confirm my hypothesis.
Can anyone reccomend a power conditioner that cleans AC noise AND gets rid of DC?2 Channel
Vandersteen 3a Sigs
Music Reference RM-200
Hovland HP-100
VPI Scout w/ Benz Ace
Rotel RCD-1072
Cardas Golden Reference Speaker Cables
Cardas Golden Reference Interconnects
Cardas Golden Power Cords
PS Audio UPC-200HB
Black Diamond Racing Isolation -
No hum with old tubes. Hum with new tubes. No hum when plugged into different outlet with new tubes. I wonder if the hum would return if you put the old tubes back in while connected to the different outlet?
You're making this more difficult than it has to be. Go back to the original outlet, replace the tubes one at a time, see what you come up with before doing anything else.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
No hum with old tubes. Hum with new tubes. No hum when plugged into different outlet with new tubes. I wonder if the hum would return if you put the old tubes back in while connected to the different outlet?
You're making this more difficult than it has to be. Go back to the original outlet, replace the tubes one at a time, see what you come up with before doing anything else.
Survey says...hum with old tubes in original outlet. No hum with original tubes in new outlet.
F1nut, will NOS that are considered "new" need time break in? I feel like every damn time I sit down to listen, it sounds different. The frequency spectrum seems all over the place.2 Channel
Vandersteen 3a Sigs
Music Reference RM-200
Hovland HP-100
VPI Scout w/ Benz Ace
Rotel RCD-1072
Cardas Golden Reference Speaker Cables
Cardas Golden Reference Interconnects
Cardas Golden Power Cords
PS Audio UPC-200HB
Black Diamond Racing Isolation -
Survey says...hum with old tubes in original outlet. No hum with original tubes in new outlet.
Ah!
Yes, they will need to burn in. 50 hours or so should do it.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk
