Prana-Bindu Posted January 4, 2002 Share Posted January 4, 2002 Hello all y'all! A problem with my system is bugging me more and more: I had some warranty work done on my VTL IT-85 integrated amp (tubes) a few months ago, because the remote would not work (it was the amp itself). When I got it back, my dealer told me they had also upgraded some of the components. Well, I think they turned up the gain or something comparable, because the hissing noise floor was increased quite a bit. I didn't complain before, because listening to music was never compromised by the hissing noise. As I've been listenting lately at lower volumes, the hissing has become a real problem. I can hear it in the room with no effort, and the volume or character of the hiss does not change when I adjust the volume. The RF-3's don't make the hissing noise when I switch to headphone operation on the amp, and the choice of source seems to make no difference. In other words, it's coming from my amp. Any suggestions beyond contacting the manufacturer? Will improperly biased tubes raise the noise floor? Old tubes? What gives? Thanks for the beta, people. ------------------ May the bridges we burn light our way.... Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted January 4, 2002 Share Posted January 4, 2002 PB- I have a twenty year old McIntosh preamp and it too has a very light hiss. Thusly it's not the amp section but the variable loudness. The more I turn down (not off) the loudness the more hiss there is. The loudness control, in this case, is just a variable choke. It had this problem when I first got the unit about six months ago. I sent it back for repairs. Only then it was a lot worse. They replaced a couple IC's and it was a lot less apparent (current state). So it may be in the preamp section. ------------------ Tom KLF-20 Mahogany (Cornell Hotwired) McIntosh C33 Preamp McIntosh MVP-841 CD/DVD Rotel RB-1080 Amp Yamaha PF-800 Turntable/ Sure V15 Type V Cartridge Ortofon VMS-30 mkII Cartridge Stanton 999SS Cartridge Yamaha K-1020 Cassette dbx 1231 EQ H.H. Scott 830z Analyzer Monster Interlink 400mk II Monster Interlink 300mk II Monster Video 2 (DVD to TV) Monster Power HTS-5000 MIT Terminator 2 Bi-Wire Speaker cables Studio Tech U-48RW Cabinet Vibrapods Enough empty boxes for a fire hazard! Quote Link to comment Share on other sites More sharing options...
Prana-Bindu Posted January 4, 2002 Author Share Posted January 4, 2002 Thanks for the help, t. I'm going to contact the manufacturer immediately. Warranties wrock! Does lowering the efficiency or sensitivity of one's speakers (like from 98 db/w/m to 92) lower the noise floor? If you add power to make up the loss in dynamics, etc., does that eliminate any benefit from lower efficiency or sensitivity? I need to find a very patient audio dealer.... By the way, does anyone know how low the Jubilee is gonna go? Thanks again. ------------------ May the bridges we burn light our way.... Quote Link to comment Share on other sites More sharing options...
Prana-Bindu Posted January 6, 2002 Author Share Posted January 6, 2002 Yes, the hissing seems exactly the same in each channel. Driving RF-3's, but seriously considering moving away from speakers using both horns and cones. Thanks for the diagnosis. I shall ask what exactly was done at the factory when I make a claim under the warranty. ------------------ May the bridges we burn light our way.... Quote Link to comment Share on other sites More sharing options...
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