VTL is pretty sure it is a problem with the tubes in the output stage. I
am buying a pair of tubes from them that they will screen for noise.
--
duke43j
duke43j's Profile:
duke43j;426351 Wrote:
Does anybody have experience using one in their system?
I've been using a PS Audio 4.6 in passive mode for about 20 years. I'm
happy with it.
Soon I'll move to using a single input stereo volume control with
balanced input and output cables.
The issue of volume
Hi Listener. Do you know what the input impedance and gain of your amp
is? Also, the output impedance of your preamp? Did you have trouble
finding cables that would work OK. It seems that this is more an art
than a science, but I would like to find out the parameters I need to
stay within to be
duke43j;427475 Wrote:
Hi Phil. Boy, you are really getting into this. I don't have a
schematic with my manual. Also nothing on their website. Sorry about
that.
I looked too - nothing on the web. Still, with only 4 valves it can't
be that complex.
I used to repair valve gear (30 years ago)
2) the hiss reduces with new valves then quite rapidly comes back (2
months?)
Yes
3) the output impedance of the 2.5 is 200 ohms, the input impedance of
VTL's own power amps is 100k
Yes
4) hissing noise is not due to impedance problems IME - and according
to the specs you shouldn't have a
duke43j;426822 Wrote:
Shortly after I bought the VTL I took it back to the dealer to try it in
his system. The noise wasn't nearly as pronounced through his McIntosh
amp and BW 800 speakers. I had to put my ear right up to the speaker
before I heard any noise. From that demo I concluded that
Hi iPhone. My VTL 2.5 preamp has quite a bit of noise through my
speakers. The noise is quite audible from 9 ft away during quiet
passages (not noticeable during moderate or loud passages). New tubes
solve the problem for a month or two, but they eventually get noisy
also. The preamp is also
duke43j;426731 Wrote:
Hi iPhone. My VTL 2.5 preamp has quite a bit of noise through my
speakers. The noise is quite audible from 9 ft away during quiet
passages (not noticeable during moderate or loud passages). New tubes
solve the problem for a month or two, but they eventually get noisy
Shortly after I bought the VTL I took it back to the dealer to try it in
his system. The noise wasn't nearly as pronounced through his McIntosh
amp and BW 800 speakers. I had to put my ear right up to the speaker
before I heard any noise. From that demo I concluded that my preamp
wasn't broken,
A couple of thoughts:
1) You shouldn't get audible hiss from 9ft away at normal listening
levels from ANY amp
2) the hiss reduces with new valves then quite rapidly comes back (2
months?)
3) the output impedance of the 2.5 is 200 ohms, the input impedance of
VTL's own power amps is 100k
4)
I've been looking into passive preamps on the web. They sound
interesting because they should ideally have no noise or distortion. The
biggest issue is the input and output impedance, and how well it matches
up with the source and power amp. Based on some of the articles, it
seems they can be
duke43j;426351 Wrote:
I've been looking into passive preamps on the web. They sound
interesting because they should ideally have no noise or distortion. The
biggest issue is the input and output impedance, and how well it matches
up with the source and power amp. Based on some of the
Thanks Phil. That was pretty much the impression I was getting from
reading through dozens of web pages. But the idea of a passive preamp
sounded so good I was hoping that they were just nit picking. I got the
idea of a passive pre when I connected my DAC directly to my power amp.
The biggest
I have been using a Creek OBH-12 remote passive attenuator for over 10
years. This discontinued component has to be 1 of the cheaper passives
at under $300 new. Before owning this I owned, auditioned, demoed, and
borrowed many preamps. They all imposed themselves, in some fashion, on
the
I have tried a variety of passive and active preamps (too dang many
really), and if you can get it right, the passive approach provides the
best result in my experience. Assuming you've already achieved a good
match between speakers and power amp: Make sure the power amp has an
input impedance
duke43j;426351 Wrote:
I've been looking into passive preamps on the web. They sound
interesting because they should ideally have no noise or distortion. The
biggest issue is the input and output impedance, and how well it matches
up with the source and power amp. Based on some of the
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