[Jos]

Just received my Sensation 451.

Plays wonderfully but gives quite a bit of hiss on my 96 dB speakers. Does this completely disappear when you switch to battery?

Jos

[dburna]

Do you have the Dodd tube buffer?  If so, that problem may not go away with the use of battery power.  I also have 96dB speakers and, though I loved the sound of the Sensation, had to return it due to the hiss.  Virtue were most gracious/accommodating about the return.  I had tested a Sensation w/o tube buffer prior to purchase with absolutely no problems whatsoever, so I assumed that it was the addition of the tube buffer (or a ground plane issue) that complicated things.  I can't say for certain that this was the source of the hum, though.  Just to be certain, if you have a chance to swap out the tube, I would give that a try -- can't hurt.

Regards,  -dB

[jb26]

Hi,

I occasionally get his from my 901 with Dodd buffer and battery. I find it's worse after powering up when it's been off for a while and gets better after a few hours play. Strangely, also touching the metal side on the right as I look at it, same side as buffer is on can help. Maybe static?  Otherwise a different tube makes a difference, newer rather than nos seem to have less hiss ( there's a few treads in this).  Not sure if that helps, but u doubt batteries will solve the hiss, that assumes t's the power supply causing the hiss.

[Jos]

You're right. After a few hours the hiss has disappeared.

Unit was delivered stone cold (it's freezing here) by DHL. Perhaps the sweetie had to get used to the central heating.

Jos

[Jos]

A bit premature: hiss is still there. Don't notice it though, when I crank up the volume a bit.

Still, I find it hard to accept that I've bought an amp that comes with hiss.

Jos

[Tarzan]

You're right. After a few hours the hiss has disappeared.

Unit was delivered stone cold (it's freezing here) by DHL. Perhaps the sweetie had to get used to the central heating.

Jos

Hi Jos, l have three different PSU's for my M451, and if left cold for a while( unplugged) then l have found it takes an age to for the sound to come "back on" if you like.

I have just taken the battery PSU route and in my room, system, ears, the battery PSU dramatically drops the noise floor, it is very,very quiet, plus you get a truckload more power, in fact an improvement in all areas

[Jos]

This is a very odd amp.
When you hold your hands on the side panels, preferably near the front, the hiss almost disappears.

An obscure grounding problem?

Jos

[django11]

I cured a hum/buzz problem (with a different amp) by removing my power bar as per a member's suggestion.  Might work...

[Jos]

  But I am serious. An amp shouldn't produce loud hiss and when this disappears when I hold it, shoes still on, no joke, it treminds me of the turntable problems i.e. grounding.

Should I drill a hole into the bugger, fasten a wire and connect it to my central heating? Would surely make a picture.

Jos

[django11]

I was serious as well.  Using a dimmer in the room produced a good buzz out of my amp.  Without the dimmer in use the amp produced a hum.  Once I removed the switched power bar and plugged directly into the wall outlet I have dead silence with or without the dimmer in use.  This is probably not your problem but worth bringing up...

[Jos]

Django, sorry. I misunderstood you; I'm not a native speaker and I thought you meant removing the plug from the socket. Then the amp would of course be dead quiet.

i still think my problem may have something to do with grounding. And there are unfortunately more people with the same problem. i think Virtue should sddress this.

Jos

[Jason T]

But I am serious. An amp shouldn't produce loud hiss and when this disappears when I hold it, shoes still on, no joke, it treminds me of the turntable problems i.e. grounding.

Should I drill a hole into the bugger, fasten a wire and connect it to my central heating? Would surely make a picture.

Jos

do NOT add any ground wires to the amp.
if you ground it to the wall it will cause huge issues as the amplifier is all DC power after the power supply.

either you have weak/bad grounds in your house or (if buffered) the tube buffer is causing noise.

when did you buy the amp?
how old is it?
does it have a tube buffer?

don't rush into anything let me help you with this

[Jason T]

Django, sorry. I misunderstood you; I'm not a native speaker and I thought you meant removing the plug from the socket. Then the amp would of course be dead quiet.

i still think my problem may have something to do with grounding. And there are unfortunately more people with the same problem. i think Virtue should sddress this.

Jos

my amps have no hiss whatsoever. I don't have tube buffers.
the others that have a hiss have tube buffers and this is and was a known fact about them.
different tubes help, batteries also help.

first lets get to the bottom of the problem.
please email me with pictures of your power supply. check to make sure your power cable that plugs into the wall has the grounding prong on it.
cables
@
virtueaudio
.com


sorry trying to avoid spam mail from bots

[django11]

Django, sorry. I misunderstood you; I'm not a native speaker and I thought you meant removing the plug from the socket. Then the amp would of course be dead quiet.

i still think my problem may have something to do with grounding. And there are unfortunately more people with the same problem. i think Virtue should sddress this.

Jos

No problem.  You are in good hands now.  Jason will work this out.

[virtue]

Guys,

The Tripath technology has modest PSNRR (Power Supply Noise Rejection Ratio).  In most circumstances, with residential power lines, commodity power supplies (our 30/130w is medical grade, whatever that means) with sensitive speakers you will hear a hiss.  This is not news. 

When you run from batteries, you'll get less hiss.  The amp is sensitive to PSU quality.

There is newer technology that filters out line noise better.  There is a disagreement on what sounds better.  I used to have a big KT88 tube amp that hissed like a MoFo.  It sounded great.

So, there is some tweaking you can do but don't expect no hiss.  There will be a hiss if only faintly.  With sensitive speakers (if you're running 5w tube amps you got a pair!) you're going to hear it or not, mind it, or not. 

With regard to the tube buffer... don't get me started.  Different tubes affect hiss and sometimes jiggling wires has some effect.  The tube buffer is Gary's and many people LOVE IT.  What can I say.

If it's clearly defective, let us know.  If you just can't stand an amp that is sensitive to the PSU and tubes, etc. sell it.  We sold those amps for way less than they cost to make and there's quite a large secondary market for them on Audiogon.  You won't lose money.

With love - seriously.

Seth

[Randy]

A bit premature: hiss is still there. Don't notice it though, when I crank up the volume a bit.

Still, I find it hard to accept that I've bought an amp that comes with hiss.

Jos

Hiss was audible with my 901 only when cranked up to max volume setting. Backed off just a notch and it essentially disappeared. I now use it with a passive preamp, and there is no hiss at all. Battery? Yes, a no brainer, imo, and the principal reason I looked to Virtue in the first place, to get off the grid.

[Rclark]

Mine has zero hiss, at all. On top of that, it gets a real nice boost in the musical noise floor when on batteries.

I miss my Two. I kinda want to bust it out tommorrow and reinstall it for a while.

But yeah, no speaker hiss at all.

[Jos]

His Seth,

Thanks for your reply.

I don't mind a bit of hiss; I play with a tube amp as well, but it doesn't deliver hiss.

The amp is in perfect condition; it sounds terrific. Way too good for the money. The hiss is very apparent after I've switched on the amp: low volume passages in the music are accompanied by this steam train sound. However, the good news is that seems to get less after an hour or so. Then I can still hear some hiss, but only at very low level.

I would go for a battery if the black lightening thing weren't so expensive here in Holland: 900 Euros.

Lets first try some other tubes. Again, I love the sound, that's why I want to solve this problem. If it sounded poor, I wouldn't bother and sell the little bugger.

cheers,
Jos

[Jason T]

His Seth,

Thanks for your reply.

I don't mind a bit of hiss; I play with a tube amp as well, but it doesn't deliver hiss.

The amp is in perfect condition; it sounds terrific. Way too good for the money. The hiss is very apparent after I've switched on the amp: low volume passages in the music are accompanied by this steam train sound. However, the good news is that seems to get less after an hour or so. Then I can still hear some hiss, but only at very low level.

I would go for a battery if the black lightening thing weren't so expensive here in Holland: 900 Euros.

Lets first try some other tubes. Again, I love the sound, that's why I want to solve this problem. If it sounded poor, I wouldn't bother and sell the little bugger.

cheers,
Jos

Jos

building your own SLA battery kit is a breeze!

if you are willing and feel comfortable doing so but want help with it please let me know.

[Jos]

Jason,

Thanks,

When I'm that far I'll certainly contact you.

Last question about the hissing thing and I will no longer bore you with it.

When I've just switched the amp on, it hisses a lot. When I put my hands on both sides of the amp, it almost vanishes. Any idea how this is possible?

Jos