[superjohny]

Just got my v8p today, linked to stock v-dac with a decent cable

i am hearing hiss when the volumn is after 3 o'clock, very noticable.

but at least when the volumn is around 11am, it's deadly quite.

i am pairing it with D5000.

hope it wont hiss when i got my pinkie + siemens E88cc tubes.

 

[Gradofan2]

Try removing the tubes... cleaning the pins with ProGold.

Then gently spread the pins a bit... and reinsert them.

This should remove the oxidation and make them fit tighter.

And... will eliminate tube noise / hiss in many instances.

 

[nikongod]

Quote:

Originally Posted by superjohny /img/forum/go_quote.gif Just got my v8p today, linked to stock v-dac with a decent cable i am hearing hiss when the volumn is after 3 o'clock, very noticable. but at least when the volumn is around 11am, it's deadly quite.

To be clear on this...
Do you mean that the amp hisses when the source is connected? How do you know its not the source thats hissing and the amp only lets that though some of the time?

I would disconnect the source and try some more. If you have shorting plugs install them on the inputs of the amp.

On that note, do you listen with the volume knob up that high? I would not worry about it.
Quote:

Originally Posted by Gradofan2 /img/forum/go_quote.gif Then gently spread the pins a bit... and reinsert them.

Clean tube pins are always good but I would be quite hesitant to bend the pins if it can be at all avoided. Bending the pins on a noval tube (actually any tube where the pins go directly through the bottle: noval, loctal, 7-pins, novar, etc) causes microscopic cracks in the glass envelope which eventually cause the tubes to go gassy.

 

[superjohny]

source is ok, i tried source=>D5000 and it made no hiss.

 

[nikongod]

Quote:

Originally Posted by superjohny /img/forum/go_quote.gif source is ok, i tried source=>D5000 and it made no hiss.

You mean you hooked the source up directly to the D5000. That does not account for output impedance of the source, or the fact that the amplifier amplifies whatever signal comes in by a decent chunk. Noise that is inaudible may become audible when amplified.

I stand behind trying out the Xcan with no source.

 

[pekingduck]

My V8P (purchased last week) hisses with the 64-Ohm DX1000 (stock PSU, stock tubes).

The hiss is there even though there's no source connected, and is not dependent on volume level...

Any hints?

 

[nikongod]

Try different tubes. Perhaps they do just hiss. If its as high on the pot as the PO mentions I would not worry.

 

[superjohny]

I'll try loud volumn with little pinkie and diff tubes when they arrive and see if it still hisses.

 

[Neeley]

Mine hisses too, it's very quiet and doesn't increase with the volume knob. It's only just audible when nothing is playing.

Whacking on a cheap 5amp transformer helped, done wonders for the sound too.

 

[Gradofan2]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif ...On that note, do you listen with the volume knob up that high? I would not worry about it. Clean tube pins are always good but I would be quite hesitant to bend the pins if it can be at all avoided. Bending the pins on a noval tube (actually any tube where the pins go directly through the bottle: noval, loctal, 7-pins, novar, etc) causes microscopic cracks in the glass envelope which eventually cause the tubes to go gassy.

The only time I had to turn mine up that high was with less efficient, higher impedance phones - such as Senns. And... you didn't notice any noise / hiss at normal listening volumes and with a signal.

And... yes... you do have to be very careful to avoid cracking the glass, when bending tube pins. The pins on the 6DJ8/6922/7DJ8/etc. family are very thin and easily bent. I usually support the base of the pin with needle nose pliars, or some counter pressure, while bending the tip in the opposite direction. That relieves the pressure on the base, which enters the glass. But... you have to be very careful.

 

[mironathetin]

Can the hiss come from the low impedance of your headphones?
I have HD650s (300 ohm) and with them the x-Can is absolutely quiet at any volume (with the stock power supply).
My ie7 (16 ohm) on the other hand, produce a very noticeable hiss, independent of the volume.

 

[Zombie_X]

My X-CANV8P hisses with all my low Z phones, especially the hyper sensitive Grado's. I don't get any hissing on my higher Z phones like the HD600's and DT880 600Ohm's.

So the hissing is very normal on low impedance stuff. IMO changing tubes does help a little but you will never eliminate the hiss.

If anything you can throw a 75Ohm adapter in there to solve the problem. It works wonders for my Grado's..

 

[entrope]

Haven't noticed any hissing even when the volume is set to maximum (V8P + PSU + HD800)... not that I listen at that volume (; but I'm always curious to see how much hissing I get out of speakers or headphones when the volume control on the amplifier is set to maximum.

 

[superjohny]

actually, i found that my v8p has some left-right imbalance.

i have to adjust my music player abit more to the right to feel the singer singing in the middle. anyone came across the same problem?