[Big Red Machine]

I cannot shake that booger.  No matter what types of devices I use I still have a low level hiss from my tweeters.  I cannot hear it at my chair but I know it is there and I want it to go away!

I know it is not the dac as when it is off it is still there.

It comes up when the volume is turned up so it is the pre or the amps.

Anyone have this?  What might it be?

[jtwrace]

Anyone have this? 

Nope.  Mine is silent with my ear to the tweeter with volume at max.  The way it should be! 


I highly doubt its a power issue though.  Since you use a tube pre & dac and the whatever the amp topology is I'd say it's there. 

[macrojack]

I had that noise too. Turned out to be coming from my DBX Drive Rack PA. My horns were about 108 db efficient and the Drive Rack had a noise floor around -100db. When I shot off the DBX the noise remained -- when I replaced it the noise was gone. However, the XTA speaker management system I brought in was great sounding and utterly silent when programmed by a pro, it was too difficult for me to calibrate. Now I use a passive network and has made everything silent and beautiful. Praise for simplicity.

The moral of this story is: Turning off your gear may not remove the noise it generates. I know this doesn't appear to make sense. Might help you suss out the gremlin though. Good luck.

[zybar]

I cannot shake that booger.  No matter what types of devices I use I still have a low level hiss from my tweeters.  I cannot hear it at my chair but I know it is there and I want it to go away!

I know it is not the dac as when it is off it is still there.

It comes up when the volume is turned up so it is the pre or the amps.

Anyone have this?  What might it be?

Do you have tubes in the chain?

If so, it is a strong probability that is your root cause.

Depending on what tubes I use in my preamp, I can hear the tube rush you are talking about at various distances from the speakers.

George

[poseidonsvoice]

Do you have tubes in the chain?

If so, it is a strong probability that is your root cause.

Depending on what tubes I use in my preamp, I can hear the tube rush you are talking about at various distances from the speakers.

George

George is probably right. BRM, do you still have the Dude? It uses 6SN7's which is a great tube but with many tube products you will hear that 'tube rush' sound. Fact of life. When your room is quiet, it is even more prevalent. Unlikely to be the Sampsons, however, you can rule that out, by putting the Dude on Mute and then listening to the speakers. If you hear a buzz or such, then the amps are also involved.

Best,
Anand.

[WireNut]

In my case it has been hiss from either one or more of the 8 tubes in my preamp. It only takes 1 tube per channel to make my tweeters hiss even if the noisy tube is used in the cathode follower positions. Lightly tapping on each tube with a plastic kitchen spoon found the culprit.

Anand is right. If I put my preamp in mute everything is dead quite, put it in operate and I get tube noise.

[jd3]

Pete I have the same issue and I have all SS equipment.  I didn't have it in with my current amp (Pass 250.5) when it was upstairs, but now that it's in the basement I do, so I suspect my issue is ac line related.   Plus, my amp's transformer is humming as well now. 

[Triode Pete]

I have "dead silence" with my ear to the tweeter on my 104 dB sensitive Volti K-horns...

However, few years back, I had a annoying tweeter hum on my system. I traced it back to my McIntosh MR-78 tuner which had a capacitor fail on the antenna boost circuit (a cap that was NOT needed in my system). I removed the capacitor & the hum was gone. Funny thing was, during troubleshooting, the MR-78 was switched off and still got hum. It wasn't until I "unplugged" the tuner that the hum went away... Also crazy that it was my only solid state piece in my rig contributing the noise!

My point is that it can be many anomalies causing the tweeter hum. With methological troubleshooting, you'll find the source of your hum.

My $0.02,
Pete

[doctorcilantro]

I tested a Bel Canto SS amp and heard this type of hash/hiss, my Decware tube amp was much quieter but has a bit of 60hz hum, very low-level though.

[paul79]

My system is dead quiet. Tube monos fed direct from a Bel Canto DAC.

Put shorting plugs on the RCA inputs of the amps and see if the hiss goes away. If so, systematically work your way back using the shorting plugs at inputs of the preamp, etc...

Be careful and make sure everything is off before connecting/disconnecting...

It could also be a cable picking up noise.