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Slight speaker white noise from hybrid BHK 300 monos and BHK pre normal?

There is a faint white rushing noise from my Focal Kanta 3s. Left channel slightly audible inches from speaker. Right channel slightly more audible approx 1 ft from speaker. Inaudible when music is playing.

Is this normal for tube/hybrid equipment like the BHKs? In addition to BHK 300s and BHK pre, I use a tube modified Modwright Oppo Sonica DAC. Tubes are NOS Telefunken RCA and Siemens.

Had a similar issue with my previous Audible Illusions L3A linestage. My tube guy suggested the following which successfully reduced the noise floor - though not to silent.

“A flake of cathode material may have migrated into the grid of the tube. Try removing the tube and tapping it firmly on a table top, then reseat it and burn it in for 12 hours and the noise should be gone.”

I did this to all my tubes but still hear the white noise, albeit faintly. Is this a characteristic of tube/hybrid vs solid state which is dead silent?


128x128cantorgale
8 responses Add your response
cantorgale's avatar
cantorgale OP
149 posts
 
@tweak1 Am using XLRs thx
tweak1
3,658 posts
 
Are you using XLR cables? If not, try them. I have owned a good bit of tube kit, but always XLR
lowrider57's avatar
lowrider57
5,417 posts
 
All tube systems tend to produce some hiss which is audible up close to the speaker. The sensitivity and the amount of gain from the preamp and amp play a role in tube hiss.
Check the specs of your amp, preamp and speaker sensitivity to know for sure.

And of course buy NOS tubes from a reputable dealer. Ask for low noise, low microphonic tubes.

cantorgale's avatar
cantorgale OP
149 posts
 
@jbrrp1 thanks good info to have.  I"ll swap the pre tubes and see if there is an improvement.  
jbrrp1
423 posts
 
I run both the BHK pre and the BHK 300's and I have this tube rush noise.  I had it pretty badly with one pair of Amperex 7308 tubes on the pre that just didn't age well (started out quiet enough, but got really noisy in aboout 6 months' time).  A change of tubes markedly improved things, but there is still noise.  When the music is on I have no awareness of this tube noise, and these BHK pieces deliver a lot of musical enjoyment for me, so I think it is all just fine.  That's my experience.
three_easy_payments's avatar
three_easy_payments
2,097 posts
 
White noise is simply the fact that tubes aren't 100% silent, especially under some decent amounts of gain.  You could try going for SLN tubes from Roger at TubeAudioStore and see if they make a difference.  In my conversations with him he felt that his SLN tubes could lower the noise floor by a few dB or more in my phono stage.  The question is whether the juice is worth the squeeze. $$
cantorgale's avatar
cantorgale OP
149 posts
 
Thank you.  More efficient Kantas recently replaced my Harbeth m30.2s. May explain why slightly more audible.  Using Syn Research Power Cell 8 UEF so probably doing all I reasonably can then.  
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