2. amps-preamps
  3. 1138726066

Tubes and microphonics

I want to know when microphonics affect the sound.
I have a Sonic Frontiers Line 2SE Preamplifier. I tried many tubes like Valvo, Siemens, Reflector 6H23NEB.
Recently I bought two matched pair of Amperex 6922PQ White Label Made in USA. I think that the Amperex are better than the others, but I could see that they are less silent.
When I knock the cover of the preamplifier I can hear the knock clearly in the speakers. That not happen with the others tubes. The 6H23NEB are the most silents.
I think that Amperex have more gain than the others. But I don´t know when that is critical to the sound.
Please let me know your experience with your tubes and preamplifiers.
Thanks,
Pablo
elduende14
rwwear
2,692 posts
 
I could be wrong but, I don't think the 6H30s can be used as direct replacements for the 6922s without some adjustment.
jax2
3,031 posts
 
I could be wrong but, I don't think the 6H30s can be used as direct replacements for the 6922s without some adjustment.

You are quite right, my bad. It is a 6H23 that I was thinking of. Thanks for picking out the mistake.

Marco
elduende14 OP
51 posts
 
Marco,
the Reflector (Russian) 6H23NEB are very good tubes (much better that the standard Sovteks)and they ultra low noise (an excellent tube for Audible Illusions preamplifiers) but the Valvo 6dj8 and the Amperex 6922PQ are really better. Unfortunally I tried the Siemens E88CC but for me the Valvo and the Amperex are better.
You can contact to Mr. Chris Johnson at Partsconnexion. He sell the 6H23NEB at 45u$s(matched pair) and the Valvo 6dj8 at 75u$s (matced pair).
The Amperex PQ are really difficult to find but for me they are the best.
Thanks for all for your answers.
jax2
3,031 posts
 
Just one clarification Pablo - The Siemens I liked best were the E88CCa. They are not the same as the E88CC. You can see the entire range of various brands and pricing here to give you some idea of the relative price range. I never heard the Valvo or Amperex, and even if I had it would have been in a different piece of gear so the differences between tubes would not correspond exactly to your experience with your SF2SE (nor, of course, would my preferences necessarily correspond with your own). I would always encourage others to roll their own and make their own judgements where these things are concerned. Just sharing my own experiences here. YMMV.

Marco
eldartford
4,262 posts
 
All tubes are microphonic, but some tubes are more microphonic than others. And it makes a difference where in the amplifier circuit the tube is used.

A severe case of microphonics is certainly bad. However, it may be the case that a trace of microphonics contributes the "warm" sound that characterizes tube electronics.
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