2. amps-preamps
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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
yioryos's avatar
yioryos
723 posts
 
Thanks guys
Marco the NOS Siemens CCa must be expensive ,no?
George
jax2
3,031 posts
 
George - Unfortunately, yes, they are quite expensive and sometimes counterfitted or sold in less than desirable condition for large coin. If you go that route definitely go with a reputable resource. Expect to pay $75-150/tube (crazy!). Alternatively, in current production (or NOS if you like) I'd give a try to the Russian Rocket tube, I think they are 6H30 and are drop-in for most 6922 applications, but take care in which variety of that tube you use. I think BAT uses them in their gear. Worthy of a listen and much cheaper than NOS. YMMV and check on the application with your specific piece of gear.

Marco
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.
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