2. amps-preamps
  3. 166424-2183

Can’t use any other tube??!!?

I just got a used Rogue Cronus Magnum 2, and I want to roll a few tubes I have into the center 21au7 spot to see if I can beat the stock JJ.

Every tube I try is noisy - crackling and hissing. Even tubes that I take from another amp where they are crystal clear.

But when I put the JJ back in - it’s quiet again.

I have tried new production Mallard and two different NOS Mullards.

Any ideas why only the stock tube is working? 


stephenjess

Showing 1 response by avanti1960

avanti1960
1,545 posts
 
It can be done!  I tried dozens of preamp tubes on my old CM Ii.  Excellent sounding amp that upgrades nicely with small signal tubes. 
See Brent Jesee Audiotubes.com.  Spec  low noise screening for an extra 10 bucks.
My favorite was Amperex NOS.  Buy an off label Amperex and save $
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