2. amps-preamps
  3. 1282804225

I need a lower gain 12au7 for Mastersound

I recently purchased a Mastersound Due Venti. It has 2 JJ ecc82 gold pins in the preamp. I find them to be a little high gain for my tastes. They do sound quite nice though don't get me wrong.

Could anyone recommend a 12au7 or variant that naturally has less gain than the JJ but still retains quite a lot of detail and low noise? New or NOS, doesn't matter to me.

Any responses or suggestions would be greatly appreciated!
Or if anyone has a Due Venti maybe they could let me know what preamp tubes they prefer?

I'm running it with a pair of La Scala's, they're just a little too efficient maybe...

Thanks for your time!!
ddderek
rrog
1,958 posts
 
Are you sure those are preamp tubes? Mastersounds claim to fame has always been their passive gain stage. The 12AU7 tubes are drivers for the output tubes. Using one of the low gain alternatives will result in a very dull sound.

Apparently yours is a CD based system. What CD player are you using? Do you know what the output voltage is? If you want to cut back the gain someplace the source may be the best place to do it. The other alternative is a less efficient speaker.
allenwright
17 posts
 
There is no "lower gain" 12AU7. There are tubes with less gain but nothing that can just be swopped over without major wiring changes inside = very good technician = $$$.

La Scala's are way more efficient than the current norm, but can sound great.

The attenuator is the best idea.

Regards, Allen
hifiharv
351 posts
 
I'm no tech. expert, but I always thought the 12AU7 was designed as a "unity gain" tube. Meaning it does not provide gain at all. Usually used at the end of a preamp as a cathode follower to improve that circuit's ability to drive the cable and the next amplifying device. By experimenting you will probably find another 12AU7 that you " perceive" to have lower gain.
ddderek OP
9 posts
 
I guess I'm just looking for a smoother tube with a "Perceived" lower gain. I'm using a TT with a cambridge 640p on MM for my input.

I guess I'm just trying lower the gain of the whole amp. Seems to be a hiss running through the speakers, even with the volume off. Cd or TT doesn't matter. Unplugged all accessories, doesn't matter.

Maybe I just shouldn't be trying to run this amp with my La Scala's. Higher volumes sound amazing!! Lower, I get a hiss.
rrog
1,958 posts
 
The 12AU7 is the lowest gain tube in that family of tubes. The problem is not the amp. The problem is between the speaker and the source.
More to discover