[ProCast99]

Hello:

I am a new owner of a previously-loved NS-30 amp, have been pestering Blair with some questions, but thought I'd ask the community for their insights as well... I'm sure Blair is a busy guy.

Having bought the system from an eBay seller, he did not have the specs; I've been able to work out the basics, but I'm just wondering if there is anyone out there who has the full list, as for the other NS-amps that are posted.

...and some detailed questions - is the "adjustable bias" knob the inside or outside knob - on my amp, the inside knob seems to affect the amp's volume more than anything, and the one on the outside affects the bass/treble - or clarity/fuzziness factor....

...do you have any favourite tubes in the amp - there are some Sovtek 5881s in there right now, they sound pretty good, with RCA 6SN7s...
...can the 6SN7s be replaced by 12AU7s?
...any other tube thoughts?

Many thanks!

[Niteshade]

Hello!

The bias knob is the one which you are thinking of as a volume control. That one is pre-set at the shop for the 12 O'Clock position to provide the correct bias. You can deviate from the middle position  to find the best place to run the tubes. Operate the tubes to provide the best sound with the least heat output.

The other control which acts like a tone control is for variable feedback. Set this where it sounds best with your speakers.

12AU7's use a different socket, so you have to stick with the 6SN7 family.

I have been busier than normal with the other business for the last few months and my computer time has been limited- but I am around.