[fado]

In October 2012 I purchased a Modwright LS100 pre-amp and got both the Shuguang/Psvane CT 181T and the Sophia Electric 6SN7 tubes to try with it. (I thought I had ordered the CT 181Z Psvane but received the CT 181T and failed to notice the mistake until I decided to try them again in 2018.). I liked the Sophia Electic tubes much better and used them most of the time. I got a new DAC in December 2018 and the Psvane CT 181T's sounded much better with it although I stlll had a slight preferece for the Sophia Electric's. Both 2012 Psvane and Sophia Electric tubes seem to be causing noticeable static so I am looking to replace them. Has anyone tried either or both of the newer 6SN7's listed below. I really don't want to buy a pair of each.

Treasure Globe 6SN7-SE  :   http://psvanetube.com/wordpress/store/products/treasure-globe-6sn7-se-pair-gf-limited-special-edition/

Sophia Electric Blue Glass 6SN7   :   https://sophiaelectric.com/collections/vacuum-tubes/products/pages-se-new-6sn7

My system: Modwright KWA150 SE; Modwright LS100; Acoustic Plan Digimaster NOS R2R tube DAC; Bryston BDP-1 digital player; Ayon 07-s CD player; Daedalus DA-RMa V.2 speakers.

[JakeJ]

Those globe 6SN7s look interesting but the blue glass does nothing for the signal so I wouldn't bother.  Possibly try a NOS pair?

Could you describe this "static" more thoroughly. When does it start?  Does it stop?  Does it happen with the volume up or down?  Does it occur on all inputs and outputs?  Does it sound crackly?  Crunchy?  Wooshy?

If I understand correctly you got the Psvane and Sophia tubes from Modwright when you bought the unit?  Maybe contact Dan and tell him what you have going on and he can solve it quickly. 

[fado]

I have been in contact with Modwright. I have had this problem before and it was corrected by turning a screw on some "trim pots" which can oxidize and cause the speaker static. Turning the screws several times each way then returning to the same position cleans the oxidation and eliminates the static. There are four trim pots and this time I was turning the wrong ones which did not correct the problem and led me to consider tube issues.

I went back and reread Dan's 2015 email and discovered my mistake - turning the correct ones eliminated the problem. Dan said that he has corrected the issue with a different design but I forgot to ask him when that change was made. As usual, Modwright was very responsive. In fact, over the years I have had reason to contact Modwright, Bryston, Daedalus Audio and Ayon (USA Tube Audio) and am always impressed by their pleasent, professional approach to problem solving or information about updates. I have not yet had many questions about my Acoustic Plan DAC. The German manufacturer has been responsive to my few emailed questions.

Thanks for your guidance.

[JakeJ]

Ah, the devil is in the details.  Glad you discovered your mistake and solved your problem.  Maybe Modwight can update/upgrade your unit and make this issue go away?

[fado]

Yes, they can do it, a little for parts and ~one hour labor. As long as I know where to put my screwdriver and it continues to correct the noise I will just do it myself. If I need to ship it to Modwright for any other reason I would definitely have it done.