Tube favorites for Modwright LS100?

Howdy Friends,
Are any of you having success with a little tube rolling for the Modwright LS100 preamp...either the 6SN7's or the 5AR4? And I am sorry, but I am not interested in anything costing dern near as much as the preamp itself...$500 or more for a pair of vintage 6SN7's? Not happening in my monetary (read "happily married") world.
Thanks to one and all for your kind input and experience!
Try the new production Tung-Sol 6SN7-GTB at about $20 a tube
They are really excellent. I am using them in ASL Hurricanes
You could also try some Sylvania 6sn7 "Bad Boys" or some of the early 1950's Russian (Sovtek) 6sn7 with the metal base.

I agree that the new production Tung-Sol's are very nice.

Also check here for more info:
For the 6SN7 I'd give the Shuguang CV181 Black Treasure tube a shot. These take a bit of break in time and in my experience will fluctuate widely in performance in the first few hundred hours, but the stable performance after that will be worth the patience. I do not have experience in that preamp though. You might be able to find a used low-hours pair for $150 or so. There are some NOS Russian variants that are quite good too, but their prices seem to be going up dramatically lately...I think the pair I have that I really liked is a metal-base 6H8C with round-hole plates. The plastic base version of the same tube is also pretty good and cheaper. As far as the rectifier tube, a sleeper tube in that family is the GE copperplate. You might also try a 5U4G, like an NOS Tung Sol in there as I think you can use that tube family as well.
Thanks friends for your thoughts. I must admit a certain fascination for the Black Treasure tubes, even though they are obviously a bit dear in the British sense of the term. I should perhaps not be so brash as to completely discount the reported superb sound quality of the best available vintage tubes, but is the often very high cost of admission really worth it?
I preferred the Black Treasure tube in my MWTP over the very dear NOS TungSol round plates. I also prefer the Black Treasure in a headphone amp I'm testing out right now, compared to the same TSR. Go figure. I did not like the Black Treasure tubes right out of the gate though. I think you'll find there are bargains to be had from those who don't give them enough time to burn in and just sell them out of frustration. I have not tried any of these tubes on the LS100 you own though so take this input with that caveat.
Hi Bob,

I have used the Black Treasure KT-88's and I like them very much but never tried the CV 181. You might want to try the Chinese 6N8P-J military tube. They work well in my pre-amp and they are cheap.
I have received a pair of Shugang Black Treasures and put them in the LS100. Below is the email I just sent to Dan Wright and Grant Fidelity...

I received the Shuguang CV181-Z (6SN7) Treasures and a NOS 5AR4 and burned them in for a few hours yesterday. Even though the LS100 and the tubes have only a few hours on them, I was quite unprepared for the sounds I heard during my first listening session. For the first time in my audio life my speakers literally disappeared, and the imaging filling my room was almost palpable...very 3-D indeed, to the point of being almost scary-real. I sat in wonderment; left wanting for nothing with the music being produced with such crystal clarity and startling precision from top to bottom. I can only anticipate what further improvements may happen as both the preamp and tubes continue to settle in together.
To be brief, my searching for the next best preamp is over, as is my searching for the next best tubes to put in that preamp. This combination has taken my humble audio system from good to "wow"!
Thank you Dan for designing such a wonderful preamp at such a fair price, and thanks also to Shuguang for producing a pair of tubes that have taken that preamp way over the top in audio quality. Job well done!
I must add an addendum to my LS100 tube review above. After spending a good deal of time with the Black Treasures I decided to try the Sophia 6SN7's as suggested by Dan Wright on the Modwright website. I must concur with him (and others), that the Sophia tubes are absolutely wonderful in all respects, bettering even the very good Black Treasures. I must (somewhat sheepishly) now recommend that you try them in any piece of equipment that calls for the 6SN7 tube. They really are quite special, and reasonably priced to boot.
Happy listening!
I just received my LS100 installed NOS 1963 Tungsol 6sn7 and a NOS Sylvania GZ34. Down the road I'll try the BTs (have a quad of BT KT88s in my Ayon Spirit and really enjoy them) or the Sophias
I have about 100 hours on the LS100 which I understand requires at least 400 hours of break-in to reach their intended sound. Have liked the sound of the NOS Tungsol and Sylvania as they and the amp have been working themselves in, but decided to go ahead and pick up a pair of the Black Treasure CV181s. Will say that with only about an hour on these tubes they already offer more top to bottom detail than the Tungsol's. Will look forward to trying the Sophia's at some point.
Anyone try the Synergy HiFi/Create 6SN7's and/or 5AR4 in the LS100?
I am auditioning a LS100 with stock tubes.

I find the top end a little hot, bright, slightly harsh.

My reaction may be due to my age and too much rock and roll in my youth, my hearing is down quite a bit at 10,000 hz and higher.

Do you think upgraded tubes for the LS100 will tame the top end or just add bass and expand the sound stage.

I purchased the LS100 w/o the ability to audition and went right to using a NOS rectifier and the Black Treasure cv181 based upon prior experience with the latter's KT88s and am very pleased - that said the amp needs about 450 hours or so of break and to my ears continually improved over that period
I've had my LS100 for about 18 months now. It does require 400-500 hours to fully break-in.

I would really recommend that you swap out the rectifier and the 6SN7 tubes. I have tried MANY different tubes and found the Shuguang Black Treasure CV181 and the Mullard 5AR4 to be the best FOR ME. The Sophia Electric 6SN7 tubes are really nice also.

So, between full break-in and new tubes, I'm pretty sure the LS100 will be what you are looking for. Of course, I'm biased because I LOVE mine!!!!

There are several threads here on Audiogon and on Audio Circle that talk about tube rolling in this unit.
Alfa Lover, did the harsh, bright, hot top end ever dissipate? Just curious. In the next couple of months I may be in the market for a preamp, and was considering adding the LS 100 to my list but harshness is the last thing I want, I want some warmth.
My ls100 is harsh and bright but I am still breaking it in. I hope it smooths out
Jimbones, Dan will tell you that it takes a few hundred hours to break-in. I haven't had any concerns about the sound being as you describe and find it very musical. What tubes are you using?
Stock: Tungsol, Shaugang. Yes, Dan did say 200-400 hrs. This unit is not new but a "demo". I have a feeling it was sitting for a while. I only have about 70-90 hrs on it. I guess I thought that since it was used previously it would only take a light break in. OK so I'll have to just get through another 300 hrs or so.
Have 300 hrs on it now. Replaced the stock tubes with rca. Sounds much better
Just put a new set of GE 6sn7GTB tubes in a few days ago. It only took about 30 hours for them to start sounding nice. Initially they sounded thin with no bottom end. They are balanced with good upper end extension and solid bass. Nice tubes for $45.
My LS-100 had a set of Sophia's in it, but they were terribly noisy. Seller said they were good, but somehow before they arrived they got very noisy, one a lot more than the other. Seller packaged them separately and wrapped well. I'll probably try another set in the future after many people said they're excellent tubes.
I just missed the UPS man today who was bringing my set of Shuguang Black Treasures. Will have to wait until Monday for them now. :(