Hmm, that could be why I've been shying away from my 6SN7's lately. I do really like the CV-181Z with the 7236.
Hmm, that could be why I've been shying away from my 6SN7's lately. I do really like the CV-181Z with the 7236.
If I did not have the 2C50 tube I might have not stick with the 7236 tube and might have tried the 5998 next. The 2C50 did not make as much of a difference with the 6AS7 tubes as it did with the 7236. The more I listen to the 2C50 and 7236 combination the more I feel it is the perfect choice. I am glad that I send the amp back to Glenn and the 12SN7 adapter he made set in motion a chain of events that paved the way to great sound.
12SX7GT RCA gray glass with twisted heater. You can just see the two glowing filament wires together (top middle) of tube. Will be using this tube later. Still savoring the time with the 2C50 and 7236. Supposedly twisted heater gives less hum.
As my audio journey continues, the insights here has been fantastic! When I look back to compare June 2012 with June 2011, it's going to be fascinating... thanks to all of you!

I was thrilled to hear from Glenn earlier today. That's always a pleasure. He's just a stand-up, classy guy.
Agreed. But, especially when he's got the goods! I'm still waiting for my refund to hit any day now, so I can send the amp back to the studio; meet its maker.
I'm in week three from getting the return authorization > Shipping the SB Touch > awaiting Accounts Payable... and they booked the unit in for evidence some 7-10 days ago.

Despite getting a really good deal on the box, sometimes the service one receives from a vendor can justify paying a few dollars more. Except, I never imagined I'd end up returning the unit and went for the rock bottom price.
Can't wait to shove the Silver Hawk out the door!
Nice photo John, Thanks.
I see exactly what you mean, beautiful tube.
Happy listening.

I am glad that stepped attenuators are working out since not everyone likes it and you need the right taper curve and that seems to be the case here. One of the reasons I am using the 2C50 tube with Glenn 12SN7 adapter is that the 2C50 tube has MU factor of 10 instead of the usual 20 but has much higher output current capability than the typical 6SN7 tube. This helps to control the overhaul gain range of the amp using output tubes that have higher MU factor. The 2C50 seem to tighten up the sound on my TS 7236 tubes much more than using the Russian TS 6SN7. The 2C50 does not appear to make of a change with the TS 6AS7 tube as much it did with the TS 7236 tube. The TS 7236, Sylvania 7236 and the TS 5998 all have very different plate structures. The box, conventional and the domino plates. I am not going to bother trying the Sylvania 7236.
I have a few 12SN7 tubes that came in two Ray’s at $3 a piece one short with side getter and one tall with bottom getter. One RCA gray glass 12SX7GT with twisted heater. I wonder about the claim of twisted heater until I tested the tube and noticed that the two filament wires on top were together on one side of the tube instead of one at each side of the tube.
Great news! Glenn just informed me that my amp already has the filaments floated at 1/2 the power supply voltage; started doing this to all the amps. Again, your amp is trailblazing for the rest of us. So, all I need now is for him to make me a 12SN7 adapter. 
When I got my amp back from Glenn the voicing seems to be much better than it ever did. There is more relaxed character to the sound with strength. There is less listening fatigue for long periods of time. The sound is sweeter than usual while still have great detail. There is greater front to rear depth to the sounds. The brass is not as much in your face but still have the proper bite to the sound. I still trying out the rest of my headphones collection but there seem to be more sub bass present. It is good to have people like Glenn arround.
I tried the RCA gray glass 12SX7GT and did not like it. The tube even hums a bit during warm up and was a bit too soft sounding. Next I tried the Ray $3 12SN7 tubes and they sound much better. I am in the habit of pre-testing the tubes and putting it in the amp to find out if they are keepers or to be returned. I understand now why Glenn did not like the Sylvania 7326 since the 6SN7 tubes just cannot drive them properly or do them justice. When using the Chatham 6AS7 tubes switching the Russian TS 6SN7 and the 2C50 driver did not make a huge difference. When using the 7236 tubes it was more of a night and day difference switching back and forth with the 6SN7 and the 2C50 tube. Also Grokit post #136 stated that his 6SN7 tubes did not work well with his 7326 and he currently using the CV-181Z with the 7326. I like the 2C50 7236 comb so well I have ordered another pair of TS7236 tubes from a fellow Head-Fi’er meaning that all of my audio equipment budget for the year is used up and well spend. ![]()
The 12AV7 and 12AZ7 family tubes drive the 6AS7G's nicely.
Maybe worth trying next.
John budget and tubes don't go together!![]()
Oh... and I kept following in his footsteps.

I tried the RCA gray glass 12SX7GT and did not like it. The tube even hums a bit during warm up and was a bit too soft sounding. Next I tried the Ray $3 12SN7 tubes and they sound much better. I am in the habit of pre-testing the tubes and putting it in the amp to find out if they are keepers or to be returned. I understand now why Glenn did not like the Sylvania 7326 since the 6SN7 tubes just cannot drive them properly or do them justice. When using the Chatham 6AS7 tubes switching the Russian TS 6SN7 and the 2C50 driver did not make a huge difference. When using the 7236 tubes it was more of a night and day difference switching back and forth with the 6SN7 and the 2C50 tube. Also Grokit post #136 stated that his 6SN7 tubes did not work well with his 7326 and he currently using the CV-181Z with the 7326. I like the 2C50 7236 comb so well I have ordered another pair of TS7236 tubes from a fellow Head-Fi’er meaning that all of my audio equipment budget for the year is used up and well spend. ![]()
By March 2012, my audio budget was already down-the-street!
My 2012 New Year's resolution was NO More Tubes.
Didn't last more than a couple of hours!
That you even bothered isn't troubling, it's tickling!
