2359glenn | studio - Page 9

So how are fellow owners doing for amp burn-in/settle in?  Every time I turn mine on it sounds better than the last time, a fact that astounds me more and more each time I experience it.  Sibilance?  Harshness?  Completely non-existent now, even on bad material.  The presentation continues to gain depth, as though you can dive into every individual note as deeply as you want to.  I burn my amp in by listening to it, so it has probably taken me longer to get there than some of you. 

This amp is probably the single best purchase I have ever made.  I can't thank Glenn enough for sharing his talents.

I came round-robin the other day and finally went back to my Sylvania chrome dome GT driver.  The BGRP started acting up again and I ran out of patience for it.    I had previously bellyached that my beloved Sylvania sounded harsh when the amp first came back from its mod.  Now it sounds hauntingly beautiful, different in ways from the Tung Sol but really just as good overall.  It brings the emotion out of the human voice in a way that is very right.  Clearly something was in need of some burn time when the amp came back, be it the 5998s at their new operating point, the pot, the resistors or who knows, but I'm glad things have gone where they are now.

I'm getting really excited about my amp now. Can't wait!!

No word on a shipping date yet. Glenn said he would contact me. I'm patient, but excited nonetheless.

Quote:

Originally Posted by Silent One 
 Low-level listening has been out of the question with the D7000's. They're so efficient, I could plug them in to a transistor radio!

You're getting the stepped attenuator right?  That will cure this problem.  The original Alps pot has a poor taper and doesn't provide enough resistance.  I can get 7 or 8 steps into the Valab pot before it really gets loud even with the 5998.  I have settled on steps 5 and 6 for most normal listening, and the first two steps are very quiet.  That was a huge improvement over the old pot which was like an on/off switch with the 5998.  I was a little worried the jumps in volume in between each step would be too much, but that hasn't been the case for me.  If you need really fine or small changes in volume this pot won't be able to do that for you though.

Quote:

Originally Posted by wotts 

No word on a shipping date yet. Glenn said he would contact me. I'm patient, but excited nonetheless.

He must be waiting on parts.  I recall he was almost out of transformers for the OTL amps, and to get the right taps you basically have to have them made to order I think.

Yeah, the shipping hurts on something this heavy.  I'm glad the Valab worked out, as it was kind of a shot in the dark when I originally ordered the first one to have put into my amp.  Glenn said it tests extremely well electrically.

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.  

John how can you tell they have twisted heaters?

Any chance for a close up photo please?

BTW I have found out that whereas the 2C51 and Bendix 6385 with a 2C51 to 6SN7 adapter drive the 6AS7G/5998 type tubes very well they struggle with the 7236 in my SP amps.

Out of the TS 7236/TS 5998/Sylvania 7236 I prefer the Sylvanias with my WA22.

The 2C50, 2C51 and the 2C52 are very different tubes

2C50  Raytheon like a 6SN7 but 12v with MU of 10

2C51=396A?  but is not a Raytheon tube but like this

2C52 Raytheon is like the 6SL7 but at 12v with a MU of 90

The 2C50 and the 2C52 are both Octal tubes

The 6SN7 has  a bit of trouble controlling the 7236 not the 2C50 which improves the sound dramatically with the 7236 tubes

2C51=396A=5670=6385

They are 6.3V 9pin tubes.