 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
Thank you for your comments earlier to BAT VK-60 Tube Rolling Reccos. Last night inserted in lieu of the Sovtek 6SN7's the quad of Raytheon VT-231's(driver tubes #7 and 8) -- and was never so disappointed in my life -- lost detail, the bass became almost non-existent; the high end/vocals were curtailed; and the soundstage seemed to go into deep recess. I had expected that on a scale of 1-10 that I would have 'heard' 3-4; instead I heard -2! Is there a 'burn-in' time for these tubes -- are they closed in initially and then later open up -- all I can say is that it would have been the height of folly to throw $400 at a quad of the 'remarkables' i.e., ECC-34's and the like and have received what I got last night.
Follow Ups:
Thank you all for the time and effort you put into your responses -- I learned more in 30 minutes of reading compared to 30 days of 'random shots' in the dark-type approach.I was premature in my early assessment -- I cleaned the pins carefully with de-oxit and iso alcohol and switched their positions -- I received last night completely different sonics/10x -- now much closer to what most have positively said about this 1942/Phil. Raytheon VT-231 in prior postings. Saturday, I will have the tubes tested -- and then matched.
I have also learned not to even consider ECC 34 or 32's -- no matter how great their rep/in lieu of a true 6SN7 for my BAT VK-60 monoblocks -- I believe that it was Robert who mentioned that potential damaging effects on a PS.
Thank you again.
So are you using vt-231's or ECC-34's. If Robert H doesn't chime in soon, you should do a search for the archive of this asylum for the ECC-34's. IIRC, they are not the same tube.
When I had my Bat vk-60 monos I tried the Raytheon Vt-231 and they sounded great. I don know what your problem is. JM
You should be sure you have the right vintage of tube. There are maybe three or four "flavors" of Raytheon VT-231. The good ones have "JAN-Cxx-xxxx" actually printed on the base, directly below the "RAYTHEON" logo. ("x" represents different lettering.) If does not have this "JAN" number, it's probably not the best version of this tube.FWIW, it seems like I always go back to the Tung-Sol '40's "Round Plate" VT231/6SN7...
Todd,That has always confused me. The "VT" designation is the US Army code for its mil spec tubes up until mid WW2. Then, it seemed that the Army & Nany started the "Joint-Army-Navy" or "JAN" designation. So, I think that the "VT" and "JAN" names may have overlapped only during the first few wars of WW2. This would place the birthday of those Raytheons you have to somewhere in the early 40's.
The Raytheons I've seen seem to carry the JAN-CRP designation. I remember seeing a site which has these JAN manufacturer's codes, but can't find it.
The ECC34 is NOT electrically equivalent to the 6SN7. I recall that the ECC32 is kinda close, though I never used an ECC32 in the place of a 6SN7GT---so I can't personally say that they are equivalent tubes.
Yes, the VT-231 was the military purchasing and inventory control number up until about 1945 or so. The tubes were often also marked with the JAN-xxx prefix as well. It seems that the VT-231 number was dropped around the time the WWII effort was winding down.But there was a lot of variation even before 1945. I have Raytheons made in 1943 which have only VT-231 marked on them, and the same vintage only marked JAN-CRP-6SN7GT.
Raytheon is CRP, Sylvania CHS, RCA CRC, CBS-Hytron JHY, Tungsol CTL, KenRad CKR.
It's also worth knowing that there is a common misconception about those VT-231 numbered tubes. It's nothing more than a number. If you find a 6SN7GT of the same vintage, it will be identical to the VT-231 numbered version. I have here Sylvania 6SN7GT from 1945 identical to the VT-231 numbered tube, and Raytheon 6SN7GT 1944 identical to the 1944 VT-231. Also RCA's, Tungsols, and so on. There is no magical significance to the VT-231 number. But some people think there is, because salesmen have told them so. It's become popular folklore in tube circles.
It's only so because VT-231 branded tubes are so common today, as the military kept thousands in warehouses collecting dust for decades until some bureaucrat figured out there was no equipment that would ever use them. The equivalent commercial branded tube was never kept in warehouses for decades, and in any event, most production of commercial tubes was severely rationed to keep war production up - so there were few produced with the commercial 6SN7GT branding.
You are right, the ECC34 is NO 6SN7, actually, there is no tube in the ECC series that is a real 6SN7. People will insist on trying them, though - but I respect me amp's power transformer too much for that.
PNZ,Do you have access to a tube tester? I have never used the VT-231, but have used several Sylvania 6SN7W metal based tubes. And "dead sounding" is not what I've heard from these tubes.
What you described sounds like tubes, on their last leg. Lots of mileage on them. Or the parameters of bias and plate voltage is way off from what TungSol recommends for this tube.
BTW---I still like the Sylvania 6SN7GTA or the Raytheon 6SN7WGT as my personal favorite 6SN7's. Both are tough, seem to have a healthy output. And last in guitar amps---which tend to beat the heck out of VT-231 and old 6SN7W type tubes.
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
