They are the same tube, but for filament voltage. The Tungsram 7DJ8 has a seven volt heater and is touted as the better tube. Try it, just move the jumpers to provide seven volts.
Always keep in mind however that “better” is whatever you prefer.
Yes. The 7dj8 is the seven volt version of the 6dj8, which is six volt. Either will work. (In the BHK Pre-amp, set the jumpers for 6 volts.) As Kevin says on his site, the 7dj8 is the tube Bascom recommended and they are quite a bit cheaper than the 6dj8’s. PS Audio could not use the tube because it’s new old stock and would not be available in sufficient quantities.
Thank you guys. In my exuberance to get a new set of tubes (and my usual late night shopping sprees lead to mistakes), I ordered the standard 6V Tungsram 6922’s by mistake. Time to place a new order for the 7 series.
magister said Thanks, DenisD. I probably read your post back in July but at the time I was not thinking about replacing my preamp. I'm enjoying the BHK 250 so much that getting the matching pre is awfully tempting.
DenisD said I posted my impressions of the BHK preamp with the Tungsram 7DJ8's on July 5th, post 248, in the Beta Testing the new BHK preamp thread. Several others have also posted their impressions after making the substitution. IMHO the Tungsrams moved the BHK pre up another level in SQ over the stock tubes (YMMV). They aren't that expensive and are a tweak that makes absolute sense to me. Bascom preferred them also, but they are only available as NOS. Upscale Audio is a good source for matched pairs. I'm also using them in my BHK 300's and along with the BHK preamp it is a match made in heaven.
I see on the Upscale site there are Gold and Platinum tubes and also cryo treatments. Is it worth going the extra cost for Platinum and/or cryo?
Cheers Frank
Given the nominal cost, I would spring for the Platinum just in case it makes an audible difference.
I am bit more suspicious of cryogenic treatment, not because it does not change metal treated in this fashion (it does), but whether this is actually “better” for producing sound. But again, it is cheap and Kevin has never steered me wrong.
(As an aside, cryo treated brake rotors do last longer on the track and I have found the cost is worth it for my Z06. Maybe cyro makes tubes tougher. 
)
So I purchased a bunch of the Tungsram PCC88/7DJ8 tubes from Upscale Audio but before I install them I just want to check something:
For the BHK Power amplifiers is it a straight change-over? Just replace the tubes, no voltage jumper changes?
Fro the BHK pre I know I have to change the voltage and the bias - I had a quick look inside - not much room, small fiddly bits those jumpers. Is there a video on-line which demonstrates what needs to be moved where?
Thank you in advance.
Frank
Correct Frank. The Tungsrams sound amazing! I am using them in both my BHK pre amp, with the mods you mentioned, and in my BHK stereo 250 which was plug and play. Note; the tubes slide easily into the power amp tub socks. They are a little harder to install in the preamp sockets. Push them gently in place. Enjoy! Kevin
Hi Kevin,
Well that was easier than anticipated. The power amps were simple as mentioned. The pre-amp wasn’t bad, once you remove the tubes it is easier to see what has to be moved to where. I’ll give the tubes a couple of hours to settle, playing a few tunes while I have dinner with the family and then get some listening in.
I had the same experience – the tube sockets in the BHK pre are noticeably tighter than those in the amp. But the pre tubes will go in if you take it slow and gentle.
Someone else here (sorry, I can’t give credit where it’s due) mentioned using small needle-nose pliers to move the jumpers in the pre. I did that and it made things much easier. Certainly move the jumpers while the tubes are out.
It took at least 30 hours for the Tungsrams to settle in. Their overall character was apparent almost from the beginning – more accurate instrumental tone, easier to follow different lines in the music. I observed the biggest changes in the bass. They went from being a little lean to having a little too much bass, then settling down in the middle. Did anyone else notice this?
Hi Guys,
Agreed, it takes a day or two for these tubes to break / settle in. They have been more musical, portray more detail and image bigger in my system. Had a similar bass experience to Magister as well. I initially turned my sub levels up only to later turn them back down. Until now I thought I was losing my mind.
Good feedback gents, Kevin
magister said I also found a real overall improvement with the Tungsrams. They produce a little more bass, which in my room is not always a good thing, but in general are outstanding.Magister - did you ever plug and play those Matsushitas?I have a spare second set of Matsushita PCC88s that I bought to use in my c-j preamp (about to be replaced by a BHK pre) but never installed. These are very smooth-sounding tubes and someday I will try them in the BHK. I haven’t thought vocals needed smoothing but the Matsushitas would be a move in that direction, if they sound in the BHK anything like they do in my c-j. (See Kevin’s description of these tubes on the Upscale Audio website.)
Anyone else do some rolling of note with NOS? Telefunken? Amperex? Siemens?
I have these Telefunken E88CC/6922 warming up in the BHK preamp. I have the Tungsrams as well, but decided to jump straight to the TFs. I also have some Ediswans and Nationals I might want to try, but right now, the TFs are already sounding like butter. I will probably insert TFs into the amps if they continue to sound this good in the preamp.
JM said Magister - did you ever plug and play those Matsushitas?Not yet — been busy playing with fuses and things :)
I’v got about 50 hours in now with the Telefunkens, and all I can say is wow. I was very pleased with the stock tubes. I had about 500 hours on them in the preamp when I made the first swap. I listened for a couple of days, and decided to go ahead with the swap into the amps. Soundstage in all three dimensions is noticeably improved, not by orders of magnitude, but by degrees sufficient to discern—even by my college daughter [“What did you do? It sounds, hmmm, bigger!”]. Detail remains excellent, but improved, in the way that a prime lens improves over a high quality zoom. More detail perhaps, but without adding any edginess or etching. Localization seems steadier and is especially notable on vocals, which on Cowboy Junkies, Trixie Whitley, Dead Can Dance, and Getz/Gilberto, seem to be right where the singer ought to be standing while performing. Just right there.
I also replaced the fuses in the preamp, and the two recommended by Paul in the amps, with AM beeswax. These have a 125 hour break-in time recommended. I haven’t hit that yet, but it will be interesting to see how they sound. Nothing bad so far, just waiting to hear if I can hear what others have. And then, I will probably want to switch the stock back and out to compare. One of my fuses arrived DOA, so am waiting for that replacement, along with fuses for the DS and DMP.
I wonder how the new TF compare to the NOS, just got a BHK pre
Any updates on the different tubes? Especially the Matsushitas?
Just got the pre and bhk250. I am based in HK and cant find any Tungsram tubes here.
I have a set of Mats that I have not yet tried. I also bought a stock of the Tungsrams, which I also have not tried, though the overwhelming majority here clearly love them. I know that Upscale won’t ship overseas, but doesn’t Tubemonger? I am positive they ship overseas.
I am loving the Telefunkens. So much so that I bought another set of backups for when these eventually expire.
Yes just saw tubemonger does sell and ship the tungsram. The website states tested 65%= 7,500mmhos.
Can anyone help explain what this means?
i am pretty new to tubes as have been using solid states all these years.
ksquare said Yes just saw tubemonger does sell and ship the tungsram. The website states tested 65%= 7,500mmhos.Can anyone help explain what this means?
i am pretty new to tubes as have been using solid states all these years.
Wow, that is pretty cheap for a pair. I wonder what assurance that there is that they are NOS tubes? Anyway the 7,500 mmhos is a measure of the tubes amplification and is a term called transconductance. My guess is that the 65% might be a percentage of the full scale range of the meter scale on the Hickok tester. Another thought is that it might be a percentage of what a new or new tube might measure which would say that they are worn out. They only way for me to know personally would be to get a pair and measure them against what I have in a wide variety of 6922 genre tubes. If they in fact have a amplification of 65% of normal, they would not perform well in the BHK amps or preamp.
Thanks much BHK for the information.
i am guessing maybe one reason for it to have such a low price is because of its performance capacity of running at 65% of normal. (No such thing as a free lunch, as the saying goes).
Guess i have to consider if I should take the risk.
i note in a local store there are some decent priced amperex, mullard and siemens. I will get a couple of sets and try this out first then.
If there are anyone who has bought the Tungsram from tubemonger, would be great if you can share your thoughts on the tube.