Like many others I had replaced the tubes that came with the preamp (Psvanes - not sure how to pronounce that!) with the Tungsram 7DJ8 tubes (which I’m not sure made a “Huge” difference, but sounded quite nice. Recently, as others have noted, I began to get the low level thumping noise out of one channel. This was after about 1150 hours of play time on the Tungsrams…
Thanks, Larry
Although I’ve never heard any thumping, I did swap out the Tungrams (for new Tungsrams) after about 600 hours. To my ears, and in my system, the Tungsrams produce “magic” for about 500 hours. After that, the sound from the Tungsrams is just less involving. I found myself endlessly tweaking, and when nothing helped, I swapped out the tubes, and boom, the magic came back!
So, once I run out of Tungsrams, I’ll be back to the stock Pavanes.
So far my favorite tubes I have tried are the Mullard CV4003 / 12AU7 in the BHK preamp. The BRIMAR CV4003 / 12AU7 is 2nd. I like them better than the TUNGSRAM PCC88 / 7DJ8 by alot.
I have tried the supplied Psvane 12AU7’s (meh…bested by all of the next tubes I tried), the Tungsram PCC88 from Upscale (love them in my 300 Mono’s, too “thick” sounding for me in the Preamp), then some Philips PCC88’s from Upscale (too bright/lean for my system and tastes), and finally I stopped when I put in a pair of NOS Amperex JAN 7308’s (1966) - - just seems to have it all in my system: full harmonic development, without being too thick or rounding of transients. I just love them and have not proceeded to even try the next 5 pairs of tubes I had in line for trials.
If I had more of all of these tubes, I would try rolling the 300 Mono’s, too. I bet there could be some dialing in/refinement to be had there, too.
Just to note, I need to lean my system away from too much “sparkle” or brightness, as I run TAD CR-1’s that do not need encouragement in this regard. Get 'em right, and oh man! You are there! But go over the brightness edge, and they can be relentless.
(I have tried to get my system details to show, like other posters, but my “Bio” details just don’t. Not sure what I am not doing right…)
I'll be Bach said
(I have tried to get my system details to show, like other posters, but my "Bio" details just don't. Not sure what I am not doing right....)
The display at the bottom is your signature. I copied your bio and put it into your signature so that you can see how it works. You can change the formatting, etc. so that it looks as you would like.
Bach, are you the guy from Audiogon who replaced your Aeris, to eliminate a few extra cables and boxes? If so, those TADs sure are pretty. It has to be you, not many people with the TADs and those fat power cords.
You should put a link to your system’s photos, it is worth the time to take a look. I sure was impressed.
Elk: thanks for copying over to my signature. I still do not see the place where I would manage that (like the “Bio”), so not sure how I update it. Surely, one doesn’t copy/paste into the signature area for each post.
Jeffstarr: no, you are thinking of zephyr24069 on the Gon, but there are some similarities. He has the big brother Ref Ones, I have the smaller CR-1’s, but we both do Elrod cables throughout. I would love to hear his system! He powers with Esoteric gear, whereas I use the BHK products (which is what got me on this forum). Those fat power cords sure do work well with a TAD system!
To edit the Signature click on the “Profile” box at the top of this page. In the next page click on the box “Edit Signature” and all the all the information that Elk moved should be there.
Like many others I had replaced the tubes that came with the preamp (Psvanes - not sure how to pronounce that!) with the Tungsram 7DJ8 tubes (which I’m not sure made a “Huge” difference, but sounded quite nice. Recently, as others have noted, I began to get the low level thumping noise out of one channel. This was after about 1150 hours of play time on the Tungsrams. I put the Psvanes back in and set the jumpers appropriately and the thumping noise is gone, plus the preamp is quieter (less hiss) and sound quality is still quite good. So, not sure if I’ll put out the $ for another set of Tungsrams or not - seems like a bit of a crap shoot when buying “NOS” tubes.
Thanks, Larry
Very interesting, I got the Tungsram thumping in the right channel of my BHK Pre at 1000 hours also, replaced it with another Tungsram. The left channel is still fine but now I have the two channels with 2 tubes 1,000 hours apart in age. May look for a suitable replacement downrange…
Very interesting, I got the Tungsram thumping in the right channel of my BHK Pre at 1000 hours also, replaced it with another Tungsram. The left channel is still fine but now I have the two channels with 2 tubes 1,000 hours apart in age. May look for a suitable replacement downrange…
I have tried several tubes. I am currently listening to the Brimar CV4003 from Upscale Audio. I also had a Mullard CV4003 which had almost 1200 hrs on them.
I have the BHK selects in the BHK 250. Nice combo for my system.
If you want to use a different tube than the 12AU7 you have a few things to address. The first numbers of the tube designation are the voltage. So a 12AU7 is a 12 volt tube. A 6SN7 is a six volt tube. The voltage must be addressed one way or another. The other is the size of 6SN7 Tubes. If you add an adapter, you will realise the tube up to an inch plus the height of the tube. 6SN7’s come in a variety of shapes and sizes. I’m not sure that even if you could address the voltage, that the height of the adapter would make it impossible to fit the tubes into the Preamp.
To try a 6sn7 tube with 6sn7-to-6dj8/6922 adapter, the voltage should be set to 6 and the bias set to 4ma (see earlier BHK response on this subject). Unless the CV181 is identical to a 6sn7 in its characteristics, I would be reluctant to even try it without advice from an expert like BHK. As watchdog507 and BHK both have pointed out, the tubes would stick out of the unit, preventing re-installation of the ventilation cover, which may or may not be a problem for you. So far as I know, no one has tried a 6sn7-family tube in the BHK preamp. I myself have many rare vintage 6sn7s that I’d love to try, but I don’t want to be a guinea pig unnecessarily. I have many 6922-family tubes (including the infamous Siemens Halske Cca) that I haven’t even gotten around to try yet. I absolutely love a 12au7-family tube that is in there now – Amperex 7316 late 1950s long plate with D-getter. It has good synergy with the preamp and the rest of my system.
Having read through most of the posts in this thread, I am now thinking that I have to buy a BHK Pre to use the pair of Siemens E288CC tubes that I had in a Schiit Lyr… I always get things backwards!
I have a question for you tube-rollers. If you have a pair of 6922/E88CC matched tubes for the BHK pre and both tubes in the pair have the same corresponding triode 1 and triode 2 plate current test values, what plate current test value combination would you prefer (most to least)? 15ma/15ma, 18ma/15ma, 18ma/18ma (6922 factory spec is 15ma/15ma). Assume the GM value for all tubes are at least 100% of factory spec value.
This is a multi-fold question.
Is a higher-than-spec plate current test value a good thing, contributing to better sound? If so, why?
Does it matter if the two plates have different plate current test values? If so, why?