Greetings,
We are currently finishing up the input stage for our new high power Hybrid mono bloc amplifiers. The current prototype is sounding very good but I have done all the initial listening and testing with only 1 set of decent tubes. I have a pair of Siemens E88CC tubes in it now that I am liking very much.
To give you a brief discription of the units.....The amps use a zero can "buffer' at the front end feeding a high power new Class D output stage (no, not a cheap 'off the shelf' amp).
Aside from current production stuff and very expensive NOS, what are your thoughts, likes and dislikes with some of the tubes from this family.
I had some 6922's that I got from Upscale Audio from his private stock (e.g. expensive) about 10 years ago. He doesn't carry them anymore (and I forgot the brand now, they may have been Radiotechnique's) but they were very, very nice. So when one went microphonic on me I picked up a pair of the "rocket logo" 6922's that he sells. They were almost as good, and inexpensive.
I've tried several other brands over the years, including Siemans, Mullards, Tele's, etc. but I keep coming back to these in the end. In fact, I picked up some additional spare sets even cheaper on e-bay direct from a Soviet source. You need to get the tubes made in the Voskhod, Kaluga factory. Here's a link to more info on different Russian factories and their logo's.
http://www.ominous-valve.com/russtube.html (http://www.ominous-valve.com/russtube.html)
Matsushita 6922 1970s is nice. Mullard tooling. Nicely warm but not too lush.
I really liked the 60's -Early 70's Sylvania 6DJ8, in the black and yellow box. I've not been very impressed by any of the Russian tubes I've tried. I also liked the JAN (Joint Army-Navy) 6922's...they came in a plain white box and i think they were from the same vintage.
I believe one of the highest regarded 6922 tubes was a Mullard made in the Blackburn Factory. They are difficult to find, expensive and some will wear an RCA Label.
Ken
Depends on what character you are looking for. Detailed and lively go Siemans or Tele, next up Amperex same but more body, mullard richer and fuller, RCA richest of the bunch. I perfer to compliment the next tube in line. If I was using a rich output tube than Semeins or Tele and visa versa.
Caps used also have a impact on tube selection. I would not use Siemans either a Mullard or RCA. IMO there are no best 6DJ8s it depends on the application. For example when I use a Mullard 6DJ8 as the input for my amp the driver tube is a Phillips 5687, when I use an Amperex 6DJ8 I perfer the Tungsol 5687. Which all depends on the output tube used. when using an RCA 211 output its the Amperex and Tungsol and for the GE 211 the Mullard and Phillips. Go figure. Hope this helps.
charles
PS forgot a good one the Chelmers and also agree with Richadoo about the Matushitas, great for ARC gear as inputs.
Just like everything else in this hobby, it's all about synergy........
I like warmer and lusher sound... which should mean I like Mullards... but most of the time, I don't.... they tend to sound flat and dull at times while trying to be warmer sounding...
having said that, I've really enjoyed the CV2493 Mullards in just about anything I've tried them in... nice tubes and not too outrageous on the price...
Thanks for all the feedback guys. I know it is all subjective and personal when it comes to tubes. I wasn't looking for what tube would be best in this design as you never know where and who's system a product will end up. I was simply looking for some characteristics by those who have experience with particualar tubes.
Personally, I prefer the presentation to be very open, detailed and airy rather than warm and fuzzy. Bass needs to be fast and artculate. Overall the Siemens are doing a great job. I will give up low end extension for speed.
The design does not have any additional tubes in the circuit as this stage directly feeds a Class D output stage. We have been working on this tube stage for some time and now it's time to see what different tubes will bring to the table.