Tube el34

I think JJ's are the new Tesla's.They can be a little bright depending on equipment.The SED "C"logo took over the original Svetlana Made in ST.Petersburg,which is preferred by most audiophiles over the New Sensor Svetlana's.The SED's sound rich and liquidy.Matched Quads should be available in the SED "C" logo,or JJ's .The Cryogenic freezing doesn't have my friends or myself sold.The SED's are also called Winged"C" SED,s. They are both musical for modern tubes also.

A good friend of mine and I are both sold on the new Gold Lion KT77s (new Russian manufacture) as EL34 replacements. He's using them as output tubes; mine are driver tubes in SET monoblocks. Both of us had been using "Holy Grail" Mullard xf1 EL34s prior to switching to the KT77s and find the KT77s way better sounding in all respects after 8 months in his case and 6 months in mine. Just a thought. Dave

I'm using EH EL34s in my Modified ST70. I tried the SED's, new Mullards,Sovtek current and older vintage, Tunsols, New and Old Teslas, and the winner is EH EL34's. The old Teslas are really the best of all but so hard to get. The SED's were clean and quiet but lacked life and bloom and high end extension (to my liking). The Mullards were BLAH, just boring just like the SED's. I just epent $90 on a matched Quad. The older Sovteks were pretty good but they lacked dimensionality. The Tunsols were pretty much the same as the others BLAH. No excitement!
The EH's in my circuit has top end extension, excellent midrange, clean sounding but bass needed a little more control.The entire audio spectrum is better than all the other tubes. I did the same test on a friends ST 70 with the Triode input board with the SED's in the first round, then the Sovteks, and then Mullards (new). I then put my EH's in there and it was a night and day difference. I do suggest whom ever you buy them from that they do their own testing and give you a warranty. My last 2 sets or EH EL34's matched quads were purchased from Jim McShane. They lasted 2 years. I just bought a new set. All but one tested
good and I noticed the channel imblance in my amp. That's my amps way of letting me know when a tube is weak. I have been living with it for nearly 11 years. I have tried to replace it with many much more expensive amps but none were able to. My ST 70 requires a match Quad. No other configuration will work well in it. I'm dying to purchase a Matched Quad from Jim McShane of Gold Lion KT77's. They may sound better than the EH's but for the $$ how long will they last? If I am to spend $200 to $400 on matched Quad it better last as long as some of the NOS back in the day. So, why spend $200 to last me only 2 years when I can spend $70 and it last me the same lenght of time and I get 98% of the sound for less money. Same for NOS I can't justify the extra $$$ if they don't last longer. I'm not sold on cryo either! Google Jim McShane you won't regret it. Ask him about his warranty too.
Thats my 2 cents worth.

Contact Kevin at Upscale Audio, tell him what equipment you are using and your taste in reproduction(which varies widely, person to person) and he will hook you up. His matching, testing, and burning in procedures are second to none(as is his customer service). (http://www.upscaleaudio.com/bEL-346CA7-Typesb_c_86.html)

I always get a kick out of people who rant and rave about how good the Dyna ST-70 is. It is a nice sounding amp, but certainly no world beater. I owned one back in the day that I picked up from the original owner in beautiful condition. My next tube amp after that (this is going back some years)was an ARC D-76. The D-76 is so far superior to the ST-70 that it is like compairing a boy to a man. The poor ST-70 was a wimp in comparision to the D-76.