CJ uses a EH 6922 or Philips PCC88. The Philips is a little more reliable, I’ve had a 2 new EH’s from CJ that were noisey from the get-go.
The EH does sound nice, the Philips does as well with a little less sparkle. I am using a Siemens ECC88 6DJ8. It is more refined in the midrange and top end than both in my ET5.
The Gold Lion 6922 is a nice tube... it is the only tube to last long in my Classic 2 SE. I went through a few EH that were from CJ and went noisy soon. I have a EH in there now because i was trying to pinpoint a low level hiss and it sounds good and is dead quiet, but for how long? I will pick up another GL soon as it seems to last and sounds good.
c-j preamps used to be really hard on tubes. They had 29 dbs of gain which required that the tubes be driven hard. Driving the tubes hard makes them go noisy quickly. I see the ET 7 has 25 dbs of gain which is better but still probably not easy on the tube.
I suggest you talk to Kevin Deal at Upscale Audio. He will tell you which tubes can handle the punishment your pre dishes out.
Kevin is a controversial guy, some like him, others don't. I hope we don’t have that debate again. You will be clear about what he thinks after you talk to him. You can decide for yourself whether you want to do business with him. One 6922 won’t be big money by Audiogon standards, so I say give him a try.
I have an email into Upscale. I have purchased mullards NOS 12au7s for an amp based upon their recommendation and was very happy. curious if he recommends the matsushita/national that dill suggested above.
AI second that. I haven`t tried the ET series preamps, but the ET 250 S has 2 driver 6922/6DJ8/Ecc 88 tubes. They wear out after about 1000 hours.
That said, the best sound I have had was with a pair of Mullard Ecc 88s.
My only possible contribution to this thread is my opinion about the use of 6922 and PCC88/7DJ8 in my Audio Research LS7 and LS2.
In comparison to CJ preamps they offer less gain (LS7: 12dB, LS2: 18dB instead of CJ's 27dB e.g. of the Classic 2).
My first choice is Telefunken PCC88/7DJ8 as Telefunken ECC88/6DJ8 are far beyond payability. IMO nothing compares to the sparkling highs, the depth of soundstage and the reliability of Tellys.
Runner up: Tungsram `88 (both ECC and PCC). Close to Telefunken.
And Siemens E88CC - fine tubes, but a little noisy.
Third: Philips PCC88, but be carefull: These are available made in Heerenveen/Netherlands and German production (by Valvo/Hamburg.) They are easily to distinguish: German Valvo/Philips sport a symmetrical two-point pyramidal getter-holder, Dutch Philips a one-point rod instead. The Dutch Philips offer a refined, airy sound, the Valvo/Philips give more (but less defined) bass at the cost of a little lack of detail and resolution.
Worth a trial is the use of PCC189/7ES8. These tubes work very well in my LS2 and LS7. They are similar but not the same as 7DJ8 but do a very good job especially in preamps. I prefer these as tube no. 1 and 2 in my LS7. I found more coherence with these. But keep in mind that these types are no officially recommended replacement for the 6922/ECC88-family. Despite that they show great results in my preamps.
The Telefunken's (6922/Ecc88) sound the best to me, followed by the Siemens 6922. The Telefunken is from 1967; the Siemens from 1972 +/-. They both offer far better dynamics than the OEM EH tubes.
I can't figure it out--$10,000 or more for a preamp, and a $29.00 crappy sounding tube in the box.
I pushed them all around while tube rolling. These tubes can be readily aquired at reasonable costs.
When rolling, I use to make a note card detailing each tube. Let your ears judge each.
The response from Upscale Audio:
“As we're not a Conrad Johnson dealer, we just don't have enough information on their units to be able to answer your questions. You would have to contact the manufacturer or a CJ dealer.
1- dill- at such a low price of $35, the matsushita/national seems like I can’t lose giving it a try, compared to the high price telefunken. What other tubes have you listened to for comparison, and in which preamp?
2- have any of you suggesting the telefunken listened to the matsushita?
3-jampro - any issues using the 7 volt 7dj8 in a 6 volt system? Certainly these are much lower in cost that the 6 volt telefunken, but wondering if their is a compromise somewhere in the circuit.....
The best sounding tube for CJ Amperex 6922 not cheap though.Brent Jesse has them its a big upgrade in sound.
Sorry, was away for some days.
--> 7DJ8 as 6,3V-tubes: No, any issues. 7V biased at 300mA is equivalent to 6,3V biased at 360mA. The 7DJ8 will work well in place of 6DJ8/ECC88 (in both my ARs and another pre w/ 7DJ8 as a cathode follower).