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In Reply to: 6922 does always equal 6DJ8 posted by warnerwh on September 28, 2004 at 09:09:52:
warnerwh,This is a bit confusing. If Leonard told you that ECC88 / 6DJ8s will survive the LS16- I'm sure he's correct. However, I think you may have misheard that 6DJ8s can always be used where 6922s went before- as TH says. Did you read about the possibility of over-stressing 6DJ8s in the manual?
"TH" is correct about the upward-only substitution of the ECC88 to E88CC to E188CC (6DJ8 > 6922 > 7308) as the higher rating is to allow a higher continuous current. You can always use the higher rating in a less demanding circuit, but not vice versa.
These ratings are as follows:
6DJ8 family ratings:
ECC88 = 6DJ8 > 130V/1,8W
E88CC= 6922 > 220V/1,8W
E188CC= 7308 > 250V/2W
6N23P/ Sovtek 6922 > 300V/1,8W
6N23P-EV/ EH 6922 > 300V/2W
Note how the Volts and Amps increase for each variant. The highest ratings are for the Russian 6922 equivalents.
There seems to be a somewhat inverse relationship between the ratings and sound quality. I've found the 6DJ8s to sound the best- such as Amperex Bugle Boy and Amperex A-frame, but if the equipment pushes these, they become sacrificial. The 7308 is not as open or dynamic sounding to me as the 6DJ8. there are some very good sounding 6922s also.
I'm sensitive to the issue of overstressing preamp tubes as this is the modus opperandi of my ARC SP10 in which even rugged Siemens 6922s do not last very long. I believe some Audible Illusion preamp owners are in this club also. In my SP10, only the Sovteks and E188CC (7308) last. This was an expensive education too!
Have alook at "Joe's Tube Lore" in the FAQ section of this site. This is a detailed descrption of every member of the 6DJ8 family you'll ever happen upon- and some models that are today "non-obtainium".
Cheers,
Bambi B
Follow Ups:
I'm still a bit confused. I told Leonard I'd read that the heater or plate (forgive my ignorance) current was spec'd differently and he said they are the same. He said "you can use a 6dj8 anywhere a 6922 is used". This conversation was this morning but my memory still is fairly good. I did alot of research here is how I learned the two tubes were different. Leonard's tone, if I read him correctly, was that people are making a big deal out of nothing.
warnerwh,I'm reasonably certain that Leonard would not have said that 6DJ8s can be used [absolutely] anywhere a 6922 is used, but that he may have meant that the LS16 in particular could use the lower rated 6DJ8.
I'm guessing a bit, but all the LS series that I know of that use the 6DJ8 family specify in the tube complement to use E88CC/6922.
However, a line stage- is not pushing out the last dB of gain the way a phono section must to amplify low output cartridges. The output of a typical CD player must be 2 or 3V and some are powerful enough to directly drive the power amp- with no preamp. An MC cartridge may put out only 1/100th the output of the CDP. So, with the lower stress, a 6DJ8 is possible- it's only that a 6922 is rated to last twice as long at the rated value.If we knew the current to the 4-6922s on the LS16, we could have an idea of how far these tubes are pushed.
The case is moot on the LS16/ MKII as those use 6H30s.
Cheers,
Bambi: I may be incorrect but I certainly got the impression by the way Leonard explained it that 6dj8's could indeed be used anywhere a 6922 is used. The numbers in your other post obviously make perfect sense as to why a tube designed to handle a lower amount of current may not last with the higher current. I will call Leonard again tomorrow and see what I can learn. My curiosity/learning is the only thing important as I know the 6dj8's are fine and also are the best sounding of anything I've tried. It was your recommendation (many months ago) btw that I check with ARC before using 6dj8's and btw thank you. These 6dj8 tubes I just put in are clearly the winners. Also I'll see if I can find out the current to the tubes. Thanks for everybody's help.
- and some models that are today "non-obtainium".Like the "pinched waist" USA Amperex 6922s? I like the sound of them in my rig.
in my opinion is a pretty nice tube.ja in partly cloudy, sun going down with the polarized rays hitting the tries, Tucson, AZ
The Elaborate DAC=55/76 or 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
flat black plate, triple mica, rather rare, 6n1P. Yes the filament draw is twice that of a 6DJ8 but the tube is more life like and has better dynamics. It sounds nothing like the later grey plate and different construction 6N1P's.ja in clear, breezy, and the sun going down, Tucson, AZ
The Elaborate DAC=55/76 or 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
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