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In Reply to: RE: JJ 6550's posted by Sondek on February 16, 2015 at 15:39:58
JJ has very nice sounding tubes and I can't take that away from them however,until I see evidence that they have improved their octal base tubes for reliability,and I mean in dramatic fashion,I just don't feel comfortable recommending them.I do know that McIntosh is using JJ tubes as original equipment for the KT88s in the MC275.This shocks me for the simple fact that the original MC275 used Genelex KT88s..Being they wanted to replicate the original MC275 in most every way possible,this didn't make much sense.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Edits: 02/16/15Follow Ups:
The JJ KT88's as supplied by Mike Sanders in my Quicksilver Silver 88 monos have proven very reliable and good sounding.
I know that Mike tests every tube and runs in every amp.
I have also seen (in person) how McIntosh tests every output tube. They were distressed when Svetlana (the manufacturer, not the brand) stopped production in St. Petersburg,
It's possible that the JJ 6550's are very good tubes indeed.
Agree that testing procedures is key here. I too have QS amps equiped with JJ kt88s and they have been nothing but spectacular in sound and quality for years now. Whatever Mike does to these guys in terms of screening and burn in is really really special. Too bad the manufacture got so far away from QC in years past. Good to hear they are coming back around with better product, if that is truly the case.
Edits: 02/17/15
Bill
There is no denying the wonderful sound quality of JJ tubes. Jim McShane even knows that.As long as they corrected the issues with their octal based tubes,I'm all for giving them another chance.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Hi Sam
Good to hear from you.I love your reviews..It makes me wonder if the US is getting different JJ octal tubes than other countries.The reason I ask this is, I don't hear about these issues in other countries.AAMOF,when I first started getting the JJ KT77s about 8 years ago,I called up Tomas at JJ and I told him about many of the tubes having crooked bottles,under sized pins,and flashing in the wrong places..He wasn't even aware of these issues and that made me wonder if the US distributor was buying B stock or factory rejects..Jim McShane is one of the most reputable tube dealers on this earth and he also had so many bad JJ octals that he wouldn't chance carrying them..The 6BQ5s,the 9 pin miniatures,and 300b and 2A3 tubes are all up to the minute..I even have a quad of Groove tubes JJ KT88s with less than 200 hours on them two of them have shorts and one has flashing over 85% of the tube along with a ring getter that fell off inside.
If they genuinely rectified those issues from before,I would be more than happy to give them another try.I do love the sound of JJ tubes.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Edits: 02/16/15
I thought the new Telefunken Black Diamond lineup was the answer to that question. So, I searched a little.
On the Tube Depot site, it states "The TELEFUNKEN EL34-TK has been designed to handle a slightly higher grid voltage than the traditional EL34." I got into looking for close up photos of the glass. The grid posts have been changed. There seem to be physical differences worth considering O.o
Photo of the EL34-TK
http://www.telefunken-elektroakustik.com/images/tubes/black-diamond/el34-tk-tube-box.jpg
Photo of the JJ E34L/EL34
http://amp8.com/etc/amp-inho/jpeg/vvinfo-1.jpg
Photo of the JJ 5550
http://www.thetubestore.com/JJ-6550-Audio-Vacuum-Tube-Image.jpg
Photo of the 6550-TK
http://cdn1.bigcommerce.com/server1200/b633e/products/7848/images/24267/16550tk__79386.1406938395.1200.1200.jpg
So, while it doesn't answer your question, I have opened new ones!
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
May your tubes be warm, long-lasting, and always lively. Holy be thy heater.
It could be possible that the US distributor got some bad JJ stock. I've been using all kinds of JJ tubes for years, and have seldom had any issues although there were a few minor ones with ECC82's and 3's. Power tubes have not been an issue.
In fact I've had far more problems with the much acclaimed Gold Lion KT88's than I have with JJ. I have to admit though, I've never tried a JJ 6550.
Dan Santoni
Thanks, Mike. I'm aware their rep for octals had been bad in the past. They've really stepped up their game with their nine-pin offerings. Maybe their power tubes have gotten better since the dark days. Hard to know cause I just don't hear people mentioning them. Not for quite a while anyway. Interesting that Mc uses them. Wonder what kind of reject rate they get on them?
JJ 6550 works fine in europe.I have 4 of them in my vta since 18 months,they
still hols bias and still sound good.
Note that the metal base is no more on jj6550, they are only on the tfk-branded ones. jj6550 has a black base,like the 6l6.
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