Hello again. I've tried a few different tubes in the JOR, so here's an updated review.
*
If you need a bit of extra power (as I did), swapping out the KT90s for KT88s improves things noticeably. The qualifications regarding piano and orchestral dynamics no longer apply in my system. In fact the KT88s saved me a sizeable amount, because I had returned to the dealer with every intention of purchasing a demo Defy7 - the latter still sounded as good as a year previously, but impending home renovations saw me vacillate - and as a compromise I thought I'd try new tubes for the JOR. The KT88s frankly saw the JOR produce a sound which I prefer to that of a Defy 7 (heard with a current Jadis preamp). On the advice of Audiogon members, I opted for the JJ brand KT88s - these are said to emphasize the upper bass, and I like this trait - it lends a plushness to orchestral pieces, and a nice full body to piano works; with jazz it can get a little too emphatic, but the JOR has subtle tone controls and these, together with adjustment of the REL sub, generally see things right. Two of these JJKT88s developed a hum, one immediately and the other a week after installation, and thetubestore.com offered replacements, which have been working perfectly for over a month now. Others laud EL34s, including Pierre Gabriel, but the lower power output did not augur well as a match for the Wilsons - no doubt worth a try, however, if your speakers are willing.
*
With the 12 AX7s I tried four current production types. The long plated JJ803S; Ei Elite gold pins; Electro-Harmonix; and Shuguang, triple mica. The JJs were very disappointing - the mids and upper bass were far too thick for my taste, and worst of all the highs verged on harsh - a week of burn in saw no improvement. The other three were all perfectly listenable, and I imagine preferences here would be solely matters of personal taste. The Eis offer a sound which I found slightly congested, but I could imagine others would find rich - they certainly were not harsh as per the JJs; the EHs were very clear and smooth, while my favourites remain the Shuguangs, which seem to add a little warmth while retaining the EHs clarity.
*
I spoke to Pierre Gabriel, calling at midnight Sydney time (10am Canadian time) and he was very helpful and incredibly enthusiastic - he mentioned that most people hold the misconception that the JOR has a passive pre-amplifier stage, whereas it is active and, surprisingly, it is solid-state - there is a single transistor in the signal path for each channel. He did imply that the JOR, while excellent, does sound different in tone to the other Jadis amps. He also described the SE version, which has KT88s fitted as standard, along with some internal changes - including silver wiring. He waxed lyrical regarding the Jadis range of CD players...in the end I had to bid him au revoir...he was only warming up, but I had to go to sleep!
*
Overall the change in tubes has, for me, only improved an already terrific amplifier. A year on I'd recommend the JOR still more unreservedly.
*
If you need a bit of extra power (as I did), swapping out the KT90s for KT88s improves things noticeably. The qualifications regarding piano and orchestral dynamics no longer apply in my system. In fact the KT88s saved me a sizeable amount, because I had returned to the dealer with every intention of purchasing a demo Defy7 - the latter still sounded as good as a year previously, but impending home renovations saw me vacillate - and as a compromise I thought I'd try new tubes for the JOR. The KT88s frankly saw the JOR produce a sound which I prefer to that of a Defy 7 (heard with a current Jadis preamp). On the advice of Audiogon members, I opted for the JJ brand KT88s - these are said to emphasize the upper bass, and I like this trait - it lends a plushness to orchestral pieces, and a nice full body to piano works; with jazz it can get a little too emphatic, but the JOR has subtle tone controls and these, together with adjustment of the REL sub, generally see things right. Two of these JJKT88s developed a hum, one immediately and the other a week after installation, and thetubestore.com offered replacements, which have been working perfectly for over a month now. Others laud EL34s, including Pierre Gabriel, but the lower power output did not augur well as a match for the Wilsons - no doubt worth a try, however, if your speakers are willing.
*
With the 12 AX7s I tried four current production types. The long plated JJ803S; Ei Elite gold pins; Electro-Harmonix; and Shuguang, triple mica. The JJs were very disappointing - the mids and upper bass were far too thick for my taste, and worst of all the highs verged on harsh - a week of burn in saw no improvement. The other three were all perfectly listenable, and I imagine preferences here would be solely matters of personal taste. The Eis offer a sound which I found slightly congested, but I could imagine others would find rich - they certainly were not harsh as per the JJs; the EHs were very clear and smooth, while my favourites remain the Shuguangs, which seem to add a little warmth while retaining the EHs clarity.
*
I spoke to Pierre Gabriel, calling at midnight Sydney time (10am Canadian time) and he was very helpful and incredibly enthusiastic - he mentioned that most people hold the misconception that the JOR has a passive pre-amplifier stage, whereas it is active and, surprisingly, it is solid-state - there is a single transistor in the signal path for each channel. He did imply that the JOR, while excellent, does sound different in tone to the other Jadis amps. He also described the SE version, which has KT88s fitted as standard, along with some internal changes - including silver wiring. He waxed lyrical regarding the Jadis range of CD players...in the end I had to bid him au revoir...he was only warming up, but I had to go to sleep!
*
Overall the change in tubes has, for me, only improved an already terrific amplifier. A year on I'd recommend the JOR still more unreservedly.