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Audio Research State of the Art Audio Reproduction |
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#11
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#12
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#13
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The ref 40 uses 2 pcs of 6550 for power supply. No need to use KT120 at all.
Lifespan of 6550 in this application is around 1600hrs. The signal tubes do last longer though. Mine is around 3200hrs & still sound good. I think ARC recommends a change at 4000hrs Regards, Joe Ling
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Source 1 - Bergmann Sleipner + Benz Micro LP-S + ARC ref phono 10 (should have done this ages ago) Source 2 - Avid Acutus SP reference + Thales Reference tone arm + Benz Micro LPS (DS Audio Master 1 broken tip repaired but cost me USD2k. Still having issues - channel imbalance - back to dealer. However, channel issues not withstanding, sounded very very nice. Need to get it back soonest) Source 3 - DCS Vivaldi + Antelope reference clock or Cybershaft Op18 (not floating my boat so far) Source 5 - ROON ROCK with Aurender W20 as NAS & 2 units of SOTM switch with 10M input (the new frontier but still cannot beat CD for now) - ROON endpoint - Vivaldi upsampler Amplification - Naim Statement Speakers - ProAc Carbon 8 + JL FM113 x2 (replacement purchased - Stella Utopia EVO but due to lockdown, could be a year's wait) Purepower 2000 x 2 (&$@#% but sounds nice) Shunyata Denali X 2 |
#14
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Hi,
When do you guys change tubes? ARC recommends 2000h fpr the 6550s and 4000h for the others. I think it is too optimistic. I have changed the 6550s once with 1700h on them aprox. The change was very audible, and should have changed them earlier for what I saw. Now I have 3100h. Wondering if I should change the whole kit or wait a bit longer. Sounds good still but the sound degradates gradually and so you dont really notice till you change acording to my experience. |
#15
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I would follow ARC instructions but just to be sure you can shorten the replacement intervals if you feel like.
I have REF3 which had 6550 running 2500h and after replacement I noticed slight difference but it might as well have been because the new 6550 was different brand than the original. 6H30 in DR-variation has 10000h specified lifetime. ARC uses new production 6H30-Pi which may not be up to DR specification but is still one of the strongest small signal double triodes manufactured. I do check my tubes occasionally with tube tester to find any "bad apple" which might fail prematurely. |
#16
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2500 hours is very good for the 6550 according to my experience. Moreover if no changes were aparent after such time. I changed mine with 1700h and did notice a material improvement. Not minor for sure. The soundstage had become small by comparation all around. Dynamics were down big time too. All over improvements but remember those 2 were the most evident. I guess different tubes can last more or less randomly. Also the ref 3 may be less demanding with the 6550 (just guessing, may actualy be the other way around).
The thing is that sound degradates gradualy and very slowly, and so you dont really notice. I changed mine last time cos it was doing funny things with soundstaging and balance when turned on. After a while it would get back to normal, but it was taking longer and longer to "warm up" to play normal. This was diferent than the normal warm up to operational temperature. Changed the tubes to see if it would get solved not really expecting a gain in performance given the time on them. But there was a material one. Left me thinking I should have changed the tubes before. Now the preamp has started doing it again. To a much lesser extand than I remember the other time. Doesn't do it everytime and the effect is not as evident and gets back to normal soon but I assume all of it will grow if it is like the other time. And leaves me wondering if it is time for a change again. Although with 1400h, I would have thought it is too early by any count. |
#17
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eeliio8: Curious about your balance problem with the Ref40. What exactly does it do? Mine sometimes gets out of balance but then it will return to normal - I'm wondering if it's the preamp. I was told by Kalvin at ARC that there was a revision to the microprocessor at some stage during Ref 40 production as the earlier units (like mine based on serial #) were susceptible to static electricity. His advice was to try turning it off, unplugging it for 3 minutes, then turning the balance control fully left and right with 0 volume. His other idea was sending it back to ARC as the problem for early units is covered under warranty. Haven't been able to part with it.
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#18
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Hi Barry,
I think your problem is different, although familiar to me. I probably did not explain well what I ment. What I experience is a lack of focus for a while in terms of image and sounstage. Like if it is a voice or soloist that should be right in the center and first "row" it gets slightly back and to the right. Not a balance problem as one channel not working or similar. Eventualy tubes gets warm or whatever and is solved. But it takes longer as time passes and the effect is more evident. I recall this was the same as the other time I had to change tubes and why I did it. But when done I noticed all the improvements mentioned, and so as said I guess sound degradates small steps by steps and you dont really notice. Your problem I had similar as well. My unit was one of the first ones. The volume would go crazy everytime it felt like it. And upon turning on, every now and then, one channel would go much louder than the other. Only way to fix it in my case was to turn it off and back on. Sometimes I would get a +5 vol. Level with the vol. Selected at 1. Other times one channel would go +5 db louder than the other. It was always upon turning the unit on. I went like that for a while, but it got worst and worst and a few months later got it solved under warranty. Since then I have not had the problem, or any other for that matter, even once in I guess 2 years or so |
#19
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Thanks much for the explanation. Mine isn't always cured by the "reboot" and sometimes happens well after turn on. It's seems like a balance problem but it could be the same cause as yours. Sometimes the system does seem like it's flat - like it has less gain than usual too but never louder than the setting. Since my system is pretty complicated (tri-amped) I wasn't always sure what was causing it and just hoped it wasn't the preamp, It's driving me nuts enough when it happens I may have to send it back. Arrgh.
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#20
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I wouldsSend it back. Is a pain in the *** the wait, but well worth it to be trouble free afterwards. Just make sure before you do it it has nothing to do with other parts of the system.
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