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Just got it, letting it burn in on triode. EH tubes were a little harsh in UL mode. I'm a newbie to power tubes so I have a few questions:
- I tried switching from UL to triode with the volume all the way down and still got a loud pop from my beloved speakers. The manual does not give guidance on changing mode so I'm now doing it with the unit shutdown which is not convenient. Is this normal?
- any guidance on which order to power up equipment? I have a tubed phono pre and a tubed DAC. The phono pre (AAV1) manual says it should be powered on first so I've been doing it that way without issue. Again very inconvenient if I want to switch to LPs after tuner or CDs for warm up and I need to shut everything down. Also, my tuner is really a Mac mini and DAC for Internet radio. I usually turn on the Mac mini first so it can boot up and start Pandora. I get a soft pop even with the DAC shut off and the Cary volume all the way down.
- any tips or input, including tube rolling but I've already read quite a bit on that, are appreciated!
None of the noise issues happen with my Plinius 9200.
Follow Ups:
Switching between UL and Triode gives a loud pop on my SLI-80.
Coincidently, I had one of those switches fail on me. Service tech guy was very surprised as he said that the switches used were of very high quality.
There is only one bias pot per side which requires you to use matched tubes per channel.
Nicest tubes I've tried in mine (EH KT88, Genalex reissue and Shuguang Treasure) has been the Shuguang Treasure.
The stock EH5U4 rectifier doesn't last very long though. They would flash on startup after a few months of use.
Terry-
I believe Abe is a Cary fan. Hopefully he will read your post and chime in.
nt
I've got the all triode version. I can't help with the noise issues, but I will say that I'm not a fan of the EH KT-88s. I like the gold lion reissue KT-88s in that amp. Don't forget to experiment with the small signal tubes.
Jack
If you think about the system power-up logically, it should be clear that no pops, ticks, or thumps will reach the speakers until the amplifier is turned on. That being the case, turn on the sources and then turn on the amp. If you use a DAC, phono stage, or other source, power them all on before the amp. The ones not in use will simply be warming up, not a bad thing.
Never switch the triode/UL switch with the amp powered on.
Ditto about switching with the power off, though I can switch mine with the power on and the pop is not terribly loud. Maybe they're using a different switch now.As time goes by, be aware of any change in how the switches "feel." I had to send my SLI-80 back to Cary under warranty because one of them failed, which they said happens. Might be good to have a look inside, which is how I found my switch had failed – I could see the side of the switch housing was broken. Take note also of any missing solder connections or loose parts shaking around freely anywhere inside the amp... ahem.
As far as the EH KT88 sounding harsh in UL, I noticed the same. I changed to a quad of the New Sensor Svetlana 6550. They’re inexpensive, sound real good, not as harsh in UL and also not as rolled-off as the EH in triode.
If they supplied you with Chinese 6SN7, you might try something else there, too, but changing the EH KT88 might net you the biggest improvement off the bat.
Edits: 08/14/14 08/14/14 08/14/14 08/14/14 08/14/14 08/14/14 08/14/14
Do you know what the info on the EH tubes that looks like a date means? My amp has tubes with "12 05" and "12 02" and "02 04", etc., on them. If its a production date my amp has new tubes which are actually up to 12 years old.
I installed them mirror image symmetrically according to the "date".
You might actually need to install the power tubes in the order of the numbers on the boxes, 1 through 4, from left to right on the amp, if the boxes were so numbered. That's the way mine came along with instructions to do it that way. I have assumed that meant they are matched at the factory and need to be installed in that order so that the matched pairs stay together in each channel. However, in your case, if all four were properly matched together as a quad, then the installation order would not matter.
Those date codes are in a year-month format.
The age of the tubes does not really matter, as long as they are good. What matters is that they are electrically matched, accordingly. Personally, I also feel that it could be very beneficial to have date codes matched (or very close) as well, for channel-to-channel (left-to-right) consistency in sonic characteristics. I am sure some will disagree with this, but I strive for it.
If you ever replace the power tubes, buy them from someone who can match them at the plate voltage you can expect in the SLI-80. Cary quoted me figures in the high 500’s of volts, but I have not yet had a chance to measure it in my SLI-80 myself. I suggest tctubes.com
Thanks Peter! The EH power tubes all had a "54" label on the top of their individual boxes, so it appears that they are a matched quad. I think I'll switch the mirrored image arrangement (based on date codes) that I use and adopt the matched pair date codes as you suggested. That would put two 12-05 tubes on the left side and two 12-12 tubes on the right, and then re-bias them.
Terry
Actually... I don't think I was as clear as I should have been. If there is anything to my idea about date codes, I think your mirror imaged arrangement would be better, that is, a 12-05 and a 12-12 in each channel, again assuming they are indeed a matched quad.
Edits: 08/19/14 08/19/14
Cool, I'd rather listen than re-bias. Thanks again for all the info and guidance on tube rolling. I'm planning to put about 75 to 100 hours on the EH tubes prior to considering tube rolling but I'm sure I will tube roll! All of the current tubes are EH -- signal, driver, power, rectifier.
Conventional wisdom states that the amp should always have a signal going to it . Turn it on last and off first .
I would also suggest that you put 200-300 hours on everything , tubes and amp , before you make any decisions on the sound .
When I demoed a Sli-80 , I switched from UL to triode on the fly without any problems or noises , as suggested by the dealer .
Good luck
saki70
Thanks saki70! I'm definitely hearing changes as it continues to break-in. Some of the tube break-in sound mentioned by another poster is spot on to what I'm hearing, so it's going to test my patience to wait 200-300 hours. But I've experienced that type of extensive break-in with other components, the Plinius 9200 and a Shunyata Python CX power cord for example.
Thanks for the tube rolling input! All the tubes are Russian EH. The amp was harsh in UL mode until 5 to 7 hours was put on the tubes, then it mellowed out. The tubes do lack upper end, maybe some of that will happen with additional break-in.
Never switch between Triode and Pentode with the amp on. It is not good for the switches and not good for the output tubes. Goes for any amp with such switching.
As for the turn on order. Typically it's sources back to amplifiers. But it's not hard and fast. As long as there are no loud bangs or pops turn it on whichever way is convenient.
Dan Santoni
"Never switch between Triode and Pentode with the amp on. It is not good for the switches and not good for the output tubes. Goes for any amp with such switching"
Must be a brand specific rule? The brand I use can be toggled between UL/Triode from the remote, no problem. Wont mention brand to avoid jacking the thread.
I have had my SLI-80 for several years and have never heard any strange sounds when switching from triode to UL. I tried switching with every different style of outputs tubes I've used but always return to triode.
If you are on a budget try swapping the stock 6SN7 tubes with some NOS Sylvania's or the like. They can have a huge influence on the sound. If it still doesn't do it then go on to the 6922/6DJ8 signal tubes, again NOS or some of the new production from Gold Lions. Anything is better than EH from my experience.
Myself I haven't the means to go NOS output tubes. I see no need when there are such good new production tubes available these days.
I am running Tung Sol KT120's now and am very happy.
Try the Gold Lion reissues, they are spectacular.
As someone previously wrote stick with reputable dealers. Jim McShane is one. Brent Jessee is another. There are many more but I speak from my experience.
With the Cary, I now have a total of 17 tubes in my system, so I need to be somewhat cost effective regarding tubes. I've wanted to try some new production tubes in my phono preamp, so your recommendation on the new production Genelex GL tubes will likely lead me that direction. I hope their 12ax7s are as good as their other tubes!
I would contact Cary about switching mode while on.
Alan
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