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Posts by mhamel

 More updates from Elekit. The limit is a combination of the output capacity of the transformer and the rectifier in the pre tube heater circuit. They suggested using a rectifier with approximately 2x capacity of the expected current draw for the heaters. I ordered a 1000v/2A rectifier to drop in but if that runs too hot I will go up to a 3A, which will require a bit more work to fit as the package size is completely different. As long as the rectifier is upgraded, it...
 Sure... happy to. That's part of the fun of DIY to me. I did hear back from Elekit, but I also sent a few more questions. While the pre tube heater circuit was designed for the 300mA/tube draw of the 12AU7, it can handle a limit of 450mA/tube. They said that running the 600mA draw of the 12BH7 over time "may" eventually damage the transformer, but that it should be ok to test out. From that, my additional questions were: 1. Is the preamp heater circuit limit due to the...
 I've got a Lyr 1... it's a great amp, and the 2 is supposed to be even better.  However, even after rolling an insane number of tubes through the Lyr, I never quite got it to sound right with my LCD-X. Interestingly enough I liked the Lyr with the LCD-2, but I thought it made the X sound too thick and closed-in. At this point the Elekit has pretty much shelved the Lyr.
I had sent an email to Elekit Japan to get some more details on the heater circuit current capacity, but haven't heard anything back yet.   So, I probably should have dug into this before just plugging them in, but here's what I found... I think I'm looking at this correctly:   From the schematic it shows 4A from the transformer on the 6v tap, but I don't know if that's the max spec for that transformer or not.  That tap powers the DC heater circuit for the pre tubes...
 I think I've been the guinea pig on this one.  FWIW, I've got around 50 hours with 12BH7s in the amp so far without issue.    -Mike
 This is called "microphonics" and is fairly common in tubes. Some tubes will be so microphonic that any small vibration will set them ringing. If you're only getting it when tapping directly on the tube, then just don't tap the tube.  :-)  If you have a set that's very microphonic you can also use tube dampers.  They range from simple high-temperature silicone o-rings to much more elaborate/expensive devices. Check out Herbie's Tube Dampers and the dampers offered by...
 I've got the Maxi Preamp II.  I've been very happy with it so far.  It's an additional $180 for adapters if you want to test 6DJ8-family tubes.  Another small preamp tube tester I've heard good things about is the Tube Imp.  It needs to be ordered from the UK and works out to around $500.   I came to the same conclusion about vintage testers. I really didn't want to have to go through restoring and re-calibrating a vintage tester.  I'd love an AT1000 but just couldn't...
 Still burning things in, but so far the combo of 1950s Sylvania black plate 12BH7 and reissue Gold Lion KT-88 is my favorite.  I need to put some more hours on some of the other tubes before doing any sort of meaningful comparison.   -Mike
 JK-47, Thanks!  The main advantage of the RK27 blue velvet is tighter channel balance.     -Mike
  Effusion, Yes, the RCAs are the black plate versions.  I haven't run them in the amp yet, but I've heard good things about them.  At the moment I'm running a pair of early Sylviania black oval plate 12BH7s along with the reissue Gold Lion KT88s. I've heard such mixed/extreme opinions on the reissue tubes with some people saying they're every bit as good as NOS and others swearing they're so horrible they'll make your ears bleed.  Since all of the reissue tubes combined...
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