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https://www.decware.com/cgi-bin/yabb22/YaBB.pl EQUIPMENT FORUMS >> SE84UFO2 >> New UFO2.1 no sound https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1720849821 Message started by Bob Loblaw on 07/13/24 at 06:50:21 |
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Title: New UFO2.1 no sound Post by Bob Loblaw on 07/13/24 at 06:50:21 At long last my UFO2.1 arrived this week. I installed the tubes, swapped it out for the amp I had been using and after hooking everything up as I thought was correct, I noticed that I wasn’t getting any sound from the amp. I systematically tested various issues but still couldn't determine the problem. All the tubes glow when the amp is powered on but the current meters don't move above zero at all. During troubleshooting I removed and reinstalled the tubes and I believe the first time I installed the rectifier tube I may have had it in the incorrect orientation, but it still glows when turned on. I also reconnected my old amp and it is working normally. Lastly, it wasn't entirely clear to me how to hook up the rca input cables. They are hooked up 'outside'/'outside' and Ive tried both input selector positions. Can anyone help troubleshoot this? I'm hoping I'm just doing something dumb. Thanks in advance ! |
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Title: Re: New UFO2.1 no sound Post by Lon on 07/13/24 at 09:38:45 Make sure that your interconnects are properly attached--the one closest to the edge of the chassis should be the output I believe, the other the input. Otherwise it's possible that one of the fuses on the interior on the board for the rectification fuses has blown. . . .(?) Best of luck getting through this frustration to joyous listening. |
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Title: Re: New UFO2.1 no sound Post by Bob Loblaw on 07/13/24 at 10:00:31 Thanks a lot ! One of the internal 250mA 5x20mm glass fuses is clearly blown. Will order a replacement and report back. |
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Title: Re: New UFO2.1 no sound Post by Lon on 07/13/24 at 10:03:46 That's good news that you discovered that. Any wrinkle with the rectifier can cause one of those fuses to blow--and that is a good safety precaution for the component. You should be good to go once that is replaced. |
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Title: Re: New UFO2.1 no sound Post by CAJames on 07/13/24 at 14:50:50 Quote:
FYI there are two separate circuits in a tube amp: a low voltage/high current circuit for the heaters, that makes them glow, and a high voltage/low current circuit for the actual music, that is measured by your meters. So having the tubes glow is a necessary, but not sufficient condition for your amp to work, as you have seen. Hopefully all you need is a new fuse, but it is possible the rectifier itself is dead. If you don't have a set of replacement tubes I would encourage you to organize one soon, because you never know when a tube will go bad. And the best way to check for a bad tube is to replace it with a good one. Same goes for fuses. |
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Title: Re: New UFO2.1 no sound Post by MikeinMontana on 07/13/24 at 17:51:01 What James said [smiley=icqlite20.png]~ Had two rectifiers go bad, the third worked fine. The first blew the internal glass slow blow 6 amp. The second one was an internal 250 mA. I have placed the original branded good one in storage/back-up to keep. I now use a 5u4G RCA black plate NOS 1953. Top getter Not a single problem and it's a nice looking rectifier too. I also have a new in box 1941 RCA 5y3g awesome and original box. a 1957 brown base JAN RCA 5r4GY, a 1951 Zenith 5u4G bottom getter, A Svetlana 1959 black plate 5u4g, and a 1966 Svetlana (very dark grey plate?)5u4g. Get back up tubes when you can. Mike |
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Title: Re: New UFO2.1 no sound Post by Lon on 07/13/24 at 18:54:41 Since all the tubes glow that indicates to me his rectifier is probably good, especially as when that particular fuse blows you get rectifier and tube glowing but no sound. Still good advice to get back up rectifiers, Lord knows I have enough, about a dozen plus. |
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Title: Re: New UFO2.1 no sound Post by Bob Loblaw on 07/15/24 at 01:34:23 Thank you all for your responses and input ! Received the replacement fuse a few hours ago and just swapped it out for the one that was blown. Happy to report that I'm up and running and all sounds amazing ! The fuse must have saved the rectifier tube as it is working well. I will look into getting a backup rectifier and maybe invest in a NOS that everyone raves about. This is an amazing community, thank you again ! |
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Title: Re: New UFO2.1 no sound Post by Lon on 07/15/24 at 08:18:22 Great news! |
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