Bottlehead Forum
Bottlehead Kits => Eros Phono => Topic started by: Suger on June 26, 2022, 07:08:05 AM
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Hello everyone. So we're in the process of assembling an Eros 2 Phono, and are at the glow stage. The 12AU7 is definitely glowing, but I'm unsure about the 6922 and the EF86s. As it's still day out here and I know the glow can be quite hard to see, I was wondering if there were any voltage reads on the pins I could use instead of the glow test?
I'll try again after nightfall to be sure, but just in case, thought I'd ask you knowledgeable folks also
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The heater voltage will appear as 6.3V between terminals 22 and 24.
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And we have a very nice 0. So something's wrong. Either the soldering (most probable) or something in the wrong place. Just posting a picture in case there's something evident, I'll check all tomorrow with fresh eyes.
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It's extremely important that you follow the directions in the manual as carefully as possible. I can't tell if your wiring is good or bad based on your photos because it deviates too far from what we have written and photographed.
All of the shielded twisted pairs of wires leave the back of the terminal strip. They are all stripped back in such a way that you can easily see that they are all going to the correct terminals and there is no possibility of the shield drain wire or metal jacket inside the cable touching anything it shouldn't. I have attached a screen shot from the manual showing what this is supposed to look like.
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Excellent point. We'll redo it cleaner and see what happens. Hadn't actually noticed we'd gone on the wrong side. Thanks!
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Hopefully a slightly cleaner mounting now. Thanks for pointing that out.
As for the rest, there was a faulty solder on D5 (the wire from the circuit board wasn't properly soldered), and I've fixed it, so C is now glowing. Still no dice with A and B, though. Will continue to explore.
Brief update: I have 6.2V between 22 and 24, but 0 between A4 and A5 and between B4 and B5, despite the connection being seemingly OK (resistance is nominal between A4/B4 and the positive pad on the solder board, or anywhere in between, and same with A5/B5 and the negative solder pad. I'm wondering if this might be because I'm not fully plugging the tubes (am I right in assuming that, without the tubes, there is no circuit?), but I'm unsure of whether I'm doing things correctly especially because of the bayonet base which hides the pins, and I'm afraid to apply too much pressure, even if I know that the sockets can be a little rough at first). Anyhow, will continue to investigate, but any bit of advice would be very much appreciated ;)
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You can put the 6922 tube in the A and B sockets for the glow test to check that wiring. Typically EF86s don't glow all that brightly and that can be hard to see.
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And thar she glows. Thanks.