Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Effects => Topic started by: plaidzebra on September 07, 2015, 09:19:35 am
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Hey all, sorry in advance if someone thinks that this is on the wrong board.
I'm interested in making this level meter with a EM-87 magic eye tube. I found a pretty simple schematic here: http://www.audiohobbyist.com/projects/magiceye.htm (http://www.audiohobbyist.com/projects/magiceye.htm)
I got a tube on Ebay for $5 and I'm itching to use it for something cool. I have a couple of questions about how I would build this. First off, can I buy a transformer from Doug that would provide the necessary voltage for this circuit? Second, if I need a rectifier, can I use a 5U4G that I have laying around? Finally, can I use the second output from a Fender Deluxe Reverb clone as the input for this level meter?
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I have a similar circuit for using an EM80/6BR5. These are similar and the circuits are similar too. You're supposed to tap the signal off the plate of the power tube but maybe you could try from a plate off an earlier part of the circuit? If so you adjust your voltage divider and/or tube's voltage accordingly. This is one of those things where you experiment depending on what you decide. This is not so simple as taking the signal from your extension speaker jack.
Without knowing your 5V rating on the transformer you're using, the 5U4 needs 3A to supply it.
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Thanks for the other schematic, I could use as much inspiration as possible.
I don't know that I want to extensively modify the amp that I have just yet, although with enough convincing I probably could. I suppose I just need to build another one, maybe a little Tweed Champ :icon_biggrin: I think it'd be cooler to have the meter integrated with the chassis anyway.