Suitcase Record Player Amp Conversion

Discussion in 'Shock Brother's DIY Amps' started by mikestearns, Dec 9, 2019.

  1. mikestearns

    mikestearns Tele-Meister

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    I've got this suitcase record player I found on FB marketplace for 9 bucks. Beautiful wood, and the amp turned on and fired up and hummed, but the record player didn't work (which I didn't want anyway). It has 2 6V6's, a 12ax7, a 12at7, and a 6x5 rectifier tube, so I'm thinking I could make a fun little low watt guitar amp out of it. The caps definitely need to come out either way (already pulled the old can out of it). I plan to read up a little more on some other circuits to put some ideas together - judging by the tubes and the simply Volume and Tone knob setup I'm thinking I'll keep it in the vein of a 5E3 - but was curious if anyone had any suggestions or ideas of things to change in this schematic to make it more guitar-centric. (I doubt I'll keep the internal speakers for this, I'll make it to function as a head).
     

    Attached Files:

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  2. symbiotic

    symbiotic TDPRI Member

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    Well I for one can't wait to read the contributions of members who really understand all these elements but, I for one would be really curious to hear what you would get by just servicing it to a safe functional state.

    Isn't that a floating paraphase PI such as described by Merlin Blencowe here? http://www.valvewizard.co.uk/paraphase.html

    I am also curious to read what others make of the power tube biasing. What is the deal with running the cathodes through a secondary winding on the OT? Does this achieve some negative feedback?

    I haven't wrapped my head around the volume control, but it's cool to see the tone control set up like a Vox "Cut".

    Like I said off the top, it all makes me curious to know what it would sound like for guitar, as-designed.
     
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  3. Saxonbowman

    Saxonbowman TDPRI Member

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    The schematic certainly looks like it has the makings of a nice guitar amp. Your comment about the beautiful wood makes me want to see a picture! Do you have any?
     
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  4. mikestearns

    mikestearns Tele-Meister

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    Not with me, I'm at my office at the moment, but I'll post some pics later, plus I intend to document the conversion.

    As far as using as designed - I would think it would be on the weak side just because generally an amplifier made for a phonograph is going to be designed to minimize distortion, whereas one made to amplify a guitar signal would in some ways have the opposite intention, not to mention also a guitar amp would be designed to accentuate certain frequencies and cut others, whereas a phonograph is going to want a wider frequency representation.
     
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  5. mikestearns

    mikestearns Tele-Meister

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    Here's the best I've got of it at the moment, from the listing when I purchased it. I've already taken everything out of it. I want to clean up and keep the original knobs, and put the input jack on the face of the amp with them if I can make it look good andnot destroy the original material. The woods a little beat up, but not so much to make it look bad.

    IMG_1051.jpg
     
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  6. Jake Nelson

    Jake Nelson Tele-Meister

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    I built a 5e3 from an old reel to reel player and the B+ was a little low so I used a solid state rectifier and had a lot better results.
     
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  7. mikestearns

    mikestearns Tele-Meister

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    ive considered this, I know with the current rectifier tube I’m only going to get around 10 watts.
     
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