Yamaha Electone V-fet organ amp, What do I have here?

Discussion in 'Yamaha' started by Nashou66, Sep 19, 2017.

  1. Nashou66

    Nashou66 AK Subscriber Subscriber

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    I just got this Yamaha election amp section from a very nice older gentlemen up in Hamilton Canada.

    I was doing a Yamaha amp search on the bay and saw a pic of what looked like a possible V-fet transistor
    on it. This is why in the Electone thread I was asking what models of the organs had V-fets as I hear from some where that some models did have these.

    As soon as i saw 2SK76 on one of the transistors I knew i had one of those amps.

    Here are some pics of the V-Fets. I don't have time right now to remove
    and test them out of the unit but I think one or two might be good.
    I only paid 50 CND for it and the drive up and back, about 2.5 hours total.

    [​IMG]
    [​IMG]
    [​IMG]


    So what do you guys thing? What should I do here?

    I bought it for the transistors but am curious on how it might sound as is?

    anyone with schematics on this unit?

    Athanasios
     
    Last edited: Sep 13, 2018

     

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  2. avionic

    avionic " Black Knights " Subscriber

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    Not a bad price for a probably matched pair of B-2 vfets. If there still serviceable.
     
  3. Nashou66

    Nashou66 AK Subscriber Subscriber

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    Well it has two 2SJ26's and one of them has a hand written 44 on back side and then the other single 2SK76 And the good news is they all measure good, although one of the 2SJ26's only measured .9 ohms from S-D . The Diode tests also read well.

    [​IMG]
    [​IMG]
     
  4. clinic-audio

    clinic-audio all on YAMAHA untill 1990

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    what is the ref of this YAMAHA organ ?
     
  5. Nashou66

    Nashou66 AK Subscriber Subscriber

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    That is what Id like to know as well. I have read some where a list of Yamaha organs that had the V-fets in them. I vaguely remember that V-fets were first used in their organs before they used them in any consumer amplifiers. However I am not 100% sure this is correct.
     
  6. Oilmaster

    Oilmaster Drillers go deeper Subscriber

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    Fascinating !

    A bit of Wikipedia for Yamaha organ history to get some feeling....

    2SJ38/2SK98 VFETs were used in the mighty Electone GX-1 organs which came with it's own (mighty) console speaker (I expect the power amp section to be inside the speaker).

    I checked out the service manual of the GX-42 (1970), but as expected no VFETs in there as it is too early for a VFET.

    Leaves the CSY-1 (1974) and E-70 (1977) service manual to be found....
     

     

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  7. rottalpha

    rottalpha Yamaholic Subscriber

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    Yes, seen an amp on the auction site a couple of years back (parted away from the organ) but the v-fets were something other than the ones in the b-2. I passed.
    ...prolly the ones you mentioned here, but I can't recall for certain...
     
  8. dino74

    dino74 AK Subscriber Subscriber

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    Last edited: Sep 12, 2018
  9. dino74

    dino74 AK Subscriber Subscriber

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    From the e-70 manual. Looks like there are 2 2sk76 and 3 2sj26 vfets

    Screenshot from 2018-09-12 22-03-53.png
     
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  10. Nashou66

    Nashou66 AK Subscriber Subscriber

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    Do you have that E-70 Manual.

    Nashou
     
  11. dino74

    dino74 AK Subscriber Subscriber

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    Oilmaster likes this.

     

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  12. Oilmaster

    Oilmaster Drillers go deeper Subscriber

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