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Fender Ramparte - Schematic

Discussion in 'Amp Tech Center' started by GERPUD, Feb 8, 2015.

  1. jarpat

    jarpat Tele-Holic

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    Thanks! Those volts sound like 110V input? Mine is 220V, but now I know - so it should be around 320-330V.

    But, actually I was wrong about the tranny. I took out the secondary leads and the fuse blew - or so I thought. I took out wrong ones so the secondary leads were still attached. Took a closer look and found out that one of the 8,2nF/1kV capasitors was shortcut. So, after all, it wasn't the tranny...
     
  2. radiocaster

    radiocaster Poster Extraordinaire

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    No, secondaries' voltages should not change,you change the transformer or the wires on it if you have another AC voltage. Either that schematic is wrong or they have some strange way of notating it.

    No way it would function at half that because the heaters won't work at half voltage (and neither will the other stuff probably).
     
  3. radiocaster

    radiocaster Poster Extraordinaire

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    Rearranged Fender's schematic with cut and paste so it's easier to read and follows the traditional format:
    rampart-rearrang-schem.png
    but don't delete your Fender schematics, this one is missing a lot of important details and may not be 100% accurate.

    Thanks to GERPUD for his schematic, it helped me connect a few points, but unfortunately his schematic is not totally correct as it should have 6 connections on each of the 12AX7s, not 5.

    I'm not going to mess with my amp right now because I just screwed the back back on after several rigorous sessions of tube rolling , but I was curious as to why it's so bright.

    C14, C22 and C4 seem to be the cause (in my limited understanding) in the hot channel, and C21 in the cool channel. I'll probably leave the cool channel as it is, but I may mess with the hot channel in the future.
     
    Last edited: Nov 23, 2017
  4. radiocaster

    radiocaster Poster Extraordinaire

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    Does that C6 before the last preamp stage also affect the sound?

    I'm not an expert, but this is the most caps in the picoFarad range I've ever seen in an amp. I've seen many with one or two, but this one has lots.
     
  5. radiocaster

    radiocaster Poster Extraordinaire

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    O.k., so I pulled out my croc leads and started experimenting.

    (WARNING: do not try this if you don't know what you're doing, can be dangerous)

    I got some 400V caps of these values: 10, 22 and 47 nano Farads. The ones that look like little brown pillows.

    Since they just add if you put them in parallel with existing caps, that's exactly what I did.

    Across C22 they didn't do much. They had a dramatic effect across C14. They certainly did something across C4 as well, but it's a pain in the boot to get the leads in there.

    The best was the 22 nano Farad (or 0.022 micro Farads if you prefer). The 10 didn't do enough. The 47 was too dark, although considering how bright this amp is, this was an improvement as well.



    I could also get more distortion. I think the problem was that the amp was so bright before, it hurt my ears to turn up.
     
  6. radiocaster

    radiocaster Poster Extraordinaire

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    (by the way, actual Fender schematic is on page 2)
     
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