Tuesday, 2 October 2018

Marshall 1992 Super Bass

Next, the Marshall 1992 Super Bass





With a switch to go between channels


With 2 separate inputs like the amp


With both channels jumpered



10 comments:

  1. I marked it verified because I've built the this layout for a mini amp and it sounds great and spot on.

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  2. it seems the treble and mids are mixed up . i am hearing my mid knob functioning as a treble knob and vice versa . the bass channel has a bit of hum and is a bit quieter . i have a lot of long leads and its not boxed up so ... ignore me . the treble channel sounds fantastic . its not exactly high gain though . its clean . thanks for this layout . pairing it with a spring tank / driver ciruit and a class d tpa3116d2 mono board.

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  3. Is it possible to use a different Jfet for this? I'm thinking a 5457 or something? J201s are becoming hard to find in UK for a reasonable price!

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  4. sure - mind the pinout - the gain will be different . i went with smt bought daughter boards .

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  5. one other question - im considering running this into one of those pwm class d power amp boards from ebay to make a full amp with this as the preamp - can i run this circuit at 24v assuming i by correctly rated semiconductors and caps?

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    Replies
    1. Yes. I’ve already done that for one of my mini amp builds.

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  6. Having a bit of trouble with this...the gain stages don't work, but when there is no power applied, the eq section works ok. I ordered from mouser and used HV caps for the most part - would this have an effect on the gain stages?

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    Replies
    1. Using a high voltage capacitor should have no effect on the circuit. You definitely have a build error or multiples. I would post in the debugging section with pics and description of what’s going on.

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  7. It kinda works, but my treble knob acts not only as a treble, but seems to cut the volume quite significantly when turned up. Any ideas what might case this? Happens on both channels.

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  8. In preparing this build I'm looking at the top 2 rows, with the trimmers on them. Looks like it's 2 rows of +9V, isn't it possible to skip the cuts in the second row and make a single link between them? Or am I missing something?

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