This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Tuesday, June 11, 2019

EQD Bows

Here's Jamie's take on the classic Rangemaster circuit, with a NPN germanium transistor. There's an added toggle to switch between full range and treble input caps. Probably a tight a squeeze in a 1590A but should be doable. There is also a 1590A specific PCB with board mounted pot and switch in the store now (link below).

39 comments:

  1. Plissss post skema "napoleon booster" original,,thnk you frns

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  2. Is there a schematic for this ?

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    1. http://www.freestompboxes.org/viewtopic.php?f=7&t=29959

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    2. It works, and sounds great.OC139 Hpe 58 .

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  3. Any idea on ideal hfe for the transistor?

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    1. Pretty low. The transistor in the one traced on FSB had a hfe of 35. Higher gain transistors can be used, you'll just need to adjust the value of the resistor going coming off the emitter to bias it correctly.

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  4. That OC139 is pretty tricky to find. Do you know any direct replacement that i could use? Thanks.

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    1. Anything low gain will work as I mentioned above. You just may need to adjust the value of the 100Ω resistor coming off the emitter. In a typical Rangemaster that resistor is 3.9k.

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    1. I replaced the toggle with a B100k pot. It provided more options between the full range and super-treble settings. Sounds good!

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    2. Hi!How did you wire the pot in place of the toggle?Thanks!

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    3. Great !
      How do you wire the pot?

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  6. I'm the only one who needed to reverse the orientation of the transistor? I tried a few different ones, and I'm sure of the pinout (used an DCPeak Atlas DCA model DCA75), and the emitter and collector are reversed, in this layout and in the original schematic traced.

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    1. You aren't the only one. I bought a QC139 and found that the orientation was backwards. I'll have to do some more fiddling with the resistor coming off the emitter, however, to determine if really needs to be reversed. TBD.

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  7. Sounds fantastic! FWIW, I biased an AC187 with 3K.

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    1. Hi, I have an AC187, where you put the 3K resistor? tnks!

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  8. Any replacement for 5817 diode? I have 4148, 1n34a, 4007.

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  9. Hi, I used an AC187 and placed a 10K trimpot instead of the 100 ohm ground / emitter resistance, but the trimpot has no effect, the sound is always the same, any ideas? (I also put 100k and 220k in parallel instead of the 68k resistor)

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  10. This may be a dumb question but what voltage should we bias the transistor to?

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  11. Built it! I used b500k & 4n7, 22n, 0.1 caps see there: https://imgur.com/a/VhD6eCm
    68k bias i used 82k. ge npn mp38a hfe=90. Realy good working with fuzzes!

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  12. Hi, how to put a pregain on this (like on the Analogman Sunface) ?? What pot to use and how to hook it up? :)

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  13. Replies
    1. or like there https://effectslayouts.blogspot.com/search?q=royal+tone+bender

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  14. do like there https://effectslayouts.blogspot.com/search?q=katzen

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  15. Hi i built it with a 5k trimmer in place of 100ohm with ac179k.I can get to 6v at the collector.In full range it is ok but in the treble position i have a lot of noise..Is this normal or it depends on the transistor?Thanks

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  16. I have a Philips Valvo ASY29 NPN Germanium transistor, hfe = 135. Would I be able to bias with the emitter resistor, or would also have to change the resistor leading to the bias of the transistor?

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    1. I'd start by tweaking the 68k resistor for the base to ground.

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  17. Thanks, I'll read up on how to calculate and measure the adjusted hfe.

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  18. Maybe my question is stupid , but... could I use a NPN silicon transistor?

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    1. It would need to be very low hFE. A 2N2369 might work, but might still not bias correctly.

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    2. Thanks a lot !

      ... and by the way: thanks for your PCBs, they are great!

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  19. This comment has been removed by the author.

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  20. Hi,
    I build a Beauregard pcb, with an AC176, and a 5k trimmer for R5, easier to bias it.
    The treble position sounds great, but the"full" one is really really loud.

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