Friday, 21 April 2023

JPTR FX Jive

 

Marketing speil says this is a "reel-to-reel saturator overdrive" that is inpired by Akai GX 210D reel-to-reel tape machine. You might get similar sounds out of this circuit which is basically a SHO with three separate clipping switches for each clipping mode. Not sure why they did this since you can get similar clipping options with a single SPDT on/off/on switch...



 


26 comments:

  1. This comment has been removed by the author.

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  2. How would I go about putting those options on one switch? Is it as simple as taking the three pairs of leads to each set of lugs on a DPDT on/off/on or is there more to it than that?

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    1. I think the idea behind the separate switches is to mix & match different flavours of clipping. Putting them all on a single switch (which you could do with a 3PDT on/on) would give either *no* clipping or ALL the clipping.

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    2. Yes fair point. I just finished it and whilst it sounds good the range of sounds from blending the three switches isn’t particularly special. Individually they’re good, and distinct, but for blending together I think a more varied selection of diodes would suit it better.

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    3. Indeed! For a builder as into extremes as JPTR, you'd think they'd have gone with a more disparate selection, like 1 LED vs. 2 Schottkys in series.

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    4. Just tried with a better mix, including LED's. Much better! Off to finish the Miles Platting now ;-))

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    5. How does it sound with no clipping? Is it really clean or does it have some vibe to it?

      I'm looking to add an active volume control to a bass but want something with a little character.

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  3. Replies
    1. Hi Anders, do you have a link for the schematic for this?

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    2. It s basically a zvex sho with diodes stage

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    3. Yeah I know. I was wondering if the diode arrangement was correct because some of the demos seem to show more tonal variety than I’m getting.

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    4. Tbf they changed diodes a bunch of times and a couple of times they even mixed up which diodes went where etc.

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    5. Thanks Ben for verifying. Just uploaded the schematic.

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  4. Please excuse my ignorance, but why aren't the 1M resistor, d7 or filter capacitor listed on the schematic?

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    1. Anders adds them to most layouts. You can omit them if you want to. But remember to add a link where the diode was. Or just omit that cut.

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    2. What's the purpose of these additions?

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    3. The resistor on the input is a pulldown to eliminate static and hopefully avoid switch pop. The diode is for power protection to protect against reverse polarity. And the 100uf cap is for power filtering. They're just best practices add-ons. None effect the sound of the circuit very much.

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    4. Thanks. I'm trying to figure things out for a point to point build and I'm not very electrical savvy.

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  5. I have built this circuit a few times and love it. Very appreciative of the work done here. It has helped me immensely. My friend had the real deal version of this and I opened it up to see what the components looked like(all smd). I noticed that the volume pot is A500k? I guess I will try to change one of the one ive built of this. Anyone know why the value in the jupiter version is so large?

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    1. This comment has been removed by the author.

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    2. Did you ever change the volume to 500K pot? If you did, did you notice any differences?

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  6. I am wondering why the gain knob doesn't "crackle" like on a SHO pedal? Are we sure this schematic is correct? I have the real pedal and it doesn't crackle when the gain knob is adjusted but the layout is the same as the SHO.

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  7. Another simple yet effective circuit by JPTR. I like it as it is. I was happy that I was able to lay all of the diodes down. Nice compact layout. Thanks

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  8. Thank you for the layout.
    Is there any alternative to the BS170?

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    1. From what I could read on internet, it seems that 2N7000 transistors could fit.

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