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School me on the Black Magic Zendrive.

Discussion in 'The Stomp Box' started by Dann B, Jan 20, 2018.

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  1. cousinpaul

    cousinpaul Friend of Leo's

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    I read some posts on FSB that suggested what ICTRock said; that the tube was part of the clipping diode array. If so, we're probably tallking using the FET's as diodes rather than transistors. Possibly a second array after the tone control? I'm surprised there is so little known about this pedal.
     
  2. cousinpaul

    cousinpaul Friend of Leo's

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    sorry, double post.
     
    Last edited: May 24, 2018
  3. ICTRock

    ICTRock Tele-Afflicted

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    if you do a google image search for zendrive 2 you'll get some screenshots of the insides and while it is gooped where the 12ax7 joins the board it looks like the insertion point is in the feedback loop and each triode of the 12ax7 is replacing the diodes in the mosfet clipping arrangement. the answer I don't have is what the end result forward voltage of a 12ax7 triode used as a clipping diode is. if you replaced the triodes wired as diodes with jfets the body diode would be roughly equivalent to running a 1n4148 in there instead of a bat41/1n34a ... you'd just about need the 1M drive pot at that point to get the gain up enough for feedback loop clipping.
     
  4. sanfi4u

    sanfi4u Tele-Meister

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    I guess a little help from TGP is appropriate.

    Quote 1:
    "Black Magic Zen - This one is like the Gold II, but more compressed and gainer. To me, it's the same deal as the Red vs the Black - the "More" button for the Gold II."

    Quote 2:
    "Black Magic Zen came today.. First impressions.. It's awesome!! It seems a bit brighter and clearer sounding compared to my red zen with more "crunch" and less "cream" if that makes sense. A/B-ing against my red zen the black magic seems to have less output (or maybe just the pot taper is different) but I actually prefer it. Unity volume on my red is about 10 o clock and the black magic is right about noon. I tried the black magic as a boost with the gain off and volume maxed through my Vox ac15 set clean and it works great for boosting the amp into a nice overdrive. I also tried the black magic through a Mesa Rectoverb set clean and the slight cut in the bottom end of the black magic actually works really well with this amp, the pedal doesn't mud up and retains clarity through it's gain range. It's hard to describe a sound in words but owning the red, original black, white, gold, and now black magic I have to say the black magic is one of my favorite versions."

    [​IMG]

    BTW, the full name of the pedal is Black Magic Zendrive II by Lovepedal/Hermida Audio. Hope this helps a bit.
     
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  5. goodguy

    goodguy TDPRI Member

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    I heard the Zendrive is a dumble-esque pedal ... found the Black Magick Zendrive for $75 locally and wondered if the BM Zendrive would fit the bill?
     
  6. blowtorch

    blowtorch Telefied Ad Free Member

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    Fit the bill for what?
     
  7. Guitaryellow

    Guitaryellow Tele-Meister

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    How far removed are these different incarnations from Lovepedal to the original pre model, which one is the closest?
     
  8. 11 Gauge

    11 Gauge Doctor of Teleocity

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    I'm assuming you're familiar with what R.G. Keen wrote over at DIY Stompboxes:

    "A 12A?7 tube works as two diodes if you heat the heaters and ignore the grids. In pentodes, you must open circuit all three of the grids.

    In indirectly heated tubes, where there is no internal connection between the heaters and the other electrodes, you may have voltage between the heaters and the cathodes since they are not connected. They are insulated to about 300V by an oxide layer between the heater and the cathode proper. So since the heater is not connected to any electrode in a duotriode, you may use the two diodes independently.

    A single 12AX7 can be a clipper pair...If you connect pins 4 and 5 together, you can run it on 6V at 300ma between 4&5 and 9...If you want individual diodes, both plate pins (1 and 6) are anodes, both cathodes (3 and are anodes (that's the bar across the diode symbol)."

    Admittedly, that doesn't answer your question about the forward voltage, but it all but confirms that is why you don't even see a small transformer inside the ZD2 to necessitate stepping up voltage to 12V+ - it can be run at less than 9V.

    ...I'd argue that the forward voltage is "within a suitable range," given what some users have said about the sound of the ZD2 vs. the original. By some accounts, it seems that they sound mostly similar.

    So, when subbing in other types of diodes, besides the combined forward voltages when using combinations, the other considerable factor (IMO) is the dynamic resistance of some types vs. others. Ordinary silicons (e.g. 1N4148) and many germaniums have higher dynamic resistances, while Shottkys and epoxy rectifier types have lower dynamic resistances (I think LEDs have lower dynamic resistances, too). Considering that the original ZD uses 3 types of diodes (mosFET body diodes, Schottky diodes, and a germanium diode), I wouldn't be surprised if whatever is being used for this newer incarnation simply has a variation of the original solid state recipe.

    IOW, I really doubt that whatever is going on under the hood is "incredibly high tech" by any stretch. It's probably just a new diode combo that was tweaked by ear...
     
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  9. sanfi4u

    sanfi4u Tele-Meister

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    Yep, Zendrive is a Dumble style overdrive. I don't have BM Zendrive, but I own Zendrive Gold II and I like it. Definitely worth $75.
     
  10. Guitaryellow

    Guitaryellow Tele-Meister

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    I have the option of Zendrive V1 or a Zenkudo.
    I like the Zenkudo and had one a long time ago.
    I had a V2 Zen and found it uninspiring, may have been a clever copy or Chinese fake.
    I borrowed a V1 a long time ago and loved it.
    I have lots of health issues I can do nothing about, this is a welcome distraction/dilemma of which there is no answer.
     
  11. FenderLover

    FenderLover Poster Extraordinaire

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    I can confirm what RG Keen has said about the 12AX7 in the ZenDriveII, but that formula has been known for quite a while. I'd suspect that ICTRock is correct about the Black Magic. Mess with the clipping devices and gain, tune by ear, rename it.

    It's not that there is anything high tech going on, like RG says, but if you hit on the right combination of parts even within the same design it can really make a difference to feel and sound. I discovered that building my own Zendrive clone.
     
  12. Guitaryellow

    Guitaryellow Tele-Meister

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    I tried changing the switch In my wah with the bypass kit and now it doesn't work, so I'm not good at all with a soldering iron although would dearly love to be and be able to make my own stuff.
    I would love your talent to build one.
    Since my posted I got the V1 which arrives tomorrow, I've had just about everything else and hope it fits the bill.
    I got my Tele ready and my Mk2 Mesa on a lively clean so ready to go.
     
  13. DaveKS

    DaveKS Friend of Leo's

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    Nice demo.

     
  14. archiestone

    archiestone TDPRI Member

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    Can anyone school me on what the 'Voice' knob actually does on my BM Zendrive...?
    ---
    Answered my own question. For the 'knowledgebase':
    Voice - “Tunes” the pedal to the amplifier and guitar. The Voice knob performs two
    functions:
    a. Limits or increases the total amount of gain in the pedal. To limit the gain,
    rotate counterclockwise. To increase the gain, rotate clockwise.
    b. Adjusts the bottom-end response of the pedal. To increase the bottom-end
    response, rotate counterclockwise. To reduce the bottom-end, rotate the
    clockwise. Remember to adjust the Gain knob to compensate for changes in
    the overall gain of the pedal which occur during the Voice knob adjustment
    process.
     
    Last edited: Jun 2, 2019
  15. JUSS10

    JUSS10 Tele-Meister

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    I know this is an old thread but if anyone is interested, I have a black magic Zendrive 2 on my work bench and I'm in the process of tracing it. For what its worth, the gain section appears quite a bit different than the original zendrive. For starters, the only diode on the whole pedal is in the power supply section for reverse voltage protection. Also there is only one FET on the whole board. It has the label sanded of... The IC is a JRC 4560D. Volume pot is A250K, Drive is B500K, Tone is B50K and Voice is B10K. no goop on this one so it should be easy enough to trace. I'm about half way done with the schematic. Will post up here once done if anyone is interested.
     
  16. cousinpaul

    cousinpaul Friend of Leo's

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    I'd be interested. Is the board SMD?
     
  17. JUSS10

    JUSS10 Tele-Meister

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    Nope, all through hole actually. Attached is what I got when tracing it. I need to go through and verify but it looks quite a bit different than the existing zen drive pedal. I put a BS170 in the schematic but I honestly don't know what it is, the markings are sanded off. Could be a 2N7000 as well, who knows. Also need to double check cap values, not always the best at reading these film box caps.

    upload_2020-12-10_13-12-11.png
     
    Last edited: Dec 10, 2020
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  18. sanfi4u

    sanfi4u Tele-Meister

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    I've got me Black Magic Zendrive II in Nov 2018. It feels like Zen Gold II but with more gain. I'm also returning the Black Magic pic to the thread.

    [​IMG]
     
  19. sanfi4u

    sanfi4u Tele-Meister

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    Thanks for the schematic. Interesting. It's a substantial deviation from the traditional Zen diode/MOSFET clipping engine in the feedback loop. I noticed that my Zen Gold II and Black Magic Zendrive II pedals both have just one MOSFET and no clipping diodes. But I expected to find the MOSFET in the OpAmp negative feedback circuit. BTW while we are on it I guess C3 must be 100uF.
     
  20. JUSS10

    JUSS10 Tele-Meister

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    I thought the same thing but I double checked and it is indeed a 10uF. I have also traced a LP valve reamer and a LP kalamazoo black. If I recall correctly the valve reamer also only had a 10uF on the power input. These do feel like "cheaper" made pedals, not that there is a huge cost difference in 10uF to 100uF. I had read somewhere that LP suggested running these on batteries anyway so maybe they just figure if you were going to use the power jack you were already running a really nice filtered power system. who knows.
     
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