Hermida Audio - Zendrive [ goop-alarm ]  [traced]

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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby jalmonsalmon » 07 Jan 2015, 14:56

Dr Bertson wrote:Hello!

I have built the Zendrive now using the layout on this thread.
I tried with different IC's, but the best sound I got with the OPA2134 and instead of 2N7000, I used BS170.
The sound of my pedal is very close to thenoriginal Zendrive.


Good job! :applause:
I actually made one of these driving a Timmy in one pedal and it sounds awesome. I may have to try out an OPA2134 as well.
I can dial in a lot of different tones with that combo :secret:
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby Dr Bertson » 07 Jan 2015, 17:16

Good to see that tere are more people who have built this and got good sound of it.
When I built mine, I first tried with the AD712, that should be original, but that sounded too dark and not so much bite.
Also when I change to BS170, the pedal really starts to breathe.

Good work!
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby John G » 08 Jan 2015, 22:35

Hi,
After the Xmas pud had been digested, and all things Xmas was generally over I decided to revisit a couple of OD pedals.
The first being the G2D creamtone clone I had built several years ago.
I still like its sound especially with the Strat, so I left it aline.
My attention then turned to my Zen OD clone, I have always had a love hate relationship with this pedal.
What I like about the creamtone is the restricted amount of bass hitting the first stage, so I modded the Zen to have a three position input cap select switch so I can now select between 4n7,10n,and 22nF. This cleans up the congestion I was hearing.
Of course this creates a lack of bass especially in the 4n7/10n setting so I then cobbled up Barbers RIAA post tone cct around the second op-amp stage.
I found the bass control works to restore bass balance, but I found I didn't need the mid control.
While at it I adjusted the tone (treble) cct to the KOi values to give more range.
Clipping is 2N7000 and three BAT41s.
Op amp faves are TL082,NE5532,TLC2272.
I installed the pot/cap values (from what I can see from the Simble guts shots) ie Vol 100Klog, tone 50klin (KOi is 100klin) voice 10klin, gain1Mlog, and voice cap .22uF??
Does it sound better, I don't know as I don't have a comparison any more !!
Cheers
John
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby John G » 12 Jan 2015, 01:45

Hi again,
Played with the pedal over the last few days and I believe I have a more refined Zen version more polite and lets me hear more of the natural Guitar. (Just like the G2D Creamtone does)
I like the additional bass control and input select switch as this allows you to taylor the pedal to suit different guitars and different styles of music.
I have just noticed that Madbean pedals "Spark plug" uses the Barber post mid/bass network, I was unaware of this at the time, minds can think alike.
Cheers,
John
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby snofla1900 » 12 Jan 2015, 12:19

I then cobbled up Barbers RIAA post tone cct around the second op-amp stage.



John, I would really appreciate it if you could point me to the site I can find more info about this mod.
Where can I see a schematic of this circuit , I would like to try it too.

Yesterday I changed the opamp from an AD 712 to The Buur Brown mentioned and changed the diodes to BS170 an dI can say the tone changed for the better.

Alf
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby John G » 12 Jan 2015, 20:27

Alf,
Looks as if I will have to try a different IC and FETS I will need to purchase them.
Attached is the MADBEAN Sparkplug pedal which he says is derived from the Barber Tonepump. It is on his site.
The Koi values are in this thread back a few pages as is the post suggesting lowering the input cap value.
Cheers,
John

Sparkplug_rev1.pdf
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby John G » 12 Jan 2015, 22:17

Hi,
Ok so I lied about the KOi being on this thread.
Don't know where I found it, so here is the schemo
John
KOi OD.jpg
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby snofla1900 » 13 Jan 2015, 09:37

Thanks for the info John , I will try to incorporate the active mid and bass in my next zendrive type OD.

Regards , Alf
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby John G » 13 Jan 2015, 23:31

Alf,
This is the current schemo.
No mid, I'm sure there is still room for improvement, there are much greater minds than mine on this Forum.
Cheers
John
Z_drive modified.sch
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby snofla1900 » 14 Jan 2015, 10:59

Thanks John for the current schemo but Eagle 7.2 ( or an earlier 6. .. version) won't open it.
I get a remark that a start tag is expected in line 1.

Could you repost it please ?

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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby John G » 14 Jan 2015, 20:38

Alf,
Here it is in gif form.
Forgot to add to schemo teh 10Mohm ground ref resistors between the input caps and ground.
John
Z_drive modified.gif
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby snofla1900 » 15 Jan 2015, 10:29

Perfect John !

Worked like a dream. I am definitely going to try this one soon.

Thanks,

Cheers , Alf
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby John G » 16 Jan 2015, 04:38

Alf,
You could always just change the input cap to say the 10nF value, break the link from pins 6-7 on the op-amp and add the 4k7 (or 3k3 in Barbers schemo) between pin 6 and V/2, add say a 20k trim pot with the 100nF (82nF in Barbers schemo-I don't have that value) across it between pins 6 and 7 and adjust to taste.
I was lucky in that I used a large box that already had additional holes so I was able to mount the switch and the Bass contol on the front panel.
I used vero pins to attach the components I was experimenting with as this speeds the change out process up, as well as causing minimal damage to the vero board.
Cheers,
John
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby snofla1900 » 16 Jan 2015, 15:29

Good suggestions John , I usually use Bancika's DIY layout creator to make a layout so I will make some for experimentation for the parts you mentioned. I always make pcb's with photosensitive boards.

Thanks again.

Alf
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby jsaily » 17 Jan 2015, 09:34

Here's the PCB layout I drew based on frequencycentral's layout and schematic. I had to redraw because I need the gerber files for printing etching masks and I've built a couple of pedals with this and it works well. The rar-file has PDFs + gerber, silk, soldermask and drill files so you can even send it out to manufacturing if you don't want to etch your own ;-)
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby snofla1900 » 17 Jan 2015, 15:05

Thanks Jsaily but I seem to behaving trouble oping the pho files . I downloaded freeopener but it can't open those files. Do you use another programme ?
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby jsaily » 17 Jan 2015, 19:27

snofla1900 wrote:Thanks Jsaily but I seem to behaving trouble oping the pho files . I downloaded freeopener but it can't open those files. Do you use another programme ?


You need some program which can show gerber files to view the pho-files. I know there are some freeware programs for that also. However, you can just print out the pdf layout and component placement.

Here's one free gerber program you can try: http://sourceforge.net/projects/gerbv/
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby gsb » 16 Dec 2015, 17:25

Hi !

After some years brake of building -pressure was high .Here is the last build for young player (blues -rock ),Box is custom made in family metal shop -v2a,laser welded,cover plexi 2mm,Schematic original with increased gain potentiometer, IC OP 2134 ,germanium diode .In der past i have tried AD712,BB,JRC 45.. .. The last one OP2134 is my favorite now. Hera are some pictures .

gsb
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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby snofla1900 » 19 Dec 2015, 13:18

The last one OP2134 is my favorite now.


I use that one too and I like it a lot.

Yesterday I noticed a mod where sombody changed C5 into 220 N so I tried this and added a second 100N cap paralel to the existing one and so got a 220 N cap and I like the pedal much better now.
The voice control works much better for me now. I play a Les Paul custom mainly. With the humbukers I can dial up the voice and the tone controls far more up and get more bite now.

I believe I read it in a schem called the "koi drive".

Image

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Re: Hermida Audio - Zendrive [ goop-alarm ]

Postby roseblood11 » 19 Dec 2015, 14:38

my favorite is TLC2272.

great mod: make the orientationtion of the Mosfets switchable (=connect it to the other diode). So you have real mosfet clipping, or clipping of the silicon body diodes, as in the stock zendrive

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