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Updated schematic for 2019 ~ Anniversary Mods ! (Read 998 times)
Steve Deckert
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Updated schematic for 2019 ~ Anniversary Mods !
03/05/19 at 02:42:11
 

I have updated the schematic and the assembly instructions for the ZKIT-1 (model SE84DIY) Zen Triode amplifier so that all the information is up to date with the current rev.12 circuit board.

Also on the new schematic, the optional Anniversary Mods are shown which basically amount to bypassing the electrolytic with film caps.

The new instructions and schematic are here: http://www.decware.com/newsite/ZKITmanual2019.pdf

Thanks,

Steve

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benlefebvre
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #1 - 03/06/19 at 00:42:07
 
Oh man, great stuff. Thanks for that, Steve!
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benlefebvre
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #2 - 03/06/19 at 01:25:53
 
For those of us with the two 40uf 450V caps in the PS instead of 33uf 600V (following the SE84CS schematic), Id imagine the mod would require different value caps in parallel with those, correct?
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Steve Deckert
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #3 - 03/06/19 at 05:38:09
 
The ZKIT-1 being rectified by ultra-fast diodes, can actually have any value filter caps above 33uf, 450V.  47uf would make the amp quieter.

Steve
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benlefebvre
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #4 - 03/23/19 at 17:29:10
 
I just noticed that the updated schematic has caps bridging the output tube pins 1 and 3. Is that for the Hazen mod? I thought I read online somewhere that it was pins 3 and 6 that got bridged with a cap, but I may be misremembering that....
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dank
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #5 - 03/31/19 at 22:33:35
 
Steve

Thanks for the updated schematics. Deb walked in while I was viewing them and said "Oh, what nice Easter colors!". I didn't know there was a WAF when dealing with schematics, but I guess the WAF applies to just about everything.

I think you have a small error in the schematic. It's showing the 10k resistors tied to power supply TPB as AC coupled load resistors to ground.



Dan
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Steve Deckert
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #6 - 04/02/19 at 01:53:02
 

Well, I can't honestly say I'm surprised... you get so wrapped up in trying to make damn program draw the lines where you want that you loose site of the bigger picture.  I do it almost every time. In fact, that wasn't the only error on the schematic.  Thank-you for pointing it out.  I have updated the manual/schematic.

Steve

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Steve Deckert
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #7 - 04/02/19 at 01:59:38
 

Quote:
I just noticed that the updated schematic has caps bridging the output tube pins 1 and 3. Is that for the Hazen mod? I thought I read online somewhere that it was pins 3 and 6 that got bridged with a cap, but I may be misremembering that....


On the 6P15P-EV also know as SV83 tube, pins 1 and 6 are tied together inside the tube..  EL84 tubes have nothing connected to either pin.

Steve
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Divasson
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Re: Updated schematic for 2019 ~ Anniversary Mods !
Reply #8 - 04/08/19 at 22:35:06
 
Hi all,

Just ordered a couple of boards to bridge 2 zkits. I had a SE84B for 6-7 years that I sold for lack of power but I have spent many thousands thereafter and never reached the sound quality I had with the Zen. So I am looking forward to return "home".

I have some questions by looking at the schematic and comparing it with previous schematics I have seen of different Zens.

  • The resistors to ground in the grid of the output stage show as 1k while in previous schematics were 330k. With 330k and 0.1uF capacitor, the -3db point is 5hz; with 1k it is 1,6KHz !!

  • The 10k resistors were in the previous schematic connected between the PS and the 47k resistors, now they are not (and I think it made sense before)

  • All electrolytics have been bypassed except the cathode bypass in the output stage - should it?

  • If all bypass capacitors are Jupiter 0.1uF or 0,33uF, the total bill will be north of $400 in capacitors alone (I am bridging!). Which are the most critical ones apart from the coupling pairs? I have many other good 0.1uF-0.3uF polys around that could go to non-critical places.

  • Regarding dc current through the output tubes, the meters in the schematic show 25mA - but from ohm's law in several places of the circuit it looks more like 32-35mA.

  • Regarding transformers - has anyone tried something different to the Edcors? Any Transcendar? if so which? Is the 10w rating critical if the amp max output is 2.3w?

Thank you in advance for your answers!
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