Tuesday, 12 January 2021

ENGL 3

 Another ENGL amp emulator and another schematic from a russian DIY forum using both J FETs and MOSFETs. It is worth socketing the diodes at the MOSFET transistors since these only add a bit compression to the distortion.


 


 


20 comments:

  1. Hi just had a very quick look, there is no voltage arriving at Q1 drain

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    1. Are you sure? I can see that the voltage goes through 2k, 1k and the trimpot that connects to Drain of Q1?

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  2. brother again bothering with another complacency, missing this JHS Paul Gilbert, thank you very much for all this excellent work that you do with this perfect site.
    greetings and blessing

    https://www.pedalpcb.com/docs/BlueShoeGaiPan.pdf

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    1. +1 also looking to build this, maybe I will give it a shot with the schematics, Pougnet Pedals on YT did an excellent breakdown of it

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  3. I went through the entire layout and see just 1 mistake : R25 upper leg should connect to Q5 source (along with C19). that should be an easy fix by moving 2 components, a link and 2 trace cuts

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    1. Well spotted. layout is updated.
      So, I guess you are going to tackle this one soon?

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  4. The layout says 9 links but has 11 links....Thanks for all the cool layouts and hard work!

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  5. I built it....Works great, sounds great!!!!

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  6. I built it too...works actually better than great !
    I just tested it on my testbox and could'nt stop playing.
    Tons of gain (I used a 250k for the gain pot as I am out of 100ks), very tight and precise, as you would expect from the 530 preamp.
    And totally noise free, I'm very impressed, I was expecting usual oscillations and squealing we get with this kind of circuit, but niet, nada, dead silent !
    The mid pot is more a high-mid, I wonder if there would be a way to implement a low-mid control like on the original, that would be awesome. If some of you guys have an idea...
    I have yet to compare it side by side with the powerball (mighty nut), but this one surely sounds more Engl-ish.

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    1. Played around with the tonestack calculator to dial in some low mids but no luck so far...:-/
      Checked the factory scheme for the 530 pre amp.
      https://elektrotanya.com/engl_e530_sch.pdf/download.html
      Tonestack values is completely different...giving a mid control the peaks at lower mids. Sub both 22nF cap for 47nF, 470pF for 1nF and 33k for 100k.
      Might not the easiest solution but maybe a daughterboard to switch between tonestack values? Bear in mind that facory values will eat more of your output volume...

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    2. Also found this schematic of the eq section...
      http://dallashodgson.info/reviews/ENGL530/ENGL530_RE6ContourCircuit.jpg

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    3. I tried to re arrange things a bit by adding that 1M pot before the volume on the 2nd schematic, but that didn't really change Things.
      I'll keep it as it is, it really is the best sounding high gain pedal I ever played. I compared it to the mighty nut, it will kick it out of the pedal board. And it takes really well my light gain overdrive in front as a boost to make is sound even meaner

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    4. Coming from a high gain pre amp expert as you, it must be really good!
      I have project I can upload called Screamin Eagle by JOK3RX at FSB. It is almost identical to this but has a gate switch and control, a Fat switch for the treble cap in the tonestack, another gain control, a Sweep control that replaces the 33k resistor in the tonestack....so in total, seven pots and two switches....:-)

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  7. I played the beast at higher volume and started as expected to have some background noise and a little hiss.
    So I implemented the gate frome the Screamin Eagle and wow ! It works very well. I really think this is a great addition to this circuit, maybe you could consider adding it to your layout.
    I wired the pot and the switch, but will box it without the switch which I think is useless considering that pot CCW kills the gate

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  8. Built this and it sounds great. I think D3 and D4 may be mixed up though. Anyway, I switched their positions and it works just fine. Nice and tight amp gain. Thank you for posting this!

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