BJFE - Emerald Green Distortion Machine

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Re: BJFE - Emerald Green Distortion Machine

Postby Seiche » 17 May 2018, 09:50

Manfred, when did the resistor 470k on Q3s gate appear? It's not in the tagboardlayout or the other schematic.
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Re: BJFE - Emerald Green Distortion Machine

Postby Manfred » 17 May 2018, 16:09

Seiche wrote:Manfred, when did the resistor 470k on Q3s gate appear? It's not in the tagboardlayout or the other schematic.

I already mentioned above, that I miss the resistor in the tagboardlayout or the other schematic.
IMO the resistor is essential for biasing the FET Q3.
You can find a 1 Megohm or a 470 Kiloohms resistor in other circuits from BJFE on that point for.

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Re: BJFE - Emerald Green Distortion Machine

Postby Seiche » 17 May 2018, 18:32

IMO the resistor is essential for biasing the FET Q3.


that's surprising, because the tagboardlayout is verified, I understand.
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Re: BJFE - Emerald Green Distortion Machine

Postby Manfred » 18 May 2018, 00:08

that's surprising, because the tagboardlayout is verified, I understand.

Now the question is: What is verified, the layout corresponds with the schematic or/and the circuit sounds as it should?
What is truth?
I ran a simulation using the 2N5952 FET-model with and without the grid resistor.
I fed 700 Millivolts/1000Hz into the circuit.
Without the grid resistor the output gaves a very low signal with heayily deformed curve shape.
I going to order some 2N5952s for making real trials.

EmeraldWithoutAndWithGridresistorDC_Values.jpg

EmeraldWithoutAndWithGridresistorSignal.jpg
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Re: BJFE - Emerald Green Distortion Machine

Postby Seiche » 18 May 2018, 06:34

that's very interesting. Which program are you using?
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Re: BJFE - Emerald Green Distortion Machine

Postby Manfred » 18 May 2018, 07:01

Seiche wrote:that's very interesting. Which program are you using?

An old Multisim version.

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