Difference between revisions of "Noise Generator on ER-PROTO-01"

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Line 43: Line 43:
  
 
* Output seems pretty quiet (~200 mV)
 
* Output seems pretty quiet (~200 mV)
−
** Issue is 2N3904 is much quieter than a BC548
+
** Issue is 2N3904 is much quieter than a [https://www.mouser.com/ProductDetail/637-BC548B BC548]
 +
** Switched to [https://www.mouser.com/ProductDetail/637-BC548B BC548]
 
* Offset errors = about 500 mV
 
* Offset errors = about 500 mV
 
** Gain = 148, 500mV = 3.5mV offset voltage
 
** Gain = 148, 500mV = 3.5mV offset voltage
Line 54: Line 55:
  
 
[[file:ER-PROTO-01_NOISE_WHITE.PNG]]
 
[[file:ER-PROTO-01_NOISE_WHITE.PNG]]
 +
 +
==== White Noise Scopecaps ====
  
 
* White Noise Scope capture
 
* White Noise Scope capture
−
* 100 mS / div
+
* 2 mS / div
  
 
[[file:White_Noise_Scope_Cap-01.png]]
 
[[file:White_Noise_Scope_Cap-01.png]]
−
 
−
* 200 uS / div
 
−
 
−
[[file:White_Noise_Scope_Cap-02_200uS_per_div.png]]
 
−
 
−
* 20 uS / div
 
−
 
−
[[file:White_Noise_Scope_Cap-03_20uS_per_div.png]]
 
  
 
* FFT, 25HKz range
 
* FFT, 25HKz range
Line 75: Line 70:
  
 
[[file:ER-PROTO-01_NOISE_BLUE.PNG]]
 
[[file:ER-PROTO-01_NOISE_BLUE.PNG]]
 +
 +
==== Blue Noise Screencaps ====
  
 
* FFT 1mS scope setting
 
* FFT 1mS scope setting
Line 80: Line 77:
 
[[file:FFT_Blue_J4_Noise_1mS.PNG]]
 
[[file:FFT_Blue_J4_Noise_1mS.PNG]]
  
−
* Amplitude is too small
+
=== Pink Noise Generator ===
−
** Added amplifier to the output stage
+
 
 +
[[file:ER-PROTO-01_NOISE_PINK.PNG]]
 +
 
 +
=== Pink Noise Scopecaps ===
  
−
[[file:ER-PROTO-01_NOISE_BLUE_GAIN.PNG]]
+
[[file:Pink_Noise_Scope_Cap.png]]
  
−
=== Pink Noise Generator ===
+
[[file:FFT_Pink_J4_Noise_1mS.PNG]]
  
−
[[file:ER-PROTO-01_NOISE_PINK.PNG]]
+
=== Pink Noise LTSpice ===
  
 
[[file:ER-PROTO-01_NOISE_Pink_LTSpice.PNG]]
 
[[file:ER-PROTO-01_NOISE_Pink_LTSpice.PNG]]
Line 109: Line 109:
 
[[file:ER-PROTO-01_U1_PWR.PNG]]
 
[[file:ER-PROTO-01_U1_PWR.PNG]]
  
−
== Build ==
+
== Build Details ==
 +
 
 +
* Three card set
 +
** [[ER-PROTO-01]] Front Panel card
 +
** [[ER-PROTO-01]] Controls card
 +
** [[ER-PROTO-01]] Daughtercard
 +
 
 +
[[file:ER-PROTO-01_NOISE_P1090115-720px.jpg]]
  
 
=== On Controls Card ===
 
=== On Controls Card ===
Line 120: Line 127:
  
 
=== On Daughtercard ===
 
=== On Daughtercard ===
 +
 +
[[file:ER-PROTO-01_NOISE_P1090110-720px.jpg]]
  
 
* Transistor Noise Source wiring
 
* Transistor Noise Source wiring
  
−
[[file:ER-PROTO-01_NOISE_P1080760-Trans_Noise_Source_Rework-720px.jpg]]
+
[[file:ER-PROTO-01_NOISE_P1090111-720px.jpg]]
  
 
* Opamp wiring
 
* Opamp wiring
  
−
[[file:ER-PROTO-01_NOISE_P1080762_ANNOTATED-720PX.jpg]]
+
[[file:ER-PROTO-01_NOISE_P1090112-ANNOTATED-720PX.jpg]]
−
 
 
−
* Wire J38-3 or J38-5 to nearby GND
 
−
* Install U1 14 pin socket near "middle of card
 
−
** Pin 4 goes towards +12V
 
−
* Add 10 Ohm resistor U1-4 to +12V
 
−
* Add jumper U1-11 to GND
 
−
* Add jumper U1-8 to U1-9 (Blue loopback)
 
−
* Add jumper U1-6 to U1-7 (White loopback)
 
−
* Install R16 1K J1-8 to Open bus row (J1-T) - White noise out
 
−
* Install R15 1K J3-6 to Open bus row (J3-T) - Blue noise out
 
−
* Install R14 1K J4-4 to Open bus row (J4-T) - Pink noise out
 
−
* Install 100K from U1-13 to U1-14
 
−
* Install 22K from U1-13 to GND
 
−
* Add wire U1-8 to R15 (new row)
 
−
* Add wire U1-14 to R14 (new row)
 
−
* Add wire U1-7 to R16 (new row)
 
−
* Add wire U1-1 to U1-5 (NOISE_WB)
 
−
* Rest per schematic
 
−
 
 
−
== Debug ==
 
−
 
 
−
* 60 Hz rail-to-rail noise on U1-1
 
−
* 60 Hz noise disappears when scope is plugged in to output
 
−
** Likely a "scope-ism" since it's not on the output
 
−
 
 
−
[[file:ER-PROTO-01_NOISE_60Hz_U1-1.png]]
 
−
 
 
−
* Switched to BC548 - much more noise
 
−
** About 15x louder
 

Revision as of 17:19, 31 January 2023

ER-PROTO-01 NOISE P1080751-720px.jpg

Features

Noise Generator

  • Credit Moritz Klein's Designing a white, pink & blue noise generator from scratch design

  • Noise Generator

Moritz noise.PNG

  • White/Pink/Blue noise

Moritz WHITE PINK BLUE.PNG

  • High Pass Filter (Blue Noise)

Moritz HPF.PNG

  • Low Pass Filter (Pink Noise)

Moritz LPF.PNG

Build

White Noise Generator

  • Voltage Gain = 148
  • Switched from TL074 to TL084

ER-PROTO-01 NOISE WHITE Before.PNG

  • Output seems pretty quiet (~200 mV)
    • Issue is 2N3904 is much quieter than a BC548
    • Switched to BC548
  • Offset errors = about 500 mV
    • Gain = 148, 500mV = 3.5mV offset voltage
    • Add offset voltage trimmer
    • Circuit from here

OpAmp Offset Adj.PNG

  • Schematic with offset

ER-PROTO-01 NOISE WHITE.PNG

White Noise Scopecaps

  • White Noise Scope capture
  • 2 mS / div

White Noise Scope Cap-01.png

  • FFT, 25HKz range

FFT White Noise 25KHz.PNG

Blue Noise Generator

ER-PROTO-01 NOISE BLUE.PNG

Blue Noise Screencaps

  • FFT 1mS scope setting

FFT Blue J4 Noise 1mS.PNG

Pink Noise Generator

ER-PROTO-01 NOISE PINK.PNG

Pink Noise Scopecaps

Pink Noise Scope Cap.png

FFT Pink J4 Noise 1mS.PNG

Pink Noise LTSpice

ER-PROTO-01 NOISE Pink LTSpice.PNG

Jacks

ER-PROTO-01 NOISE J38.PNG

Connectors

J1 - White Output

  • +/- 7.5V swing

J3 - Pink Output

J4 - Blue Output

Eurorack Power

ER-PROTO-01 U1 PWR.PNG

Build Details

ER-PROTO-01 NOISE P1090115-720px.jpg

On Controls Card

ER-PROTO-01 NOISE P1080760-JacksRework-720px.jpg

  • Install J1, J3, J4
  • Wire J1-S to J3-S
  • Wire J3-S to J4-S

On Daughtercard

ER-PROTO-01 NOISE P1090110-720px.jpg

  • Transistor Noise Source wiring

ER-PROTO-01 NOISE P1090111-720px.jpg

  • Opamp wiring

ER-PROTO-01 NOISE P1090112-ANNOTATED-720PX.jpg

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