I am an independent builder and have nothing to do with LZX industries.
These aren't official build notes, just my records to help me trouble shoot.
It's a work in progress.
Do let me know if you spot any errors or omissions.
This is module no.9 (VCO IX).
LZX describe it as a wideband triangle core VCO.
..
ic'S used:
LM6172IN/NOPB --- this is a dual op amp... specified at ±5V power supply for low
voltage applications such as portable video systems.
LM6172IN/NOPB --- this is a dual op amp... specified at ±5V power supply for low
voltage applications such as portable video systems.
TL431BQLPR ----- Adjustable Precision Shunt Regulator
TL431 shunt regulator circuit explained
TL072IP - standard op amp
SN74HC14N - it's a hex schmitt trigger
CD4066BE - CMOS quad bilateral SPST switch
----------------------
I'm guessing that the SN74HC14N is being used as the schmitt trigger oscillator.
If I'm reading the schematic correctly, a square wave is developed from the Schmitt trigger and the triangular wave is developed across a capacitor. They are output through buffer amplifiers (LM6172).
This same IC is used in the Cadet IV Dual ramp generator
(Another IC that would probably do a similar job is the 40106 - also a Hex Schmitt-trigger Inverter..
or a 74HC4046... phase locked loop ??? ................... a couple of thoughts for another day)
DPDT & SPDT switch (on on). These aren't right angled, so I'll have to hand wire them.
We nEED matched transistors.
I had to do something similar many years ago for an ARP 2600 clone ... the TTSH
http://djjondent.blogspot.com/2014/08/transistor-matching.html
R43 -- I could use a TempCo but instead using a standard 2K resistor
Resistor 43 = tempCo?
I decided not to use a TempCo in this case. Just used a standard resistor. I like my VCOs to be untuneable. :-)
The 10k pots finally arrived. I had trouble finding these. (I got them from thonk)
ICs , parts etc used in this project:
LM6172IN/NOPB
TL431BQLPR
TL072IP
SN74HC14N
CD4066BE
Mods:
+There is a Square output on the C9 circuit. You can output it directly or use it with the triangle to drive a sawtooth waveshaper circuit.
Links:
LZX official
Muffs - Cadet series DIY/assembled
7414 oscillator -DIYTL431 shunt regulator circuit explained
TL072IP - standard op amp
SN74HC14N - it's a hex schmitt trigger
CD4066BE - CMOS quad bilateral SPST switch
----------------------
I'm guessing that the SN74HC14N is being used as the schmitt trigger oscillator.
If I'm reading the schematic correctly, a square wave is developed from the Schmitt trigger and the triangular wave is developed across a capacitor. They are output through buffer amplifiers (LM6172).
This same IC is used in the Cadet IV Dual ramp generator
(Another IC that would probably do a similar job is the 40106 - also a Hex Schmitt-trigger Inverter..
or a 74HC4046... phase locked loop ??? ................... a couple of thoughts for another day)
I had to do something similar many years ago for an ARP 2600 clone ... the TTSH
http://djjondent.blogspot.com/2014/08/transistor-matching.html
...
...
The 10k pots finally arrived. I had trouble finding these. (I got them from thonk)
ICs , parts etc used in this project:
LM6172IN/NOPB
TL431BQLPR
TL072IP
SN74HC14N
CD4066BE
Mods:
+There is a Square output on the C9 circuit. You can output it directly or use it with the triangle to drive a sawtooth waveshaper circuit.
Links:
LZX official
Muffs - Cadet series DIY/assembled
How Video Oscillators work - Muffs
---------------------------
Click here to access the Video Index page
what is that gum looking stuff you have on the IC?
ReplyDeleteBluetack. I use it to hold IC's etc in place before soldering
DeleteOk thanks for the reply. That's a good idea.
DeleteDo you think I could replace the 2 1N4148 200mA diodes with a 1N4148 150mA?
ReplyDelete