Simulations of - and a copy of the EasyEDA LM386EE spice model used in - each of the major stages used in the EasyEDA Tesseract DIY Guitar Practice Amplifier:
which includes a complete PCB design and Bill of Materials.
The EasyEDA "Tesseract" Guitar Practice Amplifier is an LM386 based low power amplifier designed to deliver up to about 500mW into an 8 Ohm speaker when run from a 9V battery. The design given here is highly flexible and allows the several options in both the build and use of the amplifier.
As well as a clipping circuit that some other designs - such as the more well known Smokey, Little Gem, Ruby and Noisy Cricket - have incorporated, Tesseract has several unique effects features designed into it:
Selectable Bipolar or Junction FET input stage for different input overload effects;
Adjustable gain and clipping 'hardness' in the Distortion stage;
An adjustable fullwave rectifier stage, driven by the distortion output, that generates a type of fuzz and frequency doubling effect called 'Wreckage';
An optional low frequency oscillator stage to sweep the
A simple mixer to blend the 'Wrecked' and the 'Distortion' outputs;
Selectable, adjustable low or high frequency boost (a type of tone control);
An important aspect of the design is that all the features and FX can be tweaked for your delight and delectation.
Most features are also optional and can be wire linked out if not required without affecting the other functions.
The design could easily be modified to suit the LM380 2.5W or LM384 5W amplifier chips (although the Boost function would have to be omitted) or a range of other devices.
The design also includes a headphone output jack.
The PCB includes dual footprinting to simplify the choice of some of the components.
To obtain a copy of the LM386 subckt model simply download a copy of the LM386EE.sub.txt attachment.
The model runs in ngspice (which is what EasyEDA uses anyway) and LTspice. It'll run in SIMetrix and probably run in PSpice.
|8||SIN(0 6 1k 0 100) AC 1 0||VSIG||2P-5.0||1|
|21||SINE(0 4 1k 0m 500) AC 1 0||V1||2P-5.0||1|
|26||PULSE(-2 2 0 999u 1u 1f 1m)||V1||2P-5.0||1|
|29||SINE(0.8 0.8 100 3m 0 -90)||VLFO||2P-5.0||1|
|33||SIN(0 4.5 1k 0 500) AC 1 0||VSIG||2P-5.0||1|