Fixing Presonus Studiolive 16.4.2 Freezing problem

We have encountered an unusual problem on our Presonus Studiolive 16.4.2 that we purchased 2nd hand. The mixer freezes after several minutes of use. The meters will freeze but controls are still functional. There is no sound output when the mixer freezes. I research for this problem and it turns out that I am not alone and this problem is a known issue to this model.

After some research I found some people that sharing how they fix the problem. 1 of them said that downgrading the firmware can solve the problem. I have tried this solution even though this means downgrading my MAC OS which is not an easy task and it will take some time to install older MAC OS on my laptop. Unfortunately this solution did not work for me. Other solution is to replace the DSP or Power supply board but this will cost much and shipping to Philippines isn’t cheap so I didn’t tried it.

Finally one shared that the freezing problem was fixed by simply adding fan. This seems an easy to do fix so I gave it a try. I have a small fan installed and tap the power to the external lamp power output of the mixer which is capable of delivering 12V 500mA which is more than enough to power a small fan. This works well and freezing problem was fix with a little issue…. There is an audible fan noise on the output. This is because I have connected the fan to the external Lamp supply of the mixer which is designed to power LEDs. So to fix this problem, I have used a separate power supply for the fan.

 

The fan with 100 ohms resistor and 1000uf capacitor for additional filter and to decrease the speed of the fan(because the fan is a bit noisy).

 

12V Power supply of the fan is a simple center tap transformer with 2 diodes and 1000uf capacitor.

Holes made a little bit bigger for the fan.

Now the mixer is working fine. 🙂

Update:

This seems to work for few months only. The problem does appear again after some time. 🙁

Hybrid Solar Power for LED TV and Electric fan

Philippine electricity is the most expensive in south east asia and it is getting more and more expensive every month. With the solar panel getting more and more affordable, is it really worth it to invest into solar power system? How much can you save with your electricity bill with these solar power system? How much will it cost to build your own? Let’s find out!

Types of Solar power

There are basically 2 kinds of solar power system and they are 1. On-grid 2. Off-grid.

On-grid Solar Power system – basically a solar power that is tied to your existing AC power from meralco of whatever your electricity provider is. This is the simplest system since it is only tied to your existing electrical power system. It is sharing power to meralco if the power is not enough to power your house. For example if your devices or home appliance is consuming around 1000W of power in total and your solar power can only produce 600W of power, the other 400W will be supplied by Meralco. This will in turn lower your bill because you will only consume 400W instead of 1000W because your solar power will handle the rest. While if on the other scenario, if your solar power system is generating power more than you need, it will be feed the excess power to the grid and will be bought by Meralco. In this case you will be a power producer to the Meralco instead of a consumer. Meralco will pay you for the power you generated. Take note that the rate at which Meralco will pay for your generated power will be way lower than what you pay for meralco per KWhr you use. Take note also that you will need to apply for net metering so you can be able to selll your excess power to Meralco and the process is not easy. There are many documents and procedures to follow before you can qualify for net metering. If you have no net metering, you might be charged when you are producing more power than you need. This is because normal meters are not designed by bi-directional current flow. So be careful with this kind of solar power system.


image from: http://energyinformative.org

The main disadvantage of On-grid solar power system is that when there is brownout, you also experience it. This is because Electric systems on each house are connected in parallel and you solar power system will overload if it will try so power during brownouts.

Off-grid Solar Power System – by its name suggest, this is not connected to your existing electrical power system. And because it is independent by its nature, it needs a battery for powering at night when there is no sun. And batteries as all we know are not cheap! And most of all, you need to replace it very 2-3 years(depending on type of battery and usage). This makes this system more expensive as compared to On-grid systems. The main advantage of this is that you can build this system anywhere as long as there is sunshine. And the biggest advantage is that you will never experience brownout as long as your battery is in good shape.

Hybrid Solar Power – This kind of solar power is just my idea, I don’t know if someone already thought of it. But because this system is very simple, it is most likely that someone out there might already built this kind of system. Block diagram below:

 

 

I call it hybrid because the output is 12V instead of 220V compared to on-grid system and it uses your existing AC power when there is no sun to power your system. I made this system so I won’t be needing expensive battery compared to off-grid systems and won’t be supplying power to the grid compared to on-grid systems.

About the Circuit

The circuit is simple, you have 2 power sources that set at slightly different voltage. The solar panel is connected to a buck converter which reduces the voltage of the solar cell from 19V to 14V. An AC/DC switching power supply is set at around 12.7V to compensate for the diode voltage drop. The output voltage of the solar is set slightly higher so when there is enough solar power, it will pull the output voltage to around 13.3V(-0.7V diode drop), this will reverse bias the diode D2 and will act like an open circuit. If the power from the solar is not enough, both diode will conduct and the output voltage will be just around the voltage output of the AC/DC converter.

Boost converter is used to increase the voltage to 19.5V to power my 32 inch Sony LED TV. I am not sure if most of the LED TV uses 19.5V but if I remember it correctly, my LG LED TV also has 19.5V supply.

What You need

On this project, those materials can be bought from online shopping like lazada or shopee.

12V output AC/DC converter

To make it more reliable, use a type with output current double than what you require. This will reduce heat and will have longer life.

BUCK Converter with adjustable output voltage

Set the output voltage to 14V before installing this. Make sure also that it have higher output current capability than what you require.

Connecting Reverse Camera for Honda Mobilio V or BRV S Philippines

Here’s a simple instruction on how to connect a reverse camera on the honda mobilio V variant and Honda BRV S variant.

You need to tap the trigger to the reverse lights positive. This will trigger the video input of the head unit and power up the camera also.

What You need

1 pin female dupont wires

Female RCA connector

Reversing camera set

All these materials can be easily bought online at lazada or shopee. 🙂

Below is the connection of the reverse camera to the head unit of Mobilio V variant or BRV S variant.

 

How to remove head unit

Video

Related Post: Connecting TVplus on Honda Mobilio/BR-V

Arduino programmer is not responding problem

Just recently I made a project with arduino nano and used my old working board. To my surprise I got an error that the programmer is not responding. After some debugging I found out that there is no problem on my wires or drivers. It looks like arduino just updated their bootloader with no backward compatibility. There is not option on the board “ATmega328P ( Old Bootloader)” but it doesn’t work.

So I decided to just re-program my arduino nano with the latest bootloader. The bootloader hex file can be found on the directory below:

To program, I used power debugger and connected it like below:

After I programmed the latest bootloader, my arduino is alive again. 🙂

The real problem here is that arduino updated their bootloader with no backward compatibility. The best fix is to program your arduino board with the latest firmware that you can find on the arduino folder on your program files directory. You can use any AVR programmer. You can also use your working arduino to program another arduino here: https://www.arduino.cc/en/Tutorial/ArduinoISP

 

Super Bass Tone Control

If you love to pump up the bass then this would be great project for your sound system. This is based on my previous tone control design with some modification to give more deeper and louder bass. It is basically the same with modified component values.

ABOUT THE CIRCUIT

The signal amplifier circuit is composed of R1-R4, C1, C2, C7, and Q1. It is configured as common emitter amplifier. It amplifies the signal because it will be attenuated on the next stage. R4 and C1 is used as low pass filter to filter out the low to high frequency ripple voltage of the power supply. It basically cleans the power supplied to the circuit. C2 and C7 is used to remove DC offset from the transistor bias. They are DC blocking capacitors, it passes AC and blocks DC. R2 is used to bias the base of the transistor to set the voltage of the collector to somewhere around the middle.  R1 and R3 sets the gain of the amplifier. To increase the gain, decrease R1 or increase R3. Always check the bias levels after changing the value of R1 and/or R3 as this might result to signal distortion.

CIRCUIT SIMULATION

Simetrix is used in this simulation. A free simulation software for individuals.

Bass Response

The problem with this kind of circuit is that the frequency response is not linear. The graph below is sweep from 10% to 100% bass setting with 10% interval while the treble is set to 50%. As you can see, the response is almost flat around 10% bass setting instead of 50%. It has around 12dB of bass boost at 50% bass setting.

Treble Response

Below is the frequency response of the treble control with the bass set to 50%. There is 12dB bass boost at 50% bass setting. The treble setting start at 10% all the way to 100% at 10% increment.

Adding output buffer

The problem with this circuit is that it changes frequency response with the next stage input impedance. If the amplifier has a volume control, it affect the frequency response.




200W Amplifier Design

Here’s a 200W amplifier design for your home audio. It is a class AB amplifier. It is capable of delivering more than 200W at 4 ohms.

About the Circuit

There’s nothing special about the circuit, you can find it all over the internet nowadays.

Simulation

I simulated the circuit using simetrix software. You can download the simulation circuit on our download page so you can play with the circuit and component values. Be mindful on the power of the output transistors.  You can increase output power by adding output transistors but you also need increase the supply voltage. You need to take note that the output transistor TIP3055 and TIP2955 can only have VCE max at 60V. In practice you don’t want to get near to that voltage. The safe supply voltage for this transistor should be around 45V.

PCB Design

The PCB design is simple and used 1 layer PCB only so anyone can build this project easily. You can also download the project on our download page if you want to modify it for your own requirements. My PCB design is simple and there are many rooms for improvements. The size of the filter 1000uf capacitor may be small in actual, you may need to check this before making the board. If you can change it with 2200uf capacitor then that would be better. But take note that this will be bigger capacitor. These capacitor are used to help supply power during big current draw. These high current draw usually happens during bass drum beats, especially if you set your bass to maximum. Supply voltage drops during bass drum beats due to high current draw and power supply output impedance.

These capacitors also helps reduce hum noise by filtering ripple voltage coming from the power supply.

The high current nodes such as power supply and output can be improved by making the trace wider. By making the trace wider on those nodes reduces voltage drops on those trace. This can improve bass performance.

3D Render

3D rendering is build-in on the KiCad software and this software is free!

Power Supply

This circuit can be powered by 24V up to 32V transformer. The transformer should be center tap and at least 8A for single channel.

 

image credits: interfacebus.com

NOTES:

If you want a very reliable design that doesn’t easily fail for years, the key is over designing. Design it to handle 200W and operate it at 100W and expect it to have longer life. This is because there is less stress and heat on each component if it is operating below its power handling. If you have computed that a resistor will consume 0.2W then use a 0.5W resistor or larger. Using a 0.25W resistor will still work but will eventually burn overtime.

DOWNLOADS





You can download the Kicad and simetrix project on our download page

3band tone control using transistor

Here’s a simple 3 band tone control circuit with 1 transistor instead of using opamps. This is using a single 12V supply. The frequency response is not as good as with using an opamp but it is still acceptable provided you just want a way to boost bass, treble, and mid frequencies. The transistor used is a BC549 but this can be replaced by any general purpose NPN transistor like 2N2222, etc.

 

VR1 =Treble
VR2 = Mid
VR3= Bass

Simulation result

As expected the response is not as good as what you can get with using an op-amp version but it is good enough for home sound system where you don’t need a very flat response. Each of the controls can affect the whole sound spectrum.

Bass Response at 0%, 25%, 50%, 75% and 100% setting

MID Response at 0%, 25%, 50%, 75% and 100% setting

TREBLE Response at 0%, 25%, 50%, 75% and 100% setting

Extreme settings:
green – bass = 100%, mid = 50%, treble = 100%
red -100%, mid = 0%, treble = 100%

As for the graph above, the mid setting will greatly affect the treble response. This is still good to use is you just want to boost bass frequency.

MIC Preamp type Circuit

The circuit above can be used for mic preamp. This is a simple but not outstanding. The performance is just ok for low end home audio. But for high performance audio, you should go with opamps especially made for audio applications.

IOT: Wifi controlled Audio tone control

Internet of things is becoming a thing these days. Internet connected gadgets and appliance are becoming more common these days. The advantage is very obvious: you can control these devices using your smartphone with internet browser, specially made apps or with voice command using google assistant. One of the goal of this project is to create a tone control with bass, mid, treble and source selector that can be controlled via smartphone or laptop with an internet browser. You can also develop an app for this but I haven’t have time to do so.

About the Circuit

The heart of the circuit is the NODEMCU – a wifi module that can be programmed using arduino IDE. If you are already familiar with arduino then this can be easy for you. It is connected to a 1.44 inch tft lcd with ILI9163 driver. The preamp is based on TDA7419, this is a digitally controlled tone control via I2C. This features bass, mid, and treble controls with adjustable frequency. This also has a 7 band spectrum analyzer which is better than using an FFT on arduino. This makes it easier for the programming since you only need to read an analog pin directly rather than doing the FFT calculations on arduino which is a bit of a headache to do.

The TDA7419 is powered with 8V so an 8V regulator 7808 is needed. It is also used to power the Nodemcu for wider operating voltage (most nodemcu can only operate up to 10V only). 7808 regulator can operate up to 35V input voltage. You can also use any regulator as long as it has 8V output and a sufficient output current.

As you can see on the schematic, there is only 1 left GPIO on the nodemcu which is the D3. There is still GPIO9 and GPIO10 but many claims that they are not usable and are not recommended to use. This is the reason why I am not continuing this project with this kind of display. By using an I2C display, I can free up 5 GPIO’s that can be used for buttons.

About the Software

The software is developed using arduino IDE. Note that this is not very well developed, there are many rooms for improvement. I won’t be improving this software further because I decided to replace the display with an OLED I2C desplay. The reason is that the ILI9163 TFT display needs more GPIO and nodemcu has very limited GPIO. Using an I2C display will free up GPIO for other functions.

The device will not start the initialization of the TDA7419 without a wifi connection. Once it established a wifi connection, it will then go to initialization on the system. That is how I designed it, because it was just a quick programming for proof of concept only. Like what I said –  there are many room for improvements here. I just posted this project for those who want to have a quick start. For the next version of this project I will be using an OLED display to be able to use the 5 GPIO for buttons and other functions.

Prototype

For the prototype, I used LM317 instead of the 7808 voltage regulator, because that’s what is readily available on my stocks. 🙂


demo: working. (Note: I accidentally cracked the LCD 🙁 )

The IP address is displayed on the LCD. This is entered on your web browser to access the controls. Take note that you have to connect on same wifi to be able to access the device.

Controlling with web browser

This is a simple webpage I made which can be improved further. The basic functions are there so you can use it as is if you prefer. There are many rooms for improvement here.

Downloads

You can download the source code on the download page

Simple Direct Injection Box

Here’s a simple Di Box that you can build. In case you don’t know the purpose of Di Box, it is used to connect unbalanced output to balanced inputs. For example, a guitar has unbalanced output and a mixer have balanced input. Balanced lines are used for long cables audio because it is able to cancel noise on long cables.

About the Circuit

The circuit use an NPN general purpose transistor. You can use any general purpose transistor here similar to 2N2222 transistor.

 

Simulation

The positive output(emitter side) has slightly higher gain because emitter current is slightly higher than collector current. The difference is minimal and may not be an issue.

Simple 9V 4 channel Mic mixer

Here’s an improved version of my simple mic mixer featured on this page. It is powered by 9V battery so you can make it portable.

About the circuit

The circuit is made of transistors only to make it simple. I didn’t use any op-amps on this project. You can basically build this circuit using universal PCB’s

It has 5 potentiometers. 1 for each channels and 1 for master volume. It can be used for guitars and mics.

Circuit Simulation

For simulation I used signal generator set with sinewave output at 50mV and each are set at different frequencies.  This is to be able to see each frequency on the output waveform. As you can see on the simulation of the output waveform, it has different frequencies.

 

PCB design

Here’s a simple PCB design that I made. As you can see, the design is very simple and only has few components. The layout is not perfect but at you can have something to start to. You can still improve this layout. 🙂

3D render by Kicad

DOWNLOADS
You can download the Kicad project file here:



Download page <- find the download here

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