27 May 2009


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I have a locally made acoustic guitar, the brand is TOYO, sound Japanese but it is actually made in Indonesia, although the sound is so so, it is faithfully with me for 25 years. 

At that time, I just want to buy a Yamaha Classical Guitar, as I take courses in classical guitar. Some advantages of Yamaha Classical Guitar is it sound better, secondly the distance between strings is rather wide, perfect for fingerstyle. My TOYO guitar is almost closed to these requirements, except TOYO price is around US$ 3 vs Yamaha around US$ 30 ( in 1980s ).

Although recently I have sufficient funds, I am not interested buying an Acoustic Guitar, my desire is to buy an Electric Guitar, is a result of the music that I like, the Jazz.

Survey leads to two types of guitars, first is Yamaha 
Silent Guitar, price around US$ 370. I tried, and indeed very good. Wide fret like Yamaha Classical Acoustic Guitar, nylon strings, and there is an echo sound processor, also a unique shape, could be detached and put in its bag.

The second Guitar category is a 
hollow body or some call an archtop guitar. This kind of guitar is widely use by Jazz or Blues musicians. The choice fell to Ibanez Artcore AG-75BS. Price about US$ 270.

Finally, I drop this option to  Ibanez Artcore AG-75BS, I fell in love with the body appearance, for this guitar, the body is thinner then the other series. Low action strings, distance between strings is smaller than Yamaha Classical Guitar but it is acceptable for fingerstyle, and the most important the tone is realy OK.

For reference see Ibanez GB-10 George Benson series, it is cost about US$ 3000 !!
. Design is very similar to AG-75BS, and by reference, the form was designed according to George Benson wishes, the AG-75BS is the economic version. Nevertheless, the quality of workmanship is very special, the connection logs and immaculate finish, and it looks luxury. 

18 August 2008



After buying an electric guitar, for about 1 month can not enjoy this guitar, I am just be amazed holding and touching it, why ?, because I do not have an amplifier.

Buy ? the price starts from US$ 40 for locally made, unfortunately box dimension is rather big, and the appearance is not attractive, I just want a small dimension, but as it was quite expensive, say brands like Roland Cube, Peavey, Bosch, Ibanez etc.. also a top brands like Polytone Minibrute.

Another alternative is to use an computer's active speaker. After trying brands such as Altec Lansing, Creative, etc.., sound is too weak and very very bad, as if it is covered or muffled, not suitable for an electric guitar at all !.

Ok, the last alternative is to make my own amplifier. I already have a speaker in my junk box, it is from my former office sound system, specifications is a full range speaker, not for woofer or subwoofer.

For amplifiers, the common criteria I need is: simple, flat frequency response, output power sufficiently to be played in a room alone.

The results of my choice is TBA810 IC, the specifications:
5M ohm input impedance as high as I expected, sensitivity is high so there should be no pre-amp, power supply voltage range of 4 to 20V, the output power 7 Watt, just try to make it and see how good is the result.

Here is the scheme. No need to make a pcb, use ugly construction, quickly becomes.


How is the sound produced? Quite satisfactory, clear, bass and treble flat and fitted played alone in the bedroom. My suggestion for a speaker, box made is ​​absolute.
To reinforce the bass, the speakers can be placed under the table or under the bed.


Now I want a bigger power, amplifier criteria same as above, simple, not a lot of components, and has a good voice. I tried searching on google with keywords STK15 IC, but this types of IC are apparently outdated.

Now there are ICs that much smaller in size, but more powerful abilities.
Election falls on the type of IC LM1875, specifications 20W output, supply voltage from 16V to 60V (for double power supply V + = 30V and V-= 30V maximum), 30W max output depending on supply voltage, low distortion.

For this amplifier, is inverted design, scheme, construction, and powersupply as follows:

For this amplifier it is required a pre amplifier, designed with three input (or more) and respectively - each have a volume control as follows: L-MP3 player, R-MP3 player and guitar itself.

If you have MP3 songs to practice ( minus one song ), say the left channel for rhythm, the right channel for the melody, one of the lines can be diminished, (without disturbing the volume of the other lines).

Pre amplifier schematic as follows :

Everything is assembled in ugly construction method, a note for pre amplifier: try input cable is quite short, check that the grounding should be the one with the amplifier circuit and the circuit power suplly, otherwise it will sound drone. Keep the pre-amplifier input of the power supply transformer, or give them grounded screen.

Now how is the sound of this amplifier?
Very impressive !!!.

You have to make it yourself to be able to feel it.

Here is the layout and images - pictures:


After a while, potensio volume control tend to be dirty and crackle noise make it difficult to fit the desired volume. I modified it with a 3-position switch: on-off-on or half volume, mute, and volume up, as follows: