H&G Amplification is an manufactory that designs and manufactures music amplifiers, speaker cabinets and boutique guitar effect pedals.
In this blog post we will describe a simple TL494 based voltage converter circuit, which is suitable for powering a preamp tube or Nixie tube.
Very briefly about its operation: it is a switching circuit that generates a higher voltage from a low voltage and can be varied within wide limits.
It often happens that we repair or simply test guitar pedal circuits and pedals. Here we use one of the most sensitive natural tools. This is the human ear.
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It’s a very nice, warm, full-tone preamplifier. The soul of the circuit is two BC109 transistors. These are old, well-proven types. Interestingly, the base of transistor T2 is connected to collector T1. This is called direct coupling, and the signal is transmitted between stages without attenuation. This means that there is no capacitor, resistor or transformer between the two transistors. This makes it less repressive to the guitar signal. This circuit does not distort, that is, only when the guitar volume is at its maximum.
This is the first version:
In this video it works on 9v voltage, see:
Leave a CommentToday’s interesting is the CD2399GP chip. A copy of the popular PT2399 effects processor.
CD2399GP datasheet in Chinese.
This is a fairly simple guitar overdrive circuit. A simple 2N5088 transistor as preamplifier and an LM741 opamp.
For the next project, a 24V power supply is required. But no transformer is needed. The big, heavy, separate regulator (LM7824) should be added etc etc … And the consumption is just a few mAs. Well, then be DC – DC converter! The point was that 12v should be converted to 24V. Be simple with few parts. Therefore, choose the old, proven MC34063 circuitry. Not complicated:
R2 is two 1 ohms in parallel. This is not marked separately in the drawing. Here is the official MC34063 datasheet, which is worth studying.
Leave a CommentOkay, this is a great product of the Princeton Company. This is PT2399 echo IC. It can make good guitar effects like: delay, reverb .. But if it’s original ..
Well, we got a fake IC. No PTC manufacturer, unknown “DTC”. Compared to the original, other exterior. And noisy, such basic noise is that: shhhhhhh(it). Oh no.. 🙁
Look:
Leave a CommentSome pictures: electronics repair. The product name: Dynacord Eminent II. This is beginning to be manufactured in the mid sixties. Initially, all tube design, and later the transistor preamp and tone section. Meanwhile, little change in design as well. This four different input and tone control. A small band certainly met at that time.Well, let’s look at what is inside.
Let’s look at it:
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