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Category: Electrontube

Tube amplifier electronics repair

Some 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.

Dynacord Eminent II
Dynacord Eminent II

Let’s look at it:

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Bassline – Bass Guitar Tube Preamplifier

So far, we do not really dealt with bass guitar  effects, amplifiers. Here, in this time of change!
One of my favorite band The Beatles, inspired a new tube bass preamp creation.
The plates can hear great tunes and sounds of the XXI century it is significant. This’ 60s-edge
tone you want to give a little back. This simple, little preamplifier may be able to create a good bass sound.

The idea

Okay, what do we need? First, a simple tube preamp and a tone sections. And yet… put a little extra! Whether it is a switch which can give more prominence to the bass sound. And finally result in the power amp section. The tube 12AX7 or ECC83 should be. And we are ready to go.

Build the bass guitar preamp

As shown in a schematic diagram, not complicated circuit. The circuits are designed triodes ordinary way. Located between the two triode the tone control section. Here we must mention the little extras are what we promise you. It was built in the SW1 signal switch and capacitor C7. This will give even more powerful bass sound.

Even a small change in the circuit (well, not so little, the C8 is quite large capacitor). The C8 was originally 100nF, it was replaced with 1uF. Thus, it improved bass response with what is perceptible difference. Suggested type for a high-quality MKP capacitor. We conducted a little experiment, was left inside the 100nf and 1uf capacitor, one switch to choose between the two, and thus is connected to the output. so you can compare the two capacitor deep voice transmission. Feel free to experiment with different manufacturers and types of capacitors.

Bassline - bass guitar tube preamplifier
Bassline – tube bass guitar preamp – click to open full size

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High voltage tube guitar preamplifier with 12AX7

The high voltage tube guitar preamplifier project is an adaptation of the famous tube preamplifier to suit the DIY’ers demands. Searching the net, I’ve never come across similar idea, so I decided to share this version of our very popular design. This a classic, conservative design, that easily matches other musical devices.
The preamp contains one channels of real-tube, high-gain circuit. This circuit uses JJ ECC83 (12AX7) tubes. Circuit uses a stabilized 12V DC voltage.

High voltage tube guitar preamplifier
High voltage guitar preamplifier circuit

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12AU7 Tube tremolo

This is a Hybrid tube tremolo circuit. It is interesting that a low frequency oscillator (LFO) in electron tube is not resolved, we do circuit transistor for low frequency.

Tube tremolo circuit
Tremolo schematic

BC547 transistors and used ECC82 or 12AU7, so the circuit operates at low voltage. Tube circuit provides classic, warm sine wave tremolo tones.

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Tube distrotion effect

 

Real tube guitar distortion effects. unusual solution works of 2n7000 mosfet transistor. After the transistor is like the valve amplifier, it is very nice and pleasant natural sound of this effect provides a true analog distortion, no digital, no modeling!

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Tube overdrive effect

A lot of effects pedals has been prepared, including the famous Tube Screamer to mimic the old natural distortion of a tube amplifier. These pedals operate a semiconductor basis, more – less successfully mimic this sound. I did this and I use it with great joy:

real tube overdrive
Test version

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ECC83 / 12AX7 tube

In this article we take a closer look at a bit of a tube guitar amp ECC83   topic. Considering dual triode structure, which means that two of the same reinforcing element is a glass envelope closed. As will become apparent in the US or the Russian 12AX7 tube 6N2P (6Н2П) signal, which is not quite the same, but rather similar; here it is already different from the heater connection. Why is it so popular?

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