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H&G Amplifiers Posts

DC to DC converter

This circuit is the old and well-known NE555 integrated circuits based. DC to DC circuit is not complicated, little parts, and doing pretty much stable voltage. It produces with the 12V DC voltage of 30V to voltage. The NE555 constant operating frequency is set. The 3 pin voltage convert of 30V. D1- D4 and C1-C5 voltage tripler circuit.  DC to DC converter is use in similar tube circuit.

DC to DC converter schematic, used 555 ic.
DC to Dc converter schematic
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Op amp inverting amplifier

This is an inverting op amp circuit. Proven operating op amp circuit that uses the old and popular LM741 (at Texas Instruments products, datapage ) circuit.  Op amp inverting amplifier circuit is very simple, some spare part.

Op amp inverting amplifier
Op amp inverting amplifier

The prototype circuit:

Op amp inverting amplifier
Op amp inverting amplifier prototype circuit
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3 Transistor Fuzz

Three transistor fuzz effect, strong sounding. Based on the famous Fuzz Face circuit, supplement with a preamplifier. Tried operating circuit!

fuzz guitar pedal effect
3 Transistor Fuzz guitar effect

Q1 2N5088 pre-amplifier transistor can be replaced 2N2222, 2N3904, BC547 type. If you need tougher sound, the Germanium Fuzz Face for you.

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The operational amplifier


The operational amplifiers built a few dozen transistors attached to direct amplification circuits with high voltage. Often referred to as “op-amp”. Their properties vary widely depending on the model. Balanced inputs and outputs are usually asymmetric, high input resistance and very low output resistance. One of them is typical linearity and low cut-off frequency.

According to their structure can be constructed of discrete components or integrated circuits. The operational amplifier are historical reasons for designation, since this type of circuit during WWII analog computer developed.

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Valve Caster tube effect

Matsumin wrote in his drawings Valve Caster 2007, the goal was to create a real tube boost / overdrive pedal that can run on a single 9-volt battery. It worked! Unfortunately defecate 9V battery snap. Valvecaster run well in a 9 or 12-volt power supply. 12V will give you more headroom and cleaner sound. It is designed with single coil pickups. A 12AU7 is particularly suited to this, by virtue of being virtually identical to a 12AU7 which was designed to be used at low voltages in old car radio circuits. Indeed some sources say that there isn’t really a difference between the two types and that 12AU7s are just selected 12AU7s that have tested well at low voltages.
This circuit is a good example of the low voltage art!

Valve Caster tube effect circuit
Matsumin Valvecaster circuit
Matsumin Valve Caster

This one is a pretty popular now overdrive the real tube. Very nice real tube amplifier has a voice, booster little overdrive sound. Many people rely on this effect. The circuit is quite simple, and best of all the ECC82 or 12AU7 tube operating voltage of 9-12. So many people are doing it from the circuit custom guitar pedal. It has a place among boutique guitar pedals. few circuit modifications everyone can find their sound.

The design tube made with the point-to-point wiring. TONE potentiometer and capacitor (R6, C4) is a passive filter. The device structure is simple, the ECC82 dual triode circuit of the soul. This tube is designed to drive the tube is thus relatively little strengthening. but larger current running as the rest of the series (ECC83, ECC81, ECC85), and this is associated with low voltage. ECC82 only the electron tube may be, or of the same type, so 12AU7, 5814 etc vacuum tube. Interestingly enough ECC85 tube works well.

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10 +1 Guitar pedal effect that is present in a Rock Concert

1 Basic chromatic tuner, it is sure to be. If you do not want to misrepresent your favorite songs play.

2 Of the noise-canceling, verily, it happens that the environment is so noisy that the guitar voice is not exactly play lyrical melodies.

3 Ibanez tube screamer basic series and its clones, bigmuff, Overdrive and Distortion (usually Boss) and Fuzz.

4 Echo, reverb, effects, these never enough to be a soft melody than for dramatic effect or even be stronger crushing.

5 Phase shifter, roll your guitar signal, whether dizziness.

6 Expensive and exotic, such as Klone Centaur (this is what is analyzed), Landgraff, Keely and boutique / modified pedals are very expensive, interesting exterior and sound, and the original 30 to 40-year-old pedals.

7 Graphic equalizer, is essential if the guitar has not “crying” you will now!

8 Tremolo to be a titillating “surge” in music.

9 Wah, it should. foot play guitar tone, too!

10 “Do not know what it is, but it sounds good” pedal, so worn or special that can not be determined what, but the sound of “oooh I must”, of course if you ask a guitarist, “what is” not to tell, and mysteriously smiling.


Usually starting band. million crammed into effect, a plastic awful sound. Brrrrrr…The devil himself.

And what effects you use? Write it to me !

By: hgamps

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Shaka HV Guitar Overdrive effect


We have built and tested in this great sounding guitar overdrive circuit.


shaka hv overdrive schematic
Shaka HV overdrive schematic


Original author’s comments:


“The shaka hv (higher voltage) is a very low to medium overdrive pedal. This pedal can give you very good clean
boost as well as very low to medium overdrive. To get 18 volts from two batteries, connect the negative of a battery
clip to the positive of the other battery clip. Now use the two remaining leads as usual wich will give you 18 volts.
All caps are film type except the electrolytics. Be sure to use at capacitors that can handle at least 18 volts rating.
The FET is a J201 and the op amp is a TI RC4558 dual op amp. You can use a TL071 single op amp as well. This circuit
uses various snippets from Jack Orman who has don great work with Fets in distortion circuits.
Note: You can also put a capacitor 10uF to 47uF in value from 18V to ground.”


Review the overdrive effect

We test op amp and dual use JRC4558 and Fairchild FET J201. The circuit is the same as Klon Centaur, it also uses a high voltage (18V) sound production.

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Klon Centaur analysis

Given a legendary and unmatched sounding overdrive pedal, the Clon Kentaur. Unfortunately the price is quite high, but the magic is never cheap. There are of course aftermarket pedals and copied, even among reputable manufacturers. Not to speak about what inspired this pedal. But let’s face it, it’s not the same. It is the “magic”.

Klon Centaur – reproduction

Body and Soul

Well, maybe you cut into it. Let’s start with the most basic buffer area. Not too complicated circuitry built around the TL072 opamp chip.
We experimented with the quality of the components and values. Audibly interesting results.

The buffer circuit

klon buffer

The circuit is not complicated, the preamplifier is used in many places. Test circuit made that we can compare what they are doing in different parts of the sound quality. The selection of high-precision components.

Buffer test circuit

There also has to be said that Gold version used TL072, Silver version uses JRC4558 chip.

Klon Centaur  the soul

We come to the most important part, it gives the familiar sound that occurs in the “magic”. This part is very interesting. Two in the loop to a double potentiometer Gain control what he does. Loop gain, low gain (P1 circle) and the larger (P2 circle) which has been cut in the resulting sound from the D1, D2 diodes, and this signal is fed back to the beginning of the loop. D1, D2 type for 1N34 germanium diodes, curiosity replacing silicon diodes 1n914.

klon soul
Klon Centaur the Soul

Tone circuit

Here’s the tone controls, Treble enhancer circuitry and power amplifier. Use TL072 circuit.

klon tonus
Klon Centaur Tone

Power supply

For experiments simple solution:

Battery pwer supply

This is once again an important part of the circuit is interesting that the pre-amp and distortion 9v work. The 18V turn tone circuit works. two 9V battery can be produced, or a special chip circuit ICL7660 or MC34063.

/ Writing is expanding, check back later! /

Until then:


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Time to prototype circuit

There are many things I want to try the circuit to experiment with different ideas. Replaced parts values, modify settings, or other circuit. As a result of this circuit. 12AX7 preamp tubes built. Very nice pleasant sounding. It reminds me of amplifiers in the 60s. Good guitar setup, the “bright” metallic voice.

Prototype circuit. ECC83 tube and 2N7000 mosfet. Low voltage power (12V) .
Prototype circuit

The circuit runs on 12V. Since such a low voltage, low gain, it is necessary to supplement MOSFET amplifier circuit. MOSFET similar characteristics as triodes, so his voice is not as annoying as a transistor 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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