Savel brain dump in English!

Older post tube amp schematics looks something like this:

Big circuit diagram for printing

This schematics and tube amplifier is not designed for tube maniacs. It is designed to test tubes. Resistor’s and capacitor’s values may differ, because I build the amp and only later draw diagram.

V1- 12AX7 (can use 12AU7 or something, when input sygnal is strong), V2- 6П14П, V3- VR150 (150V zener), R12-200K, C2-0.1μF

I have lots of 12AX7 and 12AU7 pull-outs. And I need to test them. While building some testing gear, I decided to add one more tube and transform it to tube amplifier. Why it is “second tube amp”? Because, about 20 years ago I already almost build my first tube amp.

This is photo of tube amp:

There are three tubes in amp. That fourth tube is just placed. Tubes are: 12AX7 (inserted 12AU7 too- it is working, but more quietly), 6П14П-ЕВ (6BQ5, 7189A) and VR150. VR150 is 150V “zener”, it is stabilising voltage for preamp.

Here you can see super-duper high-end guts of amp:

Everything done from scrap components. I used my beloved japan electronics from 1966. Only output transformer is used from some old Soviet TV

Here tubes glow in the dark:

My photo camera didn’t catch focus in the dark.

Removed consoles from “big” copy machines. Two from Xerox 5343C and one from some other…

There are nice graphics LCD modules with backlight and touchscreen:

As this module is removed with some processor board, when powered it tries to do something…

“Good side”

“Bad side”

It is OPTREX DMF50073N-F-FW with 15 control and power lines.

The touchscreen in these two modules are very simple- simple matrix of switches: 9×12.

The newer LCD module is more complicated. Ant touch screen is more precise- it is analogue, only 4 wires to screen. LCD module is EDMMR63WOF. With 12 wires for power and control. According to internet it is Panasonic 320×240 STN-LCD.

In older post I wrote about unified soviet tube audio amplifier. This is from “high class” device. Today, I found the schematics of “highest class”, the HiFi audio device: AM/FM radio, record player. The output is 6W of pure tube power with lowest distortion. This device was manufactured in 1964 and schematics published in popular radio magazine in 1965. With some our days modifications it is possible to build quite cool power amp with quite popular tubes.

The circuit diagram of audio amp for printing

The circuit diagram of power supply for printing

Tube data:
Л1, Л2, Л3: 6Н2П, ECC83, 12AX7 (but with heater modification)
Л4, Л5, Л6, Л7: 6П14П, EL84, 6BQ5, 7189A

Here is the guts of disposable camera.

Simplified schematics diagram of camera flash.

Some high power flash tube from scientific equipment.

Simple few transistors generator and transformer A transforms 1.5V battery voltage to few hundred of volts. This is quite high voltage. Then this high-voltage current passes through a diode, which rectifies current to DC. This DC current is stored in quite big capacitor.

The capacitor is connected to the two electrodes on the flash tube at all times, but unless the xenon gas is ionized, the tube can’t conduct the current, so the capacitor can’t discharge and tube didn’t flash.

The capacitor is also connected to a small gas discharge tube via a resistor. When the voltage in the capacitor is high enough, the small tube lights up. This acts as an indicator light, telling you when the flash is ready for action.

When you press trigger of camera, the trigger closes briefly, connecting the capacitor to a second transformer. This transformer boosts the 290-volt current from the storage capacitor up to between 1,000 and 10,000 volts, and passes the high-voltage current pulse onto the metal plate next to the flash tube. The momentary high voltage on the metal plate provides the necessary energy to ionize the xenon gas, making the gas conductive. And the flash tube discharge.

Full schematics I found in the internet

In some www I found image of HDD transformed to grinding stone. It was placed in “jokes” category. But I decided, that small grinding machine is useful for hobbyist. I use old 2G HDD “Western Digital Caviar 22500″. It is only 5K rev/minute HDD. Removed cover and all heads, magnets. Took sandpaper and glued to one disk plate.

Grinding in action!

The engine is quite weak, but this “grinding machine” is usable. Next version will be mad from some quicker drive. I am looking for 7K SCSI Barracuda… Or maybe, if I’ll find, it will be some very old, but powerful, multiplate server hdd.

Soviet radio devices used typical schematics for same class. They called it “unified chassis” or “unified frame”. Here is part of the schematics from II class radio+phone player. Power output, according to manual, is only 1.5W, but it played very loud!

Big Circuit diagram for printing.

Pin 17, line 5: +200V
Pin 15, line 3: +260V
Pin 21, line 1: +280V
Pin 20, line 2: +280V
Pin12: Audio in
R1: volume
R2: treble
R3: bass
L1, Л1: 6Н2П, ECC83, 12AX7 (but with heater modification)
L2, Л2: 6П14П, EL84, 6BQ5, 7189A

Power supply for this tube amp.

Big Circuit diagram for printing.

For recycle, we received some “Medical computer” and inside I found this nice thing. The DIMM nearby is to compare the sizes.

A small ring, or core, of ferrite (a ferromagnetic ceramic) can be magnetized in either of two opposite directions (clockwise or counterclockwise). Therefore such a core can be used for storing a bit of information. For almost 15 years, ‘core’ has been the most important memory device. The invention of core memory in 1949 was a leap forward in cost-effectiveness and reliability. This device is dated in 1966. This memory “module” is made in Japan. I think by TDK. It consist of 5 PCBs with 4 “mats”. Total 8000 bits of RAM. It is whole 1000 Bytes (0.9765625 kBytes)! Cool.

Core memory has been in use until recently for special purposes, because it retains the information when the power is switched off, and it is resistant against radiation.

The physical basis of core memory is the fact that a current sent along a wire passing through a ferrite core sets a persisting core magnetization, if the current exceeds a certain threshold. A current in the opposite direction will reverse the direction of the magnetization. In this event a voltage pulse will be induced in another wire threaded through the core, the ’sense wire’; the polarity of this pulse is determined by the original magnetization direction. Clearly reading is a destructive operation, and as part of the read cycle the original state of each core must be restored.
Core memories were often organized as a planar matrix, the ‘write’ wire being split up into two wires (row, column) each carrying half of the threshold switching current. This made it possible to address a specific core in the matrix for reading or writing.

(Smart text is copied from internet.)

BTW, this device originated such known term as CORE DUMP.

Resistor inserted into a circuit to compensate for current changes (as those arising from temperature fluctuations) [syn: ballast resistor]

b-300-G by NEC and unknown Soviet made.

Tube filled with pure hydrogen and thing iron wire inside. When iron wire is cold, the resistance is low. When temperature rises, the resistance is bigger. The difference of cold and hot resistance is about 10 times. The current going threw berretter heats the iron wire. So the current in working range is stabilized. Used in older equipment. Sometimes in filament circuit in series to tube heaters. In modern time barretter can be replaced with PTC thermistor.

From “something I found”:

The nearer thing in the photo is power supply for some medical amplifier. The further one is the amplifier by itself.

The interesting part for tube audio amplifier lovers is power supply. It is stabilised +150V power supply. Also 6.3V for heater and something like 20V stablised on current. I’ve tested power supply and it is working fine. And it is made in 1966 in Japan.

Transformer used in power supply:

Input 220V.
Output: 20V @ 0.3A, 5V @ 2A (diode heater), 2×385V @90mA (with central tap), 6.3V @ 3A.

Tubes: 5AR4, B-300G, VR-150MT

Some choke- everything is written in Japanese.
Capacitors 2×20mkf @ 500V.
Other: selecnium rectifier in 20V line, few smaller caps and resistors.

Other board is populated with tubes: 2 x 6BQ5 ir 3 x 12AX7.