Questions tagged [vacuum-tube]

Any device that incorporates an evacuated chamber in which free-floating electrons are manipulated.

19 questions with no upvoted or accepted answers
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Low power tube headphone amplifier design

I have never worked or even listened to tubes/valves before, so its about time I did. I wanted a simple design to work with being my first tube project, and have found this from diyaudioprojects.com: ...
3
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1answer
336 views

Amplify Raspberry Pi Zero W Audio with 60s Tube amplifier circuit

First of all, thank you for taking a look at my question. Electronics is not my field of expertise, and I have found myself a bit stuck. I have been restoring some old 50s and 60s tube amplified ...
2
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0answers
38 views

Vacuum tube emission (anode current, transconductance) percentage that is considered GOOD

Russian vacuum tube datasheets almost always specifies anode current like Ia = 100 mA +/-20mA at some conditions. The same with transconductance. But western tube datasheets specifies only one ...
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0answers
407 views

What is happening to this vacuum tube?

I’m trying to repair a 63 year old record player. Opening it up, all of the electronics have aged badly, except for the drive motor, which is basic enough that it operates properly. I know enough ...
1
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0answers
105 views

Guitar Amp Power Supply Issues

I have a B-52 AT100 guitar amp on my bench (naturally, it wouldn't let me attach the .pdf I have of the schematic, so I had to attach it as two .jpegs. The schematic can easily be found online though, ...
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0answers
89 views

Fuzzy digits when driving with TPIC6B595

I designed a schematic and PCB of a simple Nixie clock and I hope that someone will be able to explain what's happening. The problem is that when I'm driving the cathodes with TPIC6B595 shift ...
1
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0answers
212 views

Vacuum tube voltage regulator - capacitor on the output

I'm thinking about building a tube-based voltage regulator to provide the power for the screen grids of the output tubes. I have seen multiple designs of this and am currently thinking of doing it ...
1
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0answers
305 views

Magic Eye Tuning Tube Variable Negative Voltage

I am thinking about several applications of magic eye tuning tubes as display pieces and had a question about their operation. I have attached a sample circuit from a datasheet for an EM84 tube. I ...
1
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0answers
1k views

Solid State Output Tube Driver for a SE guitar amp

I'm learning as I go once again. Consider this output stage segment from a guitar amplifier I physically built: The LND150 is an "depletion mode" MOSFET, whereas the IRF820 is a normal "enhacement ...
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0answers
92 views

600V DC Switch method question

I am making a linear PSU capable of O/P 600v @ 300mA. This is for vacuum tube experiments. I need to connect/disconnect the load from the PSU using a switch. I will not turn OFF the PSU itself. I ...
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0answers
56 views

Designing a hybrid RF ampilifier with tube and transistors

I have an 807 vacuum tube and I want to design a RF power amplifier with it. Since I have only one tube so I want to use transistors for the rest of the power amplifier circuit. The 807 tube will be ...
0
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1answer
175 views

Restoration/mod of mid-1960s PP 2xEl844 4x6AT6 guitar amp, voltage, hum problems. Similar to Fender 5F10 schematic

Is this the right place to find solutions to the above problems? I'm trying to make this amp usable, but after some rebuilding and reconfiguring, I still have a hum problem and what seems to be odd ...
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0answers
42 views

Drive an older VFD tube via an Arduino et. al

I have a beautiful old itron DP95A4 tube that I would like to use as a small display to visualize some data. I suppose I'd need a driver and some sort of multiplexer, preferably used with an Arduino ...
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0answers
33 views

How to detect if vacuum tube is overdriven?

I want to somehow indicate(with LED diode for example) to user when vacuum tube is overdriven (When grid voltage is greater or equal than cathode voltage). My first idea was to connect a LED diode ...
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0answers
271 views

How close can an output transformer be to a preamp tube?

Imagine a layout for a tube amplifier. The power transformer is on one side, and the output transformer, input jack, and preamp tubes are on the other side. (Take a look at the Soldano SLO for example)...
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1answer
73 views

Calculating voltage, current, and impedance values on an old transformer

I'm working on an old valve amplifier, with the intention of reusing the transformers in a new project. I've used what I know of transformers to calculate the ratio of each winding the corresponding ...
0
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0answers
173 views

Ascertaining Valve Part Numbers

Old valves (vacuum tubes) sometimes do not come in their original boxes. Sometimes the part numbers seem impossible to read. Is there an easy way to read an apparently illegible part number? Would UV ...
0
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1answer
847 views

Simple vacuum tube tester design

I recently acquired a bunch of vacuum tubes from ebay and I'm in the process of trying to design a simple tester to check the functionality. Below is what I'm currently thinking about: I managed to ...
-1
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1answer
474 views

Little Bear T11 tube phono pre-amp VACUUM TUBE upgrading

I have a Little Bear T11 vacuum tube phonograph pre-amp. It has three Shuguang 6N2-J "Military Grade" vacuum tubes which I want to upgrade. The pre-amp also has a Chinese made 6z4-J Rectifier. The amp ...