• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Velleman K4040 Stereo Vacuum Tube Amplifier Volume Control

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Hello, Im going to be building the Velleman K4040 Stereo Vacuum Tube Amplifier but then i noticed something, thares no volume control. Would I be able to put a volume control feature on this amp by just putting a var resister on the output? or do i have to use something else for volume control.

You could just fit a volume control..However I would make a simple passive preamp. The reason is you will have no selection for other equipment. Also you will probably want to upgrade the pre at some point. This amp is capable of good sound and anything on the input will impair the quality. So you need a "good" passive pre, not just a get round fix!

You need no gain with this amp! Use a good quality control (var resistor) and relay selector <<tends to be cheaper than some switches.

Regards
M Gregg
 
Disabled Account
Joined 2010
Ok do you have a schematic for that type of preamp? or do you have one for an amp like this one but with volume control?

I am not sure how much electrical experience you have....asking about a passive preamp.

If you have never used valves before please be very carefull the voltages on these circuits can and do kill...They hold power after switch off..Test before you touch anything.

Please read

http://www.diyaudio.com/forums/tubes-valves/30172-safety-practices-general-ultra-high-voltage.html

Please be safe! :)

Regards
M. Gregg
 
Although I have never heard the K4040, do some searching around. The reviews that I saw were not so good vs the price. I would look at some of the goods at tubes4hifi home page . The dynaco stuff is a classic design without the mumbo jumbo of the K4040 - and I would expect to sound a lot better too. While you are there, pick up a preamp kit too. All for less than the K4040.

For the record, I have no connection to any of the companies mentioned above. Just my opinion.

If you are new to building electronics, you need to buy some tools and learn about what you are doing. Kit building can be fun, but you can wreck it and kill yourself if you do not know and abide with the basics. Maybe you have someone near by that can be a mentor to show you the ropes ...
 
I am not sure how much electrical experience you have....asking about a passive preamp.

If you have never used valves before please be very carefull the voltages on these circuits can and do kill...They hold power after switch off..Test before you touch anything.

Please read

http://www.diyaudio.com/forums/tubes-valves/30172-safety-practices-general-ultra-high-voltage.html

Please be safe! :)

Regards
M. Gregg


Haha sorry I kind of derped at the last thing you said XD. I have worked with tubes before and I am aware of the high voltages that thay need to operate. This is my first audio tube amp project however. I have a transistor amp that I built a while back and I want something with a better sound. The only mods im going to do to the schematic is use nichicon audio caps, electro harmonex tubes, add edcor transformers, and add a volume control.
 
Although I have never heard the K4040, do some searching around. The reviews that I saw were not so good vs the price. I would look at some of the goods at tubes4hifi home page . The dynaco stuff is a classic design without the mumbo jumbo of the K4040 - and I would expect to sound a lot better too. While you are there, pick up a preamp kit too. All for less than the K4040.

For the record, I have no connection to any of the companies mentioned above. Just my opinion.

If you are new to building electronics, you need to buy some tools and learn about what you are doing. Kit building can be fun, but you can wreck it and kill yourself if you do not know and abide with the basics. Maybe you have someone near by that can be a mentor to show you the ropes ...

I know what im doing haha. And Im not buying the kit, I found the circuit diagram for it and I am going to buy the parts and put it together. im also going to be making a few adjustments to the circuit and make a custom chassis out of oak.
 
Hmm, You say you know what you are doing, yet have to ask about a volume control?

The advice given is based on a perceived lack of experience. That perceived lack of experience is based on the initial question you posted.

I would suggest that if you are having to ask about a volume control or passive pre, you are probably not at a stage where you should be attempting a high power scratch built tube amp, with modifications from original, as a first tube project.

You will find most people on this site very helpful, but if your response to them is 'haha I know what I am doing', they will probably ignore you when you inevitably run in to trouble.
 
Hmm, You say you know what you are doing, yet have to ask about a volume control?

The advice given is based on a perceived lack of experience. That perceived lack of experience is based on the initial question you posted.

I would suggest that if you are having to ask about a volume control or passive pre, you are probably not at a stage where you should be attempting a high power scratch built tube amp, with modifications from original, as a first tube project.

You will find most people on this site very helpful, but if your response to them is 'haha I know what I am doing', they will probably ignore you when you inevitably run in to trouble.


>.> you must not understand what I mean by asking this. What I mean by can you put a volume control on this amp is has anyone tryed it and has it worked for them. I have worked with tubes before and I am vary famulure with transistor amplifiers. My current transiter amp I built. I asked about the passive pre because I did not understand what he was saying for a sec. Im also dyslexic and sometimes dont read things properly and have to re read it, I posted that reply before I re read it.
 
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