• 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.

Using a ignition coil for a audio transformer

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
martin clark said:
Would probably go well with that turntable with a bearing based on a Harley inlet valve...


Naughty boy! :D

Altmann DIY TT here. The man built what appears to be a satisfactory mass damped basing system. For somebody with the necessary power wood and metal working equipment, that just might be a good project. Drill 12 pockets around the periphery of the platter and fill them with Lead. An acrylic sheet as the top layer of the platter and a good clamp should finish things off nicely.
 
You can buy an inexpensive OPT for less than you would normally spend for a new ignition coil (junkyard parts are cheaper obviously).

So the rationale for using the ignition coil has pretty much gone away, and the high voltage on the speaker leads hazard would deter me from recommending it.
 
Jim McShane said:
You can buy an inexpensive OPT for less than you would normally spend for a new ignition coil (junkyard parts are cheaper obviously).

So the rationale for using the ignition coil has pretty much gone away, and the high voltage on the speaker leads hazard would deter me from recommending it.


It is easy to re-arrange the connections to the coil !!

Andy
 
poynton said:
It is easy to re-arrange the connections to the coil !!

Andy

But it is not possible to isolate the "primary" and "secondary" windings like a real OPT does, and if you are going to redesign the circuit you might as well eliminate the coil/autoformer anyway.

You can buy a real OPT for under $20 US, and a coil will as much or more unless you can get one from a junkyard.
 
I once built that circuit.....as an amplifier to take with me to the beach....

I used a 6V battery(for scooters) which used a solid state 'vibrator' to get the high voltage.

The ignition coil was from an old opel kadett (european car)

It would work for about 3-5 hours on one battery.
Sound level was about the same as those little i-pod/walkman speakers.

sound quality was reasonable, not good....

In my opinion it is just a gimmick....
 
SE cathode follower

Sal Brisindi said:
Hmmm,
I wonder how this would sound....

http://www.allaboutcircuits.com/vol_6/chpt_5/19.html

Regards,
Sal

Hmm... Looks dangerous.
05307.png


Instead what he did he could have tried SE cathode follower. Then he would have had safe DC level at the output. It would look something like this:
SE_CF_Amp.png

Image source: http://www.tubecad.com/2005/June/blog0048.htm

Since he couldn't do that with a single tube, he chose to do what he could with one tube. That is allright as an experiment, but better not to make a product of it.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.