JT-11P-1 Conversion of Unbalanced Input to Balanced.
JT-DB-E Full-featured Direct Box Application Schematic.
JT-MB-C Real Mic Inputs and Phantom Power for Sony DAT.
The S3FM is simply a 3.5-inch tube fitted with a male XLR at one end and a female at the other, with enough room in the middle to build a mike pad, low-end rolloff network, polarity reverser, or any number of other useful little gadgets.
This circuit will only work with a MOSFET type opamp, bipolar types i.e. 741 and J-FET opamps such as LF351 will not work in this circuit.
At some stage, we will all find ourselves pushing hi-fi equipment just a little too hard, and if lucky, will just find that the sound has become dirty. If this happens too often or is too severe, tweeters are the first to go - they are damaged by the excessive power generated by a combination of power compression and the harmonics created when an amplifier clips.
This circuit was invented by Dr. Horst Ludwig from Germany and published in September 1992 in Stereoplay, a German Hifi magazine.
I was looking at all my junk that I have collected throughout the last couple of years and I thought, Wow I have just enough parts hanging around to make some kind of a small amp for my son. I was going to possibly make a solid state one but I was happy to see that I had the stuff to make a small tube amp.
When your monster (or not so monster) power amplifier is switched on, the initial current drawn from the mains is many times that even at full power.
In many areas of the world, keeping an amplifier cool is no big deal, because of generally low average temperatures. In Sydney (Australia), we can guarantee at least a few days every year when the temperature will be over 40 degrees C, and we are not alone in this. With Global Warming, we might all have the same problem in a few years.