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When the EL-509 became one of the last easy to access sweep tube replacements, I changed sockets on everything from Yaesu 101's (not easy at all) to Andy Anderson 10 tubers. I even put that ceramic Magnoval socket in D&A amplifiers that already had 9 pin sockets. One day I got tired of changing...

Move the 4 big drivers into the final stage, use two of the smaller tubes as drivers, align the tank circuits for resonance again and call it a day.

Was just watching a movie streaming on Hulu that had a conversation going on inside, when a car crashed through the building. The car crash was 20 db above the conversation level. That's 100 times louder! I hit rewind to check it twice, the output on the Behringer went up less than 3 db, when...

This goes well beyond the effects of compression, raising the average volume level today. If that were the case, it would not be leaving 6 db peak excursions, to remove when the commercials come on. Compression doesn't leave noticeable peaks like this behind. It would appear that the transition...

When there is significant background noise, compression just adds to the problem by boosting it even more. At that point you are better off relying on the peak limiter and using very little, if any compression to control the program volume.

That's exactly what I was looking at before I found the Behringer at the same price and brand new in the box. Line level output is appropriate for driving an amplified computer speaker. You would only need a preamp if you were trying to feed it with a microphone level.

You can use line level compressor limiters with amplified computer speakers.

Have you noticed how they have been lowering the TV program volume so they can blast you with commercials or action scenes in a movie? I've connected a Bluetooth receiver to my home entertainment system so that I could cast the TV audio over higher quality speakers and just ended up getting...

We should also consider that if the addition of negative feedback does present a condition where the input impedance has also shifted by a factor of 3 to 1, this is likely revealing a clue that a self oscillation was present, prior to the addition of negative feedback. Self oscillations don't...

I honestly have never seen a case where adding negative feedback to a bipolar amplifier caused an input impedance to shift by a factor of 3 to 1. That means we've pulled the input impedance all the way down to 16.5 ohms. Whatever changes in input impedance occur, should be easily compensated by...

You are experiencing what's called self oscillation of the amplifier. Where it will begin to operate as an oscillator and produce a second output on another frequency that has a higher reflected power. When the oscillation is strong enough, it will sustain enough RF to keep the keying relay...

The positions they are shown in your picture, are perfect. Just leave them set where they are, there is no additional performance to extract here. Where they are set, is not as important as being set in equal positions, in order to provide symmetrical operation.

Those inductors are part of the negative feedback. Their purpose is to help stabilize the amplifier gain, across multiple bands of HF operation. They provide more negative feedback as frequency decreaes. This lowers gain, to offset the characteristic increase in transistor gain, accompanied with...

This is a good circuit. I see you have the base-emitter junction bypassed with a .01 capacitor, which effectively RF bypasses the diodes as well. I would not expect this circuit to have the ability to introduce any harmonics. Nice job. Heavy duty too.

I understand that, that's why I figured this baby is for the largest tubes ever made. Unless there is another application I'm overlooking.

Since amplifiers that can produce a carrier of 500 KW only operate with 16 KV on the anode, what in the world was the original application for this capacitor?

I thought the same thing. For mono band amps I was using a five picofarad cap driving a Darlington pair. That reactance works out to be approximately 1,200 ohms. Not too much smaller than the 2.2 k resistor used on the barefoot example. Just curious, are you using the voltage drop across the...

I made the same assumption for years and am embarrassed to admit how wrong I was, by copying an RF sensing circuit that did not use a bypass cap directly across the RF diode. When I purchased one of those small, $150 spectrum analyzers, I was shocked. In my case, the largest harmonic content by...

How about the ones that don't bypass the diode, rectify RF and inject tons of harmonics at the input of the amplifier?

Do you know if they use the same transformer? If not, I wonder if the B+ sags more under load. Just a bit more internal resistance on the windings, could be the difference. I've never seen a 350Z, that could impress a 300A owner either. To take it one step further, customers were mad at the...