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I never understood why most DC people carry tons of batteries and keep that constant charging current, cooking the alternator. I've run up to 21 Toshiba's on one Leece Neville, without a single battery connected. All it took was a couple of electrolytic caps in parallel, to get close to a Farade...

It appears that transformer has been operated above its maximum altitude of 12,000 feet... I'm assuming this amplifier runs sweep tubes and 900 to 1,000 volts AC before rectification and filtering, seems very high for sweep tubes. As I recall the D&A transformers are 660 volts AC. They work...

I had excellent results with a 6,000 as a base. Although, I've heard from one questionable source that they may not hold up as well in Mobile use as a result of vibrations. I've also seen one that had a migrating grid wire problem. A brief conversation with the car battery and jumper cables...

You are correct. The unloaded plate voltage will typically be much higher than the loaded plate voltage. You want to bring the RPMs up, only after the load is applied. The most critical part is when you unkey and remove the load. You want to be off of the throttle before you unkey the microphone...

That sucks. Although, unless the vacuum seal was compromised and burned the filiment open, many times this is just a cold solder joint on one of the tubes two filiment pins. Mechanical shock can also be a culprit for developing cracks in filiment wires. I once dropped a 8877. It still worked...

This particular phasing harness was made from LMR 600 and had no connectors on the ends. The ends passed through a grounded metal plate with with the braids bonded to that and the center conductor with its insulation extending to the other side to have both elements of the T match directly...

Things to keep in mind. That 30 watts is 50% of the drive that the six finals require, and it's arriving at the two drivers. I assure you the drivers have a power gain that's higher than two. 15 watts feeding the drivers should be more than enough. If it were me and I really wanted to run this...

As long as you understand the potential for overdrive exists and you avoid that, you shouldn't have any problems.

Six 2SC2879s have a maximum peak drive capacity of 60 watts. Two 2SC2290s can easily hit them with more than double that amount. At these drive levels, you may not actually burn the transistor up however, you will begin to scrub gain off of the parts. In other words a transistor that starts off...

Is this an appropriate place to cry about blowing up the 180° phasing cable on your Yagi's T match? It turns out sealing the ends of this cable with silicone, was appropriate for 12 years, but not 13! Corrosion between the Silicon and the aluminum or copper metals, caused this seal to fail over...

Generally speaking, two driving six is just enough to get you in trouble. Plenty of drive to place the final stage into gain compression and clipped peaks. One of the best driver stages for 6 finals, is a single ended, tuned LC circuit, with a resonant input and output. One of the most common...

If you're using it on sideband, bias settings are critical.

I wonder if 40 channels had something to do with the demise of Tram? They did in fact change the channel selector board to 40 Channels with more crystals however, that only lasted for about a year. I've actually jammed the 40 channel D201A board, into a rat's nest vox D201. I think I recall...

I like the way you reduce inductance by using the relay's common pole wires, soldered directly to the so239 connectors. That improves impedance.

When it comes to desoldering braid, it's all about how much flux is in the braid, and how old and oxidized the braid has become. Poor quality braid, becomes very usable with the addition of quality flux in liquid form. I've actually been using the braid out of RG-174 coax and adding my own flux...

Is anyone familiar with a standalone Bluetooth receiver that has the slightest ability to put out anything similar to a line level output? I've tried several and they seem to struggle to hit 200 millivolts of output and fail miserably at driving any type of line level equipment.

On another note, I have one Cetron 572B that was pulled out of an FL-2100 and never had its anode cap correctly soldered. It's essentially brand new while it's neighbor suffered a very punishing life doing the work of two tubes. Anytime I've tried to get it to play nicely with a partner, it's...

What you describe is mostly seen with the 811A tube and happens even when vertically mounted. Although, to a lesser degree. Especially when used in modes with a sustained carrier. It's pretty hard for a real graphite anode on a 572B, to melt. Having said that, I've seen counterfeit 572Bs that...

Carefully scrape the anode wire clean so solder will stick, extend it if needed to reach through the solder hole in the cap and resolder it. If you have to extend the wire, use a small enough wire so that it easily wraps around the existing one. Otherwise it may come unsoldered when resoldering...

I wonder what the waveform looks like at twice that frequency? The FQP13N10 was the fastest inexpensive transistor I can find on Mouser. It has a turn on time of five nanoseconds and a gate charge of 12 nC. There are many other options approaching half this speed. The interesting thing was, as...