Description

Here is an item I never considered as a product. But I got a request, so here it is. You're buying four of this item in one sale. Each one has a 3/8-inch spring clip for the tube's plate cap. No I don't have the smaller quarter-inch clips. Most tubes that have the smaller cap also have a "shoulder", a 3/8-inch rim against the glass at the base of the thinner cap. We simply attach the larger clip you see here to that part of the quarter-inch cap. So long as it's not a mobile amplifier, this works fine for us. A so-called "parasitic choke" is more properly a "parasitic-suppression" choke coil. It serves as an obstacle to frequencies way above the ones that you WANT to amplify. Yes, that's an oversimplification. Just the same, some amplifiers are stable and won't oscillate even if you leave this component out of the design. But that's playing russian roulette. You might win, you might lose. These parts are included in every commercially-designed tube-type RF power amplifier. This makes the way it works MORE predictable. Unless it's a Palomar 300A. People look at the bare wire that connects the four final tubes' plate caps to that big RF choke in the center of the four tubes. It wasn't just a bare wire when it left the Palomar factory. There was a tiny ceramic "ferrite" bead slid over each of those four wires. Just one problem. The bead would overheat, crack and fall off. When it's gone, nobody misses it. We learned the hard way to install a proper parasitic choke, like these, one on each of the four final plate caps. Most of the time, your amplifier will oscillate without this part between the plate cap and the plate choke. And sometimes it won't. Russian roulette. Not gonna discuss why these beads don't fall off of the plate wires on the two driver tubes. Inductance measures around 0.08 uH more or less. ALL PICTURES ARE REPRESENTATIVE. THEY ARE HAND WOUND AND WILL ALWAYS EXHIBIT SOME MINOR VISIBLE VARIATIONS. Naturally you can buy resistors, wire and wind your own. Would be a LOT cheaper, but I got asked, and here they are. NO RETURNS FOR ANY REASON NO MATTER HOW GOOD IT SOUNDS. If you don't plan to keep it, just don't buy it. Seems simple. We ship no later than the second business day following receipt of cleared payment. I prefer USPS Ground Advantage. It's been VERY reliable and comes with tracking. I will insure it for the final sale price. IF YOU PREFER A DIFFERENT **USA ONLY** SHIPPING METHOD, CONTACT ME **BEFORE** YOU PAY! I will prepare a quote for the method you specify and send you an invoice for the corrected amount. This option is available to USA destinations ONLY! !!!! NOTE !!!! Shipping to destinations outside the US are by the Ebay GSP or Global Shipping Program. How much that will cost you is anybody's guess. Ask Ebay if you want to know. Maybe they'll tell you. They won't tell me. Maybe they should rename the "GSP" the "Global Secret Program". GSP ONLY!! GSP ONLY!! GSP ONLY!! No, I will NOT ship direct if you are outside the USA and its colonies. GSP ONLY!! GSP ONLY!! GSP ONLY!! If you know what it is and what it's for, you can decide if you want or need it. And if you don't know what it is, you probably don't need it. Trust me on this. All routine Ebay precautions apply. Scammers take your nonsense elsewhere. Please. Thanks for looking and happy bidding!