Description: Here is a replacement for the final-stage plate choke used in the Palomar 300A base linear amplifier. It's a faithful copy of the original part, but with one big difference. IT HAS PARASITIC-SUPPRESSION CHOKES INSTALLED ON IT! Yes, I was shouting. The factory installed a tiny black ferrite bead on each of the four bare wires that each connect to the plate cap of one final tube. These beads overheat, crack and fall off never to be seen again. Usually around 45 or more years ago. If your amplifier is stable and behaves itself with just those four bare wires, then give a moment's thanks for your good fortune. Those four chokes are not always necessary, but if you change those four tubes you may find the new ones are not as stable as the previous set. These chokes are installed to prevent problems, even though a tube from any one factory may behave just fine without them. Including these chokes in the design simply improves your odds of having a stable amplifier. The conventional parasitic choke you see on this item, one for each final tube is what nearly everyone else in the industry used. For that matter, the two driver tubes in the 300A usually each have a conventional parasitic choke on each tube installed at the factory. Go figure. The big ceramic choke almost never goes bad, so there's not a lot of demand for it, but the four parasitic chokes are already installed on this one. Simply replacing the big RF choke with this one would save labor, compared to hand-winding four parasitic suppressors and soldering them to the big choke and each spring clip. About those spring clips. They fit a 3/8-inch diamter cap. Some tubes used in the 300A have a quarter-inch diameter cap. As a rule, these caps will have a 3/8-inch diameter base that these clips will clip onto. Should be no need to remove these spring clips and substitute the smaller spring clip meant for the smaller cap. There is a small ceramic-disc cap included to bypass the wire that connects the high voltage to the big lug at the bottom of the big choke. Too easy to damage the old one while changing out this part. If the labor this would save you pays for the cost of buying it, that's great. And if you would rather hand-wind four parasitic chokes and install them in place of four bare wires, then go for it! THE PICTURES ARE REPRESENTATIVE! The color of the bypass disc cap we provide may be different, and the color of the resistors used to make the parasitic chokes may be different. We buy those parts from a variety of sources. 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. 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!
Price: 61.99 USD
Location: Louisville, Kentucky
End Time: 2025-01-14T03:24:01.000Z
Shipping Cost: 0 USD
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Item Specifics
All returns accepted: ReturnsNotAccepted
Brand: Palomar
Type: replacement part
Model: 300A
Band: HF
Power: 300 W
