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Hey Chuck. Have not had a QSO is a long time. Where are you hanging out these days on AM? W7WRX ________________________________ Sent: Tuesday, February 4, 2025 9:38 AM To: [email protected]

Grid drive one 4-400 with bias and screen voltage. Then you can run Class C for plate modulation and bias it for AB1 or AB2 operation for SSB amplifier mode. A Johnson ranger or similar power

Are you planning on using the modulator with this amplifier? If so a Single 4-400 will do 550 to 600 carrier and would be a good match for that 350-watt modulator for AM. It's a simple circuit.

I would sell all your tubes and buy 1? ?8877.? Just my opinion.

Don, You have some mighty fine tubes to make up a bunch of nice amplifiers. My old mentor, Eric, WA4VVI(SK) would run 4 813’s at 4KV! I have an RCA SB-1K Radiomarine amp that uses 3-400Zs

Over the years I've collected parts to build an amplifier. Life got in the way during most those years but now I find myself with the time and ambition to build an amplifier for my boatanchors. As

This one is from 1965: https://www.eham.net/reviews/view-product?id=12175 A ham I know says his ant relay is stuck, its an open frame relay he says. Probably no parts for this one around

The timeline for submission of papers and presentations has been extended to March 17th.

Removed the tube sub-chassis, and have it soaking in the Fan-monia bucket.... its really got a lot of buildup as the blower was throwing it all right in there. I got a new blower from ACOM recently,

The 3-500zg tube with the graphite plate can handle 600ma ICAS ? The regular 3-500 rated 450ma CCS! ?With enough cooling (very important factor) you could run 2000 watts pep output SSB with a pair

The original? C41 cap (47 pf) is failure prone.? ?Replace it with a 50 pf TX doorknob cap.? ?The original cap? was made from pc board. C42? ( 307 pf)? is used to pad the TUNE cap on 160m

The 3 x section choke,? currently sold by ameritron,? is now screwed up.? Ameritron ran outa 28 ga wire...and started using 27 ga wire.? ?The pair of gaps is way less.? Steve at RF parts got a

Hello Thank you for this communication. Even if it does not answer my question, this document is very interesting, both at the technological and implementation level. I reformulate my

Dear Riki, Tom, W8JI,

Dear Francois, Attached, please find a great book about tubed amplifiers. '73, Hal Mandel W4HBM

I am still studying a way to cook my 3-500Z which have not been hot for at least 15 years. The idea is to cook at high current with a low anode voltage, without HF. The maximum rating of the

Yes, a “single diode path” would have made it clearer. Thanks for the clarification. What I understood is that these diodes are used to protect the galvanometers in the event of an arc in the

Hi Riki I own a 1990 HF-2500 which I got from the estate of a local ham many years ago. I had a question about it on this forum last week but through perseverance and much hair pulling, I managed to

Somebody who previously owned my Commander HF-2500 replaced the carbon resistors in the plate parasitic chokes with a different type of resistor.? This worked fine on low frequencies 160M, 80M, and

Yes, a “single diode path” would have made it clearer. Here more then 0.7V are clamped, depends on the meter or meter shunt for grid current. Zener diode can be used as well or a germanium