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Measured Voltage results of Alpha 9500 key down testing. AC Mains Voltage at Amplifier switch box. 142 VAC Amp on at Standby. 239.6 VAC Amp at 1.3 KW into Dummy load Filament Voltage 5.3 VAC at

Hey Dave, If your amp has been operating "normally" for a length of time (i.e., with apparently normal/full output) and only recently started showing signs of decreased power, then it's probably a

And a "soft" tube acts as a soft fuse. W4DNR

I bought one off of Ebay once for about $30. The seller claimed it had low output. It didn’t matter to me because at the time I was contemplating building an amp with one of them. My elmer Eric,

The duds could be eye candy for one's shack.? Maybe put them on QRZ, etc. Andy? K9ATX

I am still testing 8877s here. Two or three every day. They warm up with filament only for 4 hours before HV. What I have learned is that 8877's drawing 15 amps of filament current are bad tubes.

Yes, when shop/shack was constructed, I specified the wiring as #10 and multiple 240 outlets each on separate breakers (according to code) and over saw the construction and wiring. I know if it was

Hi Dave. My question is about your AC mains supply. Is it up to the task? Section 3.2 and table 3-1 talk about what you can expect from different mains supplies. Also, I looked in the manual to see

I’ll do that this afternoon. 73, Dave, w6de Sent: 15 October, 2023 02:04 To: [email protected] Subject: Re: [ham-amplifiers] Symptom(s) for a fading 8877 tube? No need to "side-line" your

I may just do that after I test my spare tube. 73, Dave, w6de

Plan B: The few extra hundred watts really doesn't make much difference. Just use that tube until it doesn't......

No need to "side-line" your amp... just throw that spare 8877 in and run it! Also, being that the 8877 (3CX1500A7) is a ceramic tube, there's no need to "cook" it in or do any sort of "degassing", or

Good point, if the cathode emission is down, there aren’t enough electrons being ejected from the cathode to make the higher power levels. Time to switch tubes. Since this amplifier case is

I have an Alpha 9500 and I find it difficult to get 1500 Watts out of the current Thompson 8877--age unknown. The symptom is: I can easily get 1,000 to 1,100 Watts out of the amplifier but continuing

These tubes have been sold. I am sorry I could not provide them to all who asked, but the first respondent got all three. Thanks & 73 – Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ

But it seems to work well!

Where I used to work we referred to Kroil as ‘weasel piss’ and ‘millwright’s aftershave’! Mod-U-Lator, Mike(y)/W3SLK Sent: Thursday, October 12, 2023 4:50 PM To:

Well, I pulled out one of my blunt-needle syringes that I use for applying really small amounts of stuff, and hit both bearings of the air variable with a drop of Kroil, “The oil that creeps.”

Hi Don, That's exactly what Lt.Cmdr (Ret.) MSRN Atilla the Hun advises me from time-to-time. Hal

Hi Tim, What a great idea for proofing performance on 8877's. These things are carbonized in production with burning acetylene gas. I'm sure there is a controlled process combined with high