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Title: it's starting to look like a speech amp / modulator Post by: N3DRB The Derb on October 17, 2009, 02:30:52 AM needs some more wiring, 2 4 pin sockets, the front panel put on, some 2/6A3's, and a suitable PS.
PS will be under construction next. BTW the tubes are Hytron HY40's, kinda a rare bird. they want anywhere from 700 to 1000 jolts on the plate, around -28~33 on the grid and 7.5 on the fil. at the lower plate voltage they are a good match for the S21. I would not want to try to run a hi voltage tube set on that xfmr. insulation rating not hi enough. Title: Re: it's starting to look like a speech amp / modulator Post by: N4LTA on October 17, 2009, 09:06:02 AM Derb,
You're getting ahead of me, but I am going to catch up this rainy cold weekend. It looks nice. Pat N4LTA Title: Re: it's starting to look like a speech amp / modulator Post by: ka3zlr on October 17, 2009, 10:05:45 AM Looks good from this angle... :)
Title: Re: it's starting to look like a speech amp / modulator Post by: KB5MD on October 17, 2009, 10:52:44 AM Derb, I always enjoy your project reports and pics. Keep em coming. ;D
Title: Re: it's starting to look like a speech amp / modulator Post by: N3DRB The Derb on October 17, 2009, 02:36:26 PM Quote You're getting ahead of me, but I am going to catch up this rainy cold weekend. you might, but only because I'm missing some parts & tubes. :D Otherwise, no way. As long as my left hand holds out I'm good to go. That is a big if, tho. I gotta hit the RF deck again. put in the bypasses, fil wiring, I think I'll do that today and tomorrow. I got a NIB TU 6B tuning unit from a BC 375 to rape for it's fine ceramic coils and switches. sorry you mil guys another one gonna bite it. 8) heres the datasheet for the HY40. looks like a really good match to the S21. At 700 volts I wont worry about the transformer too much. Title: Re: it's starting to look like a speech amp / modulator Post by: KC4VWU on October 17, 2009, 03:11:52 PM Lookin' good Derb!
Title: Re: it's starting to look like a speech amp / modulator Post by: N4LTA on October 17, 2009, 05:54:16 PM I'm building the Screen, Bias and Modulator power supply deck. I punched six 11/16" holes for all the pilot lamps through the steel chassis and the 1/8" aluminum rack panel plus two 1/2" ones for the switches.
That ain't easy even with the Greenlee punches. I might have something to show later Sunday. You are definately getting ahead of me. Pat N4LTA Title: Re: it's starting to look like a speech amp / modulator Post by: W1DAN on October 17, 2009, 06:20:44 PM Saweet!
The StrapMaster! Dan Title: Re: it's starting to look like a speech amp / modulator Post by: KB2WIG on October 17, 2009, 07:10:18 PM A thing of beauty is a joy for ever.
klc Title: Re: it's starting to look like a speech amp / modulator Post by: N3DRB The Derb on October 17, 2009, 08:21:46 PM soon as you get it post it. I slept a lot of the day due to the crummy wx. Wifey is sleeping. looks like a good time to build.
Title: Re: it's starting to look like a speech amp / modulator Post by: WA1GFZ on October 17, 2009, 09:09:13 PM Derb, I think Fair radio still sells the switches.
We saw the world's worst looking 4-1000A final today. Title: Re: it's starting to look like a speech amp / modulator Post by: N3DRB The Derb on October 17, 2009, 09:37:23 PM did you take a pic? I love to see fugly construction work.
Title: Re: it's starting to look like a speech amp / modulator Post by: N3WWL on October 17, 2009, 10:54:56 PM the BJB of WVa is back in black (crackle) ;D
Title: Re: it's starting to look like a speech amp / modulator Post by: N3DRB The Derb on October 18, 2009, 03:52:06 AM not yet, but I'm trying to make up for lost time n misplaced priorities. Lotsa peeps helping.
Title: Re: it's starting to look like a speech amp / modulator Post by: N4LTA on October 18, 2009, 06:11:43 PM Here's a few shot of my work this weekend.
Now I have to wire it. I have a bias supply, a variable screen supply with a variac, and the modulator supply and some 12 Volt Dc control relays for the plate voltage sense and grid trip. The screen must have plate voltage before it can turn on. Here is the top view with the modulator power transformer and choke removed - The choke will sit on the red insulators. (http://i620.photobucket.com/albums/tt286/n4lta/top.jpg) Here is the bottom view with the boards mounted (http://i620.photobucket.com/albums/tt286/n4lta/bottom2.jpg) Here is the front view with the screen voltage and current meters. (http://i620.photobucket.com/albums/tt286/n4lta/Front.jpg) Hope to start wiring it tonight. Pat N4LTA Title: Re: it's starting to look like a speech amp / modulator Post by: N3DRB The Derb on October 18, 2009, 10:26:46 PM very nice! nice choice using glastics for the choke standoffs. cant get any better.
Title: Re: it's starting to look like a speech amp / modulator Post by: N4LTA on October 19, 2009, 08:45:48 AM They are cheap and made for the power and lightning protection industry. About $2 each but you have to buy 10. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
The Hammond Choke is rated at 1000 volt and the plate voltage is about 1200. http://www.stormcopper.com Pat N4LTA |