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The Making of a DeForest Triode -- YouTube Video
The making of a DeForest triode in 2006 http://www.youtube.com/watch?v=8_eLO0exato Steve (((WG7K))) Tucson, AZ --------------------------------- Want to start your own business? Learn how on Yahoo!
By Steve Cook <vaj4378@...> · #1757 ·
Re: 4CX1500A
All boat anchors here. Either a Hallicrafters HT-32B or Johnson Invader 200 will be used. David
By David C. Hallam <dhallam@...> · #1756 ·
Re: 4CX1500A
What kind of exciter are you using? Jim SM2EKM ------------- David C. Hallam wrote:
By Jan Erik Holm SM2EKM · #1755 ·
Re: 4CX1500A
Rich, In regard to your suggestions of increasing the screen voltage to 750V or turning down the drive, these are my problems. 1. The screen, bias, and HV supplies are already built. The screen supply
By David C. Hallam <dhallam@...> · #1754 ·
Re: 4CX1500A
Correct, but since it takes 170v peak RF V to drive the grid from ¨C 170v up to 0v, the higher the grid terminating R, the leas RF power will be needed to reach 0v. It takes +105v-pk of RF drive to
By R L Measures · #1753 ·
Re: VE7RF amp
Ditto Jan, Couldn't agree more! And he takes nice, detailed pictures too! Merry Christmas & Happy New Year to you and to all!! Garry - WR4R Jan Erik Holm wrote:
By Garry <g.drummond@...> · #1752 ·
Re: 4CX1500A
I would really like to keep the exciter looking at 50 ohm so the amp could be switched in and out without retuning. David
By David C. Hallam <dhallam@...> · #1751 ·
Re: 4CX1500A
Use ALC that would control exciter power. BOB DD Sent From Mobile Device
By "Robert B. Bonner <rbonner@...> · #1750 ·
Re: 4CX1500A
Rich, So what you are saying is that it really doesn't matter from the tube's input impedance stand point what value of resistor I use. I am running 3KV on the anode and 550V on the screen. According
By David C. Hallam <dhallam@...> · #1749 ·
Re: 4CX1500A
D. -- The resistive component of the grid input Z is well over 1,000,000-ohms in AB1, and the reactive component is 78pF. With 750V on the screen, it takes c. ¨C170 grid V to establish a ZSAC of
By R L Measures · #1748 ·
4CX1500A
Does anyone have information as to the approximate input impedance of a 4CX1500A for the proper value of a passive grid resistor for this tube? I need about 100 ohm to get sufficient grid drive, i.e.,
By David C. Hallam <dhallam@...> · #1747 ·
Re: Tube rebuilder
Well, Santa brought me an $800 xmas present... I removed the HV lead from the 3CX1200D7 and cooked the filament at 7.26 volts for 6 minutes... Eimac had suggested 7.5 volts for 5 minutes but 7.26 was
By ad4hk2004 <ad4hk2004@...> · #1746 ·
VE7RF amp
Since I have forgot/lost my Yahoo password/ID and the lot for my ordinary email address I havent been able to sign in and view the pictures. Finaly I signed in with a new Yahoo ID and it was nice to
By Jan Erik Holm SM2EKM · #1745 ·
Re: Tube rebuilder
I know what I paid for my 3KU brand new... When I look at the quality of the materials, the hand made switching solenoids in the tank circuit, the silver plated 1/4" tubing roller inductor the size of
By ad4hk2004 <ad4hk2004@...> · #1744 ·
Re: Tube rebuilder
A broadband input plus g-g tells me that th
By R L Measures · #1743 ·
Re: Tube heater current
Well, today I measured the Penta 6JB6 heater current, which resulted 1.5A. or 25% more than data sheet stated (1.2A). The rig is working with two Pentas (120 watts out), and I added some resistance to
By GGLL <nagato@...> · #1742 ·
Re: Tube rebuilder
wrote: long impedence Pi- ### where have u been ? yes... it's GG. Now u know why I collect amplifier manuals.
By pentalab <jim.thomson@...> · #1741 ·
Re: Heatsink relationship
Bill it all has a lot to do with CONDUCTIVITY and stability. Whether it is electrical or thermal conduction. Copper has a large availability of free electrons. The molecules freely exchange them.
By Robert B. Bonner <rbonner@...> · #1740 ·
Re: Tube heater current
<rbonner@...> wrote: KWM-380 F'enheimer are ### The TR-7 wsn't too bad. The KWM-380 was pure junk imo. The mating outboard processor for the 380 never did work right. Funny thing though... in the QST
By pentalab <jim.thomson@...> · #1739 ·
Re: Tube heater current
Hey Gary, Heading out the door on the way to grad school. The TR-7 showed up on the doorstep, right about the same time the KWM-380 showed up on the doorstep we tested both and said, what the
By Robert B. Bonner <rbonner@...> · #1738 ·