Recent content by Y2KEDDIE

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    Need help understanding 70.7 Volt Line Audio

    Got it! Thanks
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    Need help understanding 70.7 Volt Line Audio

    I’ve been watching a few you-tube videos on impedance matching (mostly tube circuits) and allowed my self to be confused by the emphasis on matching; selection of output transformers. I know matching is required for maximum power transfer. In RF there are standing waves/reflections to be...
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    Need help understanding 70.7 Volt Line Audio

    My goal is trying to understand the effect of the changing load as speakers are added or subtracted on the 70.7V line. Starting to grasp the concept; I’m coming to the conclusion that with a fixed, finite number of speakers and power requirement, matching load to the source is of the upmost...
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    Need help understanding 70.7 Volt Line Audio

    What happens when you connect two 10 watt (500 ohm) across the output of a 50 Watt power amp? Two, 10 Watt @500 ohms each is a 250 load , but doesn't the 50 Watt amp wants to see 100 ohms. I can see how you get 20 Watts to the speakers, but isn't there a serious mismatch...
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    Need help understanding 70.7 Volt Line Audio

    Still trying to understand 70.7V systems: I have an amplifier with output labeled 70.7 V. 50 Watt, 100 ohm. I believe the 100 ohm, is the minimum impedance the amplifier can deliver full 50 Watts power. If this is correct, and: P=5000/Z: 5W=5000/1000, 10W= 5000/500, 25W=5000/200...
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    Need help understanding 70.7 Volt Line Audio

    Duke, thanks for taking the time to reply. I’d like a little more in depth explanation. Are you saying the matching isn’t as critical as long as power limit is not exceeded? What is the impedance of a single 50 Watt transformer/speaker? 100 ohms?. Then by selecting appropriate taps, (5) 10 Watt...
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    Need help understanding 70.7 Volt Line Audio

    After reading about Low Impedance (8 Ohm) Audio Output vs.70.7 Volt systems, I still have questions. I know with an amplifier driving an 8 ohm speaker, a transformer is used to match the speaker (8 ohm) to the output impedance (load resistance) of the output stage/ driving tube or...
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    2A3/ VT4-C Amplifier Design help

    Yes,I think so. The 1200 V 500 mA power transformer, two mercury vapor rectifier tubes, and 500Ma 10Hy choke, power supply is intact .. The Stancor modulation transformer is rated at 375 watts. All the components on this chassis all have good part numbers on them. I'm sure...
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    2A3/ VT4-C Amplifier Design help

    I can not seem to upload my diagram. tried resizing, still get error message
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    2A3/ VT4-C Amplifier Design help

    This is what I have. How do I apply Bias https://webmail.spectrum.net/index.php/mail/viewmessage/getattachment/uniqueId/15479/account/0/filenameOriginal/20190819_122641_resized.jpg/filenameModified/20190819_122641_resized.jpg?folder=SU5CT1g%3D
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    2A3/ VT4-C Amplifier Design help

    It appears to be homebrew. It’s built on an old radio receiver chassis. Definitely not a commercial product. Vintage components circa 1940-50’s. I bought it at an estate sale, paired with a Johnson Invader 2000. The Invader 2000 was a Single Sideband/cw transmitter which originally came stock...
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    2A3/ VT4-C Amplifier Design help

    I want to build/rebuild and amplifier using (2) 2A3 Tubes driving (2) VT4-C Tubes. This is a rebuild of a AM Modulator, similar to an Audio Amplifier. I found this inoperative chassis , with this tube line-up, but the bias circuits are missing, and I have no schematic. The audio...
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    Need help with design

    My bad, I meant primaries in parallel, secondary in series. Yes, I could buy a tapped transformer with the exact voltages, but I want to use what I have. Yes, I’ve used Auto transformers (power-stat) in a single voltage supplies. My goal is to build a multi voltage supplies. One particular...
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    Need help with design

    Experimenting with "vintage" radio circuits I find myself in need of various high voltage supplies,typically in the range of 250 to 650 VDC. I have several industrial type transformers designed to boost 120 to 220 VAC and, 220-440 VAC, at several amps. These were used for...
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    LED TV BACKLIGHT

    The set i’m Playing with is a LG 5600.` i’ve Already determined several LED’s are shorted, and some open. I decided to scrap the set because the best option was to replace all LED’S to assure reliability;not cost effective. At this point i’m Just experimenting/learning. The LED’s are wired In...
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