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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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18th Jun 2018, 10:25 pm | #1 |
Pentode
Join Date: Apr 2016
Location: Southampton, Hampshire, UK.
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How do you feed a signal into an HF43 MK2/3 amplifier?
Sorry another newbie question, but how do you feed a signal into an HF43 MK2/3 amplifier?
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18th Jun 2018, 10:50 pm | #2 |
Moderator
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Re: How do you feed a signal into an HF43 MK2/3 amplifier?
Presumably a Fidelity HF43?
What signal sources do you have?
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
18th Jun 2018, 11:17 pm | #3 |
Dekatron
Join Date: Aug 2006
Location: Madrid, Spain / Wirral, UK
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Re: How do you feed a signal into an HF43 MK2/3 amplifier?
Easiest would be to add a DPDT switch before the volume control. One position for the deck cart and one for the proposed line in. Might be worth adding a series resistor to the line in for attenuation, as it will probably be a bit more signal than that coming from the X5M or whatever medium output cart is fitted.
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19th Jun 2018, 10:28 am | #4 |
Pentode
Join Date: Apr 2016
Location: Southampton, Hampshire, UK.
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Re: How do you feed a signal into an HF43 MK2/3 amplifier?
i just wanted to test the amp before plugging into the mains really and wondered if there was a way of doing this.
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19th Jun 2018, 10:47 am | #5 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
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Re: How do you feed a signal into an HF43 MK2/3 amplifier?
Well I'm afraid you can't really. The amplfier needs to be powered up before you can fully test it under the correct operting voltages. It's a 1973/4 transistor amp which has a mains voltage down to c.20V power supply, so I can't see what harm can be done. Without this, it means you need to passively test each component for values against a circuit diagram.
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Edward. |
19th Jun 2018, 10:50 am | #6 |
Dekatron
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Re: How do you feed a signal into an HF43 MK2/3 amplifier?
Feeding in a signal with no power applied won't tell you a lot.
Lawrence. |
19th Jun 2018, 1:31 pm | #7 |
Dekatron
Join Date: Aug 2006
Location: Madrid, Spain / Wirral, UK
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Re: How do you feed a signal into an HF43 MK2/3 amplifier?
I was thinking the OP just wanted to be able to connect external devices like a phone or mp3 player through the record player's amp. My mistake! As said above, I would just go ahead and plug in. If you suspect there might be a short, just be ready to pull the plug if any distress or smoke is noted.
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19th Jun 2018, 7:11 pm | #8 |
Pentode
Join Date: Apr 2016
Location: Southampton, Hampshire, UK.
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Re: How do you feed a signal into an HF43 MK2/3 amplifier?
like that
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