Hi, Gang,
Does anyone know how many turns of what gauge wire on what diameter L1 is? All I know is that it's wrapped on a 1 ohm, 5 watt res, and that doesn't tell me much. A photo of L1/R27 should be enough.
Thank you!
Frank
Does anyone know how many turns of what gauge wire on what diameter L1 is? All I know is that it's wrapped on a 1 ohm, 5 watt res, and that doesn't tell me much. A photo of L1/R27 should be enough.
Thank you!
Frank
I have the schematic from audiokarma but not picture. It is a standard RF blocking inductor placed near the output.
Most of those are 11 to 14 turns on a 1 cm diameter form. AA battery (removed) or china marker or 1st grade pencil or 3/8" wood dowel. 23 turns would not be excessive but a lot of work. Use fatter wire, this carries speaker current and 26 ga would be too small. Solid core holds the wind better.
I had an Allen S100 amp picking up AM radio after I removed the turn off thump relay that kept blocking sound due to oxidized contacts. I put 11 turns 22 ga wire around a 10 ohm wirewound resistor soldered parallel the resistor. Mounted it off the output jack in the amp chassis by a tie wrap with a screw hole in it. Problem solved. Closer you put the output inductor to the output jack, shorter the antenna is to transmit RF to the sensitive gain transistors.
My dynakit St120 has 11 turns 22 ga stranded wire wound around the 2" diameter output cap. It is about 3" from the output jack. It doesn't pick up AM radio. When I replaced the output cap with one 1" in diameter, the coil lay there on the bottom and still blocked AM radio.
Peavey 400 w/ch amps use 16 ga solid core wire.
Most of those are 11 to 14 turns on a 1 cm diameter form. AA battery (removed) or china marker or 1st grade pencil or 3/8" wood dowel. 23 turns would not be excessive but a lot of work. Use fatter wire, this carries speaker current and 26 ga would be too small. Solid core holds the wind better.
I had an Allen S100 amp picking up AM radio after I removed the turn off thump relay that kept blocking sound due to oxidized contacts. I put 11 turns 22 ga wire around a 10 ohm wirewound resistor soldered parallel the resistor. Mounted it off the output jack in the amp chassis by a tie wrap with a screw hole in it. Problem solved. Closer you put the output inductor to the output jack, shorter the antenna is to transmit RF to the sensitive gain transistors.
My dynakit St120 has 11 turns 22 ga stranded wire wound around the 2" diameter output cap. It is about 3" from the output jack. It doesn't pick up AM radio. When I replaced the output cap with one 1" in diameter, the coil lay there on the bottom and still blocked AM radio.
Peavey 400 w/ch amps use 16 ga solid core wire.
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Yeah, I have the schematic and a friend just took a photo and measured his board with calipers. He measures the magnet wire to have 0.034" dia, the overall wire / resistor is 0.365" in diameter and the length is 0.876" - these seem internally consistent. Keep in mind the choke is in series with a 1 ohm, 5 watt resistor that doubles as the form for winding, so I'm not worried about current handling. What I'm hearing is this isn't critical but some inductance is required.
OK - the Allen S100 is a 100 watt amp, and this picture of the amp makes it seem that the coil is in the same ballpark, thank you!
https://images.reverb.com/image/upl...,t_large/v1536025254/eeviaaubmiujwdc9nr78.jpg
https://images.reverb.com/image/upl...,t_large/v1536025254/eeviaaubmiujwdc9nr78.jpg
In parallel with the 1 ohm resistor. Most other manufacturers use a 3 ohm to 10 ohm resistor, so the inductor does handle significant current. Reason it is 22 ga on 60-100 watt amps and 16 ga on 400 W amps.
No, millihenries are not critical at all.