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www.tubecad.com Copyright © 2001 GlassWare All Rights Reserved |
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<< March 2001 ^^ TUBE CAD JOURNAL ^^ Volume 3 Number 2 >> |
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Pg. |
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Your Volume Control |
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Low Noise · 24 Position Stepped Attenuator Precision Control · Long Lasting Contacts 10K - 25K - 50K - 100K - 250K |
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makes a difference. |
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Arn Roatcap, Inc. 1248 Valerian Court #4 Phone: (408) 737-3920 Sunnyvale, CA 94086-9155 E-mail: info@goldpt.com |
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The complete circuit is shown below. The idle current for the first stage is only 3.5 mA. While I usually would use more current, the aim was to limit current consumption to extend battery life. The output stage idle current is set at 10 mA, which implies a peak output current of 20 mA. This equals 60 mW into a 300 ohm load and only 6.4 mW into a 32 ohms load. |
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In other words, this push-pull amplifier is better suited to higher impedance headphones because of the current limit. How could the peak output current be increased? Another triode might give a higher idle current, but unless its rp is substantially lower that the 6922's, it to will run in into the Ipk = B+ / 2(Rl + rp) current limit. The B+ can be increased by adding more DC-to-DC converters, but at the cost of |
