Stereo amp with four 6L6-G power output tubes in each channel

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Would it be fully feasible to get about 100 watts per channel output in an amplifier of class AB type with four 6L6-G beam power tubes in each channel? Would a separate transformer and rectifier be needed for each channel, or if the power output chassis had just one transformer with dual 5V4-G rectifiers, 2 6SN7-GT phase inverters and eight 6L6-G power outputs, and another chassis had its own transformer and 5U4-G rectifier, four 6SN7-GT pre-amplifiers, one 6SK7 AM RF, 6SA7 AM Conv, 6SK7 AM IF, and 6H6 AM Det-AVC FM AFC, 6BA6 FM RF, 12AT7 FM OSC-Mixer, 6BA6 FM IF, 6BA6 2nd FM IF, and 6AL5 FM Ratio Detector.

That is a total of 26 tubes, five of which are miniature types. Three of the tubes are power rectifiers, and two are signal rectifiers. Add one more for a tuning indicator and that makes 27 tubes for a 200 watt output (since in AM and FM positions output will be mono, stereo for tape/phono/CD/or Tele). Add two more tubes (12AX7) for magnetic phono pre-amp.

That gives us a total of 29 tubes. Here they are in a more orderly fashion:

Tube compliment in power output chassis
V1 6SN7-GT Left channel voltage amplifier and phase inverter
V2 6SN7-GT Right channel voltage amplifier and phase inverter
V3 6L6-G Left channel push-pull output
V4 6L6-G Left channel push-pull output
V5 6L6-G Left channel push-pull output
V6 6L6-G Left channel push-pull output
V7 6L6-G Right channel push-pull output
V8 6L6-G Right channel push-pull output
V9 6L6-G Right channel push-pull output
V10 6L6-G Right channel push-pull output
V11 5V4-G Rectifier
V12 5V4-G Rectifier

 

Tube compliment in tuner-preamp chassis
V13 6SK7 AM Radio Frequency  Amp
V14 6SA7 AM Converter
V15 6SK7 AM IF Amp
V16 6H6 AM Det-AVC  FM AFC
V17 6BA6 FM RF Amp
V18 12AT7 FM Oscillator &Mixer
V19 6BA6 1st FM IF Amp
V20 6BA6 2nd FM IF Amp
V21 6AL5 FM Ratio Detector
V22 6E5 Tuning indicator
V23 6SN7-GT Left cathode follower input and treble amp
V24 6SN7-GT Left bass amp and AF amp
V25 6SN7-GT Right cathode follower input and treble amp
V26 6SN7-GT Right bass amp and AF amp
V27 12AX7 Left magnetic phono pre-amp and RIAA equalizer
V28 12AX7 Right magnetic phono pre-amp and RIAA equalizer
V29 5U4-G Rectifier

If the power supplied by the transformer and two 5V4-G rectifier tubes (525ma max) is sufficient, then it could be feasible to omit the 5U4-G tube and feed the whole reciever from a single power source.



-- The Tube Man (vacuum@tube.com), March 25, 2002

Answers

AM IF 455KC

FM IF 10.7MC

-- The Tube Man (vacuum@tube.com), March 25, 2002.


With the exception of the power output tubes and rectifier tubes, I am considering going to all 7 and 9 pin miniature type tubes. This drastically skrinks things down, and should improve performance in radio circuits.

Also, as the 6-pin 6E5 tuning eye tube is becoming scarce and expensive (about $30), I am also considering switching it to a EM84 (6FG6) a nine-pin miniature type.

I figure B+ will be around 300v.

-- The Tube Man (vacuum@tube.com), March 25, 2002.


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