Tag Archives: Tube

Ampex 6973 Stereo Tube Amplifier

7 Jan

Ampex Stereo Tube Amplifier

Ampex 6973 Stereo Tube Amplifier

This Ampex tube amplifier was originally in an Ampex stereo console.  It uses 4 6973 output tubes, and 2 7199 driver tubes.   Output is somewhere is about 15 watts per channel.

Check out the video of this amp in action after the break.

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Mcintosh MC-240 Stereo Tube Amplifier

4 Oct

Mcintosh MC-240 Tube Amplifier

Image Credit: LotLogginon eBay

 

Mcintosh MC-240 Stereo Tube Amplifier (1960-1969 MSRP 288 USD)

The Mcintosh MC240 is a 40 watts per channel tube amplifier first produced by Mcintosh Labs in 1960.  It uses 4 6l6GC tubes to achieve it's rated output, and a mix of 12ax7, 12au7 and 12bh7 tubes in the signal path.   The MC240 has a unique place in audio history, it was used by Brian Wilson of The Beach Boys to master Pet Sounds in 1966, one of the most famous albums in rock & roll history.

Specs:

ELECTRICAL: 40w/ch stereo, 80w mono. Response 16-40kHz (+0 -0.1dB). Distortion 0.5%. Noise & hum -90dB. Output impedance 4, 8, 16, 125 and 600 ohms. 600 ohm center tap internally grounded. (2, 4, 8, 16 and 32 ohms in mono). Output voltages 25 (isolated), 70.7 (one side grounded) and 140V (center tap grounded). Internal impedance less than 10% of rated impedance. Input impedance 250k. Input sensitivity: 0.5V (in mono or twin amp). 2.0V in stereo.

MECHANICAL: Chrome chassis. Line output octal socket for higher impedances and voltages. Barrier strips for 4, 8 and 16 ohms. Audio inputs: stereo, twin and mono. Gain controls: twin amp, balance and mono. Input switch: stereo, twin amp or mono. Can be used for 80w mono. Line voltage switch: 117 or 125V.

TUBES: 4-6L6GC/7027A output, 3-12AX7, 2-12AU7, 2-12BH7 Solid state rectifier.

Size 8"H, 10-3/4"W and 17-1/4"D. Weight 56 lb. Sold from 1960-1969.

 

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Fisher 400 Tube Receiver Wood Cabinet

1 Oct

Fisher 400 Wood Cabinet

Fisher 400 Tube Receiver Wood Cabinet

This is the matching walnut veneered cabinet, sold as an optional extra with the Fisher 400 tube receiver.  This example is a genuine Fisher cabinet, but after-market items were also made by third parties for this popular vacuum tube receiver.

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Mcintosh MC-275 Tube Amplifier

26 Sep

Mcintosh Tube Amplifier

Image Credit: Starsky on eBay

 

Mcintosh MC-275 Tube Amplifier (1961, MSRP 444 USD)

McIntosh’s MC275 may be the most famous tube amplifier in the history of high fidelity. Designed and engineered by the company’s co-founder Sidney Corderman and the McIntosh engineering team, the MC275 (2 x 75 watts per channel) was the most powerful McIntosh stereo amplifier in its day. Some say it was the Harley-Davidson of American amps, and with the big chromed chassis and exposed Gold Lion KT88 power tubes, the MC275 certainly looked the part. The retail price was $444 when the amp was introduced in 1961, and the mono version, the MC75, debuted the same year.  The original Mcintosh MC-275 was produced by McIntosh from May, 1961 through July 1973.

  • Tube Complement:
    Voltage Amplifier - One 12AX7 (drives both amps)
    Phase Inverter - Two 12AU7
    Drive Amplifier - Two 12BH7
    Cathode Follower Drive - Two 12AT7 or 12AZ7
    Output - Four KT88 or 6550

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