McIntosh MC240

McIntosh MC240: used price, versions, and what to check before you buy

By HiFi Registry Staff · Published November 1, 2026

In short: The MC240 is McIntosh's 40 watt per channel 6L6GC stereo tube amplifier, built from 1960 to 1969 and never reissued. Every one is at least 57 years old, so the price is set by condition and service, not by version. Unserviced examples have been selling at dealers for roughly $2,700, properly restored ones for $4,000 to $5,500, and the best restored or one-owner boxed units are asking $7,000 to $7,500. It is the smaller sibling of the MC275 and trades at a fraction of that amp's money. HiFi Registry's recorded sales for this model are in the table further down the page. Prices checked November 1, 2026.

Versions and years

McIntosh's legacy catalog dates the MC240 from 1960 to 1969, with 40 watts per channel in stereo and 80 watts in mono. Audio Classics and Ken Rockwell give the original list price as $288. It was McIntosh's first stereo power amplifier and its last new tube design, followed the next year by the MC275 (75 watts per channel, 1961 to 1971) and the MC225 (25 watts per channel, 1961 to 1967).

There was never a Mk II. Collectors split the run into early, middle and late production, the names the McIntosh compendium uses, though AudioKarma contributors and Ken Rockwell count more variants among the late units. The tells for a late unit (1965 to 1969) are round vent holes in the tube cage and speaker terminals near the middle of the rear panel. Antique Radio Classified gives the late serial range as 10G01 to 58G76; mid-production units carry a D in the same position. Retrofret puts production at 16,896 MC240s in total, 6,644 of them late. Earlier late units have a line voltage selector switch on the panel.

Where the sources disagree: McIntosh says 1960, while Antique Radio Classified and Retrofret start the run in 1961. Late units reportedly shipped without a tube cage, which owners received by returning the warranty card, so a missing cage is not by itself a warning sign.

Specs that matter

• 40 watts per channel into 4, 8 or 16 ohms, plus 125 ohm (70.7 V) and 600 ohm (140 V) taps; 80 watts mono into 2, 4, 8, 16 or 32 ohms depending on output wiring
• Eleven tubes: four 6L6GC outputs (McIntosh also specified the 7027A), one 12AX7 voltage amplifier shared by both channels, two 12AU7 phase inverters, two 12BH7 drivers, two 12AX7 cathode followers
• Unity Coupled output stage with bifilar-wound output transformers; damping factor above 10 on every tap
• Three input modes on a rotary switch: Stereo (two jacks, balance control), Twin (two jacks, separate level controls, for biamping or two programs), Mono (one jack, level control). Inputs are 250 kilohm.
• Speaker connections on a barrier strip, with an octal socket for the high impedance taps
• 16 Hz to 40 kHz at rated output, under 0.5 percent THD 20 Hz to 20 kHz, 90 dB signal to noise, 0.5 V sensitivity
• Solid-state rectification with a selenium bias rectifier and an inrush thermistor; no user bias adjustment
• Chrome top chassis with black transformer covers and sub-chassis
• 56 lb, 65 lb shipped; 17.25 x 8 x 10.75 inches
• Warranty: none. The McIntosh three year warranty covers the original purchaser of a new unit from an authorized dealer and ends on transfer. A dealer's own return window is the only protection you will get.

Used prices by condition

HiFi Registry's recorded sales for the MC240 are in the table below this guide. What the wider market shows, as of this writing:

• Unrestored or lightly serviced: The Music Room sold a cosmetic 7 unit with no service history for $2,668 and an early version at cosmetic 8 for $2,729. A private seller on Reverb asked $3,600 for a working, untouched amp in June 2026, and eBay asking prices run $2,999 to $4,200. Ken Rockwell tracked the going rate at about $2,400 in 2015 and 2021 and $3,500 in 2023.
• Restored by a known shop: Retrofret sold a 1967 unit with new power supply capacitors and out-of-spec parts replaced, missing its cage, for $3,950. Aural HiFi sold a late unit recapped with new multi-section cans, a silicon bias rectifier, a Tung-Sol quad and Telefunken small tubes, rated 9 of 10, for $5,499.
• Collector grade: SkyFi is asking $6,990 for a full restoration with RCA McIntosh-labeled outputs and Telefunken small tubes, despite moderate chrome pitting. Audio Classics is asking $7,499 for a one-owner amp with the original carton, cage and McIntosh output tubes, with lower grade units at $3,999.

The spread is wide because the restoration is most of the price. Two amps with the same cosmetic grade can differ by $3,000 depending on what is under the chassis, so a blended MC240 average tells you little.

What to check before buying

1. Power supply. Every MC240 needs, or has had, a rebuild: the multi-section can capacitors, the voltage doubler board, the selenium bias rectifier and the inrush thermistor. Shops replace the selenium part with a silicon diode and a dropping resistor so the fixed bias lands at the factory value. Ask what was replaced, when and by whom. A sticker from a McIntosh clinic is history, not service.
2. Signal path capacitors. The original Sprague Bumblebee and Black Beauty paper capacitors leak and drift; SkyFi found them out of spec on every example it has restored. Some restorers keep the Black Beauties for originality. Find out which the seller has.
3. Chrome. Pitting on the top chassis is common for this era, SkyFi says, and it is the main cosmetic variable. Replacement chrome chassis exist, but a replaced one changes what a collector will pay. Ask for photographs under direct light and check how much silkscreened lettering survives.
4. Transformers. Confirm the output and power transformers are original black McIntosh units with their decals, and that the leads are sound. Restorers remove and test them.
5. Output tubes. No user bias adjustment, so it needs a matched quad. McIntosh specified the 6L6GC or 7027A; owners also run the 7581A, a higher dissipation 6L6GC that Jeff's Place preferred to the 7027A. One long-time AudioKarma owner reports MC240s going through output tubes faster than MC275s. Ask what is installed and how many hours.
6. Hum and noise. Listen at idle with the inputs shorted. Buzz at the chassis is normal; hum through the speakers points to the filter caps or a tube.
7. Controls and switches. Run the mode switch and both level controls. Crackle means a cleaning at minimum. Check that the stereo/mono switch cover is present; it goes missing.
8. Version against serial. A late-style chassis with a mid-style serial is not evidence of a swap, per AudioKarma. Price it on condition, not on the letter.

Who it is for, and what else to consider

The MC240 is for someone who wants a 1960s McIntosh tube amplifier and does not need 75 watts. Forty watts of Unity Coupled power drives sensitive speakers with ease, and the twin mode makes it a natural choice for a biamped horn system. People who have owned all three versions report no preference once the amp is restored, so buy the best-condition example rather than hunting for a specific year.

Within the vintage McIntosh range, the MC275 is the obvious step up and the MC225 the step down; the mono MC30, MC60 and MC75 are the alternatives if you want separate chassis per channel. The period partner is the C22 preamplifier or the MX110 tuner-preamp. If you want McIntosh tube sound with a warranty, only a current MC275 Mk VI bought new from an authorized dealer will give you one.

Frequently asked questions

What is a used McIntosh MC240 worth? Roughly $2,700 for an unserviced example at a dealer, $4,000 to $5,500 restored by a known shop, and $7,000 to $7,500 asking for the best boxed or fully restored units. See the condition notes above and the recorded sales table for what has actually changed hands.

How much power does the MC240 have? 40 watts per channel in stereo, 80 watts in mono. Ken Rockwell measured 47 watts per channel at 1 kHz under 0.5 percent distortion on his restored unit.

What tubes does the MC240 use? Four 6L6GC (or 7027A) outputs, three 12AX7, two 12AU7 and two 12BH7, eleven in all.

Does the MC240 need biasing? No. The bias is fixed and there is no user adjustment. Use a matched quad, and make sure the bias supply has been rebuilt with a silicon rectifier so the voltage is correct.

Can the MC240 run in mono? Yes. The Stereo/Twin/Mono switch puts both channels together for 80 watts into 2, 4, 8, 16 or 32 ohms depending on how the outputs are wired.

Does the McIntosh warranty cover an MC240? No. The warranty covers the original purchaser of a new unit from an authorized dealer and ends on transfer. On a 1960s amplifier the only coverage is whatever the selling dealer offers.

Related

• A Buyer's Guide to McIntosh
• McIntosh comps: MC275, MC225, MC75, MC60, C22
• Live McIntosh listings on HiFi Registry
• Sell your MC240 on HiFi Registry, $25 flat, no commission

Written by HiFi Registry Staff. Not a review: HiFi Registry has not owned or auditioned this unit unless the text says so. Price ranges describe open-market sales and dealer asking prices observed on the review date and are not offers to buy or sell. How we research these guides