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RE: Not happy with my refurbed MC225:(

Posted by Bambi B (A) on December 31, 2009 at 10:31:04

In Reply to: Not happy with my refurbed MC225:( posted by The Keester on December 31, 2009 at 08:37:51:

The Keester,

I sympathise with your dissatisfaction with the sound of your McIntosh MC225 after a redo. I had a McIntosh MR67 (tuner, tube, 1965) redone in 2005 and it seems to have lost a lot of the magic and incredible soundstage. I replaced all the tubes with the best NOS tubes I knew- Telefunkens, Amperex 6GH8A for 6U8, exotic pinched waist Valvo E80CF fro the 6BL8, Raytheon black plate 7543's for the 6AU6 and the detail and dynamics improved but the overall lush depth was diminished. It's still a wonderful sound, but definitely different.

Three ideas:

1. That said, it's possible that the new components- caps, resistors, and tubes have not settled in yet. I had the MR67 in storage awhile and believe the total time since the rebuild is less than 40 hours. So, you might give the MC225 some more time to burn in the new pieces.

2. The difference in sound merely requires adjustment on your part- getting used to the up to specification sound.

3. The tubes choices might bear adjustment:

McIntosh MC225 Tube Complement:

Voltage Amplifier—1 ea. 12AX7
Phase Inverter—2 ea. 12AU7
Drive Amplifier—2 ea. 12BH7
Output—4 ea. 7591

McIntosh MX110Z

1 6DS4 R.F. -1 amplifier (nuvistor)
1 12AT7 R.F.-2 mixer
1 6AB4 Oscillator
1 6AU6 IF-1
1 6AU6 IF-2
1 6AU6 lF-3/Limiter 1
1 6CS6 IF-4/Limiter2
1 12AT7 Muting/L+R Amplifier
1 6HU6/EM87 Tuning Indicator
1 6D10 FM AUDIO/Left and Right
1st Audio Amplifier
1 6U8 MPX Amplifier and 19KC
Separator/Indicator control
1 12AU7
1 12AX7
1 12AX7
1 12AX7
1 6U8
1 6U8

Certainly, the MC and MX 12AX7s should be good ones and perhaps nice old RCA 7025 or earlier Amperex/Philips/Valvo ECC83 would help it along. I find old Sylvania organ labeled 12AX7s to usually have a deeper, lusher sound. The 12BH7's too could be old RCA's or Brimar. As far as I know there is only one 7591 made today and NOS sets are difficult, but you might be lucky.

Good luck!


Cheers,

Bambi B

[McIntosh: MX110, MC240, MR67, MR77]

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