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#1
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Known Factory wiring fault in SOME McIntosh MC611 monobloc amps
I own a pair of McIntosh MC611 monobloc amplifiers that I purchased new over a year ago.
Since that time I have sensed that something was wrong and I have been continually trying to track-down an imbalance in my system. I wasted many hours, labour and equipment-switching to diagnose the problem. Only recently, with the help of the dealer and a technician did I find out what the problem was. In fact it is two problems: 1) There was a mistake made at the factory, in which plugs from the input board (J8 & J9) were reversed, resulting in one channel being out-of-phase! (improper imaging/no centre image) 2) The Single-ended/Balanced switch on the back panel does not function properly. Corrosion from the circuit board coating chemical on that switch causes intermittent problems with the signal and a lack of proper power output of the amp, resulting in a volume imbalance. (which also ruins imaging) I wasted a lot of time and trouble getting this problem diagnosed, but the McIntosh factory is not interested in making this in a general recall. So, let's call this a 'Public Service Announcement'. I would not wish for anyone else to go through this trouble, expense and aggravation. I have been told that there is a (secret) Service Advisory regarding this problem, so there must be more of you out there with the same trouble. However, you will not see any information about it on the McIntosh website! Let it also be known that it will not get detected on a test bench. See test meter readout. Also switching polarity at the speaker will bring out the problem but will also introduce harmonics – due to the nature of the circuitry. If there are more of you out there, be advised….and I think we should be entitled to some compensation from the manufacturer.
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Aurender A30 -> Mac C1100 -> 2 x Mac MC611 > Franco Serblin Accordo Essence + Pair of REL Carbon Special Aurender A10 -> Mac C1100 -> 2 x Mac MC611 > Joseph Audio PERSPECTIVE2 Graphene VPI 40th. Anniversary Direct Drive -> Audio Research Ref. 3 Phono Aurender A10 -> Ref 6 -> GS150 > PMC Fact 12 McIntosh MCD500 -> C1100 - >MC452 > PMC Fact 12 Aurender A10 -> -> E470 > PMC Fact 12 Speakers: Monitor Audio PL200 , , Monitor Audio GX200 PMC Fact 12 Tidal -> Aurender S10 -> Accuphase DC-37 -> Accuphase E-470 -> Monitor Audio GX200 Tidal -> Aurender S10 -> MD108T Signature DAC -> Mcintosh C1100 ->McIntosh MC452 -> JBL 4344 |
#2
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Known Factory wiring fault in SOME McIntosh MC611 monobloc amps
Well that would be frustrating to say the least. Good of you to post this!
Last edited by Cohibaman; 04-22-2021 at 06:49 PM. |
#3
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Thank you; I will make this a Sticky Post for now.
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Ivan FLORIDA MX136, MC1.2KW(10) MC2KW(2), MCD1100, MS750(2) MVP881, C1000C/P/T, MPC1500, HT-2 SUBS(2) HT3F(2) WS350(2) XRT2K, XCS2K, XR27(2) XCS350(2) JL GOTHAM v2 SUBS(2) SILENZIO MUSIC SERVER, LUMAGEN RADIANCE SCALER, SONY VPH-G90U 4K PROJECTOR, STEWART 120" MOTORIZED SCREEN, CINEMA-TECH SEATING, WW PLATINUM CABLES Reference System: ACCUPHASE A300 AMPS, C3900 PRE-AMP, DP1000 CD/SACD TRANSPORT, DC1000 DIGITAL PROCESSOR, DG-68 DIGITAL EQUALIZER, T1200 FM STEREO TUNER, PS1230 POWER SUPPLY, HRS-SXR CUSTOM RACK w/ M3X SHELVES, TAD REFERENCE ONE MK2 LOUDSPEAKERS, WW PLATINUM CABLES CAPE COD MX150, MC501(2) MC1.2KW(10) MC2301(2) MR88, MVP881, MCD1100, MDA1000, C1000C/P/T, MPC1500, ESOTERIC K-01X 30th ANNIVERSARY (BLACK) SACD/CD PLAYER, G02-X CLOCK, HT3F(2) XRT2K, XCS2K, XR27(2) JL GOTHAM v2 SUBS(2) JL FATHOM F113v2 SUBS(4) SOUND ANCHOR STANDS(2) KALEIDESCAPE STRATO & TERRA SERVERS 80-TB, LUMAGEN RADIANCE SCALER, SONY VPH-G90U 4K PROJECTOR, STEWART 120" SCREEN, SONUS FABER STRADIVARI, SILENZIO MUSIC SERVER, FORTRESS SEATING, WW PLATINUM CABLES Analog Rig: CLEARAUDIO INNOVATION WOOD, UNIVERSAL ARM w/ Da VINCI' CART, 2nd UNIVERSAL ARM w/ GOLDFINGER STATEMENT CART, HRS-MXR REFERENCE RACK-GLOSS BLACK w/ M3X SHELVES, AESTHETIX RHEA SIG PHONO-PRE, BRYSTON BHA-1 HEADPHONE AMP, WW PLATINUM CABLES Reference System: BURMESTER 911MK3 AMP(3), 088 PRE-AMP, 089 CD PLAYER, 100 PHONO PRE-AMP, 948 POWER CONDITIONER, ACCUPHASE DG-68 VOICING EQUALIZER, AVID ACUTUS REFERENCE SP TT, GRAHAM PHANTOM II SUPREME ARM, BENZ MICRO LP-S CART, GRANDIOSO P1X/D1X STACK, G1X RUBIDIUM MASTER CLOCK, N05 NETWORK PLAYER, SILENZIO MUSIC SERVER, HRS-SXR CUSTOM RACK w/ M3X SHELVES, SONUS FABER AIDA SPEAKERS, JL FATHOM F113v2 SUBS(2) SOUND ANCHOR STANDS(2) WW PLATINUM CABLES Library System: GRANDIOSO M1 MONOBLOCK AMPS, C1 LINESTAGE PRE-AMP, K1X CD/SACD PLAYER, G1 MASTER RUBIDIUM CLOCK, E02 PHONO-PRE, SILENZIO MUSIC SERVER, AERIAL ACOUSTICS 20T V2, AERIAL SW12 SUBS(2), CANTON REF K1’s, VPI HRX TT w/ SDS POWER SUPPLY, ORTOFON CADENZA BLACK CART, KLAUDIO RCM, SHUNYATA DENALI 6000/S v2, SHUNYATA OMEGA QR’s, WW PLATINUM CABLES Esoteric/Bryston System: ESOTERIC C02-X PRE-AMP, P-02X TRANSPORT, D02-X DAC, G02-X CLOCK, BRYSTON 28B3 CUBED MONOBLOCK AMPS(4), BRYSTON BHA-1 HEADPHONE AMP, SHUNYATA DENALI 6000/S v2(2) EVEREST 8000 POWER CONDITIONER(2) ALTAIRA CG & SG HUBS, AMR-DP777-SE DAC, SILENZIO MUSIC SERVER, TAD REFERENCE ONE MK2 LOUDSPEAKERS, QUADRASPIRE RACK, WW PLATINUM CABLES Accuphase/Canton System: ACCUPHASE E800 INTEGRATED, DP570 CD/SACD PLAYER, T1200 FM STEREO TUNER, DG-68 VOICING EQUALIZER, PS530 POWER SUPPLY, CANTON REF K3’s, CANTON REF K5’s, SILENZIO MUSIC SERVER, HRS MXR REFERENCE MAHOGHANY RACK w/ M3X2 SHELVES, WW GOLD CABLES |
#4
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Thank you.
Let also be known that if someone gets BOTH MC611's that are wired wrong, it would be very difficult to tell - except the harmonics in the SQ and poor bass.
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Aurender A30 -> Mac C1100 -> 2 x Mac MC611 > Franco Serblin Accordo Essence + Pair of REL Carbon Special Aurender A10 -> Mac C1100 -> 2 x Mac MC611 > Joseph Audio PERSPECTIVE2 Graphene VPI 40th. Anniversary Direct Drive -> Audio Research Ref. 3 Phono Aurender A10 -> Ref 6 -> GS150 > PMC Fact 12 McIntosh MCD500 -> C1100 - >MC452 > PMC Fact 12 Aurender A10 -> -> E470 > PMC Fact 12 Speakers: Monitor Audio PL200 , , Monitor Audio GX200 PMC Fact 12 Tidal -> Aurender S10 -> Accuphase DC-37 -> Accuphase E-470 -> Monitor Audio GX200 Tidal -> Aurender S10 -> MD108T Signature DAC -> Mcintosh C1100 ->McIntosh MC452 -> JBL 4344 |
#5
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Any idea if McIntosh has corrected this on more recent production? My 611's are new and I have had them for about three months. Not sure when they were actually built.
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My System: Amp-McIntosh MC611(2) :Pre-McIntosh C2700, MP1100 :CD/SACD-McIntosh MCD600 :Speakers-McIntosh XR100 :Power Controller-McIntosh MPC1500 :Turntable-VPI HW40 Ortofon Cadenza Black :Cables-Morrow PH5,MA5 and Elite Speaker Cables :Headphones-McIntosh MPH1000 :Record Cleaner Klaudio KD-CLN-LP200T Thanks, Bill |
#6
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Quote:
Great post and root cause problem solving Banter. Thanks.
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Doug 2-Channel McIntosh C2700, (2X)MC601, MEN220 Lampizator Baltic 3 Sonore opticalRendu, SGC sonicTransporter i5 (Gen 3), Roon Thorens TT TD318 B&W 803D3 JL Audio (2x)f110v2 Shunyata Denali/S v2, Alpha v2 PCs, WW Gold/Silver Eclipse Interconnects, Platinum USB Whole House Music Listening Bluesound Vault2i, PowerNode2, PulseMini2i, Pulse2, (3x)Flex 5.2 System Above using Passthru Marantz SR7012 Oppo 205, Apple TV (4th gen), Sony XBR850e65 B&W HTM2 D3 Second 5.1 System Castoffs from Upgrades LRC Paradigm Millenia 20, Velodyne MiniVee 10, KEF surrounds, DefTech AW6500 |
#7
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Looking back when I bought my 611's, the dealer got them new from McIntosh so they were recent production. This was in January of this year. I will reach out and try to find out something from my dealer. I do not seem to hear that there is any issue with my pair.
FWIW
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My System: Amp-McIntosh MC611(2) :Pre-McIntosh C2700, MP1100 :CD/SACD-McIntosh MCD600 :Speakers-McIntosh XR100 :Power Controller-McIntosh MPC1500 :Turntable-VPI HW40 Ortofon Cadenza Black :Cables-Morrow PH5,MA5 and Elite Speaker Cables :Headphones-McIntosh MPH1000 :Record Cleaner Klaudio KD-CLN-LP200T Thanks, Bill |
#8
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Yikes. That’s disturbing. Thanks for the heads up.
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Main System Basis 2200 Signature/Vector 4/Transfiguration Proteus Ortofon Cadenza Black Allnic H3000/CJ ET5/Mcintosh 501's Thiel CS3.6 Thiel CS6 MIT EVO 2 IC Straightwire Maestro II SC Shunyata Denali SV2 Shunyata Sigma XC Wywires Juice PC’s Kubala Sosna PC’s Dedicated 20 amp lines Porter Ports Arcici Ref Suspense Stand Rives acoustically designed room Shore House Basis 1400 Signature/Hadcock 228/Ortofon Jubilee ARC PH 5/Meridian 200/Meridian 263 DAC CJ Premier 14/Classe CA200/Thiel 3.6 Wywires Silver IC/Stereolab Diablo SC/MIT Z cord II |
#9
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Thank you all for your kind words. I would like to emphasize here that the McIntosh SS amps are some of the finest out there. If you have one - any model, you should have a huge sound stage and pinpoint imaging. You probably have got used to the sound quality, so invite a friend for a listen. The voices should be crystal clear with pinpoint imaging. If not, after eliminating speaker placement investigate the problems I have highlighted. They are not difficult to resolve.
If it helps, remove the preamp from the chain. Hook up a CD player with variable output direct to you amp. Also to those that think the new production would not have this problem. Here is my understanding. Both cable assemblies for the negative and positive signal is same part number. The plugs are not keyed, color coded or labeled, So very easy to get them mixed up during assembly. As to the Balance/Unbalance issue, this could be in any model.
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Aurender A30 -> Mac C1100 -> 2 x Mac MC611 > Franco Serblin Accordo Essence + Pair of REL Carbon Special Aurender A10 -> Mac C1100 -> 2 x Mac MC611 > Joseph Audio PERSPECTIVE2 Graphene VPI 40th. Anniversary Direct Drive -> Audio Research Ref. 3 Phono Aurender A10 -> Ref 6 -> GS150 > PMC Fact 12 McIntosh MCD500 -> C1100 - >MC452 > PMC Fact 12 Aurender A10 -> -> E470 > PMC Fact 12 Speakers: Monitor Audio PL200 , , Monitor Audio GX200 PMC Fact 12 Tidal -> Aurender S10 -> Accuphase DC-37 -> Accuphase E-470 -> Monitor Audio GX200 Tidal -> Aurender S10 -> MD108T Signature DAC -> Mcintosh C1100 ->McIntosh MC452 -> JBL 4344 Last edited by Banter; 04-23-2021 at 08:27 PM. |
#10
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I'll bet the input mode switch (S1) is not a sealed switch and the contamination occurred during the soldering process, be it by hand or wave soldering. Flux residue is the most likely cause. Seen this many times.
Too bad you had these problems, hope you have smooth sailing now on.
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System: ML:5206,5302 Serafino's Nordost Lumin U1 RM15 |
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