McIntosh 2105 Power Amp Restoration
schwarcw
Posts: 7,338
I recently scored a Mac 2105 of Craigslist here in Pittsburgh. The price was right at $400. I gave it to my friend and fellow Polkie falcon377 (Mike) to check out.
Mike powered up the unit, played it and said that it sounded pretty good. The plan at that point was to clean the chassis, controls, contacts, replace bulbs, repair some bubbles on the faceplate, etc.
Mike opened the unit and to our surprise, non of the caps matched the parts listed in the service manual. After several emails to Mac and additional research Mike concluded that someone has been isnide the amp and must have rebuild it using a 2505 schematic, at least that's our theory because of the values of some of the caps he found on the boards. Why the tech wouldn't replace a like for like component is beyond all logical comprehension. For example, the big power output caps were 50V, 25,000 uF made by GE (see pic)
Any email to McIntosh confirmed that they never used this part or value in the 2105.
I won't detail the differences in the boards cap by cap, but here is a view of the chassis as found:
I ordered some replacement parts according to the 2105 Service manual. Most of the caps I ordered were various radial and axial varieties of Nichicon. The large output caps that we ordered were Mallory 50V, 58,000 uF. Mike meticulously cleaned the chassis, controls, soaked the pots in DeOxit, replaced all the lights and polished the chassis to a very good condition. The apparent "bubbles on the front galss panel were actually deposits on the outside of the glass. These were removed and the unit looks and sounds fabulous. It is paired very nicely with my MX-113. Here are some pics of the rebuild chassis:
The resulting change in performance and sound was striking!!:yes: The unit was much more dynamic and had a better or lower bass response. Overall, I put about $300 into the unit, the total project cost about $700. This compares very favorably to the cost of what some of these untis are selling for.
Kudos to Falcon377 (Mike) and his expert restoration work. I can't thank you enough.
Regards,
Mike powered up the unit, played it and said that it sounded pretty good. The plan at that point was to clean the chassis, controls, contacts, replace bulbs, repair some bubbles on the faceplate, etc.
Mike opened the unit and to our surprise, non of the caps matched the parts listed in the service manual. After several emails to Mac and additional research Mike concluded that someone has been isnide the amp and must have rebuild it using a 2505 schematic, at least that's our theory because of the values of some of the caps he found on the boards. Why the tech wouldn't replace a like for like component is beyond all logical comprehension. For example, the big power output caps were 50V, 25,000 uF made by GE (see pic)
Any email to McIntosh confirmed that they never used this part or value in the 2105.
I won't detail the differences in the boards cap by cap, but here is a view of the chassis as found:
I ordered some replacement parts according to the 2105 Service manual. Most of the caps I ordered were various radial and axial varieties of Nichicon. The large output caps that we ordered were Mallory 50V, 58,000 uF. Mike meticulously cleaned the chassis, controls, soaked the pots in DeOxit, replaced all the lights and polished the chassis to a very good condition. The apparent "bubbles on the front galss panel were actually deposits on the outside of the glass. These were removed and the unit looks and sounds fabulous. It is paired very nicely with my MX-113. Here are some pics of the rebuild chassis:
The resulting change in performance and sound was striking!!:yes: The unit was much more dynamic and had a better or lower bass response. Overall, I put about $300 into the unit, the total project cost about $700. This compares very favorably to the cost of what some of these untis are selling for.
Kudos to Falcon377 (Mike) and his expert restoration work. I can't thank you enough.
Regards,
Carl
Post edited by schwarcw on
Comments
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I'd like to add that this 65 lb beast of an amp produces a clean, quiet 105 watts at 8 ohms and is capable of operation at 4 hours and possibly lower. What an amp. It powers the Spendors with ease and fill the room like a symphony.Carl
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Congrats on the score, it's a beaut!
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Looks great Carl. Mike does nice work.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Been there, done that (several times over), miss it like you wouldn't believe. Great sound, solid power.
Cheers,
RussCheck your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service. -
Wow,, beautiful,, someone certainly has a skill,,and it shows.JC approves....he told me so. (F-1 nut)
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I'd like to add that this 65 lb beast of an amp produces a clean, quiet 105 watts at 8 ohms and is capable of operation at 4 hours and possibly lower. What an amp. It powers the Spendors with ease and fill the room like a symphony.
Nice job & well worth the money & effort!!! One question for you though, can you only play that puppy for 4 hours or less & what happens after 4 hours?
I just had to ask!! 
:D "2 Channel & 11.2 HT "Two Channel:Magnepan LRSSchiit Audio Freya S - SS preConsonance Ref 50 - Tube preParasound HALO A21+ 2 channel ampBluesound NODE 2i streameriFi NEO iDSD DAC Oppo BDP-93KEF KC62 sub Home Theater:Full blown 11.2 set up. -
Congrats Carl, enjoy! Nice project"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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He most likely ment 4 ohms Phil, anyway, nice score and a great amp to boot. Who says vintage gear won't compete with todays. Mac always made some gorgeous looking stuff.HT SYSTEM-
Sony 850c 4k
Pioneer elite vhx 21
Sony 4k BRP
SVS SB-2000
Polk Sig. 20's
Polk FX500 surrounds
Cables-
Acoustic zen Satori speaker cables
Acoustic zen Matrix 2 IC's
Wireworld eclipse 7 ic's
Audio metallurgy ga-o digital cable
Kitchen
Sonos zp90
Grant Fidelity tube dac
B&k 1420
lsi 9's -
Beautiful! Got to love those blue eyes!
Gordon2 Channel -
Martin Logan Spire, 2 JL Audio F112 subs
McIntosh C1000 Controller with Tube pre amp, 2 MC501 amplifiers, MD1K Transport & DAC, MR-88 Tuner
WireWorld Eclipse 6.0 speaker wire and jumpers, Eclipse 5^2 Squared Balanced IC's. Silver Eclipse PCs (5)
Symposium Rollerblocks 2+ (16)Black Diamond Racing Mk 3 pits (8) -
Thank you Carl, it was a privilege to work for you again.. I will admit that amp sounds incredible!!! I was able to hear it in my system, with my Perreaux pre-amp, and Infinity Kappa 7 speakers and was shocked at bottom end of the frequency response, my system never sounded so good!!!!
Then when you invited my son and I over to your house, we were again floored, this time by the Spendor speakers you are selling here on this forum. Those are serious hi-end speakers that will amaze you!! wow, can't believe no one has bought them yet.. Also can not believe you want to sell those.
Thanks again Carl for the kind words, and having us over to your home. It was a great time.
Mike -
Congrats on the acquisition Carl. Nice job Mike! High marks!Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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Congrats Guys! Cheers all around. Sounded like both had a great time. Great looking Mac and nice job!I am sorry, I have no opinion on the matter. I am sure you do. So, don't mind me, I just want to talk audio and pie.
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Looks great. Congrats guys.HT and Music Rig
Receiver- NAD T765 HD
Mains- Polk Audio Monitor 70
Center- Polk Audio CS2
Surrounds side- Polk Audio Monitor 60
Sub- Polk Audio PSW505
Windows 7 Media Center
T.V.- 40" Sony Bravia LCD 1080P
Blu-Ray- 80 GB PS3 -
I'm glad you found a mate for the pre/tuna.SRT For Life; SDA Forever!
The SRT SEISMIC System:
Four main satellite speakers, six powered subs, two dedicated for LFE channel, two center speakers for over/under screen placement and three Control Centers. Amaze your friends, terrorize your neighbors, seize the audio bragging rights for your state. Go ahead, buy it; you only go around once. -
105 is MIN ... The last time mine was bench tested it hit 133 per before any distortion came up on the scope.
Great looking unit. Heavy SOB's too!! Did you get a wood case for it also?
I have mine running SDA 1.2's on the 4 ohm taps.
My only complaint with the unit is the taps. I wish they had regular speaker terminals.
Congrats on a great sounding unit!!Klipsch The Nines, Audioquest Thunderbird Interconnect, Innuos Zen MK3 W4S recovery, Revolution Audio Labs USB & Ethernet, Border Patrol SE-I, Audioquest Niagara 5000 & Thunder, Cullen Crossover II PC's. -
I almost forgot, the headphone amp also sounds fantastic on this unit also!!Klipsch The Nines, Audioquest Thunderbird Interconnect, Innuos Zen MK3 W4S recovery, Revolution Audio Labs USB & Ethernet, Border Patrol SE-I, Audioquest Niagara 5000 & Thunder, Cullen Crossover II PC's.
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very nice. I love just the look of McIntosh gear. Beautiful to the eye and to the ear IMO. Great find and great work! congrats to both of you!
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nice amp
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Carl, What speakers will you be using now that you sold the Spendor's?
Inquiring minds want to know!!
