BillH2121 Posted January 3, 2005 Share Posted January 3, 2005 My Mac 2105 has Powerguard and the indicator lights on the front panel that indicate when Powerguard is working. I've noticed some discussions on other forums where the thought is that the 2105 did not have Powerguard and it was only available on later amps. What's the real chronology? Quote Link to comment Share on other sites More sharing options...
dodger Posted January 3, 2005 Share Posted January 3, 2005 The 2105 has Powerguard. One of the confusions is whether a McIntosh unit has meters. This is for non black and chrome units. 2100 - no meters 2105 - meters both of these 105 watts/channel 2125 - meters 2120 - no meters both of these 125 watts/channel This is where the confusion usually is. The meter and non meter units in the examples each have the same power only a different numeric to indicate no meters. I believe the 2105 was the first to have the Powergard. dodger Quote Link to comment Share on other sites More sharing options...
j-malotky Posted January 3, 2005 Share Posted January 3, 2005 Bill Are you sure you have a 2105? The 2105 does not have Powerguard, just the early autoformers that they called Sentry Monitor. But there is no light for this on the 2105. I think the autoformers came in in the later 70's designed units. Say '75 or '76 on. FYI - the best MC amp resource on the net is: http://www.roger-russell.com/amplif1.htm JM Quote Link to comment Share on other sites More sharing options...
BillH2121 Posted January 3, 2005 Author Share Posted January 3, 2005 dodger - that could be - but I could swear that I just saw a picture of a 2105 for sale on another website that did not have the Powerguard indicator lights on the front panel. Quote Link to comment Share on other sites More sharing options...
BillH2121 Posted January 3, 2005 Author Share Posted January 3, 2005 JM - I' m sure its a 2105 - there's a switch on the back to turn the Powerguard on or off and indicator lights on the front panel to show when its working. Although I don't remember much from 30 years ago, I remember the salesman telling me how great the feature was to prevent clipping. Quote Link to comment Share on other sites More sharing options...
dodger Posted January 3, 2005 Share Posted January 3, 2005 I owned an MC2105 and if my memory serves correctly it had the powergard. If I am wrong, my apologies. dodger Quote Link to comment Share on other sites More sharing options...
dodger Posted January 3, 2005 Share Posted January 3, 2005 Okay, now I'M confused. I swear that my 2105 had powergard. Just did a search on Google, they note 2150 as having powergard. Not noted for 2105. will check more. dodger Quote Link to comment Share on other sites More sharing options...
BillH2121 Posted January 3, 2005 Author Share Posted January 3, 2005 Okay - I just found the picture of the 2105 without Powerguard again - its on the 3rd page of the Mac amps section at www.AudioClassics.com. The 2105 pictured does not have the indicator lights while the 2205 below it does and an annotation in the info states that the 2205 has Powerguard. Quote Link to comment Share on other sites More sharing options...
j-malotky Posted January 3, 2005 Share Posted January 3, 2005 FWIW My '73 vintage 2105 does NOT have PG. I always refer to Rogers web site as it is easy to cross numbers.... MC 2105 Solid State Power Amplifier ELECTRICAL: 105w/ch. Response 20-29kHz (+0 -0.1dB). Distortion 0.25%. Noise and hum -90dB. Output impedance 4, 8 and 16 ohms. Damping factor 10. Input impedance 200k. Input sensitivity 0.5v. Headphone impedance: low. Sentry Monitor. FRONT PANEL: Glass panel. Illuminated. Power level meters (meters read +3 at 100w). Gain controls. Meter range sw: off, -20, -10 and 0. Speaker sw: on or off. Power sw: on or off. Headphone jack. BACK PANEL: Output barrier strips. Audio inputs. AC outlet. Input coupling sw: direct or normal. Fuse. Panloc mounting. Size 7-1/8"H, 16-3/16"W and 14-1/2"D. Weight 65 lb. Sold from 1967-1977. Last retail price $799.00 MC 2150 Stereo Power Amplifier ELECTRICAL: 150w/ch. (300w mono). Response 20-20kHz (+0 -0.25dB). Distortion 0.02%. Noise and hum -95dB. Output impedance 1, 2, 4, and 8 ohms. (0.5, 1, 2, 4, 8 and 16 ohms in mono). Damping factor 30 or greater. Input impedance 50k. Input sensitivity 0.75v or 2.5v. Headphone impedance: low. Sentry Monitor. Power Guard. FRONT PANEL: Anodized gold and black panel. Gain controls. Power Guard lamps: normal or limit. Power sw: on or off. Speaker sw: on or off. System test digital readout. Headphone jack. BACK PANEL: Output barrier strips. Audio inputs. AC outlet. Input level sw: 2.5v or .75v. Mode sw: stereo, mono bridge or mono parallel. Fuse. Size 5-7/32"H, 16"W and 14-1/2"D. Weight 58 lb.Sold from 1982-1987. Last retail price $1925.00 Quote Link to comment Share on other sites More sharing options...
dodger Posted January 3, 2005 Share Posted January 3, 2005 According to the Orion Bluebook, they note the 2125 as the first with Powergard. I must be remembering another McIntosh or did some have it and some not? A transition piece. dodger Quote Link to comment Share on other sites More sharing options...
BillH2121 Posted January 3, 2005 Author Share Posted January 3, 2005 Well - I'm on my way home in a few minutes and I'll check for sure. I will be really embarassed if my amp is a 2125 and I've had in my mind for years that its a 2105. Wow, its rough getting old! Quote Link to comment Share on other sites More sharing options...
dodger Posted January 3, 2005 Share Posted January 3, 2005 I just found a listing. It notes that it has special circuitry to prevent speaker damage, etc., etc.. They did not note powergard as the name of the circuit. Right again, JM. dodger Quote Link to comment Share on other sites More sharing options...
BillH2121 Posted January 3, 2005 Author Share Posted January 3, 2005 Ok, its official - I'm a dumbass! The good news is that I have more watts at my disposal than I thought; the bad news is that I don't even know what equipment I own. My amp is a 2125. I apologize for starting this whole mess. Apparently, I can remember what a salesman told me 30 years ago, but I can't remember what I saw on the front of my amp yesterday. Sorry again - thanks to all of you who tried to help. Quote Link to comment Share on other sites More sharing options...
dodger Posted January 3, 2005 Share Posted January 3, 2005 Um, Hey Bill, Some of us don't even remember what we had for breakfast today. I also received a Christmas with yearly updates. on my Mother's side, the little lad in diapers, has been promoted to Captain and is now on the SWAT team in California. 2125 sounded a little better than the 2105 with a C-20. dodger Quote Link to comment Share on other sites More sharing options...
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