rtaylor Posted April 11, 2004 Share Posted April 11, 2004 Got my macs back thursday and finally got some time to hook them up and listen to them yesterday for about 4 hours and everything sounded fine. Turned all the equipment back on this morning and didn't put in a cd right away, two minutes later I was back to the left amp motorboating. The two 6550's alternate getting brighter. Shut it down and waited, turned it back on and put in a cd right away and I'm still listening an hour later with no problems. I know the problem is still there but what next. Replaced the 4 can filters on top of the unit and thought that would finally cure it. MDENEEN's pre does sound good with the mac's and the dyna's. Randy Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted April 11, 2004 Share Posted April 11, 2004 Randy, pretty brave, such an incident would have scared me quite a bit....but of course I am a technical nobody! Anyway, enjoy your Macs...I certainly love my MC30/MX110 combo (amongst other amps and stuff ). BTW: Good to hear about Mark's preamp. I think we could do with a review! Wolfram Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 11, 2004 Author Share Posted April 11, 2004 Don't know about brave but it wasn't a loud noise or I wouldn't have tried it again. As soon as I can sort all the bullsh!t out of the amps I'll let you know what I think of the sound. Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 11, 2004 Author Share Posted April 11, 2004 Are there no Mac gurus's in here? Help R Quote Link to comment Share on other sites More sharing options...
CaptnBob Posted April 11, 2004 Share Posted April 11, 2004 I had a Mac 60 that tended to get unstable if it was pushing too long a speaker line or the other cabling was not to its' liking. The Marantz ads of the middle 1950's, when the Model 2 and Mc-60 were going "toe to toe" make a big deal about how THEIR amplifiers, unlike SOME they could mention, were unconditionally stable. This suggests to me that instability could be a problem the MC-60s were prone to. Just a thought that might bear further investigation. Quote Link to comment Share on other sites More sharing options...
garymd Posted April 11, 2004 Share Posted April 11, 2004 Where's Allan? I'm sure he could answer your question. I'm going to wait another week or so before my blueberry review. I still have a few more tests to perform and want ample listening time. I will say it bests the only other 2 tube preamps I've owned, the Marantz 7C and the Mac MX110. By a large margin too. Quote Link to comment Share on other sites More sharing options...
djk Posted April 11, 2004 Share Posted April 11, 2004 http://www.drtube.com/schematics/mcintosh/mc60.gif C9 and 10 may be leaky. Could be C7 or C8, but that would affect the driver tube too. C2 can really change the sound, a Black Gate may be the best for this cap. Quote Link to comment Share on other sites More sharing options...
arco Posted April 12, 2004 Share Posted April 12, 2004 A Black Gate is the tried, tested and generally accepted choice for this location. It's value is another issue, though...I would suggest you first try some cheap standard value caps between 100 and 400uF and, when you see what you really prefer, then buy the Black Gate. Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 12, 2004 Author Share Posted April 12, 2004 thanks for the help, I'll try replacing the noted caps.i have a print here of the circuitry. Randy Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 12, 2004 Author Share Posted April 12, 2004 ---------------- On 4/12/2004 9:02:16 AM mdeneen wrote: Randy - - Re motorboating. Let me see if I understand this. 1) You sent them out for repair? The cans were replaced? 2) Does it motorboat when: the input is shorted; the output has a 8ohm load on it? Or, only when there is input? mdeneen ---------------- A resitor and the cans were replaced. They both had been sitting for about 5 years. They had worked b/4 putting them away but when I tried them out about 5 months ago they both did this after turning them on with speakers attached and running a cd and pre to them. After the work now only one is motorboating. The first day, Saturday was fine, I had them cranked for 4 hours. It occured the second time I played them, Sunday. I did not put in a cd right away but they were hooked to speakers and the pre was on. I turned them off and tried them a few minutes later with the cd player running and decent volume, they played for four hours with no problem. Turned them on just a few minutes ago and it started to motorboat with the cd playing real soft..turned it off, waited a minute, turned it on and cranked the volume a little and it is running fine? Turned down the volume to make sure that it's not motoring and it's not! So low volume or no volume seems to set it off. Got two packages today and tho it looks like they used them for footballs everything inside is intact and looking good. Still listening after 30 minutes and still no motoring. Randy Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted April 12, 2004 Share Posted April 12, 2004 I've been here 6 months, almost to the day, and have read nearly every post since becoming a member. However, I don't recall hearing the term "motorboating" before, here or anywhere else for that matter. Could someone please give me a laymans explaination? See my signature for any and all thoughts of "Duh, what a dope this guy is!" Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted April 12, 2004 Share Posted April 12, 2004 Very nice, understandable description, mdeneen. Thank You. Quote Link to comment Share on other sites More sharing options...
Cleve Posted April 12, 2004 Share Posted April 12, 2004 Perhaps this is too obvious, but when you said you 'got them back' I'm assuming you had them serviced by an authorized McIntosh tech to correct the motorboating. Won't the service facility stand behind their work? It's not like the problem resurfaced weeks or months later, after the implied warranty has ended. If it were me, I'd ask the service facility to make it right. Also, in the worst case, the Binghamton factory will repair ANY McIntosh product. Good luck! Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 12, 2004 Author Share Posted April 12, 2004 ---------------- On 4/12/2004 7:20:18 PM Cleve wrote: Perhaps this is too obvious, but when you said you 'got them back' I'm assuming you had them serviced by an authorized McIntosh tech to correct the motorboating. Won't the service facility stand behind their work? It's not like the problem resurfaced weeks or months later, after the implied warranty has ended. If it were me, I'd ask the service facility to make it right. Also, in the worst case, the Binghamton factory will repair ANY McIntosh product. Good luck! ---------------- No, not a mcintosh tech. I went to drop them off at the local mc place and the nice man wanted $200 cash up front. This was after talking to him on the phone about the amps. Nothing was said about a deposit. He then stated it would probably be at least $400 an amp and that the 200 would go towards that, but if I didn't like the estimate I lose the $200. I left with the amps and my money. Am I wrong here? Quote Link to comment Share on other sites More sharing options...
Allan Songer Posted April 12, 2004 Share Posted April 12, 2004 Seems like it! $800 is top dollar to go through a pair of these, but if the guy knows what he is doing and REALLY does the job right . . . . Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 12, 2004 Author Share Posted April 12, 2004 ---------------- On 4/12/2004 9:48:25 PM Allan Songer wrote: Seems like it! $800 is top dollar to go through a pair of these, but if the guy knows what he is doing and REALLY does the job right . . . . ---------------- Care to elaborate? Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 12, 2004 Author Share Posted April 12, 2004 Sorry, the part about him knowing his job didn't show up at first.Just the I think so Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 12, 2004 Author Share Posted April 12, 2004 And how do I know this guy knows what he's doing or will just do a crap job? Quote Link to comment Share on other sites More sharing options...
Allan Songer Posted April 12, 2004 Share Posted April 12, 2004 You don't! Terry DeWick down in Knoxville knows these inside out and does good work for a fair price. Doesn't use exotic parts, but his prices reflect it. He did a tuner for me years ago (MR 67) and I was pleased. Quote Link to comment Share on other sites More sharing options...
rtaylor Posted April 14, 2004 Author Share Posted April 14, 2004 ---------------- On 4/12/2004 7:20:18 PM Cleve wrote: Perhaps this is too obvious, but when you said you 'got them back' I'm assuming you had them serviced by an authorized McIntosh tech to correct the motorboating. Won't the service facility stand behind their work? It's not like the problem resurfaced weeks or months later, after the implied warranty has ended. If it were me, I'd ask the service facility to make it right. Also, in the worst case, the Binghamton factory will repair ANY McIntosh product. Good luck! ---------------- Cleve,just received a reply from Mac and they will not due any servicing on my Mac's, they did say they thought it the price was high. They gave me some recommended shops and none of them are close. Quote Link to comment Share on other sites More sharing options...
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