McIntosh - Hints and Kinks
- Thread starter dewickt
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rye667
New Member
the 820k was really missing...
i guess this was the reason for the low bias in fact. i wonder why my predecessor respectively his tech didn't get there. thinking he had the amp playing this way the whole time i'm happy that nothing worse happened. but maybe the endtubes have to be replaced.after soldering in the new silicon diode and a 6.5k resistor plus 2 x 470k in series (will buy the 820k tomorrow) the bias now is at -41.2V :thmbsp:
rye667 - what's the matter with you? Don't you know we like pictures? 
Congrats on a great set of amps and your getting them going correctly.
Congrats on a great set of amps and your getting them going correctly.
rye667
New Member
rye667 - what's the matter with you? Don't you know we like pictures?
Congrats on a great set of amps and your getting them going correctly.
hi mx117.
what's the matter with you yourself? i didn't know that we're in a peepshow here
do pictures really matter? where and when exactly have you lost your proper imagination? 
anyway, let me get you some background information on my mc history. i got aware that there was a world beyond transistor amps when per incident passing by a high-end audio shop where they had such marvelous glittering devices with funny black housings and glass bulbs on it. this was about 10 years ago - a time when i used to be a poor student... you can guess i was impressed by the look and even more by the price...
after remembering those times out of a what you might call mid-life crisis (just kidding) i had a glance at the market for mc devices. first thinking of 275, 240 or 60's and then finally made my choice: a pair of mc 30. the motivation in getting those lies in my predilection for high quality, high sustainability and the concepts of long life products as well of a flair for 50ies to 70ies design. so much for the history.
i then got mine two weeks ago. after a lot of reading on how to handle, what to get aware of, a line check, sound check etc. i felt that one of the mc's was running hotter than the other one. and here we are at the start of my posting history again. thanks to Terry and one of my very friends, who is a genius in electronics (thank you so much g.) i was able to handle the issue you want me to publish pics of.
now. so you see, the restoring process hasn't finished yet. i still have to do some work. if you are patient, maybe i will do you a favour and show you some pics when i got my -42V on both amps... ;-)
kevzep
Its all about the Music
MR78 FM De emphasis
I am going to purchase a MR78. But I live in New Zealand where the FM De Emphasis is 50µs as opposed to the USA 75µs standard....
I am assuming it will be as simple as changing the cap which sets up the time constant for this.
I was looking for some guidance, and thought it could be useful to others wanting to do the same thing.
I am a tech, I am not a novice....however I am not really an RF guy....RF is voodoo technology...
Thanks in advance....
I am going to purchase a MR78. But I live in New Zealand where the FM De Emphasis is 50µs as opposed to the USA 75µs standard....
I am assuming it will be as simple as changing the cap which sets up the time constant for this.
I was looking for some guidance, and thought it could be useful to others wanting to do the same thing.
I am a tech, I am not a novice....however I am not really an RF guy....RF is voodoo technology...
Thanks in advance....
Gregory
Soundco Kid
The MR80 has selectable de-emphasis via switches on the top panel, three settings total. You might want to look at its specs and schematic.
-Gregory
kevzep
Its all about the Music
I will have a look, but I think that area in the two receivers is quite different....
Maybe one of the gurus will chime in, it wont be difficult to do....
Suggest whatever vintage McIntosh tuner you pick, if purchasing in the U.S., have it sent to Terry for a recap and alignment before shipping to you. Am guessing tuner-techs are a fairly rare breed down there and Terry is one of the best. Having had both an MR78 and my current MR80, I prefer the operation and sonics of the MR80, which has been gone through by Terry.
kevzep
Its all about the Music
There is nowhere to send a tuner for alignment in New Zealand.....
I am leaning towards your idea.....
However, if I buy one which has been serviced and aligned I would like to be able to change the de-emphasis myself rather than waiting 2 months for Terry to be able to change or remove two ceramic caps....(60 days waiting list for Terry at the moment)
That just shows the quality of Terry's work. Definitely worth the wait.
kevzep
Its all about the Music
I agree for a alignment and other more specialized development and repairs, most definitely.....
There are opportunities for Dewicked Tuners out there which I could grab.
However a de emphasis change from 75 to 50µs is very straight forward and since I am a tech I would look to do that myself, its not terribly difficult to do, I could probably work it out and most likely will, but its always good to get information from a tech who has done it before....
kevzep
Its all about the Music
Thank you so much Terry, I will be sure to check serial numbers before buying, and stick to the ones on the list.....:thmbsp:
What type of cap were McIntosh using, or more to the point, what would you recommend, I would have thought they may have been ceramic?
On another note, as luck would have it, the C32 I have just bought has been to you for re-capping and restoration along with some upgrades. I am looking forward to putting that into the system...
Perhaps McIntosh werent hitting the international market when these tuners were being produced......
We missed out down here in the South Pacific!!
Have you looked through the schematic to see what test equipment they suggest and entertain doing the alighnment yourself?
kevzep
Its all about the Music
Yes, I have a strong interest in tuners/alignment. I consider myself a Tuner Geek.
FM didnt come to New Zealand until 1983, also with the strict import laws there were no big name brands sold here, so on the service side of things it was very very slim pickings.
What this means is there is virtually no analogue FM alignment gear to be picked up locally for cheap by companies selling off old gear they no longer use etc.....
I will have to commit to importing the gear, and as soon as I can stop buying McIntosh gear, then I will do this....
Hmmmm I can feel a MC352 coming on.......:scratch2:
Hi!
Just bought a remade MX110 from Audio Classics...
Have had it for 4 days but have noticed a distinct lack of bass in the lower octaves...particularly in the phono section...
I had borrowed a friend's MX110 so I know that this guy can reach down there...
Is this a matter of burn-in?
I am a bit concerned...
Not like its not there, but one does have to crank the bass to hear what was achievable flat on the seasoned and probably out of spec unit...
Just bought a remade MX110 from Audio Classics...
Have had it for 4 days but have noticed a distinct lack of bass in the lower octaves...particularly in the phono section...
I had borrowed a friend's MX110 so I know that this guy can reach down there...
Is this a matter of burn-in?
I am a bit concerned...
Not like its not there, but one does have to crank the bass to hear what was achievable flat on the seasoned and probably out of spec unit...
Rich Andrews
Well-Known Member
Phono eq can be a problem depending on the cartridge.
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