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Chat about Equipment Info
 #77322  by mijknahs
 Tue Apr 06, 2010 10:39 am
Give it a try! You might like it. You never know.

I have an old MC50 that sounds great even for gigs and it's only 50 watts.

Jim
 #77336  by NeebruM
 Tue Apr 06, 2010 12:14 pm
MC 50's a tube though, isn't it??? (Hard to remember them all)
 #77338  by mijknahs
 Tue Apr 06, 2010 12:20 pm
NeebruM wrote:MC 50's a tube though, isn't it??? (Hard to remember them all)
No, it's a mono version of an MC250. One of the early SS power amps.

Jim
 #77345  by Pete B.
 Tue Apr 06, 2010 1:12 pm
What is the lowest power Mac model that fits the Jerry factor (Powergaurd/Limiter/Autoformer)?
One that you can run wide open at a rehearsal space, for example.
 #77347  by waldo041
 Tue Apr 06, 2010 1:15 pm
Pete B. wrote:What is the lowest power Mac model that fits the Jerry factor (Powergaurd/Limiter/Autoformer)?
One that you can run wide open at a rehearsal space, for example.
as much as i hate to say it not owning one yet, the mc50, mc250 or mc2100 are all pretty similiar to the mc2300 on a much lower wattage scale. no power guard(the mc2300 doesn't have it), but with the sentry monitor(which may or may no need to be removed) and autoformer.

prices of any of them have now officially gone up due to the jerry factor!!! :?

peace,
waldo
 #77349  by tigerstrat
 Tue Apr 06, 2010 1:22 pm
Pete B. wrote:What is the lowest power Mac model that fits the Jerry factor (Powergaurd/Limiter/Autoformer)?
One that you can run wide open at a rehearsal space, for example.
Pete, Healy told me that the Dead's Macs didn't have the limiter.
 #77350  by SarnoMusicSolutions
 Tue Apr 06, 2010 1:53 pm
Pete,

the Mc50 is the smallest of that series. They never had Power Guard, none of them. They all had "Sentry Monitor" limiters which was our theoretical limiter that we heard in Jerry's tone. But recently Dan said Jerry's 2300 did NOT have the limiter, likely referring to the Sentry Monitor since its the only limiter that ever could have been there. From what we can gather so far, it would have had to have been removed by DH as Mac has no evidence that they ever released an amp from that series without it. So the theory has now morphed into the idea that Jerry's power amp clipping was pure transistor clipping, and not the previously speculated combination of clipping and Sentry Monitor limiting.

So the Mc50 is the smallest in the series. 18 lbs. and tiny. Very portable. And about as loud as a Twin Reverb since it actually peaks at about 75 watts. It's half the Mc250. The Mc2100 is a stereo 100wpc version. I think there is a Mc100 out there too, a mono half of the Mc2100. Lately Stu Allen has been using his Mc250, each half driving its own JBL K120. If one side of the amp fails, he's still got the other half going. I like that insurance.

Stu and I experimented with the Sentry Monitor limiter in place and removed, and we both agreed that at least with the Mc250, that the removed limiter sound was better. The distortion that resulted was cleaner and purer, less fizzy and complex. The Sentry Monitor limiter kicks in as the amp reaches distortion, and imparts a bunch of its own distortion as well on top of the transistor clipping. The sound with the SM limiter is weirder and messier sounding. The removed SM, so far in our testing, seems quite spot on JG. It does make the amp a bit more vulnerable due to the lack of peak-current protection, but if a player is careful and doesn't drive the amp WAY past its limits, I think it should hold up nicely. Only testing on a loud stage with real band volumes will tell how they handle the misuse. The theory still holds that much of Garcia's Mcintosh magic comes from the abuse and misuse of the power amplifier, driving it to and past its inherent power limits.

Brad
 #77352  by NeebruM
 Tue Apr 06, 2010 2:48 pm
one reason I'm thinking on the 752 is it doesn't have any glass to break, meters to worry about (who looks at them after awhile, anyway) and is rather light. It looks more like their old tube amps in a way.

You convinced me to try it for better bass cause I play a 335 and on full chords it's pretty muddy through the deluxe. It was a little better through the twin but not much.

So maybe I'll try this and let cha' know if I found anything worth checking out.
 #77353  by mijknahs
 Tue Apr 06, 2010 2:51 pm
Brad,

How easy is it to disengage the Sentry Monitor? It is as simple as de-soldering some wires or adding a jumper wire across?

Thanks,
Jim
 #77358  by SarnoMusicSolutions
 Tue Apr 06, 2010 4:09 pm
It's as simple as lifting the legs of a couple of components. No jumpering needed. I'll have to look at the easiest way to do it without destroying the transistors that are part of the SM. Then you can restore it easily enuf.

Disclaimer: If you fry your amp because the over-current protection circuit is gone, don't come after me.

Which amp is this for? I'll peek at the circuit and see.

Brad
 #77359  by mijknahs
 Tue Apr 06, 2010 4:16 pm
An MC2505 I recently picked up for $300. Lots of cracks in the glass but everything works and it sounds good. I'd like to do that to one channel only if possible.

Thanks,
Jim
 #77360  by SarnoMusicSolutions
 Tue Apr 06, 2010 5:09 pm
I'll need a Mc2505 service manual and your amp's serial #.


Brad
 #77361  by czyfingers
 Tue Apr 06, 2010 5:29 pm
Hey Brad,

If I could trouble you, I'd be interested in doing this to my mc 2120 also, (at my own risk of course) preferably one channel as well, if that's possible. I have a pdf of the service manual I could send you with the serial#.

Thanks,
Kevin