#127731  by redeyedjim
 
I don't know that there's a right answer to this question, but I'm curious what you guys think about modding a rare amp for safety and/or ease of use? For example, if an amp still has the original two prong power cord, is it OK to have that upgraded to a grounded cord? Is it foolish NOT to? Same sort of question with older McIntosh amps that have an RCA input jack and use a terminal strip for output: Is it OK to change these to 1/4" phono jacks, or does one make do with adapters?

Case in point: After 2+ years of looking, I recently scored a McIntosh MC100. Woo hoo! I'm psyched! I want to have some basic maintenance done to it -- I assume the caps need replacing, for example, and it still has the stock two prong power cord, which should likely be upgraded for safety's sake. If the amp weren't such a rarity, I wouldn't think twice about also having the same mods done to it that Jon S. had done to his MC50 (toggle power switch, dedicated input and output jacks, etc.) But it is a rare beast, and I feel a certain amount of stewardship towards it. I intend to use it, but at the same time, I don't want to screw it up. I assume the safe answer is to upgrade the power cord, replace old caps and drifted components as necessary, and use adapters for the input and output connections. But I'm curious if there's a standard for this sort of thing?

Any thoughts?
 #127732  by Jon S.
 
You're making a piece of home audio equipment safe so you won't die using it and adapting it for a musician. That's as kosher as a pastrami sandwich at Ben's in Manhattan.
 #127734  by redeyedjim
 
Thanks, Jon (update: and gmchart). By the way (and in case you couldn't tell), I love the work you had done to your MC50! apart from the external facing changes, did you also have the capos replaced or anything done internally? And is Classic Tube Audio a good place to take my amp?

Thanks -- your posts are a great resource, both here and on TGP :smile:
 #127737  by redeyedjim
 
Smolder wrote:Unless its museum quality, and going into one, make it safe and play it. Anything else is just silly.
Fair enough, thanks. And for the record, although the badging is complete, it certainly isn't museum quality -- the finish is faded and scratched:

Image

I bought it to play it, so I might as well make it more playable.

Thanks for the advice.
 #127742  by TI4-1009
 
I've heard of top-notch techs that will refuse to work on any amp (including rare/vintage) unless it is or they can mod it to make it safe- as in a three prong.
 #127751  by Mr.Burns
 
It's your amp, do what you like to it. I don't think you have to worry about going to Hell for modding your own equipment, so the only thing to consider is the resale value. After spending two years tracking it down, it seems unlikely that you would part with it anyway. These are rare, but anything you can repeatedly find on ebay isn't so rare you should worry about modding it.
 #127761  by Jon S.
 
redeyedjim wrote:Thanks, Jon (update: and gmchart). By the way (and in case you couldn't tell), I love the work you had done to your MC50! apart from the external facing changes, did you also have the capos replaced or anything done internally? And is Classic Tube Audio a good place to take my amp?

Thanks -- your posts are a great resource, both here and on TGP :smile:
Thanks for the kind words. :oops:

Yes, Pat Hickman at Classic Tube Audio went through the entire amp and replaced or upgraded everything that needed it (which did not include the main caps - I offered to pay for replacements, Pat told me they tested fine and not to touch them - very cool). His work on my MC50 was both substantively sound (the unit sounds great and is so punchy and loud) and aesthetically perfect. He did it in about 7 weeks, if I recall correctly. This was a bit longer than he'd quoted me at first but the delay was due to a family issue (a death) beyond his control and he communicated with me throughout and still completed the work more quickly than any other quotes I'd gotten.
 #127765  by Pete B.
 
I bought an MC250 that Brad Sarno had gone through himself. When it arrived I asked him about the 3-prong plug, and he said it didn't need one. I don't see a ground switch on it either. I haven't been shocked or a had any ground noise. It looks like the original 2-prong plug is still on there.
On the other hand, I bought a '70 Fender Dual Showman Head, and on the way home from picking it up I stopped at the "Amphead" shop (our local repair/mod guy), and had him install a brand new (long, sturdy) power-cord with 3-prong plug. I have momentarily seen god a few times when touching lip to mic using Fender amps, or had an annoying buzzing sound, and sometimes could fix/reduse the problem by flipping the ground switch if there is one.
Carrying one of those electrical outlet testers is a good idea.
 #127769  by Jon S.
 
Not that it mattered for me - I went to a detachable IEC outlet and cord - but it seems to me grounded plugs for all gear other than 18V or below wall wart types. But I'll listen to a substantive explanation why someone might not.
 #127843  by ugly rumor
 
That's as kosher as a pastrami sandwich at Ben's in Manhattan.

One of my favorites! I'm surprised and pleased to see them mentioned here! Makes any trip to the City worthwhile!
 #127940  by mgbills
 
I'm in the camp of feelin' groovy about mods. Especially sensible mods like a grounded cord. It does raise some ground loop questions, but I use a Furman thingy, and have never had noise issues. For me...it's bringing new life to a great great piece of US manufacturing.

For those of you who are thinking of McIntosh work...here is another plug for Classic Tube Audio. Pat Hickman is awesome. He did my Mc2100, and he'll do my Mc250 when it needs work. I love the idea of a switch on the unit, and I'll ask him if he could create a Standby.

Totally professional. Totally thorough. Much less expensive than others I've seen quoted here. Not cheap. Not over-priced.
Peace
M
 #128016  by Pete B.
 
Concerning the 2-prong to 3-prong power cord question, here is an email exchange from Brad that covers the topic:

On Dec 17, 2010, at 1:29 PM, Pete B. wrote:
Hi Brad,
Hey do you think it is OK for the MC250 to live on top of my E120 cab?... I'm guessing it'd be about 6-8" above an E120 magnet.
'Just wondering if there is an electro/magnetic concern to the MC250?
One other quick question... Do these units need to have the power cord updated to 3-prong?... or is the 2-pronger on there good to go?
Thx,
pete b.

Re: MC250:
No problem with the magnetic field. Some would argue that it's better to isolate an amp from the physical vibrations of the speakers, but that too is no big deal.

No need to update to 3-prong. No seriously high voltages in there like a tube amp. The 2 pronger also eliminates ground loop hum.

B
 #128018  by redeyedjim
 
Thanks, everyone, for the feedback and suggestions.

An update of sorts - I received the amp on Tuesday, and it sounds pretty damn good as it is: quiet, great tone, and with plenty of power at hand :-) I may hold off on getting it serviced for a while, until my "gear fund" has recovered a bit. But I'll keep these suggestions in mind for when I do send it in for a tune up.

Thanks.