Ampex Repro Card Cap Replacement
« on: July 12, 2005, 12:37:33 AM »
I've finally got some time to do a little more in depth maintenance on an Ampex MM1100 that I have.  Curious what type of caps should be put in place of the old sprague and mallory electrolytics?  Atoms, BC components or are there some others that may be a little cheaper cost wise that would compare with the existing ones?  I think there are at least a hundred or so in there.  Thanks.

Nate


gyraf

Ampex Repro Card Cap Replacement
« Reply #1 on: July 12, 2005, 02:56:07 AM »
The 1100 was made back in the days where even the best and most expensive electrolytic was far inferior to today's types. I would use any audio-type available at a decent price..
..note to self: don't let Harman run your company..

Ampex Repro Card Cap Replacement
« Reply #2 on: July 12, 2005, 10:34:43 AM »
So I take it that the Atoms and BC would be overkill.   I guess I just need to figure out what other electrolytics are "audio" grade.  Any econo suggestions say from like digikey or mouser?

guitarmaker

Ampex Repro Card Cap Replacement
« Reply #3 on: July 12, 2005, 11:14:39 AM »
I used Atoms in both the repro and record cards on my 440C-8.  I would highly recommend replacing the electrolytics on both these cards as well as any other Mallory electrolytic you spot anywhere else.  They are all trouble from this era as said before.

Steve

Ampex Repro Card Cap Replacement
« Reply #4 on: July 12, 2005, 12:13:22 PM »
So those mallory caps aren't good.  Any noticeable changes with the atoms?  Any other maintenance things I should do while I'm doing the caps?

soundguy

Ampex Repro Card Cap Replacement
« Reply #5 on: July 12, 2005, 12:55:30 PM »
well, if you want to do it right, I would replace EVERYTHING except the transistors on those cards.  Yes, everything.  You will have an ill machine after that but its obviously a huge amount of work.  One place where calibration is a mess is with those pots on the EQ.  Replacing those with modern trimmers could be better than recapping depending on the age of the card.

all depends on how crazy you want to get and what degree of performance you are looking to get out of the machine.  Get rid of the power supplies while you are at it too.

dave

chips are good with dip...

guitarmaker

Ampex Repro Card Cap Replacement
« Reply #6 on: July 12, 2005, 03:27:16 PM »
The thing about those old electrolytics is that they can prevent the thing from calibrating properly.  They screw up the frequency response something fierce.  I would replace all the electrolytics in the repro and record cards as a starting point.  On my 440C there were a couple more coupling caps inside each electronics chassis that needed to go too.  Check the freq. response and go from there.  FWIW I also had some weak transistors that kept the low freq. from calibrating on a couple of channels.

Steve

Ampex Repro Card Cap Replacement
« Reply #7 on: July 14, 2005, 02:28:40 PM »
So what would be a good replacement trimmers?  And you'd really replace all of those resistors?  And how about those tantalums and mylars?  Maybe I'll just start with the caps and maybe trimmers.

soundguy

Ampex Repro Card Cap Replacement
« Reply #8 on: July 14, 2005, 04:03:27 PM »
It really all depends on how screwed up the cards are and what degree of reliability you want to get out of it.  Its obviously easier to change all the caps first, Id start there.  The trimmers in mine were a problem, so they wound up going next, I dont recall what I put in their place it was a long time ago.

dave

chips are good with dip...

Ampex Repro Card Cap Replacement
« Reply #9 on: July 15, 2005, 04:51:22 PM »
Well I just got my elec. caps, but it looks like some of the channels
elec. caps have been replaced with 100uf caps instead of the others
which have the original [email protected] and 25v cap values.  Any reason
why there would need to be an increase here? All other compenents
are the same throughout.

I imagin I should put in the original values, but was curious what
should be done.  Any ideas?  The Tape Machine seems to be in really
great shape.  It was from the CBC in Canada and looks to be really
taken care of.


Ampex Repro Card Cap Replacement
« Reply #10 on: July 16, 2005, 04:07:18 AM »
Here's another option if you don't want to rebuild all the cards:

http://www.rtzaudio.com/ampex.asp

But since you're in it already, yeah, replace the tants too.  Some folks claim you *shouldn't* replace the Sprague 30D type 'lytics but I've always kind felt that was dubious advice.
"The pen is mightier than a flamin' bag of poop."  --Dr. Bartholomew Simpson

Ampex Repro Card Cap Replacement
« Reply #11 on: July 16, 2005, 02:18:03 PM »
John Atwood's (One Electron transformer fame) 440C resto journal, may provide some useful info for you, may not.

http://www.one-electron.com/AG440C/Journal.html
"The pen is mightier than a flamin' bag of poop."  --Dr. Bartholomew Simpson


 

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