# Amp Restoration



## JHUSTON (Jun 19, 2014)

I am able to Re-Anodize just about ANY color of heatsink and/or powdercoating. These processes I have completed and I can also swap parts for restoration. I do not engineer this stuff so I do not put the fancy big caps, etc. I keep on hand Muse KZ, Elna Silmic II, and some OS-CON. I also have all series of Wima MKS/MKP as well. I swap typically part for parts in restoration but I am willing to increase the capacitance of the power supply, etc. at owners request.

Mostly please see pictures for an understanding of what I am offering.

Here is a OLD, BEAT UP McIntosh amp I restored. Before/After


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## EriCCirE (Apr 14, 2010)

Well, since this is a DIY site... Care to write up a brief tutorial, or point other in the direction of where you have picked up these skills?


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## JHUSTON (Jun 19, 2014)

Sure, For my line of work we do Ornamental and light structural steel (amongst other things) anwya, working with most non-ferrous metals (aluminum ie) can be a very unforgiving material. I have learned this in the hard way! When I do aluminum anodizing it is always easier and best to remove the old anodizing to truly see what the heatsink looks like raw. I have a local anodizer that happens to be world class and one of the few that still does bright dip anodizing. anyway, I have them remove the anodziing by placing the items in acid for a short while. Once back from stripping the old finish I begin sanding the worst areas with 120 grit on a pneumatic angle grinder. Its very tedious and you must watch for swirl marks, and cutting divits, etc. once I cut the worst with 120, i swap to 220 and start cutting the areas back down. then on to 600-1000 grit. after the 1000 you should nearly see a mirror finish. I then take a scotch brite pad and 00 steel wool which will identify any areas needing more work. The anodizing will bring out things you would NEVER see as an issue. You may be badly surprised when things come back with areas you never seen prior. Anyway, once I have my area sanded and tested if brushed I start this process. I typically use a block, etc. for a hard flat surface wrapped with 120-220 grit sand paper. This is dependant on the harshness of brush look. YOU MUST SAND 1 direction North/South or East/West. and it MUST BE STRAIGHT. if you go any direction besides straight the brush effect will NOT look good. I use my finger as a guide down the side of the material, etc. to keep my block straight. Once I am ok with all the brushing effect I once again knock down with scotch brite and pack with paper as to protect. Side Note: You can not have any stickers, adhesives, heatsink grease, etc. left on amplifier as it WILL infact create issues in anodizing.

Once amplifiers come back newly anodized I start assembly. If an amplifier is older I feel recapping with value for value is best. I believe this amplifier engineers spend great efforts in their sonic characteristics so I do not alter. That said I will upgrade to Panasonic FM, Elna Silmic II, or OS-CoN, and Nichicon MUSE KZ/FG series. I also tend to replace Foil type with Wima MKS2/4 and MKP2/4 I use Dow Corning 340 heatsink grease and reassemble. Let me clarify I see nothing wrong with increasing storage capacitance or filter capacitance I just do not know enough to make those decisions. same for bypass capacitors. 

Hope this helps EriCCire


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## vwguy383 (Dec 4, 2008)

Sweet right up. I know some of my favorite DIY on here are ones that people do about amp restorations. I think a lot of people also too. Its one of those things that people would love to do but A. Don't know where to start, or B. Don't know how to do it. lets see some write ups of some that you have done. That would great!

Thanks
Justin


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## RandomBeat (Aug 23, 2014)

thanks for all the info! Thats great of you to offer us some words of wisdom! And if im reading correct, you are offering up "amp restoration" services, correct? Including refinishing heatsinks, and some simple cap replacement? No other repairs, correct? ( i have one amp that needs restoring, and one that needs repair, hence my question...)


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## JHUSTON (Jun 19, 2014)

I am more into restoration and minor repair. That is due to my short amount of experience in repair. Hope that helps


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## Victor_inox (Apr 27, 2012)

JHUSTON said:


> I am more into restoration and minor repair. That is due to my short amount of experience in repair. Hope that helps


When you replace a lot of parts in process of restoration there is a high possibility you fix it in process.


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## ATOMICTECH62 (Jan 24, 2009)

Those caps leak on the board and other parts like resistors and opamps need replaced also.I had one that got into the pot for the VU meter and the switch for the EQ circuit.This is what causes the amp to start popping.It causes DC in the audio chain which in turn causes semiconductors to start dropping.
The protection circuit doesn't work all that great on these Macs.Ive seen channels go completely out on them while the others continue to work.When I see a Mac that is in protection then its really bad off.Im doing a 431 for Macs right now and its got a problem with the Power Guard circuit from a leaky cap.Of all the Dozens of these Ive done Ive never seen one effect the PG until now.


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