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MC40 pair

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The amplifiers power supplies and rectification for both B+ and the bias supply are located on the capacitor frame.  This assembly takes the bulk of the labor to rewire on this project.  The board holds capacitors for the tube circuits on one side and the resistors on the other.


The finished amp came out quite nice. 








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Now time to work on the second unit.   It's a bit different than the first unit.  I think it's an earlier production asset based on SN.


This is what I salvaged from the OEM assembly.  The power and output transformers, the capacitor frame, the phenolic circuit board and the tube sockets.  The electrolytic multi-section caps will be replaced with CE Mfg equivalents. 


The transformers show the extent of the potting encapsulant poured into each.  The output transformer is shown in the top and in the second photo.  Note the band strap clamp protruding from the potting.







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Excellent, thank you all for the nice comments.


I have a pair of MC60s here and one power supply transformer isn't providing any output voltage on the filament tap suggesting either a broken lead, or an open secondary.    I haven't gone into the transformer but it might be as simple as a cracked lead.  It the leads are ok something a bit more drastic will be required.  

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@John Warren 


Dr. Warren:


I referred a guy in another forum to you. He inherited two MC30 and an MX110 from his uncle. He lives in Boston, his Uncle, and equipment are in Omaha, NE. He has to have them shipped to him, suggested he call you first to confirm buying the shipping boxes from McIntosh or Vintage Audio (always worked for me) and discuss what is typically involved. Sent him links.



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