Modifying my Mark Levinson 332 for a unique visual experience


I bought a Mark Levinson 332 in very bad shape. It had some serious internal problems and the exterior was showing 30+ years of neglect. I wanted a Levinson amp since I was a teen but there was no way I could drop that amount of coin on an amplifier. Well after 30+  years this amp has finally found me and we have been friends ever since.

Internally is was a mess. It needed to be fully recapped, needed various components that were exploded and needed a complete voltage gain board that looked like it served a few tours in Iraq. After I made the repairs and dialed in all the adjustments all was good in the world.

An amp of this magnitude is not only an aural experience but there is a visual experience too, right?

Time to tackle the cosmetics. Initially I was going to repaint the covers that were faded from sun or smoke exposure. There were some ugly scratches in the paint too. I decided to strip the paint from the covers with acetone. I didn't realize that the top cover was some top quality aluminum and it was beautiful once the paint was gone. The TIG welds were precise and the surface was smooth. That got my gears going. I was going to take it to the next level and have a unique amp that no one else on the planet has. I was going to polish that high grade aluminum to a mirror finish. The front bezel received the same treatment, as well as the power button, which to my surprise was aluminum as well.

This amp pays tribute to so many other high end amps like Dynas and McIntosh that have some meticulously polished frames and hopefully it is one-of-a-kind. Others suggest that modding it in this manner will drive resale value down. That is not a concern for me. I think this amp is a keeper and now that it is polished I fell in love with it all over again.

Here is a public link to a photo of it:

https://drive.google.com/file/d/0B0yvjhlC62G7SHVJczc2ZUV2OGs/view?usp=sharing  

I welcome comments and thanks for looking!
generatorlabs

Showing 9 responses by generatorlabs

Thank you all for your kind words!

I bought it online with the knowledge that it was not functioning. I don't have any history on the amp but I do know there were very crude attempts at repair which probably caused more damage.  The vaporized voltage gain pcb is probably a result of amateur repairs. I am not tooting my own whistle here; I am far from a professional audio technician. I had more questions about how this amp worked than anyone! I did take my time and used sane methods to troubleshoot. An amp with power reserves like this is like a lightning bolt. It demands respect and we just have to keep that lightning controlled. I knew an amp of this age was going to need a recap anyway, so why pay premium for a working device that would probably need work? At least this way I knew it was done and could I document it. I also did many of the performance and safety enhancements that ML deemed necessary. As for the year it was built...I am not sure. There is no implicit date stamped on the back. There is only a serial number of 1618. I don’t know what the production rate of these monsters was but to me that number seems fairly low, so it could be an older unit. Thanks again.
@zavato  ...I stand corrected. I meant 20+ years. My mind is stuck in the era of the Model 23.

@jafant ...Currently the ML332 sits comfortably in my project studio. It has replaced a Carver amp which will soon earn a much deserved tear down and recap. It is being driven by a Ramsa DA7 automed console via balanced cables and it drives a pair of Event near-field monitors. Not an esoteric compliment of components but they do provide some exceptional sound.  The 332 is not really being challenged at all in its current environment but I will be damned if it does not look sexy lying there!

Eventually I may move the 332 to the main living space. I am certain it would outpace the Yamaha equipment there now. Baby steps.

I have always been an audiophile at heart but never in the practical sense. Could I get the gear? Probably, but the rational, responsible side of my brain prohibits me from making such purchases, especially brand new. I have always been the window shopping type, lurking in the shadows for the next good deal :)

Thank you all for your warm comments.
Thank you all for your positive feedback so far. Anyone who has seen it in person was really impressed as well.

I am glad I took the risk and will be lurking in the shadows waiting to find the next one to do a matching makeover on!
@hsam
Very Nice. May I ask where you got parts from.(Caps etc).
I got a 332 that needs a overhaul.

The main caps are available from Mouser.com
They are about $85.00 each. Part No. 598-3186GJ503M125DPA.
They are not exact replacements for the orginal Phillips caps but they meet or exceed the rating of the originals.

All the other smaller electrolytics were purchased from Mouser or Digikey.
You will not find exact replacements for small signal caps. You have to find suitable replacements with matching or slightly greater voltage, equivalent capacitance and equivalent size.

Mouser and Digikey offer a grid where you can filter down and find the appropriate replacement. As capacitor technology has advanced quite a bit since the late 80’s you will often find equivalent caps in shorter, denser packages. Mouser and Digikey offer top quality Nichion, Panasonic, Illinois and CDublier caps so choose your poison and then bring that glorious M.L. beast back from the grave.
@mohit789   You are in a very difficult situation. The ONLY way you are going to get any help from Harmon is by shipping your amp to them. An amp weighing 150lbs is not the easiest thing to safely ship. I don't think they will accept a shipment unless it is in the original box or crated. They will gladly sell you a box though. How nice of them :(   They will not sell parts to anyone except an authorized service center. I think the entire U.S. may have only 3 authorized service centers. Calling any of these service centers for parts support is a waste of time. They are strictly prohibited from selling parts as well. This is the one reason I do not recommend ML to anyone. They make great sounding gear but when the gear goes bad it will cost you ridiculous amounts to get it repaired. If you are willing to pay I am sure they will offer great customer service. If you cannot pay then their support sucks. I do not understand their business model. I would imagine your amp, requiring two PCB's is easily a $1200 repair. You can occasionally find parts on ebay but they are not cheap and they are not common. I had a few PCB's that I sold on ebay very quickly. What boards that remain, I will not sell for any price. If you do find a voltage gain board on ebay but it is for the wrong channel, be aware that the board can be used on both left or right channels BUT skillful de-soldering skills are required to relocate the headers and other connectors to the other side of the board. I would set up an automatic search for the ML parts you need so you can get notifications when they pop up on ebay. I wish I could offer you more help. I feel your frustration. Good luck on your search.
Pyramid is one of the 3 or 4 authorized U.S. based ML centers.
However mohit789 is in India so shipping a 150lb amp from India to Texas is a little silly. Pyramid does not sell any ML parts, not even a speaker binding post :(

@mohit789...you cannot post pictures directly in this forum. The best you can do is upload the photos to GoogleDrive, give the photos share permission and post the shared links here, just like I did with my opening post at the beginning of this thread.  As for the availability of parts, these amps are getting old. Someone correct me if I am wrong but I think the 333 has totally different output devices compared to the 332. I have seen photos of failed 333 boards. They are not pretty and they die a violent death. This may be partially due to the way the MOSFETs are internally mounted and flash up, carbonizing everything around them. The 332 uses external TO-3 can-type output devices. With that being said, I don't imagine there are a lot of failed boards that can be re-worked in the service channel. I don't know if Harmon still makes new boards for this model. They may be refurbishing boards at this point and you may be waiting on a good donor board. I am making assumptions though.
After looking at your pictures I have to correct myself. Your boards look exactly like the 332 boards. Your model just has a higher number of output transistors. The 332 has 24. The 333 should have 32. The photos of ultra violent failures that have been burned into my memory are from 336's that have internally mounted MT-200 style FETS. Sorry for the mix-up, as I don't get the opportunity to touch a lot of the other models.  Your current gain board looks pretty toasty. Some of those traces are probably vaporized. The only way to make that board work again is to clean it ultra good, cut out carbonized areas and get crafty with jumpers but it is going to be ugly and you could induce stray capacitances, etc. The components in that area of the board are readily available. The ideal repair is going to require a donor board for that channel. The voltage gain board looks like it may be salvageable in the proper hands. It is going to need a good cleaning and inspection but you may only need to replace those two small capacitors if no traces are damaged. You did not include pictures of the main board but that would plug in on the opposite side from your thermal event so it is probably still good. I would get manufacture dates from those main caps. The minute I saw them I recognized them as the original style Phillips caps. They have a high failure rate and most DIY techs replace them with Cornell Dublier caps. A secondary mylar shield is also now required between the caps and the aluminum frame to keep the outer body of the cap isolated. I imagine the caps expand and contract slightly and eventually rub through the original blue mylar coating. This is a documented inspection and repair point on all of the amps in this series. I would caution anyone against getting a replacement board and just plugging it in hoping it will bring the amp back from the dead. A faulty component upstream on another board could take out the donor board all over again. Comparative probing between the known good channel and the other channel will make swaps a lot more safe and help identify obvious bad components. Also you need to have the amp on a variac or some other current limiting method with the voltage dialed down to the minimum required to just make the amp operational. This will minimize violent failures during testing. The fuse on the amp is NOT going to save you. These amps have insane power reserves and will vaporize anything it can if you give it the opportunity. The amp is basically controlled lightning. I feel your frustration. I hope you do not have a lot of money into it. The best thing to do is wait for a scrapped out unit and buy a used current gain board or buy another used amp and make one good amp from two. You will eventually find a board or a good deal on ebay but it will take some time and a lot of patience. People trade in bad amps for new ones at high end audio shops. Most audio shops don't want to deal with violent failures and they can't get ML parts so they eventually part the amps out. I was lucky enough to get some ML boards from a police raid auction but it took a while. From reviewing the photos of my amps internals it seems the current gain board is ambidextrous, so you don't need to get a channel specific board. The thermal switch TS1 is on the upper right-hand-side of the board on both the left and right channels so outward appearances indicate they are the same board. If I happen to see anything I will make a note here.