That’s a gorgeous amp. I recommend sending the amp to ML’s authorized service center for complete check-up before you insert in your system.
Don't plug it in and turn it on. You will need to invest in a Variac. Set the Variac to 5 volts (AC) and turn on the amp and leave it at that voltage for at least six hours and then increase the voltage in 10 volt increments, with each increment at least two hours. This process will reform the power supply filter capacitors, which after 25 years are almost certain to be "dried out".
Or you can recap the amp. Pyramid Audio was quoting $1400 for cap replacement more than five years ago.
The big issue with old amps is the caps going dry, leaking, etc. and that’s what the variac should help you with. That is, they'll help you blow a fuse before you do too much damage. When those caps go bad they can take out the rest of the amp with them.
Before using though, open it up and take a look around the biggest caps you find. They’ll look like soda cans with screws. Check them for any sign of corrosion or leakage. If it looks like the Coke or Pepsi has seeped out even a little, or the cans are bulging have it serviced first.
Do the same for any of the smaller caps too. Inspect them for obvious bulges or leaks and at any signs of degradation take them to be serviced first.
Yeah, I would power it up with some care. At a minimum, make a dim bulb tester. But a Variac is the way to go. Capacitors that have been sitting so long, may not like the surge of power that the transformer will be dumping into them. Would really suck to have a cap go bad and then have it take out other components in its wake.
I was gifted a Marantz 7T that had been sitting for an unknown amount of time not being powered up. Before I switched it on, I replaced the power supply caps with some cheap ones as insurance. That, and as I don’t have a Variac, I used a dim bulb tester as “insurance”.
Clearly, this is an important piece of kit seeing as how it came from your father.
The cost to have it shipped and given a once over by a qualified tech would be money well spent I would think.
It’s a bit irresponsible to suggest firing it up as it’s not a land mine….. People shouldn’t comment on things they don’t know or understand. But that’s easy to do when dealing with someone else’s stuff.
It might not be a land mine but could be a soil your pants exciting experience. Like expensive cars, the repairs are expensive too.
I would definitely do an easy up on it. Spend the money and send it to ML service center. Or a reputable tech or service center. Remember the Mark Levinson that are in Lexus is way different than what you have!
I would look for freight shipper given the weight of amp and secure it on a pallet. It will cost you more but it’s well worth it. You don’t want to ship 150lbs amp via FedEx or UPS ground even if it’s in original packaging.
By any standard, your ML needs to be recapped. This is going to be expensive - at least $2K - but the amp shouldn't be used until it is serviced. I'm assuming that it has sentimental value and that you are going to run it in your system for some time. If that is the case then you are going to have to have it recapped. You may as well do it now before you risk any damage. If a board is destroyed the amp is likely to become a boat anchor. If it's like my Krell KSA 300S, replacement boards are rare or not available.
@ imhififan's comment is worth noting. It may not work to hook up a Variac to this amp because it may not trigger the power function with low voltage.
If you don't intend to keep it then I suggest that you sell it as is and don't turn it on. Explain the circumstances in your listing. This is a classic piece of gear and there will be buyers who will gladly take it off your hands in this condition. There are vey few amps available today that can double their power down to 2 ohms and they are extremely expensive. If someone is running vintage Wilsons, Thiels, Apogees, or other speakers with a brutal impedance curve, this amp was designed to drive them.
25+ years without power? Potential big trouble.
If it were mine, and I was short of cash, I’d pull the big caps and power them up one by one, very carefully with a variac, as @gs5556 suggested. And I’d put them inside a metal box beforehand - big caps can explode and throw caustic debris around. Then I’d let the cap under test sit, fully powered up, for a day. Then I’d turn off the power and see how long they kept their charge. Then re-install and power up carefully.
It doesn’t matter how good the quality is - an electrolytic cap is an electrolytic cap, and they do age. A sensible technician will power up his unused test equipment every month or two just for this reason. And some of that stuff, like my vintage Tektronix scopes, cost as much as a new Mercedes back in the day. That’s quality parts.
Or, you could just install new electrolytics. If it were mine and I had the cash, that’s what I would do.
Just an amateur, but I've been doing this for 20 years. Actually, electrolytics usually go bad with heat, not use. They dry out. So, the power supply for my main amps is located in another room, a cool one, with all electrolytic caps well below all sources of heat.
Given the value of the ML piece, 25 years is pushing it too far. IMO.
My suggestion is to look inside first to make sure that it not too dusty or any dead fauna, insects etc inside. From personal experience I can tell that it’s very common to find some dead insects inside old equipment. Clean it if needed and live it ON for a couple of hours, not connected to anything except power, observe it, smell it for any burn. If everything looks fine then clean all the contacts with contact cleaner, make sure if the specifications are corresponding with your system and connect it to the system. Start to listen from lowest volume.
Thanks again for all of your inputs. Some more background on this particular amp that it occurred to me I should’ve mentioned at the outset.
This amp likely has very, very few hours on it. It was used with a a pair of B&W Matrix 800 Series Ones. He quickly switched to Jadis electronics (which I also have and need to revive) and never looked back. I’m surprised he kept the ML335 but he might’ve been thinking “bi-amp” but didn’t get around to it.
All of his system is in storage, brought back from FL to the PNW and I’ve been wanting to integrate some of the components into my system until we move to a home I can set up the entire rig again.
The idea of having clean, effortless power for my meager 1+1s is rather enticing!
@mofimadness i think that amp needs some larger panels to take advantage of all that power. I have Spectra 33's along with a pair of TNT200'S, monoblockeded. Everything modified and upgraded by Roy Esposito.
That's a BEAST of an amp.. I would be willing to trade my 2 amps for that Beast... Would love to hear that on my panels ...
@gumbedamit...totally agree! More panels are ALWAYS better!!! That is indeed a fantastic amp.
Your Spectra 33's are one of favorite Acoustats. Only surpassed by the 66's.
Nice system! Roy does excellent work.
@musicfan2349 I seem to remember an article i read saying Levinson (Harmon) no longer services ML amps that are older than before Harmon purchased Madrigal Audio Labs which included Levinson--ie amps they didn't manufacture--but Harmon will refer owners to a third-party expert to fix/service--you should call them first to see if that's true or my memory is failing (which it is ever more every day!)
Circling back: I spoke to Chris at http://www.pyramid-audio.com/levinson.html
He was quite friendly and helpful regarding my ML335. As you can see at the link they have quite a bit of experience with ML gear. They also have engineers that specialize in the differing series, e.g. 400 vs 300.
He also gave me some great advice concerning packing and how the original foam may be deteriorated enough that it won't do the job. How thoughtful is that? He also said that UPS Ground will be fine.
Without seeing it he guesstimated $1600, $2200 if it needed the four big caps replaced. Considering the price of audio these days? Money well spent. They'd also check the smaller ones that can melt their boards if they fail. (yikes!) So yeah, I'll be sending it in here in a few weeks. Will update y'all in a few months.
Thank you again for your helpful advice and encouragement.
@musicfan2349...you sure have more will power than I. I would have had that amp up and running minutes after I got home. Patience I have not. 🤪
Probably for the best to send it in.
Let us know the outcome...
@mofimadness believe me, until I posted here I was on course for exactly that!
However, sometimes I actually use my big head to think things through. 25 years is a long time for electronics to lie dormant, especially something as sophisticated as this. It might've worked. Or I may have courted disaster needlessly. Some of those boards are unobtanium... So I wanted to do it right.
Besides, the thought of facing pop in the afterlife if I blew up his stuff doesn't bear considering! 😏
Now that I must say is a wall of drivers sitting as a certain curtain backdrop! If I were you & you were me, without hesitation I’d let electricity in & fire up. Correct me if I’m wrong, but the ML-335 came standard with soft start protective circuity? Wouldn’t mind owning such Instrument or perhaps just a comparison against Dan ModWright’s (Lead, Alan Kimmel) KWA150 Sig. Yes, foolish of 150 to even contemplate a first place medal.
Big Boi rapper from OutKast, album Speaker / Boxxx cover art, sides A thru D I’m reminded of.
Sorry, circuitry. Reading glasses elsewhere, honest typo. Killer amp btw … designed & built on excellence possibly exceeding any individual’s lifespan. In agreement of others on when their is doubt send out for diagnostic.
Praying maybe for a day where OBD2 / Scanners are standard protocol on equipment starting at $10k and above. Sure would help DIY repairs.
Older unit and nowhere near the performance level of your Levinson but a Yamaha CR series receiver took me 12 rounds & one month before narrowing down to one faulty output transistor out of four. Many of us would decide replacing all four at this point, much wiser. And since the unit was opened up decided replacing yet (again) the dial LED cursor bulb which was blown, though I’d completely forgot they’re wired in parallel! Poof, two outta three boutique fuses destroyed.