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Vintage receiver, keeping it as close to original as possible

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Good morning/afternoon guys/gals.

Disclosure;
*I am not a DIY guy, I do not do my own repairs, other than simple soldering of something like a wire coming off. My point is that I’m not a technician, nor do I want learn how to do any of this project myself. I am willing to learn, but this is out of my league*

I am looking to purchase a Marantz receiver from approximately the mid-1970s too late 1970s, and I believe I have settled on the 2385. after reading the what’s on your bench right now thread that’s going on, I came across some really interesting posts, especially by @restorer-john and some others. I hope he does not mind me tagging him here because I would really appreciate his input as well some of you guys/gals that do rebuilds, and have the experience that I lack, so I can do this correctly.

Please don’t try to change my mind about what model # or brand, and although it’s not set in stone as of yet, the answers I’m seeking can pertain to any piece of gear being rebuilt IMO.

This era in my opinion was a very good one, and there were real manufacturer battles, for specs, for looks, for features, for everything. There are good offerings from Sony, Yamaha, Onkyo, and others and you may be able to flip a coin and have yourself a very nice piece of gear indeed.

I was going to buy (eventually) one of the Marantz units already serviced, buy I’m glad I did pull the trigger yet. Because it was being discussed on the thread that I mentioned earlier about the sonic properties, the sonic signature, how that piece of gear from back in the day will sound with modern parts.

It was also suggested that I try to find one that has not been touched, and original, and one that hasn’t been “rebuilt” and yes everybody seems to have a drawer full of capacitors anymore, and the first thing I see is just that… it’s serviced, rebuilt. I’ve seen them and so have you, dented in metal case, dings everywhere, and you can let your imagination run wild as to what that poor piece of equipment went through.

Let’s say I find a good one for a decent price and it’s original and untouched as far as anyone knows. Let’s also say that it needs some capacitors, although my experience tells me that they’re all not going to be bad, and some will likely fall within spec.

What led up to this seeking out of what some consider a relic and a waste of time from audio yesteryear? Just about the time I was able to drive, some of the late 1970s Marantz‘s, Yamaha‘s, and others were on display at a local audio store. you guys remember the stores, the ones that used to be packed with people especially on Saturdays and evenings, and that’s what we did… we demoed. But this is not the only reason, because they are very good performers, and they look amazing.

I find my present preamp (one of them) unengaging, although it was measured as one of the best preamp‘s on the planet. Don’t get me wrong, it is all that and maybe more, and coupled with my amplifiers and speakers, very revealing and if you don’t have a good recording it’s going to show up. Anyway I thought it lacked character, and it’s sitting collecting dust, because although I wanted to like it, I just don’t.

There’s something to be said about vintage gear, and I’m trying to pick an era when it was done right, and without some of the hiccups of earliest solidstate, and before some of these companies started plasticizing everything, and putting in cheaper parts.

When/if I find the correct piece of gear chances are there’s going to be some capacitors, transistors, whatever it may be that needs to be replaced, or something needs to be aligned.

Are my choice of capacitors or other parts going to change the sign of characteristics of this and other pieces of vintage gear?

Are there other areas or pitfalls that I need to pay attention too?

In the US, does anyone have experience with a technician that I can trust to take the time to get this project right?
 
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sergeauckland

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My approach to vintage gear, and I'm a fan of old stuff, is to try and get it as original (unmolested) as possible, then first off, measure what it does, and compare it with the spec. If it meets spec, it ain't broke so no need to fix it. Maybe some cosmetic cleaning up and polishing, maybe some contact cleaner in the pots and switches, otherwise leave it alone.

If it doesn't meet spec, or switches and pots are crackly, then it may need some work. 40-50 year old power supply reservoir electrolytic capacitors could well be changed if there's too much 100-120Hz hum, other electrolytics as well if distortion is high or the frequency response is off, especially in the bass. Polystyrene and other plastic film capacitors rarely are faulty. Similarly, low power resistors tend to be OK unless clearly overheated, or very old cracked-carbon resistors used up to the mid 1960s.

Noisy pots and switches are probably the hardest to replace as there are mechanical considerations insofar as they have to fit the boards, have the right type of knob fitting or the right number of ways. Wafer switches can be a real bugger to replace, as can banks of push-buttons.

Whilst I love the look of these classic receivers (I have a Yamaha CR1000), they are complicated to work on, have lots of knobs and switches, and it may not be (financially) sensible to restore them fully, just accept some faults, e.g, the loudness control doesn't work, or the treble tone control is scratchy.

As to the tuner section, realigning a fully analogue tuner is certainly possible, but there are much fewer technicians about who have RF test equipment available (and know how to use it!) Unless FM (and AM) is important, then you may have to accept that the alignment of the tuner isn't as good as it could be.

Apart from that, I love the idea of keeping this old stuff going and out of landfill.

Good luck with the search. The Marantz 2385 is a beauty.

S.
 

restorer-john

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The issue/s of course are these:

You buy an vintage product, you find a trustworthy tech and you get him to fully test the piece from end to end. He says it's fine and to spec.

You ask him what it needs and he is perfectly honest and tells you it needs absolutely nothing right now, but he cannot predict what it will need in the future as the item is already way past its service life and every component inside is technically not just outside the bathtub curve, but into uncharted territory. Like going where no man has ever been...

What do you do and what does he recommend? What can he recommend when you say to him "I want it to last another 40 years. I want to give it my grandson"? He recommends a complete rebuild as components can only last so long- or can they? We don't actually know.

I have amplifiers that are 50 years old and untouched. Test as good as the day they were made. I have 30 year old gear that is perfect- Sony ES from 1990/1/2 that I will not touch, only if and when it needs it. It tests as new in every respect. There is zero deterioration.

Old capacitors from the major Japanese manufacturers have proved to be phenomenally reliable. Of course there are failures. Bear in mind, people like me (extreme vintage aficionados and hard-core restorers) generally only see stuff that needs work, is already dead or someone wants it to last a century. Transistors become noisy, particular and known types, as well as random ones. That is easy and obvious to solve. Wholesale shotgun replacement of all semis is not a 'restoration', it is a lazy man's gloss-over job.

I guess I'm saying there is no one answer. Every piece of gear is different and every approach is tailored to the specific product, the way it was treated, repaired or stored. Its original design- was it poorly built, full of design flaws or just not a good piece of HiFi in the first place?
 
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Perfect thank you.

Ideally this is what will take place, and I really don’t want to talk upgraded capacitors, and other items. If it last 40 more years I’ll be passing that down to one of my children, and that’s exactly what I’m looking for. Thanks for the post.
 
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Bump;

Anyone want to comment on my above post, if it’s true or not that changing the larger black parts that sit next to the transformer will or will not change the sound signature of that receiver?
 
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I'm far from an expert but these look like motor run capacitiors, they are meant for motors. I don't know why you would put that into a reciever. A proper electrolytic/film capacitor is usually what you find in there.

If you replace a failed part with a part that has similar specifications it will sound exactly the same. There are people who play around with fancy capacitors and resistors and claim they sound better, but this hasn't been shown to change measurements or improve things and may actually decrease performance. It looks like someone has been "hotrodding" that thing. If you want it to sound like original I would suggest looking for another receiver that hasn't been tinkered with in this manner.

You could also check hifiengine and try to find a service manual to check if the new parts are within specifications, but I get the feeling this may be more trouble than it's worth.
 
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Looking at it, I would say that they have something to do with the main power transformer.
 
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OK. Sometimes those large vintage capacitors are difficult to source in the correct size and value, so substitutions are often required. It's possible they used two in parallel to increase the capacitance and there's nothing wrong with doing that. Like I said if they put another capacitor (or more in parallel) of the same specifications in there it should sound the same.
 
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OK. Sometimes those large vintage capacitors are difficult to source in the correct size and value, so substitutions are often required. It's possible they used two in parallel to increase the capacitance and there's nothing wrong with doing that. Like I said if they put another capacitor (or more in parallel) of the same specifications in there it should sound the same.
That would make sense, and yes putting them in series is definitely done to get a certain value like you said. It’s just the first one that I’ve heard of like that, and every rebuilt Marantz receiver I’ve seen retains those large capacitors. But that doesn’t mean that it’s not done just because I haven’t seen it. That’s why I wanted one of the vintage rebuilders to comment and I’m sure they will.
 
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not series, parallel, it'll make a difference in the final output. series will diminish capacitance. it depends on one's objective how they are installed but generally the larger ones are more difficult to source.
 

mhardy6647

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The big black cans are the power supply filter capacitors. It should be possible to get "close enough" substitutes (higher working voltage is fine; capacitance "in the range" of the nominal value, tending towards slightly higher, should be fine, as well*). The trick is the "form factor" -- IMO this is the time one has to face facts -- 1975 (give or take!) was a long time ago; do you want the component to work or to look like new? I.e., acceptable replacements can be "MacGyvered"** in! :)
Yes, capacitances in parallel are additive, as mentioned above -- many ways to skin the metaphorical cat.

I will say this: the high-power Superscope-era Marantz receivers are big, heavy, complicated, and rather fully packed. I don't know about the 2385 in particular, but they tended to be pretty unreliable, both back in the day and perhaps even more so now. Do some searches on woes with big Marantz receivers at 'vintage audio' forums like audiokarma.
The lower powered Marantz of that era are probably going to be a lot less trouble in the long run, unless one is hell-bent on that testosterone rush of more power a la Tim "the Toolman" Taylor***! ;)
(just opinions, obviously -- but not arbitrarily formed opinions)

___________________
* The 'tolerance interval' for the nominal capacitance specification for electrolytics in the 1960s and 1970s tended to be very wide.
** Do you know the MacGyver TV series? He was a guy who'd jury-rig solutions to his pressing problems, to great dramatic and even comic effect. :)
*** Do you know the TV series Home Improvement? The lead character, Tim, was all about manly manhood (nowadays, we might call it 'toxic masculinity') and MORE POWER. ;)
 
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The big black cans are the power supply filter capacitors. It should be possible to get "close enough" substitutes (higher working voltage is fine; capacitance "in the range" of the nominal value, tending towards slightly higher, should be fine, as well*). The trick is the "form factor" -- IMO this is the time one has to face facts -- 1975 (give or take!) was a long time ago; do you want the component to work or to look like new? I.e., acceptable replacements can be "MacGyvered"** in! :)
Yes, capacitances in parallel are additive, as mentioned above -- many ways to skin the metaphorical cat.

I will say this: the high-power Superscope-era Marantz receivers are big, heavy, complicated, and rather fully packed. I don't know about the 2385 in particular, but they tended to be pretty unreliable, both back in the day and perhaps even more so now. Do some searches on woes with big Marantz receivers at 'vintage audio' forums like audiokarma.
The lower powered Marantz of that era are probably going to be a lot less trouble in the long run, unless one is hell-bent on that testosterone rush of more power a la Tim "the Toolman" Taylor***! ;)
(just opinions, obviously -- but not arbitrarily formed opinions)

___________________
* The 'tolerance interval' for the nominal capacitance specification for electrolytics in the 1960s and 1970s tended to be very wide.
** Do you know the MacGyver TV series? He was a guy who'd jury-rig solutions to his pressing problems, to great dramatic and even comic effect. :)
*** Do you know the TV series Home Improvement? The lead character, Tim, was all about manly manhood (nowadays, we might call it 'toxic masculinity') and MORE POWER. ;)
Thanks for responding.

Most of them that I see still working, and even ones that guys have had recapt still have those large filter capacitors.

Is it possible that they are within spec after all these years and that’s why they reuse them?

What would happen if they were out of spec?

PS;

As good as MacGyver was he can stay away from my two channel setup lol. Wrapping tin foil around blown fuses does not sound like a good idea anymore

As manly as Tim was, he isn’t or others like him are not getting anywhere near my gear.
 
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sure better parts can work fine for many years, I think 30-40 years for good parts is generally accepted, but some do fail and drift. Tell tale signs are mishshapen, corroded and material leaking from enclosure. The only way to be totally certain is to measure the gear and/or the parts. If the parts are still in spec they will work. If the gear is in spec then that's OK too. Depending on how bad they are performing will determine the symptoms,i.e.- power surge, power drop, loss of output, noisy, channel imbalance, etc. If this amp was serviced by a reliable tech, that should have all been addressed. You have seen other builds with original caps so I would assume they can be OK.

as mhardy stated there is some forum chatter about trouble with some builds. You might try Audiokarma to find out about what to check for with this build. Unless, of course someone here can chime in with specifics.

This is kind of the joy and pain of vintage gear.
 

mhardy6647

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Thanks for responding.

Most of them that I see still working, and even ones that guys have had recapt still have those large filter capacitors.

Is it possible that they are within spec after all these years and that’s why they reuse them?

What would happen if they were out of spec?

PS;

As good as MacGyver was he can stay away from my two channel setup lol. Wrapping tin foil around blown fuses does not sound like a good idea anymore

As manly as Tim was, he isn’t or others like him are not getting anywhere near my gear.
In terms of your last two comments -- well, that's good! ;)

Could they still be good? It is possible -- it's not likely. The useful life of electrolytics (especially of the 1970s) is maybe a decade... maybe two. Not four or five. That first filter capacitor in a linear DC power supply has the hardest life and is, a priori, the one most likely to be 'bad'.

Symptoms of 'bad': First and foremost, audible hum (even with the volume control turned fully down).
I am way more familiar with higher-voltage power supplies for vacuum tube amplifiers. My test procedure (which, mind you, I am not advocating) for HV power supply filters: Fire up :) the component (we typically bring 'em up slowly with a "Variac" variable autoformer) and run for a few minutes at steady state (if it will do so). After running for a little while, I (yes) feel the electrolytic 'can'. If it is "cold" (ambient) and if there's no P/S hum, the cap's probably OK -- at least for now. If it is warm (and the warmth isn't coming from a nearby component -- in my case, e.g., a vacuum tube HV rectifier, which gets hella hot) the cap's on its last legs (or already... umm... Tango Uniform, as ex-military types might put it).

Now, one other thing about electrolytics (again, mostly from HV P/S experience) -- they don't like disuse, but (like rogue politicians and Abominable Snow Monsters) sometimes they can be reformed. The process involves slowly increasing the AC voltage 'felt' by the capacitor over some period of time... and is out of scope for this discussion per se.

EDIT: A modern capacitor tester (capacitance meter) won't tell you much about the health of a power supply filter cap. A modern ESR (equivalent series resistance) meter can give insight into the health of a capacitor. An old-time capacitor tester (e.g., a Heathkit or EICO) is much more useful for testing the actual "capability" of an electrolytic, at least of the HV kind.

Heathkit_IT-11.jpg
 
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I’ve been looking on audiokarma and other sites, quite a bit of info out there about the 2385. The general consensus seems to be that it is pretty reliable. There doesn’t seem to be an abnormal amount of complaints about this model, and just people coming online looking for help rebuilding, which is good. I would think heat is the number one problem with all of these so-called monster receivers. I’ve had a lot of good luck with using an exhaust fan on my amplifiers, and even on one of my present preamp‘s that runs very warm for a preamp. I don’t mind a little fan noise to get rid of some of the heat buildup.

I recently sent my Classe audio m700 monoblocks from 1993 for service up to United Radio in Syracuse New York. All the online chatter says that the caps would be bad after 20 years or so, so I set mine up after they were 28 years old. They blew fuses on me a couple times, so I started to get a little worried, and although they were each on a dedicated 20 amp line I thought something was wrong. It comes back as there was only three or four capacitors in the standby section that were bad. That’s between the two amplifiers, three or four capacitors, and nothing wrong, not one capacitor out of spec anywhere else. I had the wrong fuses in them, and somewhere along the line the fuse type/specs were changed by either the manufacturer or United radio or another factory service center. United radio said that these amps were overbuilt, and the parts, capacitors included were so good that they last a long time. So much for the online 20 year rule for capacitors lol.
 
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In terms of your last two comments -- well, that's good! ;)

Could they still be good? It is possible -- it's not likely. The useful life of electrolytics (especially of the 1970s) is maybe a decade... maybe two. Not four or five. That first filter capacitor in a linear DC power supply has the hardest life and is, a priori, the one most likely to be 'bad'.

Symptoms of 'bad': First and foremost, audible hum (even with the volume control turned fully down).
I am way more familiar with higher-voltage power supplies for vacuum tube amplifiers. My test procedure (which, mind you, I am not advocating) for HV power supply filters: Fire up :) the component (we typically bring 'em up slowly with a "Variac" variable autoformer) and run for a few minutes at steady state (if it will do so). After running for a little while, I (yes) feel the electrolytic 'can'. If it is "cold" (ambient) and if there's no P/S hum, the cap's probably OK -- at least for now. If it is warm (and the warmth isn't coming from a nearby component -- in my case, e.g., a vacuum tube HV rectifier, which gets hella hot) the cap's on its last legs (or already... umm... Tango Uniform, as ex-military types might put it).

Now, one other thing about electrolytics (again, mostly from HV P/S experience) -- they don't like disuse, but (like rogue politicians and Abominable Snow Monsters) sometimes they can be reformed. The process involves slowly increasing the AC voltage 'felt' by the capacitor over some period of time... and is out of scope for this discussion per se.
This is why I wish I could do this kind of work and testing on my own. It’s just hard to find someone that treats your gear with that kind of care and concern so to speak.

I think the takeaway for me is that even if those filter capacitors go bad, they sound like they’re very replaceable. It also doesn’t look like a hard fix for someone that knows what they’re doing, and as long as the parts are available it looks very doable.
 

DMill

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I’ve been looking on audiokarma and other sites, quite a bit of info out there about the 2385. The general consensus seems to be that it is pretty reliable. There doesn’t seem to be an abnormal amount of complaints about this model, and just people coming online looking for help rebuilding, which is good. I would think heat is the number one problem with all of these so-called monster receivers. I’ve had a lot of good luck with using an exhaust fan on my amplifiers, and even on one of my present preamp‘s that runs very warm for a preamp. I don’t mind a little fan noise to get rid of some of the heat buildup.

I recently sent my Classe audio m700 monoblocks from 1993 for service up to United Radio in Syracuse New York. All the online chatter says that the caps would be bad after 20 years or so, so I set mine up after they were 28 years old. They blew fuses on me a couple times, so I started to get a little worried, and although they were each on a dedicated 20 amp line I thought something was wrong. It comes back as there was only three or four capacitors in the standby section that were bad. That’s between the two amplifiers, three or four capacitors, and nothing wrong, not one capacitor out of spec anywhere else. I had the wrong fuses in them, and somewhere along the line the fuse type/specs were changed by either the manufacturer or United radio or another factory service center. United radio said that these amps were overbuilt, and the parts, capacitors included were so good that they last a long time. So much for the online 20 year rule for capacitors lol.
I have a Cary I took to guy for caps. Said pretty much the same thing. Everything is testing fine, bring it back if it starts acting up.
 
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I have a Cary I took to guy for caps. Said pretty much the same thing. Everything is testing fine, bring it back if it starts acting up.
That’s a good example. I mean when you take the cover off and you look inside of them, many just don’t look like 30 years old, amazing.
 
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Funny!

I have a couple pieces like that, if they ever fail and they’re too much to fix… you could use them to anchor your boat.
 
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