That's a bad ass lookin AR amp.
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- Thread Starter
- #382
At least that amp is not boring
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restorer-john
Grand Contributor
That’s what this Time calibrator is for.
Audio Research provide 4x1R2W resistors in line with each cathode. Those resistors were not just close to 1R, they were exact to two decimal places with my ESR meter- something I checked first as they are 40 years old. The beauty of 1R is current is a direct read on the mV scale for mA.
Not an amplifier for the efficiency greenies eco-warriors. Pulls 250W continuous at idle, but she sure is a gorgeous thing.
Here's some more pics:
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restorer-john
Grand Contributor
The trouble with an essentially complete rebuild, like the JBL SA-600 @amirm just reviewed, is no matter how carefully it was done, is the amplifier is likely to perform quite differently to the way it did when new.
As such, you have no reference to compare. Even if you did, that reference would be over 50 years old in the first place and likely deteriorated too.
I'm dealing with such an issue with these classic Marantz 1060s on my bench right now:
No, you're not seeing double!
The top one is my father's 1060 bought in 1972 and kept boxed for 40 years. I fully restored it about 5 years ago as it had deteriorated in the box (caps of course), but didn't change any semis as they were all in spec and silent (no noise). I borrowed it yesterday for the purpose of comparison, as I have all the data and know exactly what I did and how it tested. All the FR plots and performance details are in my records for that amp.
The bottom one is a friend's 1060, one he bought on my recommendation which he thought was likely original. It wasn't. It had been completely (and very well done) rebuilt including all the front end (phono/pre/tone) semis, caps etc replaced. PSU and amp caps as well. But It sounds like #ss to him.
Now I'm delving into what exactly is causing these two essentially identical amps to sound totally different.
More to come...
As such, you have no reference to compare. Even if you did, that reference would be over 50 years old in the first place and likely deteriorated too.
I'm dealing with such an issue with these classic Marantz 1060s on my bench right now:
No, you're not seeing double!
The top one is my father's 1060 bought in 1972 and kept boxed for 40 years. I fully restored it about 5 years ago as it had deteriorated in the box (caps of course), but didn't change any semis as they were all in spec and silent (no noise). I borrowed it yesterday for the purpose of comparison, as I have all the data and know exactly what I did and how it tested. All the FR plots and performance details are in my records for that amp.
The bottom one is a friend's 1060, one he bought on my recommendation which he thought was likely original. It wasn't. It had been completely (and very well done) rebuilt including all the front end (phono/pre/tone) semis, caps etc replaced. PSU and amp caps as well. But It sounds like #ss to him.
Now I'm delving into what exactly is causing these two essentially identical amps to sound totally different.
More to come...
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D
Deleted member 50971
Guest
Beautiful piece of history, thank you for that.
I would like to know more about how a rebuild could change the sound of a preamp, receiver, or amplifier.
I’m thinking about getting a mid to late 1970s Marantz receiver. I see some of them are original, more expensive ones have been serviced, some including caps.
Specifically looking at the Marantz 2385, that’s the high powered unit. I am wondering if I would end up with something different than what I heard when I was a younger?
restorer-john
Grand Contributor
For me, I want original where possible. That is due to the fact often more time is spent reversing and rectifying mistakes made by a weekend warrior with a bag of capacitors, a plumber's soldering iron and no-idea. They mean well, but often cause collateral damage to otherwise great examples.
It's better to find a completely dead original, untouched amp/receiver for not much money, than pay absolute top dollar for a dubious or undocumented 'restoration'. But that is with the caveat of either being able to rebuild them yourself or have a genuine vintage expert do it for you. As time goes on, I've seen plenty of restorations on top of restorations.
The 2385 is a big heavy receiver and is likely to have taken a few knocks and bumps over the last 45+ years. Finding a good original example in a wood sleeve will be hard. There are some magnificent cabinets being made in Europe which not only look the part, they are better made (fit and finish) than the originals. I'll post a few pics.
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D
Deleted member 50971
Guest
Thanks for this I appreciate it. I saw a guy on Reverb selling a really nice case for one that looked original, but like you said better built. But I believe he was from Serbia, and I am in the US.
I may start to look for a Marantz that’s never been touched, and there’s actually one online that claims to be from the original owner, and they got it in an estate sale. Very expensive, But I’m not quite ready yet, and I want to do better research before I pull the trigger. Thanks for the advice.
I may start to look for a Marantz that’s never been touched, and there’s actually one online that claims to be from the original owner, and they got it in an estate sale. Very expensive, But I’m not quite ready yet, and I want to do better research before I pull the trigger. Thanks for the advice.
restorer-john
Grand Contributor
The original 2275 is in my opinion, one of the best. It's not too expensive, has a ton of power, is well made and comes from the pre cost cutting era of Marantz classics.
You will pay an awful lot for a 2385. But is a hell of a receiver. Like the Pioneer SX-1980 and SX-1250, they are highly desirable and eminently collectible.
I had one of the 1060s and 1030?s. Neither lasted very long, both failed (out of warranty) fairly soon, so were my last Marantz's.
In fact, I do believe the failed 1060 is what got me in to the JBL SA660.
But they sounded very nice, and had plenty of power for large 2-way JBLs.
Again, can't fault the ergonomics, styling, or switch quality.
In fact, I do believe the failed 1060 is what got me in to the JBL SA660.
But they sounded very nice, and had plenty of power for large 2-way JBLs.
Again, can't fault the ergonomics, styling, or switch quality.
D
Deleted member 50971
Guest
I will look at that one also, thanks.
restorer-john
Grand Contributor
Marantz 2226 weekend project for my friend who has been buying too many basket cases...
This is Marantz stupidity at its finest. The input selector and phono stage PCB is inverted, sitting right under the ventilated grille. 45 years worth of dust and dirt and clearly a drink or two.
More pics to come.
This is Marantz stupidity at its finest. The input selector and phono stage PCB is inverted, sitting right under the ventilated grille. 45 years worth of dust and dirt and clearly a drink or two.
More pics to come.
Hipocrates
Member
I'm working on a 2238, same thing. I find those faults kind of funny. Specially when enthusiast talks about how great the building quality and design were "back in the day".
Ricardus
Addicted to Fun and Learning
Some KM84 clone PCBs, and some API preamp clone PCBs.
Not exactly "on the bench" or audio but I spent the day replacing 65 year old relays and microtherm switches for the mouthpiece and pot thermal controls on my Linotype machine with some Chinese PIDs. Precise control, necessary for casting good type. New red synthetic belting to replace some worn leather too!
Whadya think, needs tubes?
\
Whadya think, needs tubes?
restorer-john
Grand Contributor
restorer-john
Grand Contributor
The same inverted phono stage PCB ran through several receiver ranges and integrated amplifers and caused a ton of issues, especially once you had super high gain MC stages with exposed tracks to attract dust, bugs and moisture.
That said, they were doing a good thing (partly) by moving the actual input selectors close to the terminals and driving it with a shaft to the front panel knob. A simple metal, or even elephant-hide cover would have saved many from failure.
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Hipocrates
Member
mmmm I like that idea
restorer-john
Grand Contributor
Elephantide | An Excellent Insulation Material
Elephanthide paper is an excellent insulation material, used to insulate electrically hot items, such as terminals and from accidental contact.
www.ukinsulations.co.uk
JayGilb
Major Contributor
Hence your avatar name/image. Thanks for showing us.
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