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Marantz PM-90 Review (Vintage Amplifier)

Paco De Lucia

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Is the mains noise possibly caused by slightly tired smoothing capacitors in the power supply ?
 

Herbert

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Being a now old UK based bod and in the industry at this time, I feel very sad indeed that these massive top line amps never really found their way over here in large numbers, although maybe they could be found in London's Tottenham Court Road stores which has huge ranges of everything except the smaller 'enthusiast audiophile' brands. I seem to remember the last was a PM94 which was black with gold lettering and wooden? end cheeks. Our upper-mid level market was mostly UK made badly measuring tat basically I now understand, with a shouted story (and contrived sound quality) to tell that we lapped up in our ignorance. Sony, JVC, this era Marantz, Yamaha and no doubt others, made good solid meaty stuff like this but were not to be seen in higher end HiFi stores as I believe 'we' had to buy in the entire range rather than cherry pick - not all of it was good and it rarely lasted for sale beyond a season or two if we were lucky. In any case, big-box amps like this were right out of fashion. Looking back I could weep at my/our ignorance :(

We did see the upper end Marantz CD players though - CD80 and 85, CD10 (which I owned for a short while) and the golden slimmer CD 17? from a later generation, which 'KI' had apparently looked at to deserve a 'Signature' badge (usually the kiss of death away from the press fervour).
Coming from Germany, I remember travelling to Ireland by ferry and bus in 1990.We made a three day stop in London and walked more or less the tourists‘ routes. I do not remember any dedicated HiFi-Shops, audio was sold together with vacuum cleaners and TV.
 

DSJR

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British Hi-Fi pretty much "owned" the review press in Europe at that time, the Germans following but behind, even in their own country.
In countries like Poland there is still a preference for British stuff, at least it was last time I checked (which was before Brexit).
Maybe one of the reasons is/was, similar living rooms, rather small for the most, not much need for beefy amps and speakers.
Money was the other factor, not so many were able to afford Marantz, Accuphase, T&A etc.

The UK did come up with then-worthy designs at not silly-high money, but it was 'our' attitude which prevented big far eastern amps like these from even being looked at, let alone listened to or tested properly. HiFi Choice books are full of immaculately 'measuring' amps which failed in the listening tests (all sighted as far as I can see) and only one or two came through in the 80's, such as the HK 645 family - I'm told the mid noughties HK990 was liked as well, but limited distribution was a key by then. The 90's base models such as the everlasting Yamaha amp chassis would have been tested possibly in the monthly mags, but I have no access to them I'm afraid and by then, we weren't buying said mags on petty cash...

Sorry to drift...
 

DSJR

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Coming from Germany, I remember travelling to Ireland by ferry and bus in 1990.We made a three day stop in London and walked more or less the tourists‘ routes. I do not remember any dedicated HiFi-Shops, audio was sold together with vacuum cleaners and TV.

The Totenham Court Road didn't sell vacs as well as audio I promise you and the Edgeware Road was often component shops at one time (Help me please Serge and Keith :D )
 

Paco De Lucia

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The Totenham Court Road didn't sell vacs as well as audio I promise you and the Edgeware Road was often component shops at one time (Help me please Serge and Keith :D )
you beat me to it
 

respice finem

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The UK did come up with then-worthy designs at not silly-high money, but it was 'our' attitude which prevented big far eastern amps like these from even being looked at, let alone listened to or tested properly. HiFi Choice books are full of immaculately 'measuring' amps which failed in the listening tests (all sighted as far as I can see) and only one or two came through in the 80's, such as the HK 645 family - I'm told the mid noughties HK990 was liked as well, but limited distribution was a key by then. The 90's base models such as the everlasting Yamaha amp chassis would have been tested possibly in the monthly mags, but I have no access to them I'm afraid and by then, we weren't buying said mags on petty cash...

Sorry to drift...
Many listening tests were just as much humbug then as they are today ;) and measurements by many of the press titles back then were scarce, with only a few exceptions. Today, in the "wider" audio market, the hifi-hype is IMHO pretty much gone anyway, we here @ASR are not the average buyers (who are happy with a soundbar and a pair of BT earbuds).
Old farts like me still appreciate good old-fashioned stuff, not that I need such an amp...
 

nagster

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Ah I guess that's why its labeled processor and not pre-out or something like that. How nice of them to think about all those MiniDSP users ;).


Japan is not really a small country, 126 million inhabitants (11th in the world).
I probably made a mistake.
It was not "small" but "narrow".
 

peng

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Wow, @amirm , this is the best ever objective review I have ever read!! Thank you very much for the class A vs class AB measurements too. May be you can measure crossover distortions on a more recent class AB amp as well, or even one receiver or AVR.

Thanks again for providing such great service to the scientific facts based audioholics and hobbyists.
 

restorer-john

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According to this block diagram the processor loop is before the pre-amp section, the bass and treble control and the volume control. So if that is the case it is strictly a processor loop and not a pre-out.

Around this time, the "processor loops" were simply the equivalent of another tape loop for a graphic eq etc. The preamplifier section was either non-existant or very low gain as it was with this implementation. All you are doing by separating the jumpers is basically skipping the input selector and tape out loop. It's not remotely power amp in.
 

dualazmak

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Last Tuesday, I wrote here;
Here in east part of Japan, electricity is 100 V 50 Hz, and in west part of Japan it is 100 V 60 Hz.
It is interesting that (as far as I know
[at present] ) only microwave ovens do not compatible for both of 50 Hz and 60 Hz. I moved west to east, east to west, and then again west to east, three times, in past 30 years, and every time we needed to purchase a new microwave oven for our kitchen!

In any way, I feel this nice and valuable report by @amirm would considerably support and relieve my recent decision (please refer to my post here and here) on rather traditional style (but modern) Japanese HiFi (rather heavy duty) integrated amplifiers in my multichannel multi-driver multi-way multi-amplifier project.

Under the present uncertainties of global COVID-19 pandemic, the durability, enough warranty, and availability/accessibility of domestic maintenance and repair services, are also important factors in my (our) amplifier selections.

Thank you again, @amirm!
 

pma

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Is the mains noise possibly caused by slightly tired smoothing capacitors in the power supply ?

Almost certainly no. The mains components are in fact very low considering the unregulated linear power supply. You need to re-calculate dB to real voltage level to be able to tell anything about the audibility. Simple “eye view” is misleading.

This amp under review has excellent output spectrum at the level measured by Amir. We would be able to tell more if he also measured 50W and 100W spectra. We would also see the transition into AB if it was measured.
 

sarumbear

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GXAlan

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Almost certainly no. The mains components are in fact very low considering the unregulated linear power supply. You need to re-calculate dB to real voltage level to be able to tell anything about the audibility. Simple “eye view” is misleading.

This amp under review has excellent output spectrum at the level measured by Amir. We would be able to tell more if he also measured 50W and 100W spectra. We would also see the transition into AB if it was measured.

The question I had earlier was that at 5W, it has “high THD” which is all in the mains. If you truncate the noise to something like -100dB, there is nothing but the 1kHz tone whereas other higher performing amps have lower overall THD but have some spikes of 2nd or 3rd order distortion that peaks above -100dB.

In any way, I feel this nice and valuable report by @amirm would considerably support and relieve my recent decision (please refer to my post here and here) on rather traditional style (but modern) Japanese HiFi (rather heavy duty) integrated amplifiers in my multichannel multi-driver multi-way multi-amplifier project.

The other interesting point which I shared on the previous page is that all but the highest end Class D amps have variability depending on frequency, so your selection based upon specific range certainly makes sense. It would be good to get a REW/UMIK-1 measurement and compare it to incorrect amps. (That is, if you mixed your amps for the your levels) to test audibility.
 

YSC

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when the 90s they can produce such performance with 16 bit distortion free range... really a shame for those who still can't
 

acetogen

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I used a high power variac. There are a bunch on Amazon: https://smile.amazon.com/VEVOR-Tran...child=1&keywords=variac&qid=1632013087&sr=8-4

71GRG3jVTiL._SL1500_.jpg


Owner found and is using these cute ones: https://www.amazon.com/dp/B07L57MTF...odel_k0_1_6&crid=2NCXCXQVJQD8T&sprefix=100v+t

719CXqqRYbL._AC_SL1500_.jpg


FYI I compared my Variac against the lab generator and performance was identical.


The Variac that you show is a nicer version than the green ones that organic chemists use in the lab for refluxes and solvent distillation.
 

thyristor

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Marantz-PM-75.jpg

I have Marantz PM-75 that I'm in the process of recapping. It's from 1989 and has an internal DAC (Philips TDA1541) with optical and coaxial inputs. Marantz called it "Digital Integrated Amplifier." It must be one of the first amplifiers with internal DAC. I hooked my LG OLED via toslink to it and it works fine. Pretty amazing for an 80s amplifier.
 

617

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Excellent phono performance. What a great looking unit.

What I like most about these stereo receivers is the wide range of functionality with good performance. I really wish that Topping or someone made a similar product for the modern era where active speakers and headphones were more common. Something with a few source inputs, a first class phono input, a good, powerful headphone amp, filtered subwoofer outs, maybe a tone control, a first class DAC and a nicely made remote.

Back in the day you could buy one of these and a CD player or record player and have a complete stereo. I hate all the tiny looking crappy boxes modern hifi stuff comes in. Give me one nice looking box.
 

respice finem

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