Marantz CINEMA 70s AVR - Teardown, personal thoughts and a few measurements

[Thomas_A]

MultEQ is essentially useless for bass correction, it just doesn’t have enough filter taps. Since bass is where correction is needed most, best leave it turned off.

Multeq XT32 does have decent bass correction, but is not available on lower end devices like the 70s. Doesn’t bother me as I have my room correction done off board in a MiniDSP 4x10HD, but worth noting for possible buyers.

Not useless at all. It worked fine here reducing my room bass peaks for the subwoofer.

 

[Thomas_A]

Aren't the results here just predictions which MultEQ generally makes very optimistic?

REW confirmed my results, as well as listening. It reduced those room modes significantly, especially a nasty 47 Hz peak.

 

[mcdn]

REW confirmed my results, as well as listening. It reduced those room modes significantly, especially a nasty 47 Hz peak.

Glad it worked for you - there’s a long thread here about the differences:

Thread 'Difference between Audyssey Multeq VS Multeq XT Vs Multeq XT32'
https://audiosciencereview.com/foru...sey-multeq-vs-multeq-xt-vs-multeq-xt32.14786/

but the implementation may have been improved over the last 3 years. Audyssey have removed a lot of the technical info from their site as well.

 

[Thomas_A]

Glad it worked for you - there’s a long thread here about the differences:

Thread 'Difference between Audyssey Multeq VS Multeq XT Vs Multeq XT32'
https://audiosciencereview.com/foru...sey-multeq-vs-multeq-xt-vs-multeq-xt32.14786/

but the implementation may have been improved over the last 3 years. Audyssey have removed a lot of the technical info from their site as well.

If I understand the table the 128x for the MultiEQ vs the 512 for the XT32 in subwoofer means a 4x higher resolution. Not a very big difference, especially if you compare to the high-pass section (2x vs 512x = 256x difference). I use it only for the subwoofer since it is where the main room troubles are found.

 

[mcdn]

If I understand the table the 128x for the MultiEQ vs the 512 for the XT32 in subwoofer means a 4x higher resolution. Not a very big difference, especially if you compare to the high-pass section (2x vs 512x = 256x difference). I use it only for the subwoofer since it is where the main room troubles are found.

Without knowing the actual number of taps we are a bit in the dark. For comparison a MiniDSP 2x4HD has 4096 taps, which at 48kHz sample rate means the frequency resolution is around 12Hz. Whatever resolution base MultEQ has, it's a quarter of MultEQ XT32. So it makes sense it can fix one or maybe two broad dips/peaks. I'll go edit my post to remove the word useless, perhaps "limited" would be better.

 

[popej]

For comparison a MiniDSP 2x4HD has 4096 taps, which at 48kHz sample rate means the frequency resolution is around 12Hz.

Just side question: doesn't Marantz/Denon's DSP work at 88/96kHz?

Looking at Amir's measurements it seems, that Marantz/Denon and Yamaha use 96kHz but Onkyo/Pioneer work at 48kHz.

 

[Thomas_A]

NR1710 power amp measurement updated here:

A few measurements of the Marantz NR1710 slim line AV amp (update jan 2024, power amp section)

Looking forward to your measurements of the Marantz poweramp. I have another question - do you notice any soundimprovements with the topping d10s compared to the Marantz dac ? Regarding differences - I have not really tested. The only thing I could think of is any combined effect of the early...

www.audiosciencereview.com

 

[dalbert02]

For what it is worth, the unit is good and fits my needs, especially space limitations. I am using it with Parasound Z-amps, one amp in mono-mode for each channel with KEF speakers. The ability to stream Pandora and other services with the HEOS app is very convenient. The Marantz AVR app is also convenient for changing settings. I am definitely not a videophile but I am a long time photography enthusiast, and I'd swear the contrast and saturation is a bit better than what I was familiar with on my Emotiva. I am not sure how that is possible, but I also can't deny the picture quality is slightly better. Sound quality I'd classify it as upper mid-fi. It is no Krell or Levinson or other high-tier brand but I think it is a step up from most of what is sold in big appliance stores. In summary, it is not great but not terrible either. It does what it is supposed to do very well but at the same time doesn't get you excited about anything either. My only complaint, in the middle of listening, it decided to do a firmware update. No warning or asking for permission, it just froze and said "updating" on the front screen and took 10 minutes to complete the process. Good thing it wasn't in the last few minutes of a big game with friends and family over! For me, I feel satisfied with the $700 I paid for it. If I had to pay full retail and shipping, I'd probably consider something else.

 

[trl]

First thing I did when I powered it ON for the first time was to manually lookup for firmware upgrade and let it finish updating, then I disabled automatic fw update. Now I'll be the one taking care of upgrading the fw, not the AVR itself.

 

[trl]

I managed today to measure SINAD on the Front PRE-Out when streaming from iPhone 14 Pro -> TIDAL as well. Source track was B.A.S.S. - 1 kHz; probably with better sources measurements would be better, but I couldn't find a better measuring track.

Streaming from cellphone TIDAL -> AppleTV A1469 [HDMI Out] -> Marantz CINEMA 70s [HDMI ARC] - 1 kHz (B.A.S.S. artist)
Same graph when TIDAL -> AppleTV A1469 [HDMI Out] -> Samsung TV [HDMI Out] -> Marantz CINEMA 70s [HDMI ARC] - 1 kHz (B.A.S.S. artist)

Streaming from cellphone HEOS -> TIDAL -> HDMI Marantz CINEMA 70s (Direct/PureDirect) - 1 kHz (B.A.S.S. artist)

Streaming from cellphone HEOS -> TIDAL -> HDMI Marantz CINEMA 70s (Stereo) - 1 kHz (B.A.S.S. artist)

Streaming from cellphone TIDAL -> AirPlay Marantz CINEMA 70s - 1 kHz (B.A.S.S. artist)

Streaming from cellphone TIDAL -> AirPlay SamsungTV -> Marantz CINEMA 70s [HDMI ARC] - 1kHz (B.A.S.S. artist)
​

From how I see this, I could get a decent SINAD of 94-95 dB when streaming via Apple TV (ver. 1469) under Direct/PureDirect/Stereo and HEOS under Direct/PureDirect, while with HEOS Stereo I could only get a SINAD of 57.6 dB. Not sure why switching to Stereo changed the SINAD so much, but worth noting that HEOS with Direct and PureDirect measures quite well.

Streaming directly from TIDAL to my Samsung TV or directly to Marantz CINEMA 70s returned subpar results, no matter I was choosing PureDirect or Direct or Stereo, so we should probably stick to HEOS app or stream via an Apple TV if HEOS is not an option for some of us.

Choosing HEOS as output source vs. streaming via Apple TV -> Samsung TV [HDMI ARC]​

 

[Thomas_A]

Sorry to ask, are these pre out results?

 

[trl]

Thanks Thomas, I've added the Front PRE-Out in the first paragraph now.

 

[trl]

I'm not sure the output stage of the CINEMA 70s was properly driving the input stage of my measurement E1DA Cosmos ADC due to its low input impedance, so I couldn't get 2V RMS on the PRE-Out (between 86-90 volume), but I estimate that adding a Cosmos Scaler in the middle might improve the measurements a bit (I don't have a Scaler yet). I see that with the same AppleTV (A1469) I was able to get a SINAD of 102 dB when streaming from the same cellphone to the same AppleTV, but using Topping D90 MQA as transport, versus the 94-95 dB I was getting on the CINEMA 70s.

However, a SINAD of about 94-95 dB is still a respectable figure for the PRE-Out of such an AV Receiver and perhaps the limiting factor is the inside preamplifier. After all, Amir got about 94 dB as well when using HDMI or TOSLINK as inputs, so it's good to see that streaming from a cellphone app is not losing any dB.

 

[Thomas_A]

Marantz/Denon installed test points in there to be easier and safer to adjust the bias voltage; same they did in CINEMA 70s as well (there are seven 3-pins test points there). Each testing point has a couple of 10 KOhms resistors added in series. This way, if someone short-circuit any of those pins, nothing bad will happen, due to the 10 KOhms resistors in series with the emitter resistors from the output transistors.

View attachment 338055
Test point TP4800 from Marantz NR1506 AVR (similar to other D/M AVRs)


View attachment 338047
The test points where a relative biasing voltage can be measured in CINEMA 70s.
However, service manual is needed for finding the proper biasing voltage, but like @Thomas D. said, 2 mV might suffice.​

So, those 2 mV does not represents the actual biasing voltage across the two serialised emitter resistances, but a value that is directly proportional to the biasing idling voltage. Instead, what I was adjusting was the actual biasing voltage measured across the two emitter resistors from the output transistors, not the voltage across the test points (without having the service manual there's no sense to measure across the testing points, because I don't know for sure what values should be there).

Do you know why there are three pins on the test points? Not sure which ones to measure, if I do that. The NR1710 (as the C70s) has an overheating safety function (auto shut off with red diode flashing as indicator), so I could test to increase bias. If nothing happens I could perhaps improve SINAD at low power.

 

[trl]

No, I don't sorry, as I preferred to do the measurements old school, directly on the emitter resistors (kinda risky to not do a short-circuit in there, so totally not recommended).

However, you might measure the bias voltage across any two of those three pins and see between which 2-pins you have 2-3 mV.

 

[Mikec1231]

To all,
I am considering the MARANTZ 70s to replace my Sony SN 1030 AVR. I very much appreciate this forum although a lot is way over my head. My situation is this. My home was previously hard wired with ceiling speakers in the bedroom, living room, lanai (Klipsch outside) and 2 sets in the family room (tv room). I started looking for a multichannel amp to drive music to the rooms independently of each other. I thought why not use the Sony avr (7.1) in the family room and feed back to the amp from zone 2. (My zone 2 only feeds analog not digital.). I have AppleTV gen5, Sony Bravia tv, Atlantic Audio center channel, and a powered sub from Definitive Technology pro sub 800. BTW, we’re retired and trying to get this all done on a limited budget.
Since I can’t find a multichannel amp that works with my Sony, I thought I would upgrade to the Marantz and then look for something later to power the other speakers.
Any thoughts?

 

[trl]

Hi @Mikec1231 and welcome to the ASR forum. I recommend you to create a new thread with your request and kindly upload a few drawing with each room, no. of speakers (in-ceiling speakers too) and what exactly do you want to achieve. Maybe line amplifiers might better suite your needs, because regular AV Receivers usually works better for home theatres.

However, looking forward for your new thread, so please post the link here as well, so I can follow it.

 

[MarkBauwens]

Can you tell something about the Phono Preamp? Or maybe you have a schematic diagram or picture from the Phono board? In the past I could find any Service Manual from Marantz but not anymore now unfortunately.

 

[trl]

Schematics are probably similar, if not identical, with previous Marantz models, at least for inner preamp and amp sections. I've no idea about phono stage, sorry, but I'll get back here if I'll grab anymore info about it.

 

[MarkBauwens]

Thank you very much for your response. I know there has been an upgrade to their "basic" phono preamps which now use FETs (2SK2145) between input and Opamp (see PM7000n diagram). As far as I know, this upgrade has been implemented on the PM6007 (PM6006 still without FETs, see diagram). I was curious whether this upgrade has also been implemented on the Cinema 70S. Too bad there are no longer service manuals available for download.
Thanks again and I look forward to hearing from you.