Marantz DR700 (CD Recorder - 1998)

[NTTY]

This is a review and detailed measurements of the Marantz DR700 stereo player, CD recorder and transport.

As I've already mentioned, I'm a lot into CD players and especially old ones, such as the Marantz CD-73 which I already reviewed.


Marantz DR700 - Presentation

This CD recorder from 1998 had a high price tag at the time, and a pro version (CDR-630) of the same was available with rack mounting front face.

I got interested by this player (and as a CD Player only) because it's using an old 1bit Philips converter which I did not test yet, the TDA1305T. It is a relatively low cost DAC, all integrated, with oversampling and noise shaping. It features a THD+N in the range of -90dB to -81dB, limited that is.

The back panel is a little more busy than usual, of course because it includes digital and analog inputs of top of standard outputs:

The pro version offers XLR outputs on top.

The inside is full of emptiness:

The reason is that both ADC and DAC are located under the drive, on a small card which also includes servo control and decoding. The right side, I suppose, hosts the analog output card for XLR out on the pro version.

Using this player is a real pleasure, with a super fast drive, I love it. Also the Play/Stop/Pause buttons are easy to spot, not cryptic, that I like a lot too. Funny, it has a view meter, like an old cassette deck, nice. Skipping a track back and forth is ultra fast, so cool! And note that one track back does not get you to the beginning of current song but the one before. Maybe a pro habit.

The feel and touch is surprisingly pleasant, in par with the price of the time, I’d say.

When I first powered on the Marantz, I could hear the power supply buzzing, not good and I suspected I would find some issues there.

Let's check what this old tech has to tell us.


Marantz DR700 - Measurements (Analog out)

From now on, I will be consistent with my measurements as I described them on my first review, with the Onkyo C-733 review. So over time, this will help comparing the items I reviewed.

The Marantz DR700 outputs 1.89Vrsm, a little less than the standard 2Vrms.
Here you go with the standard 1kHz sine @0dBFS (dithered) from my test CD (RCA out) :

Both channels are represented but only one gets evaluated in that window. Left channel is less performing, but other than H2, rest is very similar. The THD+N is in the published performances of the DAC TDA1305T, which means it's well implemented here (no surprises from Marantz).

You probably already noticed some power supply–related spuria in its output (at-100dB at 50Hz and 100Hz and other harmonics):

No surprise, the buzzing I could hear leaks into the circuitry. Does it require some service? Maybe, and it's good to remember that 20+ years old devices might need some attention before performing as new.
And well, I tried to listen to noise through the output, and I could not hear, I think it is in a area where our ears have a natural high attenuation in loudness.

Next on my list is the bandwidth:

We see a gentle roll off at both ends, just like the Marantz CD-73 with much less ringing from the oversampling filter though. So that's ok.
As you can see from the plot on the above graph, the two channels are perfectly matched, 0dB difference, this is very good.

Staying the oversampling filtering effect, let's have a look at wide band (up to 48kHz) :

Sorry, it's only up to 48kHz, but that's my standard measurement of this. We see the oversampling filter ringing above 22kHz, which means it's old fashioned, lacking computing power, but again "à la" Marantz CD-73. The filter is otherwise relatively sharp but attenuates poorly at -50dB only.

This view contains an overlay of the AES IMD test (18kHz + 20kHz) so that you can see how their artifacts are attenuated at 24.1kHz and 26.1kHz (roughly -60dBr).

Let's continue with multitone test (1/20 decade):

Quite clean, only one spike at 150Hz, else it's free from distortion to protect CD Audio content.

The DR700 showed very low Jitter:

The red trace is what's recorded on the CD (taken from the digital output of the Onkyo C-733). We see some additional side band frequencies, but it's very low in level and can't be heard. The noise floor is higher than other CD Players, that's the true limitation here, and it's been from the beginning.

I forgot to add other measurements:

• SNR : 92.4dB (1kHz @-60dBFS without dither)
• Crosstalk : -126dB (@1kHz)
• IMD AES : -82dB (18kHz + 20kHz 1:1 @-5dBFS)
• IMD DIN : -87dB (250Hz & 8kHz 4:1 @-5dBFS)

And of course, one of my favorite measurement, the THD (without noise) vs Frequency at -12dBFS. I already commented elsewhere that I use it especially to test older R2R architectures as it shows their difficulty to be linear below full scale. Below are measurements of the Left and Right channels, overlaid with the previously tested (and near best in class for a CD Player) Onkyo C-733:

Well, yes, the Marantz DR700 suffers here as we have more distortion than usual for a 1bit DAC. You also see right channel doing 4dB better. All that said, good luck to hear -90dB harmonic distortion at -12dBFS into musical content


Marantz DR700 Measurements - Optical and Coax Out

As usual, let's have a look at how this player behaves when used as a transport.

First the digital output (optical and coax show the exact output) is as what we expect it to be, perfect :

That's the content of the CD, nothing more, nothing less. Distortion is buried in the dither noise and therefore non existent. Noise is limited by that of the dithered one present on the test CD.

About the digital output quality, I already suggested here the use of an undithered 1kHz sine at -90.31dBFS to verify the quality of the drive, should we have doubts. With 16bits, the signal should appear (on a scope) as the 3DC levels of the sign magnitude smallest digital signal, which is what we get with the Marantz DR700:

That's the smallest 16bits digital signal. At this level, the digital content is only -1, 0, 1. And so it outputs a scare wave with ringing due to bandwidth limitation (Gibbs Phenomenon).


Conclusion

I hope you enjoyed reading this review as much as I enjoyed writing it.

Considering the compact build, inside, it's performing well, and that was more than 25 years ago. Plus it records on CDR!

I did not test the performance when recording, it would be long and I don't expect anything interesting. That said, and it's to note, the Marantz will stop recording after 3 seconds of signal at less than -50dBFS, considering it is silence

When used as a transport, it's flawless. So a little modern DAC behind, and it'll be perfect. Add to that speed of the drive, plus touch and feel and you get a lot of pleasure at very low price.

I hope you enjoyed the review, and again let me know how to improve and if you have questions. I have recorded all the 44 measurements and if you want me to publish others or run one of your choice, feel free to ask.

Enjoy the weekend.

--------
Flo

 

[AnalogSteph]

When I first powered on the Marantz I could hear the power supply buzzing, not good and I suspected I would find some issues there.

The transformer may have a screw loose. Like, literally. You can try tightening those down. Unfortunately it's not uncommon for transformers to be run slightly into saturation. Should you happen to have a Variac, you could try to reduce mains voltage a bit using that.

Note the "grass" (spuriae) that seems to be quite typical for older 1-bit converters IME.

No surprise, the buzzing I could hear leaks into the circuitry. Does it require some service there, maybe. It's good to remember that 20+ years old devices might need some attention before performing as new.
Well, I tried to listen to noise through the output, and I could not, I think because it is in a area where our ear have a natural high attenuation in loudness.

Good luck trying to hear anything at -100 dBFS, let alone 50 or 100 Hz. No surprises there. We had a small dynamic range listening test here a while back, and even -80 dBFS is quite challenging. Not to mention the issue of the player's noise floor literally being higher than -100 dBFS already.

Redressing the power supply wires may help get rid of the 50 Hz at least. I'd be tempted to unplug the transformer primary cable (brown / blue) and give it a few twists, then reroute a bit closer to the chassis.

Now, let's have some fun with the bandwidth :

Would you mind zooming in on that a bit?

Here are the digital filter specs for the TDA1305:

Passband ripple is a bit meh if on par with a bunch of older onboard audio and whatnot, while stopband attenuation actually is half-decent.

Sorry, it's only up to 48kHz, but that's my standard measurement of this. We see the oversampling filter ringing beyond 22kHz, which means it's old fashioned, not so performing, but again "a là" Marantz CD-73. The filter is otherwise relatively sharp but attenuates poorly at -50dB only.

Filter response generally seems to conform to spec. I suspect the spikes poking up beyond may be related to some sort of jitter issues, note how a bunch of them are already present at lower amplitude in the 19+20 kHz test.

Looks about in line with what the datasheet says:

Overall, it's obviously not a record-breaker but then the TDA1305 was not a high-end DAC even by 1998. (Hmm, I just noticed I don't have it on my converter history page, oops.) When the thing out came out in 1994-ish, a double speed mode (up to 96 kHz) was really novel and mostly intended for high-speed dubbing to tape, I imagine. That was all the rage in the early '90s.

I did not test the performance when recording, it would be long and I don't expect anything interesting.

Doesn't this unit have a monitor mode? With DAT recorders you could generally put them in rec pause and they would output the recorded signal digitally. Sure beats having to burn a CD and rip it, and you already have the facilities to record SPDIF.

The performance probably wouldn't be anything exciting, mind you. SA7366 specs are DR >90 dB, THD+N <-80 dB, filter passband ripple ±0.1 dB and stopband rejection -60 dB (that's pretty crummy even for a consumer ADC, mind you it again is from 1994).

 

[NTTY]

Thanks for the interest.

Yes, zoom on the bandwidth, I already prepared the same view as the one I posted on the Marantz CD-73 review, here you go:

Before your reply, I was already tempted to put my hands into that power supply, so now, how can I resist? And thanks for the tips!

The spikes seen in the wideband analysis of 18kHz + 20kHz are either artifacts (replicates) of the the initial two tones, and intermodulation distortion generated by them and the artifacts again. That's the problem when the attenuation of the oversampliing filter is not high enough. Add a little power supply related noise on top + lack of linearity, and here you go.

1kHz @-60dBFS with dither is below:

THD is well contained at that low level. Noise from the power supply is the problem. But yes, that means we can meet the THD+N specs of the TDA1305T, with some work on the power supply.

 

[AnalogSteph]

It's weird how the strongest power supply related spikes are all odd-order harmonics of 50 Hz. That really reeks of transformer current and inductive coupling into something... but where?

Wait. The yellow secondaries which are feeding the +/-12 V regs are exiting the transformer on opposite sides? Now that's stupid. That's one heck of a loop with the yellow wires routed like that. You should be able to reduce loop area a lot by rerouting them, even if twisting is not an option.

I would also prefer to see some heatshrink over the brown/blue wires given how they are intermingled with the secondaries. Not sure how easily those can be depinned at the connector though, usually there's some trick to it (like a small tab that needs to be pushed in to unlock the pin).

 

[NTTY]

Thanks for your insights. I’ll try to have a look at that and run the measurements again.
I’ll update soon

EDIT: Twisting the brown and blue nearly stopped the buzzing. Transformer's screws were a bit loose too, and that completely stopped the buzzing.

Measurement wise, we see almost 10dB less of noise in power supply!

--------
Flo

 

[AnalogSteph]

EDIT: Twisting the brown and blue nearly stopped the buzzing. Transformer's screws were a bit loose too, and that completely stopped the buzzing.

I think the first was just a coincidence, you probably put some force on the transformer when handling the primary wires and moved it around a tiny bit. The real fix was tightening the screws.

I've had to do the exact same thing twice before... one was an old Onkyo Dolby Surround receiver which obviously has a rather chunky transformer, the other a generic regulated 13.8 V 10 A supply (think ham radio) that had its entire transformer core held together with nuts and bolts.

Measurement wise, we see almost 10dB less of noise in power supply!

Looks more like 6, but I'll take it. More than I would have expected to be honest. Mind you, the routing is also slightly different now, which could definitely be a factor.

What about our yellow wires? I think they could be tied together quite neatly above / slightly to the right of the transformer.

BTW, if you connect a chunky wire between the CD player chassis and MOTU chassis and the mains harmonics go away, you've got leakage currents going down the signal wires and most likely electrostatic coupling to the mains.

On the subject of unwanted things, the spurs flanking the 1 kHz tone at +/-100 and 200 Hz suspiciously look like power supply hum. This may be getting into the DAC via its supply rail, which would be either of the +5V ones I guess. If we're assuming the PCB layout around the 5 V regulator 7101 is properly done, unregulated voltage ripple in capacitors 2109 / 2136 may be worth checking. (BTW, the spec of >4.9 V seems a bit optimistic even for an LDO. That has a nominal dropout of 200 mV still.)
Hmm, looking at the trace layout (Power Supply Board, Component Side, p. 1-29), the ground routing partially seems to be on the "bad wiring" side as per

Simple Voltage Regulators Part 2: Output Impedance

I think star ground is supposed to be below fuse 1130 / right next to jumper 9000. If so it's correct for regulator 7101 and output capacitor 2111, but things slightly fall apart before that, as the run towards smoothing capacitors 2136 and 2109 is just tacked on to 7101's connection.

Hmm, I also spot a small ground loop: From 9000 up underneath 1130 and 1131 to the ground leg of capacitor 2119 and back down on the left through the 7101 ground connection. Great, now you've got part of 2119's charging current running through there, just what you want in a critical spot.

(2119 is responsible for +12V.)

I would consider running a wire for reinforcement (about as thick as you can manage) on the underside of the board, from the ground leg of 2136 to the right-hand leg of 9000, precisely following the ground routing on the top side including passing underneath 7101.

That should take a bunch of current away from this critical point. It's about the least invasive mod I can think of. Ideally the scalpel (/ grinder) would have to come out to cut the ground in two places and one more wire soldered in before this is "starred" properly, but I think the prospect of soldering a wire seems daunting enough to you at this point...

 

[NTTY]

You’re right, I was optimistic, 6dB that is.

I tried to place the yellow wires in different positions, exactly as you suggested, but it did not change the measurements.

I can try connecting the chassis of the Motu and the Marantz indeed, it’s a simple test. I’ll report.

For your other investigations, it’s really cool, thank you. I’ll consider when/if I find time.

 

[Haskil]

The interior resembles (the particular color of the printed circuits) a Philips model with a double plate (CDR 765 and CDR 775), therefore two mechanics on the other hand but the "engraver" is identical from memory to that of the Marantz. The Philips comes from the Hungarian Philips factory and not from the Belgian one like the Marantz... At that time Marantz belonged to Philips.

 

[Limopard]

Wasn't it a slightly refined version of the Philips CDR 880? This one could be tricked into writing non-audio-blancs by manually open and close the drawer. Those were the days...