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Power Requirements: 120V a.c. 50 to 60Hz - Power Consumption: 650 watts at full power. - 60 watts at no Signal - Dimensions: 19" x 5" x 15" - Weight: 52,8 lbs (25 Kilo)
Price : Main unit Marantz 4400 = $ 1.250.-
SQA-1 = $ 49.95 - Matrix Demodulator
SQA-2 = $ 79.95 - Matrix Demodulator
CD-400 = $ 99.95 - CD-4 Demodulator
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It has to be to incorporate all the features build into it. Examining the front panel, we see a family resemblance to other top-of-the-line Marantz receivers.

Large, thumb wheel-edge tuning knob at the right, multi-purpose oscilloscope display at the left these are all Marantz "originals." Along the bottom section if the gold and black front panel are a pair of front and rear headphone jacks, a Dolby selector switch (with positions for FM Dolby decoding, play, off and record I and II), program selector switch, three-position tape monitor switch, mode switch (with positions for MONO, twochannel, discrete four-channel, vari-matrix and SQ decoder - if the optional module is installed).

An adjacent "dimension" control alters the built-in simple matrix parameters to create varying four-channel effects with stereo or matrixed four-channel recordings. There are also separate bass, treble and mid-range tone controls for front and rear channels (mounted as dual concentric controls), a master volume control and a separate power on-off switch.

The previously referred to Dolby selector switch permits direct playback of Dolbyiced FM broadcasts, playback of other Dolbyized program sources, bypassing of Dolby circuits for conventional program sources including internal FM, proper recording of non-Dolbyiced signals and finally, proper re-recording of previously Dolbyized program sources in a non-Dolbyized fashion.

At mid-panel level, just below dial scale level, are a series of 12 push buttons - six at the left and six at the right. The first of the left-most cluster selects left or right channel calibration of the Dolby level set meter located just above this button. Next is a button which, when depressed, provides a built-in 400Hz tone for Dolby calibration. The remaining four buttons are used in conjunction with the scope display, the first button turning on power to the scope, the remaining three determining the type of display that is to be observed, such as audio presentation (for mono, stereo, or four-channel quadrant displays), FM tuning, or FM multipath. The six symmetrically arranged buttons at the right take care of such functions as loudness control, FM muting, low and high frequency filters, and selection of either main or remote (or both) sets of speakers.

Located at center-panel are three slide controls which control front-rear balance, front-left-right balance and rear-left-right balance. The dial scale itself is well-calibrated in both FM and AM frequencies and includes a logging scale and an illuminated dial pointer. Above the dial scale, various written designations light up to denote settings of the mode and program selector switches and there is also the usual stereo indicator light which lights up in the presence of a received stereo FM signal.

Four small knobs adjacent to the scope display take care of record and playback calibration of the Dolby circuits, and the instructions for these calibration steps are well explained in the instruction manual.

A view of the rear panel is shown in Fig. 1. Speaker connections for both main and remote quartets of speakers are made by means of piano-key spring loaded terminals which virtually preclude (ausschließen) the possibility of short circuits.

Antenna connections are made to similar terminals. There are a pair of a.c. convenience receptacles (US 110V Norm Buchsen) below the speaker terminals one switched, one unswitched, a line fuse and a selector switch for changing operating mode from four-channel to higher-powered two-channel operation.

A detector output jack, identified as "FM Quadradial Output" is provided for connection to a four-channel FM adaptor at some time in the future. Dolby FM calibration controls for left and right channels, though factory preset, may require readjustment and are therefore brought out to the rear panel for customer access. Vertical and horizontal centering controls, as well as brightness and focus controls are also available for setting up the scope display.

A muting level control is also located on the rear panel. Jumper blocks are installed between the preamplifier outputs and the main amplifier inputs. These can be removed and the two sections may be used independently. Phono and high-level in-out jacks, tape monitor out and in jacks (two complete circuits), a chassis ground terminal, remote control socket and switch, and an FM deemphasis switch complete the rear panel layout.

This last item represents a bit of foresight on the part of Marantz's designers. Just a few days before this receiver was evaluated, the FCC authorized transmission of FM signals using the Dolby noise reduction process plus 25-microsecond pre-emphasis (as opposed to previously employed 75 microsecond pre-emphasis).

Owners of the Marantz 4400 and a limited number of other fine tuners and receivers will be able to enjoy this new, more effective Dolby FM broadcasting from the moment it originates in their area.
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• Anmerkung : UKW Dolby kam über den Probelauf bei ganz wenigen Sendern in den USA nie hinaus.

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An internal view of the Marantz 4400 is shown in Fig. 2. Construction is modular and the amount of circuitry contained in this well laid out unit suggests that it could not have been made much smaller in size. Yet, serviceability seems excellent and there is a minimum of point-to-point wiring for all the circuit complexity.

The front-end includes an FET r.f.-amplifier, and FET mixer, and a double-tuned tank circuit between stages. The i.f. section contains six transistors and three stages of dual ceramic permanent filters. Symmetrical diode-limited circuits utilize "Hot Carrier" diodes and the i.f. limiter-amplifier is said to have a small dynamic symmetrical aperture, so that distortion-producing AGC circuitry is not required.

FM stereo decoding is accomplished by means of a phase-lock-loop IC circuit. Muting circuitry includes a two-transistor noise amplifier and a three-transistor switching circuit.

The AM circuitry of the 4400 consists of a multi-purpose r.f.-oscillator-mixer-i.f.-detector IC plus a transistor amplifier. A three-section variable capacitor is used in the AM section.

Tone control circuitry is of the feedback type and utilizes a two-stage direct coupled NPN-PNP configuration with an R-C feedback network. Each power amplifier includes a preamplifier stage, driver, electronic protection and output circuits.

The amplifiers include direct-coupled differential stages. Silicon output stages are arranged in a full-complementary Darlington format direct-coupled output.

The electronic protection circuits, consisting of three transistors and four diodes in each channel, sense peak output current and limit current fed to the driver transistors to a safe maximum value. A block diagram of the entire circuit of the Marantz 4400 is shown in Fig. 3.
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Referring to the published specifications at the start of this report, you will note that Marantz chooses not to mention IHF sensitivity, but prefers instead to reference the signal required to achieve a nominal 30dB of quieting.

While we do not particularly object to this format, it may be confusing to the reader who is accustomed to seeing an IHF sensitivity spec, which combines readings of both residual noise and distortion.

As a matter of fact, taking Marantz's statement, they actually do better than claimed, reaching 40dB quieting at just under 2uV input. However, if it is IHF sensitivity you want to measure, it takes just under 3uV to reach 3% combined residual noise and distortion. 70dB of quieting was reached with an input of just under 100 microvolts and remained at that level for higher signal strengths, as shown in Fig. 4

Stereo quieting was almost as good, measuring 69dB without inserting any low-pass filters. This means that 38 kHz and 19 kHz product rejection is excellent too. Ultimate mono THD measured 0,14%, better than claimed, while stereo THD just missed the 0.3% mark at 0.32%.

The Marantz 4400 really comes into its own when considered as a four-channel amplifier. The distortion plots in Fig. 6 show that at all but maximum power output, THD and IM are at just about the level of our audio signal generator (0.015%) and as close to being "distortionless" as it's possible for us to measure.

Even full power output is conservatively rated. At 50 watts output per channel, with all channels driving 8 ohm loads, THD was still a low 0.06%. Rated THD was reached at an output of 56 watts per channel under the same driving conditions, and rated IM of 0.15% was read for an output of 58 watts per channel, again with all channels driving 8 ohms. Two-channel power was 135 w/chan. at rated distortion, 20 Hz-20 kHz.

Even more impressive is the power bandwidth of this brute amplifier (shown in Fig. 7) which extends from 6 Hz to 80 kHz.

In trying to plot THD versus frequency. we ran into a problem of having to show an expanded distortion scale on our standard graph presentation, so that for all intents and purposes, it's difficult to read just how low the THD readings really are at the frequency extremes at full rated power output.

In case you have trouble interpreting the "almost straight line" curve, suffice it to say that at 20 Hz, the 4400 was still producing its rated power output of 50 watts per channel with less than 0.1% THD and at 20 kHz, the THD for 50 watts output per channel was a mere 0.055%. These results are plotted in Fig. 8.

Phono overload was measured at 120 mv, better than the 100 mV claimed. Phono hum referenced to 2mV input and full power output was a very excellent 70dB. Many manufacturers claim that figure, but few actually attain it, especially when referenced to such a sensitive, high-gain phono preamplifier circuit.

The omission of the RIAA curve from the manual was evidently an oversight on the part of the printer, because in fact, RIAA equalization was accurate from 30 Hz to 20 kHz within +0.5 dB.

Overall frequency response extends from 10 Hz to 25 kHz within 0.25 dB, with input applied to any of the high level input jacks. Signal-to-hum level for high level inputs measured a satisfactory 86dB.
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Tone control, filters, and loudness characteristics (for a -30dB setting from CW position of the volume control) are all shown in Fig 9. Filter action for both low and high filters is steep and effective in reducing rumble and hiss without seriously affecting response musically. The mid-range control (unlike some) does not provide too much presence boost - just a nice moderate amount which is easily and uniformly controlled and the center of which is at a preferred lower-mid frequency. We liked its action.
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Considering the FM portion of the Marantz 4400, there's no doubt that a scope display for tuning beats any meter arrangement, as we have said in previous reports on equipment that provides this luxury. In the case of this unit, the display serves a triple purpose. When used for tuning, a vertical bar trace indicates correct center tuning as well as relative signal strength. When the FM multjpath button is depressed, degree of station modulation as well as multipath distortion can be easily observed. Finally, the display is useful in observing audio signals in mono, stereo and four-channel modes.

We cannot guess what percentage of the cost of the Marantz 4400 is bound up in the scope display feature (probably a good 25% of the parts cost), but there is no doubt about its usefulness in every one of its functions.

Aside from the slight discrepancy in quieting sensitivity, the tuner section performed well, with a minimum of audible distortion on all but the very weakest signals. Stereo reception was excellent, with very positive switching occurring between mono and stereo reception. In fact, all the controls of this fine receiver have a very positive feel and transmit a sense of the ruggedness of the entire instrument.

One cannot but help be influenced by the high cost of this receiver in conducting listening tests and use tests. Certainly, the amplifier section of this unit performs flawlessly - fully as well as some of the separate integrated amplifiers and even separate power amplifiers to which we have listened.

There is a lightness of bass, and an ease of power handling that is rarely found in all-in-one receivers, least of all four-channel units which often compromise amplifier power and performance in favor of quadraphonic circuit needs.

Marantz has chosen the opposite approach. They have designed, first and foremost, a quality quartet of amplifiers, but chosen to leave the choice of system and sophistication up to the user by means of the "hidden pocket" system.

The built-in four-channel synthesizing circuit does do some interesting things for both stereo records and matrix encoded discs. It does not, however, decode them as their producers intended them to be reproduced, nor does it have any logic circuitry, so that separation is minimal and instrumental placement is arbitrary and does not conform to expectations.

We checked this out by alternately playing several SQ records, first using the built in four-channel synthesizer and then using a separate, full-logic SQ decoder (not the one supplied as a plug-in module by Marantz).

Naturally, the full-logic decoder produces superior results. That means that unless you wish to confine your four-channel listening to discrete four-channel tapes, you're going to have to spend more money for the SQ decoder of your choice.

You can purchase either Marantz's SQA-1 ($49.95) which has front-to-back logic - or the SQA-2 ($79.95) which has full logic.

• Anmerkung : Den Unterschied habe ich noch nicht erklärt bekommen.

If you want CD-4 record reproduction, you will have to use an outboard demodulator such as Marantz's Model CD-400 ($99.95).
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In short, the Marantz 4400 is an excellent piece of electronics in its own right, though not a universal four-channel receiver unless you spend a bit more money than the initial $1250.00 required to buy the receiver.

And keep in mind our arbitrary figure of 15% of the total cost for all the benefits of the triple-purpose scope, which amounts to nearly 300 dollars. The additional cost of $50-100, which is less than competitors' comparable units for a plug-in decoder or demodulator still keeps the price of the 4400 within the range of several other top-of-the-line four-channel receivers.

Obviously, Marantz could have easily raised the price even higher and included the extras. The fact that they did not suggests that they believe there may be further improvements in SQ decoding techniques and they may well be correct in this surmise. In any case, with the externals added, this receiver is in no way a "compromise" design because of its four channels of audio. In fact, when the pairs of amplifiers are operated together for stereo listening, there aren't too many receivers around that can deliver its 125 watts per channel so effortlessly at any price.

Leonard Feldman

AUDIO • SEPTEMBER 1974
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If you consider power output alone (as, unfortunately, so many uninformed buyers do) you might well wonder what right the company has to charge upwards of $1.200 for this 4-channel/2-channcl unit. This only goes to prove that there is more in front and behind a front panel than watts of audio power and elegant styling.

Marantz has styled this impressive unit in keeping with the family tradition of that famous brand of components, as can be seen in the front panel view of Fig. I. There is edge-flywheel tuning (which they call Gyrotouch tuning), a feature that we still feel makes for the smoothest type of station frequency selection possible.

The center of the upper portion of the dial becomes illuminated in blue frequency markings for FM and AM. The FM scale is linear and a supplementary 0-100 logging scale is provided between the FM and AM frequency scales.

Above the frequency markings are a series of illuminated words that indicate the program source selected, the presence of a stereo broadcast and whether or not the Dolby circuitry has been activated. Yes, the receiver is fully equipped for Dolby FM broadcast reception, but more about that in a moment.

The left end of the panel is pictured in the close-up detail of Fig. 2. The famous Marantz oscilloscope tube is there, an ongoing reminder of the venerated Marantz 10B tuner where it first made its appearance many years ago.

Four pushbuttons just below select one of the three uses of the scope display (audio display for stereo or 4-channel tuning, and multipath, plus a button to turn the scope feature on and off).

This sort of scope display, when properly calibrated, is, in our opinion, still the most useful and accurate way to tune FM. To the left of the scope display are four tiny level controls, two for calibrating Dolby record level and two for calibrating Dolby playback level (yes, you can use the built-in Dolby with your open-reel or cassette tape deck, if either or both of these units does not already have the Dolby feature built in).

A tiny meter at the extreme left of the panel assists in these calibration procedures. The remaining two buttons in this area of the panel serve to introduce a built-in 400-Hz tone for calibration purposes and to select left- or right-channel connection of the level meter.

The central section of the front panel contains three slide controls that handle front left-to-right balance, front-rear balance and rear left-to-right balance.

Six more symmetrically positioned pushbuttons at the right, under the tuning wheel, activate loudness control, FM muting, low and high cut filters and select main or remote pairs or quartets of speaker systems.

The lower portion of the panel is equipped with nine gold colored metal turned knobs, a power on/off pushbutton switch and a pair of headphone jacks for connection of front and rear plugs of a quadraphonic headphone.

The knobs are master volume, treble, bass, mid-range, a dimension control that is associated with the built-in matrix decoder circuit, a mode switch, tape monitor switch (that selects source or one of two tape-monitor circuits), program selector switch and a dolby selector switch (with settings for Dolby FM, Dolby playback, settings for recording non-Dolby or Dolby programs and an off position).

In the specifications as supplied by the manufacturer, we noted that an optional SQ decoder costs $79.95. That was not meant to imply that this 4-channel receiver comes without matrix decoding facilities. It does.

In fact, the built-in matrix decoder has a dimension control that varies the decoding parameters over a wide range. It is, however, what the industry has come to call a "basic" matrix decoder.

That is, it contains no logic circuitry and therefore provides only minimal channel separation when listening to matrix encoded records.

For this reason, Marantz very wisely chose to provide a "pocket" under the receiver into which can be popped SQ decoders of increased sophistication as they become available.

There are two advantages to this approach. If you find that the built-in decoder gives you all the 4-channcl effects you would want, leave well enough alone.

If, however, you seek the ultimate in 4-channel SQ reproduction, add Marantz's latest full-logic decoder (which, at the moment, is their model SQA-2B which was included in our sample) for another $80.00 or so. A view of how the module fits in under the chassis is shown in Fig. 3 and the whole idea is also designed to prevent obsolescence as more sophisticated logic circuits are developed. Instead of having to scrap a $1.250.00 receiver, you can buy an even better logic decoder later on, assuming improvements are made in the future.

The rear panel of the Model 4400 will elicit as much delight from the seasoned audiophile as will the front panel.

In addition to the sixteen speaker terminals for two full quartets of speakers (main and remote), there are the usual tape in, tape out and phono inputs, and the scope controls, that position the scope trace and adjust focus and intensity, a variable FM muting control, an FM deemphasis switch (Dolby broadcasts use 25 microsecond deemphasis instead of the usual 75 microseconds), a remote control switch (that permits connection to an adjacent receptacle of a remote control attachment), Dolby FM preset level controls, a detector output jack, jumpers to connect the preamp output to the main amplifier input, a power mode switch that selects higher powered 2 channel operation or 50-watt-per-channel quadraphonic operation, a pair of convenience AC receptacles, a line fuse, a pivotablc AM ferrite bar antenna, and a chassis ground terminal.

• Anmerkung : Sie haben richtig gelesen ---- das war ein einziger Satz !

A view of the complete rear panel is shown jn Fig. 4.

We removed the metal enclosure (a wooden cabinet is also available) to get a better look at the insides of this circuit-packed receiver and found that major assemblies are individually shielded with black metal covers, as can be seen in Fig. 5.

A better idea of the complexity of this receiver can be had by consulting the overall block diagram shown in Fig. 6.
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Field-effect transistors are used for both the RF amplifier and the mixer in the FM front-end of this unit. The IF section consists of six transistors and four stages of dual ceramic filters.

Limitcr circuitry consists of gold bond hot-carrier diodes and an IF limiter amplifier and the output of the FM detector feeds a buffer amplifier, that is followed by the FET muting circuit.

The signal then goes to a phase-locked-loop IC stereo decoder circuit. The muting circuit consists of a two-transistor noise amplifier and a three-transistor switching circuit.

The AM tuner section consists of a single IC, a transistor amplifier that follows AM detection and a three-section variable capacitor. A ceramic filter is also used in the AM circuitry and the AM IF amplifier incorporates an "automatic gain control" circiut (AGC). Tone control amplifiers use a two-stage direct coupled NPN-PNP in/out configuration followed by an R-C feedback network. The power amplifier sections consist of four direct-coupled differential amplifiers and silicon output transistors are arranged in a full complementary Darlington format.

The driver stage uses a pair of push-pull complementary symmetry transistors. The elaborate electronic protection circuitry consisting of three transistors and four diodes for each channel, senses peak output current and limits the current to the drivers to a safe maximum value.

The oscilloscope display circuit consists of two deflection amplifiers and a cathode-ray tube. Each signal to be displayed is selected by the appropriate front panel push button switch and 4-channel signals are maimed into the oscilloscope display circuits.

Of those specifications that are supplied by Marantz, every single one was exceeded by a wide margin in our test measurements, as can be seen in the results shown in Table I.

Note that Marantz does not publish an IHF sensitivity figure, but prefers to quote only the more meaningful quieting slope results. In the case of our sample, 50dB of quieting in mono was achieved with a signal input of only 3,1uV (Marantz claims 5uV for 55dB of quieting). Ultimate S/N measured 78dB in mono (far better than the 70dB claimed) and a satisfactory 64dB in stereo.

All distortion figures were notably better than claimed, and even at 6kHz in stereo (for which no figures were given by the manufacturer) THD remained low, at 0.5%. Other results, ranging from very good to superior, can be seen in Table I.

While we do not normally make extensive laboratory measurements of AM performance, we did measure usable sensitivity for the AM section of this receiver and found it to be 17uV for mid-band frequencies using an external antenna and 420uV when using the built-in ferritc bar antenna.

Our amplifier measurements are listed in Table II and can be compared with manufacturer's ratings. Even at the difficult frequency extremes, the power amplifier delivered 58 watts-per-channel (at 20Hz) in the 4-channel mode and 180 watts-per-channel in the stereo "strapped" mode. In 4-channel operation, only 8-ohm loads are recommended and our measurements reflect this limitation. Overall, power ratings as stated are extremely conservative and at the rated 50 watts-per-channel (in 4-channel mode), the actual distortion for mid-frequencies measured a mere 0.007% compared with the rated THD of 0.15%. Damping factor measured 65 which is excellent and all hum and noise figures are substantially better than claimed.

Action of the BASS and TREBLE controls is shown in the graphs of Fig. 7. It should be noted that the knobs used on these controls, though equal in depth to those used for switches, are in reality two half-depth knobs mounted on dual concentric shafts for individual tonal control of front and rear channels.

The same holds true for the mid-range control. The response and range of the mid-range control is shown in Fig. 8. High- and low-cut filter responses are shown in Fig. 9.

Phono overload occurred at 120 millivolts as against 100 mV claimed, a high enough figure for most modern recordings played with typical magnetic cartridges, but not as high as some we have measured on a few stereo receivers in the high price category.

Since our unit came equipped with the add-on SQ decoder previously mentioned, much of our listening concerned itself with SQ source material.

We were impressed with the added dimensional realism afforded by the full-logic circuitry of the decoder and decided to measure separation, using a CBS supplied SQ test record and a Shure V15 Type III phono cartridge. We played a left-channel-only SQ encoded signal at various frequencies through the entire system and came up with the results shown in Fig. 10.

Note that no graph is provided for the right-front channel under these test conditions, because in the SQ system, separation from left- front to right-front is theoretically infinite (or at least stereo cartridge). At frequencies below 100 Hz, the logic circuitry does not improve separation to a great degree beyond the 3dB inherent in the SQ system.

It should be noted, however, that separation at very low frequencies is not an important requirement for the enjoyment of multichannel musical reproduction. Above 100 Hz, cross-talk into both related channels (left-back and right back) is reduced to values ranging between 15dB and 20dB, providing very effective quadriphonic listening.

The SQ adaptor module in question, though quite small, contains three IC's (two from Motorola, the other a Sony SQ IC) and more parts than we cared to count. To give you an idea of the complexity of this little module (and why Marantz asks just under $80.00 for it), we photographed the inside of the module, as shown in Fig. II.

It took us several hours just to try out all the many features of the Marantz 4400. It is, indeed, an audio purist's dream in that its designers have not overlooked any feature that might prove worthwhile in stereo or 4-channel use. As we said earlier, the built-in matrix decoder is not nearly as effective in reproducing matrixed 4-channel discs with full dimensional realism as compared with the results obtained from the optional SQA-2B module. This a pity that Marantz was not able to include a CD-4 module option (in another possible pocket under the chassis) so that all 4-channel facilities could be self-contained, but we could understand the problem when we later examined their separate well engineered Model 400B outboard demodulator accessory.

As for FM reception - it was flawless, limited in quality only by the station's transmission practices. Since our lab is equipped with a rotator that controls the orientation of our outdoor 5-elemcnt directional FM antenna, we were able to watch the multipalh problems disappear on the scope display as we leaned on the rotator control. To use anything but this arrangement with a set of this kind is to do its display features an injustice, for you can literally "tune" your antenna for best reception of each station as you watch that clever scope presentation. Then, when all was right, we switched over to the audio display and permitted those four radiating traces to mesmerize us as we listened to our favorite stations and records. Certainly, the scope display adds a considerable percentage to the final cost of this well equipped receiver, but after a few hours of use, it all seemed worthwhile.

Our summary comments will be found along with our overall product analysis ratings in Table III. R-E