ONKYO TA-6511: Honest and solid one

Submitted on: 07 Jan 24

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Category: Analog recorders/players

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I envisioned this text a bit differently – instead of a classic review of a deck, I will compare it to most other features with a similar deck from the same period and the same price, but from a different manufacturer.

In the mid-90s, as I’ve mentioned several times, HiFi equipment manufacturers almost gave up on decks. Devices of middle or lower-middle class took precedence. Denon had a model DRM-650S, a two-head, two-motor device from 1996, priced at 300 EUR. Onkyo had a similar model, the TA-6511. While the DRM-650S was a top model, above the 6511, there was also a three-head, three-motor, more advanced model, the TA-6711. The difference between the 6711 and 6511 is significant, both in construction and features, almost as if they were not made by the same company or the same development team. However, interestingly, the 6511 had Dolby S, while the 6711 did not. Although not evident from the designation, the 6711 was slightly older and was the first model in the 67/65/6211 series to hit the market.

Why did I buy the TA-6511? Simply put, ten or fifteen years ago, I had it in my collection, along with the 6711, both in a beautiful champagne color; I bought them together. Now, currently, I have the 6711, as well as the 6511 and 6211 (which I will write about later), but in black. I remember that the TA-6511 surprised me more with its sound than the TA-6711; it wasn’t better, but it was incredibly close.

Since I recently acquired a Denon DRM-650S, I was curious about what it would be like to directly compare these two decks. I was interested in what the manufacturers had actually achieved with lightweight devices of cheap and simple mechanics and a lot of integrated electronics, at the twilight of the compact cassette as a medium.

These were, in fact, cheap Dolby S decks.

The picture would be complete if I also acquired a Yamaha and NAD from that period (e.g., 613), as well as an Akai DX49 (which I owned), but I don’t have the conditions to keep 50 decks in the apartment :).

Another reason for comparison is that Denon, plastic and almost poor in some segments (please forgive me, Denon almost always spared greatly on the housing, etc.), has surprisingly good sound, so much so that, as far as sound is concerned, I could live with it and not regret it. Provided that the simplicity of its mechanism doesn’t bother me.

Onkyo is a decently made deck and feels noticeably sturdier compared to Denon, and a couple of centimeters deeper. Take the term “decently” with a grain of salt because we’re talking about the mid-90s. Relatively sturdy metal housing, thick metal tape door cover, and a nice, thin front panel of brushed aluminum, here in black, are made to look much thicker than they really are. The design is modern for its time, especially with the transport in the middle. The controls are nicely grouped engineering-wise, but there is a gap on the left side below the display, while the right side may be a bit crowded.

In contrast, Denon is much more of a classic design, almost boring, but with nicely arranged controls and a large potentiometer button for recording level. Speaking of which, the sensation of rotating the smaller button on the Onkyo is better; on the Denon, it feels “cheaper.”

Regarding the display, Onkyo has a far greater advantage: a larger, more informative display somehow completes the impression of this device, while with Denon, part of the display window is seemingly large, but part of it is occupied by the remote control receiver, and the rest is the screen. The peaks are good, the resolution is decent (12 segments), especially around 0 dB (-3, -1, 0, +1 +3. excellent), but other information is scarce and small. The peaks themselves are more dynamic on the Onkyo, but I have no way of measuring the peak decay time.

Onkyo has resolution within -4, -2, 0, +2, +4, which is worse but still quite usable in most cases. I must mention that the display on the Onkyo deck is actually for models without Dolby S and auto-calibration, so it does not display whether any of these options are enabled (except for a modest message at the counter location, upon pressing a button… “ACCU”), instead, they added LED lights for that, which ruins the impression because you have to look both left at the display and right at the LEDs. With Denon, everything is concentrated on the display, just as it should be.

Regarding options, both decks have two heads, Dolby S, and auto-calibration of sensitivity and bias. They work quickly and easily, not like some other decks (e.g., Beocord 9000, JVC DD9, etc.), but they do the job. Denon uses, in addition to the standard 400 Hz frequency, another one of 12.5 kHz, instead of the most commonly used 10 kHz (as with TA6511), which is interesting.

Among other options, Onkyo has a much better song search system and repetition of the entire side of the cassette or music block, while Denon has a Rec Cancel function that returns you to the beginning of the recording, manual bias (which I didn’t need), a decent headphone amplifier, remembers the counter value when turned on, and resets it when the cassette is ejected. Additionally, it has a counter memory that I use from time to time. The counter on the Onkyo deck has exactly 50% better resolution than the one on the Denon, which is fantastic, although the one on the Denon is quite good. Somehow, although it seems more modest, Denon has more useful options, at least for me.

I must mention that I liked how the Denon autocalibration start process was solved: with Onkyo, it is classic – pause for recording and pressing the autocalibration button. With Denon, it starts directly from Stop mode, but to avoid making a mistake and erasing the tape, the autocalibration button needs to be held about half a second longer to activate the process. Brilliant, you start everything by pressing one button, but if you miss the button, nothing will happen until you are really sure that you want to perform the autocalibration.

The cassette door and cassette holder on the Denon are ordinary, the cover is made of metal and plastic, while on the Onkyo, the cassette holder is secured with a metal frame, and the cover is more massive, which gives Onkyo a sense of seriousness compared to Denon.

Both decks use almost identical mechanisms; I think it’s an ALPS product. Two-motor, with an electromagnetic actuator for raising the heads. Onkyo’s is better. Denon’s flywheel is of such mass that I have seen larger ones on the most ordinary mono radio cassette players from Hong Kong during the 80s. That’s why the declared W&F value is poor, 0.07 (Sankyo three-motor direct drive, with two flywheels in a closed loop, has about 0.030), while according to the DIN standard, the difference is even worse. I can’t understand why they did this; they probably went to the very bottom of the human ear’s ability to detect whining and trembling and made this junk… just to save money. They could have easily put a DD motor or a more massive flywheel, but that would have cost a dollar or two more, and as we know, manufacturers are quite greedy for money.

Onkyo was smarter and put a larger flywheel on the exact same transport, which is felt in the sound. I didn’t want to compare the W&F of these two decks; I would probably just get annoyed.

Truth be told, this type of mechanism doesn’t break and is easy to maintain – replacing rollers is easy, and the belt can be replaced with a little effort and without disassembling the mechanism, but it is necessary to have a belt of high quality and precise dimensions; this transport is not tolerant.

Interestingly, Denon heats up more (power section) than Onkyo.

During fast forwarding, Onkyo has some kind of soft stop, while Denon, when stopping after playback, recording, or at the end of the tape, returns it slightly backward – to tighten the tape, actually, which is great and rare on two-head decks.

As for some audiophile additions, neither deck has any exotic solutions, components, or, for example, amorphous or amorphous heads – both decks have heads made of hard permalloy, very shallow to resemble those on a Walkman, but of a different type.

Neither deck has a backlight for the cassette, and it is difficult to see how far the cassette has progressed if the lighting conditions are not optimal. With a little effort, this can be nicely solved by using one or more LEDs.



Both decks seem neat, with Onkyo being slightly easier to service (the spring of the cassette holder is the troublemaker in Denon).

Denon has two basic printed circuit boards, one for power supply and drive mechanics, and the other for audio.

Everything in Onkyo is on one board.

The Dolby S circuit is on one larger board in Denon, while in the Onkyo deck, it is on two small ones.

Denon uses the CXA14175 specialized Dolby S circuit, produced by Sony.

Onkyo also uses a Sony circuit, but a more modern CXA1417Q.

And the sound?

Onkyo is surprisingly detailed for a relatively cheap cassette deck; I noticed this many years ago when I owned it for the first time. It is extremely clean, without any cloudiness, and, partly thanks to that, it has excellent scene width, which fascinates from time to time, making it clearly better than Denon. The bass is solid, powerful, but in most cases, it lacks extension and is more rounded. Extension at the upper end is solid, but it is better on Denon.

On the other hand, Denon is in the same category of detail but more neutral: slightly darker, but in fact, as I said, more neutral and with excellent, rich, deep bass, giving it a noticeably better sound compared to its price. Harmonious, moderately warm, with good dynamics – it’s a real shame it doesn’t have a more quality mechanism; the impression would be even better. It is more dynamic and simply sits better with my ear; despite intensive listening sessions, I couldn’t catch Denon pretending, performing intense compression, and introducing an artificial sound. Maybe Onkyo even has a cleaner sound than Denon, but Denon is simply better and can compete with three-head decks of lower and middle class.

It shouldn’t be thought that Onkyo is bad – it is average for its price or even slightly better, while Denon has a more expensive sound than its category.

Which one to choose? I would take both, and then put the transport from Onkyo into Denon and make a winning combination :). Just kidding, you should choose the one in better condition.


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