Hello Everyone,
This is a review and detailed measurements of the Accuphase C-200X peamplifier.
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Accuphase C-200X - Presentation
The Accuphase C-200X is a vintage preamplifier that was available from
1980 to 1983. It is the successor of the C-200S which was itself an evolution of the original C-200 that was first released in 1973.
In today's money (2026), the Accuphase C-200X would cost roughly $4'000, not cheap.
If the look of the C-200X is close to that of the C-200 and C-200S, its internals were updated and the most significant difference was the addition of a "Head-Amp" as Accuphase calls it, understand a Phono MC input on top of the MM. The C-200X offered three MM inputs, one with a fixed input impedance of 47kohm, and the two others with a selectable input impedance of 100ohms, 47kohms, 82kohms and 150kohms. The MC input had a fixed input impedance of 100 ohms and was available on any input because the MC electronic card is separated and switched on by the action of a button.
Selected frequencies for tones control were offered (200Hz/500Hz and 2kHz/7kHz) and adjustments could be done independently Left/Right.
There was a wood case offered as an option. Mine does not have it, but I must say I love the technical aspect of this unit and the staggering finish everywhere I look (that's an Accuphase, I must say). It is a big fat baby and a picture is better than any measurements here (you'll get the specs later
) :
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The C-200X was followed by the C-200L in 1984 which added balanced output, selectable input impedance for MC cartridge, but lost the variable impedance for MM cartridge.
The ultimate version, the C-200V, released in 1987, added a high level input called CD
, and 2 balanced inputs. It dropped the turntable input at front panel, but offered a more luxurious presentation, wooden side panels becoming standard to replace the optional wood case. Last and not least, it replaced the separate left/right Bass/Treble 4 selectable frequencies (200/500Hz & 2k/7kHz) tone controls by 4 stereo tone controls with an extended and refined set of frequencies to chose from (40/100Hz, 500Hz, 2kHz, 8k/20kHz).
Out of the five C-200, I went for the C-200X because of the technical/industrial look, and the small buttons on the front, that both match my good old Accuphase P-600 amplifier, which the C-200X has been driving for one year and for my great pleasure.
The back of the Accuphase C-200X features the beautiful home made (and I think not rubidium plated yet) RCA connectors:
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This back is not so busy with two tape connectors, a pair out stereo output, two line level inputs and two Turntable inputs. This relative simplicity is because the rest of them are on the front, as I already mentioned:
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Below the front brown panel, we get one more tape in/out, a low level input ("Disc") and line level (AUX) connectors. There is also an additional output which means it is convenient to plug in all sorts of temporary devices available at the time, Turntables, line level devices, Cassette decks and amplifiers, without having to pull the C-200X out of the rack and/or to access the back panel. I love this feature which probably comes from the pro world.
The C-200X's brochure was providing a very good set of specifications and measurements, that I think all suppliers should replicate. I copy/paste them here for easy comparison with my measurements to come:
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It is rated for 126mV (-15.77dBu) input and 2V (8.23dBu) output, meaning an exact gain of 24dB for line level. It is important to take this into perspective when measuring such an old device, as the CD Player and its "standard" 2Vrms output was not yet released.
From the above, you can also see that the Accuphase offered a wide range of Voltage input/output which inevitably means an additional technical challenge when it comes to managing noise which must be very low. The theoretical advantage is that this old preamp is still quite capable with our most recent Hi-Fi and/or professional devices. The Accuphase C-200X is happy with sources having a much higher than 4Vrms output and will very happily output 10Vrms to the benefits of low gain amplifiers.
To finalize this long introduction, I must show you the internals, although not as beautiful as with the
C-280:
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This top view and the below one partially reveal the "computer-like" arrangement with preamp cards in the plug-in sockets of an epoxy-glass motherboard.
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The five, easy to remove, cards are for the High and Low levels input of each Left and Right channels. The fifth one is the dedicated Phono MC preamp card. Then, under the two metallic shields, we get the power supply at the back, and the equalizer at the front with numerous features: tones control, subsonic and high filter, two-level loudness compensator, all of which can be deactivated.
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User experience
I’ve been discussing this more personal perspective about the devices I review for quite some time. As a preamplifier, the level of interaction is somewhat restricted to volume up or down. And it does that so well:
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This button seems to be floating in the clouds, being so light with the near perfect amount of feedback. Besides, the complex shape of it, being everything but basic, as the rest of the front knobs, ti demonstrates attention to details, as often with Accuphase. I am clearly addicted to that.
Like I said, everywhere I look, I see a crazy finish, even where unnecessary, which means Accuphase never goes easy. Devil is in the details, but not with Accuphase!
It is funny that when changing an input, the C-200X takes its time, up to 2sec before the relays act and let me hear another source. And each time, I get the same feeling from that experience, and that is "Let's take our time to do that properly, gently, without harm to other components". Efficiency over speed that is.
Other than that, I guess you saw the brown front panel showing some marks. I could not get rid of them as I usually easily do on these old devices with aluminium parts. I don't know what was splattered against it, or if it is a weakness of this brown finish.
I love the possibility to plug everything at the front of it, this is sooo convenient! I did it many times as you know me loving to test a
CD player or DAC every so often. By the way, these front in/out connectors are 2dB noisier compared to the rear ones, with a bit more random noise.
Measurements
I previously reviewed the
Accuphase C-280, a much higher-end preamplifier of a much higher cost, released couple of years later. I encourage you to compare the measurements since I kept them aligned for that purpose.
The channel imbalance of the Accuphase C-200X is a small 0.1dB and the phase is almost flat (-8.6° at 20kHz).
Let's start with the standard 1kHz at max gain (24dB), from a 0.5Vrms input since I did the same with the C-280:
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Compared with the crazy good and more expensive
C-280, we only lost 0.6bits of full resolution. At -106dBr, the THD+N (dominated by noise) is comfortable, providing a clean signal to the amplifier. The C-200X loses the 0.6bits in low level correlated and random noise in the lowest frequencies, where our hears are less sensitive.
Let's try the same at unity gain, with 2.2Vrms input/output:
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This is 4dB less of SINAD than the C-280, but it is still better than the theoretical max of the Audio CD... at a time it did not exist
And note that unity gain (meaning no gain change from input to output) is not the comfort zone of a preamplifier. So we should try to avoid this case by all means, to leverage as much as possible the full performance of it.
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Note that there is a small PS leakage as we can see on the zoomed view below:
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At -110dBr or below, the few spikes (50Hz and harmonics) coming from the power supply, will be easily hidden into music. And knowing that this is from a 45 years old device, with RCA input/outputs only, I think this is good.
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Let's continue with the famous Multitone, from the AudioPrecision file that Amir shared a while ago:
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We get nearly 19 to 20bits of distortion-free range! That is very nice, and only a little less than the Accuphase C-280. We have many modern devices that don't do better than that.
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For once, I'll show you the bandwidth and phase:
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This only one channel, the other one is identical beside 0.1dB channel mismatch.
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The below is a measurement of THD+N ratio vs frequency, with an extended bandwidth to capture all distortion and noise components up to 90kHz:
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This is dominated by noise, as we see only a small rise of distortion beyond 10kHz. In 1980, I'm sure nobody thought about such a punishing test, and an SACD player would massively "fail" this test because of the quantization noise that DSD generates beyond 30kHz, so...
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Let's move on to intermodulation test, with the IDM SMPTE (60Hz & 7kHz 4:1) sweep vs input level:
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The above is for unity gain, which means it's not the best this Accuphase is capable of, but you can compare with the
C-280 which did 5dB to 10dB better.
The sweet spot is at 1Vrms input, and the distortion is generally very low, although not as low as with the C-280. No concerns here, even if intermodulation distortion is easier to hear.
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Other measurements (not shown):
- Input voltage clipping: above 4Vrms (I can't measure more with unbalanced).
- Output voltage clipping: above 10Vrms (I can't measure more).
- Dynamic Range (CCIR 2k weighted): 119dB at unity gain and 120dB at max gain. This is very good.
- IMD AES (18kHz + 20kHz 1:1) : below -119dB from unity gain and above!
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The line stage of this preamplifier offered staggering performances at the time it was released. And even with our today's crazy standards, it is not ridiculous by far.
It is funny to see that 7 years before the first CD player from Accuphase, this Preamp offered a higher resolution. When coupled with the Accuphase DP-70, it is totally transparent. Straight wire with gain, that was/is.
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Accuphase C-200X - Measurement (Phono MM)
That's a well designed Line Stage amplifier, no surprises, but I'm expecting a lot from the Phono stage as this is were these vintage gears really shine.
Let's start with the standard SINAD, with an input of 40mVrms and 40dB gain:
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This is the signal as it comes out from the Phono preamp, meaning I did not compensated the RIAA curve. The results are very good, although not repeating those of the
C-280 because of the higher noise at low frequencies. Yet, 13bits of clean signal is much more than any turntable will ever need...
Now, let's correct the RIAA curve, with the software, to simulate how a record would be created, with the opposite curve:
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This time the SINAD is better than the C-280 because the C-200X has less random noise at high frequencies.
Note: I use a 40mVrms input for that test because some dynamic cartridges (eg:
Shure M44-7 - 9mVrms for 5cm/sec), together with over-cut records, would be reaching a
speed velocity of 30cm/sec, meaning they'd reach or go
beyond 60mVrms. And to add to that, I'm using a 40dB gain amplification, as this is very common, and so with 40mVrms at the input, we get 4Vrms at the output, for the above test.
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Next set of measurements for a phono preamp is related to the above. It is important to know at what point it will clip, depending on the frequency. We need a good headroom, and all ancient phono preamps were known to excel on that perspective.
This is measured with a sweep of THD vs input level, at different frequencies:
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The above results match those published by Accuphase 46 years ago, and they are crazy good!
I mean that at 1kHz the C-200X will clip beyond 400mVrms. Whaaaat? This is nuts, and I must say a real pleasure to witness. What a performance!
At 10kHz, and again as Accuphase published, it clips beyond 2Vrms, completely overengineered
As with my other measurements, the level of distortion is negligible, especially in the noisy turntable environment.
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Ok, bandwidth, as we need to check the respect of the RIAA curve:
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Accuphase said "guaranteed +-0.2dB", I see below +-0.05dB, and even better than the
C-280.
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Oh, yes, for the fun, as
@amirm likes the below measurement. It is a sweep of THD only (no noise) with an extended bandwidth up to 90kHz to capture distortion at high frequencies too:
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Again very close to the C-280, only a little more distortion.
On my perspective, the phono stage of the Accuphase C-200X is outstanding, as I expected.
Conclusion
All the above measurement are sufficient to kill the perception that this preamp would modify the sound of any other device, or that it would sound different from the previously reviewed
Accuphase C-280. The bandwidth is flat, the distortion nearly absent, and there's only random noise below the resolution of the Audio CD, when it comes to line stage.
Outstanding performances are delivered by the Phono stage, to keep it totally transparent.
All in all, it means this is straight wire with gain, with low or high level inputs, and whatever the applied gain is.
What more to desire? I honestly do not know, but I am impressed by this (soon to be)
half a century old device. It still delivers a wide range of very good performances, even by today's standards.
The only downside is the 80W power draw, but it definitely keeps both the room and me cozy. And it might even give the music a warmer feel
I hope you enjoyed this review and I wish you a nice weekend!
)
