Accuphase C-202 Line-Level Preamplifier Service & Review

The Accuphase C-202 line-level class-A preamplifier is an extraordinary piece of hi-fi gear. Come with me as I review and service this amazing preamp.

The Accuphase C-202 is a line-level, class-A, fully balanced preamplifier, with dedicated CD buffer circuit. By any measure, it is a superb piece of gear. It’s not one of Accuphase’s best known pieces however, good news if you decide to buy one.

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The overall layout of the C-202. Note the large number of high-value electrolytic capacitors. More on this later.
Design

Key features include fully balanced operation from input to output, JFETs at every stage, completely symmetrical layout, Class-A operation and no ICs or capacitors in the signal path.

There are lots of capacitors in the C-202, associated with the power supplies for each circuit block. Every circuit block has its own dedicated capacitor bank, lowering the source impedance of each local power supply. Let’s take a look…

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Main power supply, featuring large toroidal transformer, and 40,000uF of reservoir capacitance, more than many amplifiers!
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Closer view of the ‘Elna for Audio’ main filter capacitors.
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Input end of the C-202. Note the four dual JFET input packages, one for each channel, hot and cold. Note also the array of high-quality Elna 1,000uF electrolytic capacitors, located where they are needed, minimising power supply source impedance. There are 16 of these 1,000uF caps, this certainly is a ‘luxurious’ circuit design, to coin a term Accuphase themselves use in their literature.
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Here we see TO-220 output devices mounted to large heat-sinks, dissipating the heat generated by class-A operation.

The C-202 draws 40 watts all the time, courtesy of that class-A operation. That’s more than most modern power amplifiers draw at idle. She gets warm, but not hot, the chassis is well ventilated.

Features

The C-202 has some very useful features, for those who like their preamps to actually have some functionality. For example, there are three switchable outputs, two unbalanced, one balanced.

This is really useful, you can feed high-end balanced amps, I use it to provide two seperate feeds to my B&W subwoofer. In this way, I have two separate subwoofer set-ups, one for hi-fi, one for home cinema. I just switch the output selector according to what I’m doing.

There’s also a built-in headphone amplifier, capable of driving ‘phones of up to 100 Ohms impedance. The C-202 will drive my HD580’s, which are rated at 300 Ohms, but it isn’t totally happy doing so. Still, this is better than having no headphone amp at all!

Headphone socket and output switching. It’s only when you have these features on a preamp that you realise just how useful they are.

One of the most interesting features is the dedicated CD circuit, separate from the other line level inputs. The CD circuit features its own dedicated volume control and bypasses additional controls and switches, providing the most direct signal path possible. You can also select balanced or unbalanced inputs to this dedicated CD buffer.

Two volume controls, but why not? It guarantees the purest signal path for the CD input and this is how my DACs are connected.

There is full tape monitoring and switching provided, great if you are getting back into cassette tape as I am right now. There’s even an attenuator button, which drops the volume by 20dB, useful if you get a phone call or what to change something and return to precisely the same volume setting.

I could go on, but let’s just say the C-202 is not short on features. About the only thing it doesn’t have is a built-in phono preamp.

Specifications, Courtesy of Audio Database:
FormStereo preamplifier
CD Inputs
Frequency response1.0Hz-400,000Hz+0 -3.0 dB
20Hz-20,000Hz+0 -0.2 dB
THD0.005%
Input sensitivity/impedanceBalanced input: 1.0V/40kohm
Unbalanced input: 1.0V/20kohm
Output power/impedanceBalanced output: 4.0V/50 ohm
Unbalanced output: 2.0V/1 ohm
Headphone jackImpedance: 4ohms – 100ohms
GainBal-in -> bal out: 12dB
Bal-in -> unbal out: 6dB
Unbal-in -> bal out: 12dB
Unbal-in -> unbal out: 6dB
Signal to noise ratioA-weighting: 108dB
Maximum output levelBalanced output: 10V
Unbalanced output: 5V
Maximum input levelBalanced input: 10V
Unbalanced input: 8V
Minimum load impedanceBalanced output: 600ohms
Unbalanced output: 1kohm
Tape Rec: 10kohm
Attenuator-20dB
Line Inputs
Frequency response1.0Hz-500,000Hz+0 -3.0 dB
20Hz-20,000Hz+0 -0.2 dB
THD0.0055%
Input sensitivity/impedance200mV/20kohm
Output power/impedanceBalanced output: 4.0V/50 ohm
Unbalanced output: 2.0V/1 ohm
Headphone jackImpedance: 4ohms – 100ohms
ProfitBalanced output: 26dB
unbalanced output: 20dB
Signal to noise ratioA-weighting: 110dB
Maximum output levelBalanced output: 10V
Unbalanced output: 5V
Minimum load impedanceBalanced output: 600ohms
Unbalanced output: 1kohm
Tape Rec: 10kohm
Attenuator-20dB
Loudness Compensation
(Volume control-30dB)
1:+3dB(100Hz)
2: +8dB (100Hz), +6dB (20kHz)
Subsonic Filter10Hz, -12 dB/oct
General
SemiconductorsTransistor: 110 pieces
FET: 54 pieces
IC: 12 pieces
Diode: 79 pieces
Power sourceAC100V/117V/220V/240V, 50Hz/60Hz
Power consumption40W
DimensionsWidth 475x height 135x depth 373mm
Weight11kg

 

Servicing

The  C-202 is generally a reliable preamp, like most Accuphase equipment. The inputs are electronically switched via relays, so there isn’t much to go wrong there. There are some mechanical switches under the front panel flap though, these might need attention over time.

This particular unit was previously owned by a smoker. I removed the main circuit board to address some dry joints and clean the tobacco residue which was causing issues with some of the mechanical switches. I use a washing process, based on how test and measurement equipment is cleaned. This process effectively removes just about every last trace of residue and contamination from board and other parts.

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You easily can see the completely symmetrical arrangement of the hot and cold elements of each channel. It costs a lot to build something this way. This image shows the board after washing / drying.

After drying and reinstalling the main board, I left the C-202 to warm up for a couple of hours. Referring to the service manual, I adjusted all eight DC offset adjustments for each of the two balanced amplifier stages per channel and replaced a blown fuse.

The service manual is critically important here. I was finally able to locate a hard copy of my own and it’s now one of the most treasured manuals in my collection!

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Note the beautifully symmetrical arrangement of components, with the same signal paths, same trace lengths etc.
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Here we just see the 8 x 1,000uF filter caps, plus the heat-sinks for the first bank of transistors.
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Behind them are a second bank of eight Elna 1,000uF reservoir capacitors. The two leads are for my test setup. This makes for a total of 40,000 + 16,000uF of energy storage in this pre-amp – 56,000uF in total, and definitely more than many amplifiers.
Why Aren’t All Preamps Made Like This?

Good question, simple answer – it costs too much to build standard consumer equipment this way. Sure, zero capacitors in the signal path is the best way to go. But it requires DC servo circuitry for every stage, expensive to design and implement. It also requires eight adjustments per preamp on the production line, and this adds to the unit cost.

Mirror-paired JFETs are expensive and there are lots of them in this preamplifier. Add in the heat-sinks for class-A operation, other closely matched components needed for balanced operation, and the costs keep rising.

Sound Quality

How does the C-202 sound? In a word, sublime. You would expect this, given the design, premium parts and beautiful layout. Deep, clean bass, sparking, airy highs, grain-free, fluid mids. This preamp has all of this and more. She is dead quiet and of course produces her very best when fed with a balanced signal into the dedicated CD buffer.

The Bottom Line

You get what you pay for with audio gear and this preamp is a good example of that. Having said that, the Accuphase C-202 is one of the best kept secrets in audio.  Not many people know about them or how amazing they are, so prices are still sensible. If you need a line level preamp, I can hardly imagine anything better. I strongly suggest you grab one.

Accuphase C-202 Stereo Preamplifier

$1000 - $2000AUD
9.6

Chassis / Build-Quality

9.0/10

Features

9.5/10

Sound Quality

9.5/10

Serviceability

10.0/10

Bang-Per-Buck

10.0/10

Pros

  • Superb construction, parts & layout
  • Superb sound quality
  • Loads of inputs & outputs
  • Dedicated CD input & volume control
  • Subsonic filter, loudness, tape facilities

Cons

  • No phono preamp

6 thoughts on “Accuphase C-202 Line-Level Preamplifier Service & Review”

  1. Hi,

    I have a C 222, and I am planning on buying this C202. In your opinion, sonically, would that be astep up or down?

    Please share your thoughts. I would really appreciate that.

    Best Regards

    Kal

    1. Hi Kal

      The C-202 is a line level only, fully balanced from end to end preamp, quite different from the C-222, which is singl-ended only. The Class A, push-pull, fully balanced config, plus the dedicated, balanced CD only input make this preamp quite unique. Truly an awesome line level only preamp, but you need a very good phono stage to match! Regards, Mike.

      1. Hi,

        Many Thanks for your reply,
        You are absolutely right, this C202, sounds amazing, warm, detailed yet smooth without sounding boring,

        I still have two questions, hope you won’t mind. Is it ok to leave C 202 on all the time?
        Second, would it accommodate those Accuphase cards in the back for analog playback, or would you suggest a separate phono stage, which would go perfectly with this preamp?
        Many Thanks for your educational and informative response Mike.
        Best Regards
        Kal

        1. Totally OK to leave on all the time, though bear in mind it constantly dissipates around 40 watts due to class A operation. It does not accomodate cards, it’s a line level only preamp. You would need to choose a phono pre or pre and transformer to suit your requirements and budget, though any phono pre will interface with the line level inputs of the C-202. Cheers, Mike.

  2. Hi, Im planing to buy this pre amp but is 100v, in my country we use 120V. Is the transformer multivoltage?. Can i change it by rewiring?

    Thanks

    1. Hi, this depends on the individual example and you would need to check the one you are purchasing. Mine was configurable from memory, but I’d suggest checking your unit to be certain as the same model can vary in terms of being configurable or not. If not, you can always use a small step down transformer, 100 watts would be enough. Regards, Mike

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