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Cambridge Audio Duo Phono Stage Review (Updated)

Rate this phono stage:

  • 1. Poor (headless panther)

    Votes: 5 3.3%
  • 2. Not terrible (postman panther)

    Votes: 10 6.5%
  • 3. Fine (happy panther)

    Votes: 62 40.5%
  • 4. Great (golfing panther)

    Votes: 76 49.7%

  • Total voters
    153
Is this one and the same as the Alva Duo? (seems to be)


If so;

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Either way, thanks for the follow up testing.


JSmith
I bought a new ALVA SOLO last month. The box and manual say ALVA SOLO, but there is no ALVA written on the main body or inside. 2017 is written on the board.
The serial number written on the box and the serial number on the main unit matched.
The only thing that seems to have been updated with ALVA SOLO is the box and instruction manual. The same may be true for ALVA DUO.
 

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I'm considering grabbing a Duo, Solo or a Mani as they're all under $350. While the Solo is the leader in SINAD, the RIAA frequency response is not totally flat per below. Is it correct to assume that a slightly uneven FR would be more noticeable (while listening) than slightly less SINAD? Wondering what peoples thought are here.


Cambridge Audio Solo Frequency Response Audio Measurements.png
Cambridge Audio Duo Phono Preamp stage MC MM Frequency Response RIAA EQ Measurement.png

Schiit Mani2 Measurements Frequency Response Phono Preamp Stage Budget.png

Screen Shot 2024-02-01 at 9.39.47 AM.png
 
I'm considering grabbing a Duo, Solo or a Mani as they're all under $350. While the Solo is the leader in SINAD, the RIAA frequency response is not totally flat per below. Is it correct to assume that a slightly uneven FR would be more noticeable (while listening) than slightly less SINAD? Wondering what peoples thought are here.


View attachment 346577 View attachment 346578
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I think the flat RIAA curve is way more important than SINAD.. Especially when you have somewhat older ears..
 
I'm considering grabbing a Duo, Solo or a Mani as they're all under $350. While the Solo is the leader in SINAD, the RIAA frequency response is not totally flat per below. Is it correct to assume that a slightly uneven FR would be more noticeable (while listening) than slightly less SINAD? Wondering what peoples thought are here.


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I was debating the same thing originally, and here's what it came down to. The SINAD is beyond what vinyl can do, so that doesn't really matter. The frequency response of the Duo is the best, and you should want a bass roll off to prevent feedback into your cartridge. For me it was between the Solo and Duo, but the Duo was "too big" for my setup. I ended up fixing my Muffsy PP-4, but if I ever buy a Preamp I'm going with the Duo.
 
Hello amirm and All,

Last fall I began building and testing a RIAA pre-amplifier with the APx555 that sits on my bench.

I support testing the Moving Magnet pre-amplifier with 5.0 mV input and letting the results fall where they will.

The pre-amplifier gain means everything to what the output voltage will be. The ASR measurements show what the output voltage is depending on the measured gain. The RIAA pre-amp gain and output voltage are the first things that I look for.

The next thing that I am looking for is output noise. The worst offender is power supply harmonic peaks.

From measurement to measurement of different pre-amps using 5.0 mV as the input voltage the output voltage will fall where it will. The same is true with the power supply harmonic series peaks they will fall where they will as well.

Using a dBVrA scale on the FFT plots with the 1kHz output always at 0dBrA does not show the actual measurement values. It is difficult to visually compare RIAA pre-amplifier output noise between measurements and different pre-amplifiers.

The APx555 and APx500 software will plot FFT’s with an output scale in Amplitude Spectral Density dBV/Rt (Hz). The FFT noise floor is shown in real measured values. Plus the measured 1kHz output voltage is also measured in real units rather than relative units.

While you are changing things up consider scaling the FFT in real numbers, dBV/Rt (Hz).

Thanks DT

A couple of plots for fun

Amplitude Spectral Density.PNGP3 Stepped Input Level THD+N Ratio + THD Ratio.png
 
Just got my Cambridge Audio Duo phono pre after scouring this forum for reviews — was originally considering a Pro-Ject Phono Pre but saw the Cambridge was just much better on the charts - I can confirm that I am very happy with this using it on my Pro-Ject Debut Pro White turntable. I was previously coasting by on my old DJ II Art Pre and they are worlds apart in terms of clarity and definition - my records don't sound as muddy, fuzzy or distorted on the higher frequencies and it's got a much better interpretation of the RIAA curves. I can't believe I was listening to such fuzzy sounding records for all these weeks since purchasing my TT! Thanks for all the reviews. Hope this informs someone else's upgrade plans as well. Cheers
 
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I recently picked up a Duo as well based on reviews. I’m not entirely happy with it, but I made so many changes at once that I’m not sure what (if any) the issue is. I replaced my old entry level turntable (purchased new in 2005) with a used 2008 ultra high end model. It came with a moving coil cartridge and I figured the Duo would be my best bet. I’m happy with the overall clarity and complete lack of hum and environmental noise, but I’ve noticed a distinct lack of bass. I wonder if it’s something in the setup or if it’s related to the Duo’s rumble filter or lack of loading adjustments.
 
I recently picked up a Duo as well based on reviews. I’m not entirely happy with it, but I made so many changes at once that I’m not sure what (if any) the issue is. I replaced my old entry level turntable (purchased new in 2005) with a used 2008 ultra high end model. It came with a moving coil cartridge and I figured the Duo would be my best bet. I’m happy with the overall clarity and complete lack of hum and environmental noise, but I’ve noticed a distinct lack of bass. I wonder if it’s something in the setup or if it’s related to the Duo’s rumble filter or lack of loading adjustments.
Lack of bass is certainly not caused by the Duo IME. However it is possible that your old phono preamp was not linear, but I rather suspect the old TT to have overblown bass.

If you own a recording both in digital and vinyl use the digital as reference how it should sound. E.g. Dire Straits Brothers in Arms sounds very close from CD and with an AT33PTG/II and the Duo in my system.

Use tone controls.
 
Lack of bass is certainly not caused by the Duo IME. However it is possible that your old phono preamp was not linear, but I rather suspect the old TT to have overblown bass.

If you own a recording both in digital and vinyl use the digital as reference how it should sound. E.g. Dire Straits Brothers in Arms sounds very close from CD and with an AT33PTG/II and the Duo in my system.

Use tone controls.
The old setup ran an Ortofon 2M Red direct to the receiver‘s MM input. The new setup is basically a higher-binned Denon DL-103R that was repotted From plastic to metal. Old setup gave up the ghost, which is how I managed the upgrade. Unfortunately, it means I’m not able to A/B them. I could switch back to the 2M, but I’m apprehensive about messing with it. The tonearm would be a financial nightmare to repair or replace, the wires are very small, and my hands are not as steady as they used to be.

I do have quite a few records with digital copies, it’s one of the main reasons I like buying vinyl. They usually come with a download or access on a streaming platform. I’ll cue something up and give it a listen. I kind of hate doing it because only a couple of my records are better than their respective digital versions. I don’t need any more reminders that vinyl‘s technical prowess as a medium has come and gone.

A final thought- my old TT wasn’t really known for its bass output, but my new (to me) one very much is.
 
Quantity or quality of bass, or both?
Quantity. It’s still there, just less of it. The more I think about it, the more I suspect it’s the built-in MM pre’s tuning on the Arcam.

I did my best to A/B with digital recordings, but because of the input level difference between the two, I had to mess with the volume a lot between tracks. Not really a fair comparison or true A/B. What I noticed most was the treble on the digital version- it stuck out as being harsh. To be fair, it was Blood, Hair, and Eyeballs by Alkaline Trio. The digital copy just isn’t that good.
 
ASR citizens,

I need to connect this (Cambridge Duo) to a Flex8 (which does not have analogue IN). So I need an ADC :(
I dont know anything about gain mismatch and stuff like that - will any ADC, say a Scarlet 2i2 (4th gen) or Cosmoc ADC etc work.
PS: My TT is Rega RP1.
 
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ASR citizens,

I need to connect this (Cambridge Duo) to a Flex8 (which does not have analogue IN). So I need an ADC :(
I dont know anything about gain mismatch and stuff like that - will any ADC, say a Scarlet 2i2 (4th gen) or Cosmoc ADC etc work.
PS: My TT is Rega RP1.
I don't think the Scarlet 2i2 is the right choice. It has a good ADC, but how do you get the signal into the Flex8? I don't think USB would do the trick.
You basically look for a ADC with SPDIF/Toslink output. Sadly i don't know such a device.

I think i would use a RPi and connect the Scarlet to it, then output sound with a simple USB-to-SPDIF adapter:

It's rickety, but i don't see a problem in terms of fidelity.
 
Bought a duo on the strength of the data, can't be sure it sounds any better than the stage in my Yamaha A-S501, but about to waste even more cash in pursuit of nostalgia on a new cart so figured this would be a bit of future proofing and opening up MC as an option.
I'm intrigued by alternative grounding options, my device isn't silent. Hum is inaudible playing a record, but it's there if you increase the amp vol, which is what I expected, not silence as there is on other source inputs.
 
Btw, I found (I think) a solution. I had purchased a Wiim Pro (not yet delivered).
My understanding is that it has a good enough ADC. So that should be OK.
 
How is it when you have the TT connected? Be sure to connect the ground wire from the Rega to that threaded post to the right of where the cables connect. The ground is very important.
Yes, the MA6800's ground is well connected, the ground here is very good, straight from the energy company, everything is new. The Rega, as I showed in the video, is completely disconnected from the MA6800, even to see that the noise is generated by the MA6800 and not by the Rega.
 
Yes, the MA6800's ground is well connected, the ground here is very good, straight from the energy company, everything is new. The Rega, as I showed in the video, is completely disconnected from the MA6800, even to see that the noise is generated by the MA6800 and not by the Rega.
as a reminder, a normal mm stage 35-40 db of gain...and a more or less related background noise ,-)
 
Yes, the MA6800's ground is well connected, the ground here is very good, straight from the energy company, everything is new. The Rega, as I showed in the video, is completely disconnected from the MA6800, even to see that the noise is generated by the MA6800 and not by the Rega.

I'm referring to the ground wire that has to go from your turntable to the Amp, not the mains power ground.

Right, left and ground should be coming out of your turntable.

I'm wondering what the noise will be when you've got the three wires between your turntable and your Amp connected.

It may be quieter with it all connected.
 
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