Cambridge Audio Solo Phono Preamplifier Review

[LTig]

Thanks for the graphs and measurements. I am puzzled how this zoomed version matches the sample I just post above.

Here is the Audacity project in a zip-file. You can look for yourself.

 

[amirm]

If you have no DSO use the Scope in REW, it should work (never used it, but there are trigger settings).

I have both a Tektronix and a Keysight DSO. I just hate dragging them out for just one test.

 

[Delacroix]

The Cambridge CP2 (MM + MC) has been reduced from £150 to £99. Does anyone know if it's closer to the Duo (its successor) than to the Solo? I can't find measurements anywhere.

Where?

 

[watchnerd]

Had any fun checking your tracking alignment (Löfgren, Baerwald, etc.)?

Yes, it's fun!

It's like pruning roses, for me.

Approach when in the mood to be patient, and delicate. Walk away and do something else when not.

 

[AudioSceptic]

Where?

You mean where for £99? <https://www.cambridgeaudio.com/gbr/en/products/hifi/phono-stages/cp2>. UK site, so I don't know if you can get it for that.

 

[restorer-john]

It doesn't matter what the frequency is in this case.

Of course it matters! The sample tick you referenced is 44 samples long at 192KHz sampling rate and has a 229uS period. It is approximately 4.364KHz.

If you want to simulate click, tick and pop style overloads and what that does to an RIAA stage, you cannot do it with a 10Hz toneburst. The overload margin at 10Hz is completely different to the midrange frequencies.

For fun, I just put a Yamaha CX-600 preamplifier on my bench and here's the overload results at 100Hz, 1Khz and 20KHz for a continuous sine. (MM input to tape out). This little Rigol scope is great for screen grabs via USB with the Ultra Sigma software they give you, so I used it instead of my old skool CRO.

Firstly, 1KHz reference of 5mV in gives 2.99V out, a gain of 55.45dB:

Yamaha rated 2.5mV for 1.5V out, or 55.56dB so we are on the money.

Now let's push it to clipping and back it off to be right on the edge:

We get 199mV @1Khz to give 12.0V out at the onset of clipping.

Yes, real phono preamplifiers can swing a decent voltage, none of these weak ass D/A numbers of a few volts here! Our overload margin at 1KHz is 32dB with respect to the 5mV. Yamaha rate the maximum input at 1KHz to be 170mV, but they specify a low THD of <0.01% at that figure, so we are right on the money again with clipping at 199mV.

For the record, here's clipping at 12.4V out and 207mV in:

Now, let's have a look at ~100Hz at the onset of clipping:

Notice how our overload margin has now dropped. Just 46.8mV will overload the RIAA stage due to the EQ. We have only 19.4dB over 5mV.

Let's look at 20KHz:

At 20KHz, we can inject nearly 1.2V into the MM front end before overload, but notice our maximum swing has dropped to 8.86V. This is evidence of the overloading in the front end of the RIAA stage, not the output stage which we know is happy running right up to ~12.0V RMS.

Considering the rails are +/- 21V and we can get 36VPP, this little RIAA preamp can drive anything.

A click or pop is a midrange to upper frequency transient impulse, and a standard 1KHz overload test with sine waves is more than sufficient to determine the overload margin and behaviour at clipping. +16dB on a single drum beat tracking test will throw many cartridges out of the groove. Once past 20dB at mid to low frequencies, nothing will stay in the groove.

The actual overload margin in mV or dB with respect to rated sensitivity is what people need to know. "Recovery" time for an overload at 10Hz is just a pointless exercise IMO. Just my 2c.

 

[Wombat]

You mean where for £99? <https://www.cambridgeaudio.com/gbr/en/products/hifi/phono-stages/cp2>. UK site, so I don't know if you can get it for that.

It is discontinued.

 

[AudioSceptic]

It is discontinued.

Yes, they were selling off old stock. Looks like that boat has sailed. :-(

 

[audio_tony]

Thanks for the graphs and measurements. I am puzzled how this zoomed version matches the sample I just post above. The case I am trying to simulate is the worst case where we go from near silence to the spike that LP produces. I have heard them loud enough to make me jump out of my seat!

There is a good article by Tomlinson Holman here:
http://www.ka-electronics.com/image...phic_Preamplifiers_Holman_Audio_July_1977.pdf

Referenced to the input, overload capability of 100mV at 1kHz will handle all the signals in the sonic range; however if the preamplifiers' input overload curve followed inverse RIAA equalisation (which many do), it would overload at 10mV RMS input at infrasonic frequencies. In order to accommodate the worst set of conditions at 3 to 4Hz, the input overload should be on the order of 35mV RMS minimum. And this strong infrasonic signal must be handled without intermodulating the program material.

Douglas Self also references this paper in his book 'Small Signal Audio Design'.

EDIT: corrected my poor speeelling...!

 

[anmpr1]

A click or pop is a midrange to upper frequency transient impulse...

A related point-- below is an excerpted discussion of Richard Burwen's TNE 7000 (transient noise eliminator device marketed by by KLH), taken from the May 1978 Stereo Review. Back then, there were several add-ons you could buy from different companies to address the problem of record pops and clicks. I remember one from Garrard, also.

"Burwen found that musical transients have a typical attack time of about 2 milliseconds, after which they gradually decay over a period ranging from a tenth of a second to several seconds. Noise transients, in contrast, are much faster and shorter, with an attack time of from 50 to 200 microseconds and a duration of no more than 2 milliseconds (2000 microseconds). Because of its rapid rise, a noise transient has considerable energy content in the ultrasonic region (20 KHz to 50 KHz) where there is little or no musical content.

[Burwen’s device] monitors the program energy from 30KHz up (and cuts off sharply below that frequency to prevent its being triggered by HF program harmonics). The sensor also monitors the difference between the two signal channels, since a physical scratch will not normally damage a groove in such a way as to produce equal amplitude, in phase outputs from both channels. The muting circuit turns off the sound for the duration of the transient, which is usually in the range of 80 to 600 microseconds. [The device’s overall delay is] 40 microseconds, which Burwen claims is less than that of any other currently manufactured noise suppressor."

One note: the Burwen device was not suitable for use with CD-4 discreet four channel records due their encoded in the groove HF sub-carrier.

When digitizing analog recordings I've expanded the waveform in Audacity and edited out the click spike. That usually works well [that procedure may have already been mentioned].

 

[JohnBooty]

I just got back from Capital Audiofest and was mildly frustrated that many vendors showing off their amplifiers and speakers chose to do so with vinyl playback. Give me pure digital audio as a source if I'm trying to evaluate speakers and amplifiers, please. However...

I do wonder how long the vinyl resurgence will last, once people realise those "vinyls" deteriorate over time, require careful looking after, a new stylus every couple of hundred hours etc.

This is a slightly less rude way of saying that those who enjoy vinyl are stupid or ignorant. Do we need this? Unless somebody is making factually incorrect claims, I don't see the need for potshots taken at any person or group on ASR.

 

[audio_tony]

This is a slightly less rude way of saying that those who enjoy vinyl are stupid or ignorant. Do we need this? Unless somebody is making factually incorrect claims, I don't see the need for potshots taken at any person or group on ASR.

Gosh, that escalated quickly.

I meant nothing of the sort actually. I was primarily referring to the many people who have jumped on the "vinyl is fashionable" bandwagon - you know, those with the Crossley player who think "vinyl sounds so good" when we all know that a Crossley is about as far from HiFi as one can get.

I've no idea why you seem to have taken this so personally, and are apparently speaking for an entire group of people.

 

[617]

Gosh, that escalated quickly.

I meant nothing of the sort actually. I was primarily referring to the many people who have jumped on the "vinyl is fashionable" bandwagon - you know, those with the Crossley player who think "vinyl sounds so good" when we all know that a Crossley is about as far from HiFi as one can get.

I've no idea why you seem to have taken this so personally, and are apparently speaking for an entire group of people.

I agree with you. I listen to vinyl due to the fact that I have some old weird records never put on CD to say nothing of Spotify or whatever. It is an extremely cumbersome format to extract any kind of sound quality from. I think the resurgence will continue because I don't actually think people are buying records and listening to them with any frequency. My brother has 50 LPs and no record player. Been in quite a few apartments with similar situations.

I'm honestly considering digitizing some of my records at some point, would be fun to listen to them and get them on my music drive.

 

[JohnBooty]

I've no idea why you seem to have taken this so personally, and are apparently speaking for an entire group of people.

So in other words, you're saying "people" are "lacking knowledge or comprehension of the thing specified?" Yes, that's calling them ignorant. Stand behind your words.

https://www.merriam-webster.com/dictionary/ignorant

I certainly wasn't bothered on a personal level because it does not apply to me. But, I don't think we need that sort of thing on ASR.

Let's have fun and enjoy the music (and science). If you have something constructive to say than this thread would be a great place for it! If you don't enjoy vinyl, there are a lot of other threads that aren't about it...

 

[audio_tony]

I'm honestly considering digitizing some of my records at some point, would be fun to listen to them and get them on my music drive.

I have digitised a few 12" 'specials' I have, that appear to be unobtainable.

I do note though in more recent years, a lot of tracks that were strictly vinyl only are finding their way on to Spotify and other streaming services.

 

[audio_tony]

So in other words, you're saying "people" are "lacking knowledge or comprehension of the thing specified?" Yes, that's calling them ignorant. Stand behind your words.

https://www.merriam-webster.com/dictionary/ignorant

I certainly wasn't bothered on a personal level because it does not apply to me. But, I don't think we need that sort of thing on ASR.

Let's have fun and enjoy the music (and science). If you have something constructive to say than this thread would be a great place for it! If you don't enjoy vinyl, there are a lot of other threads that aren't about it...

So to be clear I said: (in part)

"once people realise those "vinyls" deteriorate over time, require careful looking after, a new stylus every couple of hundred hours etc."

I think it's probably fair to say that many of the type of people who have gotten into vinyl because it's fashionable have little to no idea what they are letting themselves in for in terms of maintenance and upkeep of the records.

You seem to have read my comment completely out of context.

It was not (and never was) my intention to imply that 'people' in general were stupid / ignorant / call it what you want, and I suspect the many other people who have read my post realised that to be the case.

But if you would kindly just let this go and let me be that would be good.

Thanks.

 

[watchnerd]

So in other words, you're saying "people" are "lacking knowledge or comprehension of the thing specified?" Yes, that's calling them ignorant. Stand behind your words.

https://www.merriam-webster.com/dictionary/ignorant

I certainly wasn't bothered on a personal level because it does not apply to me. But, I don't think we need that sort of thing on ASR.

Let's have fun and enjoy the music (and science). If you have something constructive to say than this thread would be a great place for it! If you don't enjoy vinyl, there are a lot of other threads that aren't about it...

It doesn't apply to me either cause I don't use a Crossley, I guess.

But I do find it odd.

I'm not sure why anyone cares what formats other people use.

I don't usually see people who like digital streaming calling out people who still like terrestrial FM radio.

It seems (especially with the Crossley caveats) to be some proxy for mocking hipsters.

Which is somewhat understandable.....

 

[JohnBooty]

Not only do I not run a Crossley, I replaced a friend's Crossley with something slightly less bad. Fighting the good fight, lol.

It seems (especially with the Crossley caveats) to be some proxy for mocking hipsters.

I think you hit the nail on the head. Folks should make fun of hipsters directly if that's their intent.

 

[Martin]

Conclusions
The Cambridge Audio Solo is an attractive, well-designed phono stage. Alas, it is not a defeatured Duo. Performance is a step down in the important frequency response. So my recommendation is to stretch your dollars and buy the Duo. It supports both MC and MM cartridges and has a headphone amplifier to boot. /

I returned the refurbished Solo I purchased on eBay and bought a refurbished Duo. Cambridge Audio's eBay store pays for return shipping within 30 days.

Martin

 

[Voxy]

I returned the refurbished Solo I purchased on eBay and bought a refurbished Duo. Cambridge Audio's eBay store pays for return shipping within 30 days.

Martin

what’s wrong with the solo and how the Duo perform against Solo for MM?