I have been very interested in this product since first reading about it and so I was very grateful for Paul Whites' "field test" but disappointed not to get a full "spec check".
I know the device is not expensive compared the stuff Hugh usually nabs but it IS supposed to be very high quality and would therefore, I would have thought, been eligable for the full battery of tests?
Most important of all of course is the noise performance. Is it so good as to make the alternative purchase of a (far more versatile) conventional pre amp not cost effective?

Dave.

The product didn't come to me to review and PW doesn't have suitable technical equipment to make those kinds of measurements. There is a new Cloudlifter now though with switchable input impedances which I hope might come to me to review... and if it does I'm sure the relevant measurements will appear in the mag...

However, my own brief listening tests to a Cloudlifter suggest that it is very quiet indeed and the negligible noise it produces is more than compensated for by the benefits of additional front-end gain when used with budget preamps.

If there is a downside, though, I fear it is that there is virtually no bandwidth limiting at all in the Cloudlifter circuitry -- and the gain stage is DC-coupled. This means that subsonic rubbish from the mic is presented at a very high level to the following preamp -- which might well cause overload problems -- and there might well be a much greater susceptibility to RF interference. The former is likely to be an issue in any situation whewre the mic is being handheld, or in a position where there are significant air currents, or where substantial vibration is passed along the mic stand. And the latter could be an issue where there are radio mics, digital cables and mobile phones in near proximity.

I should emphasise that I don't have first hand confirmation of these potential concerns; they are conclusions I have arrived at from reading the product decsriptions, listening to the units and from feedback received from genuine users.

None of these potential issues are insurmountable, of course, and some may not prove to be practical concerns at all...

Hugh

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Technical Editor, Sound On Sound

Thanks Hugh.
I am rather suprised that the device did not get passed onto yourself for detailed measurement, it is after all a quite "professional" device it seems, very solidly built and £156 is quite a wedge for "just" an inline pre amp with no controls. It is also rather unique?

The extended bandwidth is worrying. I have long been sceptical of the merits of DC coupling for audio circuits, I put "bad sound" from electrolytics firmly in the Not Proved, Russ Andrews camp!
Only in audio do engineers design for (or can't be bloody bothered to curtail!)bandwidths far outside the signals of interest. If the Cloudlifter IS open to mobile phone chatter it is going to be next to useless.

The insidious thing is, PW is very taken with the box but who knows 6months down the line what sort of problems he might encounter at some other venue? I lived and worked with the socking great field strengths of Rugby and Daventry (Daventry Pattern?)for 30years!

Dave.

Quote ef37a:

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I am rather suprised that the device did not get passed onto yourself for detailed measurement, it is after all a quite "professional" device it seems

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I'm not surprised. It's a neat and well made device, but I would have no need of it given my 'professional' preamps which all have more than enough gain to cope with ribbon mics etc. It is intended as a problem-solver for the budget end of the market wishing to use low output mics with inadequate budget preamps.

The CloudLifter isn't unique, by the way. There are other similar devices from other manufacturers. The link below, for ecample, is to a review I commissioned for a now defunct broadcast sound trade magazine which I edited, and is a more technical appraisal:

http://www.ibs.org.uk/files/09_Fel_Micboosters.pdf

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The extended bandwidth is worrying.

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Yes it is... if true. I have to repeat that I have no first hand evidence to support this assertion, only received feedback from others...

Quote:

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If the Cloudlifter IS open to mobile phone chatter it is going to be next to useless.

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It is housed in a decent metal box, and it seems reasonable to assume decent grounding practices are in use. PW didn't report any issues with phone breakthrough... but equally he doesn't appear to have made any specific tests along those lines.

If the unit hasn't been returned yet I'll try to get hold of it and run some tests...

hugh

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Technical Editor, Sound On Sound

Well Hugh.
Dare I say I find you definition of "professional" a bit restrictive. Just because you have suitable pre amps does not mean everyone does or if they do they might not want to drag them out on location? What about wildlife recordist? I doubt many capacitor mics would last long in boggy Essex in the rain and those few that would, very expensive.

Point has just come to me. Is an SM57(say)+Cloudlifter quieter than a good cap'?

Re the bandwidth. In my experience if positive steps are not taken to keep RFI out it will get in.

In anycase, who decides which bits of kit are "beyond the pale" please?

Dave.

Quote ef37a:

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Dare I say I find you definition of "professional" a bit restrictive.

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Each to their own. I find your definition a little unrealistic! I think that's 15-all!

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Just because you have suitable pre amps does not mean everyone does

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No, but I would suggest that 'professionals' would have...

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What about wildlife recordist? I doubt many capacitor mics would last long in boggy Essex in the rain and those few that would, very expensive.

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Capacitor mics are used all the time in the field -- Schoeps and Sennheiser mics are the professional sound recordists' favourites, in fact. And I should know -- I was one for many years! It is a well known fact that the MKH's RF-capacitor operation makes them utterly impervious to the perils of Essex bogs! And a decent professional location sound recorder and/or location mixer would have more than enough gain on hand to cope in most situations without needing a Cloudlifter.

However, I'm not denying that there are applications where a Cloudlifter or similar might prove useful to the professional on the odd unusual occasion.... I was merely offering a suggestion as to why the review was handed to PW rather than me. It use is more appropriate and necessary in semi-pro and budget situations to help compensate for the inadequacies associated with that type of equipment.

Quote:

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Point has just come to me. Is an SM57(say)+Cloudlifter quieter than a good cap'?

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I should imagne the noise performance would be similar... but it very much depends on the performance of the main preamp it is feeding and the capacitor mic you have in mind (capacitor mic self noise can lie anywhere between about 3 and 30dBA depending on design). And of course the bandwidth and transient performance of most dynamic mics will be inferior...

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Re the bandwidth. In my experience if positive steps are not taken to keep RFI out it will get in.

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Mine too... but that doesn't necessarily require curtailing the bandwidth of the amplifier stage itself. Employing suitable filtering on the I/O is often sufficient. But again, as I said earlier, I have no first hand experience yet and PW didn't appear to have any issues with RFI.

Hugh

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Technical Editor, Sound On Sound

oh dear, maybe i should take some of my mic pre's out back and shoot them , it must be a kindness, what with them having a nominally flat F/R to over 100k

Quote Off duty BBQ lighter AKA Idris:

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oh dear, maybe i should take some of my mic pre's out back and shoot them , it must be a kindness, what with them having a nominally flat F/R to over 100k

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Depends how it's done my scaly friend. If the response is engineered for a 3dB point at say 130kHz no great harm (tho' I would prefer 3dB at 50-60kHz)but you might like to keep away from R4 LW transmitters!
The "extended bandwidth" debate has run for decades. It made little sense when it was a bloody good tape machine that reached 30kHz and makes even less to me for digital with a brickwall at 22kHz (and before anyone shouts! Check conveter specs', some do not track upper cut off with 1/2 sample rate, they chop at ~25kHz for everything).

Peeps today are probably fine in the genteel surrounding of their studio or home but I started with PA when transistor equipment was just arriving and in addition to the aformentioned Rugby and Daventry blasters they later stuck up a potent VHF TV TX at Bedford (ch 6). Happy days!(bloody weren't)....And leave us not forget taxis, emergency services and *&^%$ng CB!
Dave.

Quote Hugh Robjohns:

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If there is a downside, though, I fear it is that there is virtually no bandwidth limiting at all in the Cloudlifter circuitry -- and the gain stage is DC-coupled.

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Some people actually want to amplify signals in the subsonic region or at high frequencies. I've used audio gear for both seismics and high frequency sonar testing. It may be a bit of a limited market but some people find the extended bandwidth useful.

James.

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JRP Music - Audio Mastering and Restoration.
http://www.jrpmusic.net

Fair enough James but the Cloudlifter specifically is aimed at dynamic and ribbon mics and most of the former and virtually all of the latter use transformers so sub 20 Hz (from an SM?)is not on and tho' many a good traff might make 60kHz no "dynamic" mics that I know of will!
Then, as a recent paper on mic splitters that Hugh pointed to mentioned, mic cable itself starts to intrude if you have a lot of it.

Horses for courses surely? If you don't need/can't use the bandwidth, chop it.

Dave.

Quote James Perrett:

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Some people actually want to amplify signals in the subsonic region or at high frequencies.

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Of course... but these are usually specialised situations and the equipment is being used knowingly by informed users for that specific purpose.

However, the vast majority of potential users of the Cloudlifter and similar products for musical applications are probably unaware of what lurks in the sub- and ultra-sonic regions, and have no means of monitoring them. In these cases, such 'unwanted' signals are likely to cause problems and considerable confusion.

I've seen signals approaching 0dBu at 15-20Hz coming from a wide-bandwidth capacitor mics placed unknowingly in a draught before now. Not audible on small monitors, but caused a lot of distortion and headroom issues! The application of windshields and in-line high-pass filters cured the problem. Console high-pass filters did not because the front-end preamp was being overloaded. In general, I'd say ultrawide bandwidths have their place, but their application does need to be considered, and facilities included to resolve potential problems.

And Dragon... no need to shoot those preamps. I run a sanctuary for them. Just send them to me to look after...

hugh

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Technical Editor, Sound On Sound

lol.....

the chaps and I (the same trio as you came along with to Durham) had lots of fun mic'ing a candle lit choral event in a large church in London earlier this week (Album release event for Decca)....

lots of head scratching about positioning to be out of both updrafts AND camera shots..... and still make it sound nice... not to mention slinging without sensible prepared fixing points , in a place where even the dust is grade 1 listed......

you REALLY need to hear these new Neumann jobbies the bearded wonder has acquired.... think M50 , minus the outer casing...

(leave credit card in SWMBO's hands afterwards though , coz you will want some, and just before Xmas , probably not the best time.... )

Quote Off duty BBQ lighter AKA Idris:

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you REALLY need to hear these new Neumann jobbies the bearded wonder has acquired.... think M50 , minus the outer casing...

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I'm drooling already. Model numbers?

Hugh

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Technical Editor, Sound On Sound

ask J.W they're very very new.... don't think they've been added to site yet, and i can't remember offhand....

I've managed to get my hands on the Cloudlifter that PW reviewed recently, and ran it through some Audio Precision tests.

Further to the discussions here recently about the Cloudlifter in-line phantom powered microphone gain block, I have now been able to run some tests on the SOS review sample.

The measured gain was 29.5dB -- rather higher than the claimed 20-25dB. However, it turns out that the gain is dependent on the input impednace of the connected preamp. In my initial test the AP test system loaded it with a very high 200k Ohms, and consequently the Cloudlifter provided a lot more gain than normal. When loaded with a more representative 1.7k ohms the gain fell to 18.5dB.

The bandwidth, measured at the -1dB points was 6Hz to 30kHz, tailing off smoothly at both frequency extremes.

This is very tidy... and the low end is a direct result of the DC-coupled circuit design, but I'm not sure a bandwidth extending to 6Hz is all that helpful. There's an awful lot of subsonic rubbish that no one really wants -- or can hear -- but it is a potential source of trouble for other stages of the signal path. In particular, a lot of shock mounts will be resonating at this kind of frequency, as will ribbon diaphragms, and air currents and wind noise lives down here too. Personally, I'd have preferred to see a controlled roll-off below 30Hz or so, possibly with a bypass switch for anyone wanting to capture earthquake rumbles!

The designer chose the DC-coupled route to avoid placing any capacitors in the signal path, as he feels they can result in audible distortion. It seems to me to be a case of lesser evils... and I'd have gone the other way and used capacitors in the signal path to help control the subsonics.

No issues with the top-end roll off above 30kHz (-3dB at 60kHz), that seems fair enough to me. I detected no breakthrough from mobile phones in close proximity. Seems that rumour is unfounded!

It measured polarity-correct (ie, non-inverting).

Maximum input level for 1% THD was -18dBu. So it wouldn't be a good idea to use the Cloudlifter in situations where you're expecting reasonably loud outputs from the mic... but that's probably self-evident anyway.

Signal to noise ratio referenced to the max input level of -18dBu was 105dB.

Residual averaged noise floor sits below -135dBu across most of the spectrum.

Referenced to a more practical -30dBu input the signal-noise measured 93.5dB

On that basis, the EIN figure is around -123dB (with a 100 ohm source). That's very good for a gain stage like this, even if it might appear poor when compared to a typical mic preamp claiming -129dB or so. The reason for the discrepancy is that the EIN figure is derived by adding the amount of gain provided by the preamp to the measured noise floor. Adding 60dB to the noise floor results in a much more impressive figure than only adding the 20dB or so provided by the Cloudlifter. Remove the 40dB gain difference and you can see that the Cloudlifter is actually a VERY quiet gain stage.

Hope those interested in the Cloudlifter find this information helpful.

hugh

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Technical Editor, Sound On Sound

Edited by Hugh Robjohns (05/11/11 03:27 PM)

Quote Hugh Robjohns:

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Quote Off duty BBQ lighter AKA Idris:

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you REALLY need to hear these new Neumann jobbies the bearded wonder has acquired.... think M50 , minus the outer casing...

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I'm drooling already. Model numbers?

Hugh

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Pls don't.....no money....

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Samplecraze
Stretch That Note

Apparently they were Neumann KK133 omni capsules on KM-A bodies and with the SBK spheres attached.

Nice!

hugh

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Technical Editor, Sound On Sound

that's the buggers.... "nice" ? honestly...... that's got to be understatement of the decade.....