Lehmannaudio Decade Phono Stage Review

[amirm]

This is a review and detailed measurements of the Lehmann audio (one word?) Decade Moving Coil and Moving Magnet phono preamplifier. It is on kind loan from a member and costs US $2099.

As you see, it comes in two boxes with the one on the left being the power supply and on the right, the preamp. A high pass filter is provided as well as four gain settings. The two boxes are interconnected using a 4-pin XLR connector:

I was disappointed to not see labels on the RCA connector. They are under the unit as well as switches to select loading. Otherwise, the two box solution looks nice.

The Decade is the mid-level unit and I think came out some 10 years ago but still being manufactured.

Lehmannaudio Decade Measurements
I measured the Decade in three gain settings:

This is good performance going by our rankings of noise+distortion as expressed in SINAD:

RIAA equalization is passive and looks nice other than a slope down toward low frequencies:

I don't understand the usefulness of the high-pass filter (dashed green). It seems more like a subwoofer crossover than rumble filter for a phono stage. Company even documents it as such saying corner frequency is 50 Hz.

Despite having an external power supply of their design, the headroom is not sufficient to deal with loud clicks and pops:

Such noises will clip, accentuating their impact. I would like to see performance twice as good.

Sweeping frequencies, we see that the headroom shrinks even more at higher frequencies:

Ticks and pops are liable to have high frequency energy making it even more important to do well here.

Back to distortion, we see that is very low:

Conclusions
I like the look and feel of the Decade although one could argue it is not $2,100 good. Noise and distortion performance is very good to excellent. Headroom is limited however.

I would not pay $2,100 for the Lehmannaudio Decade but putting aside the cost, it would go on my recommended list. You could say I have a soft spot for German engineered hardware.
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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[Jimbob54]

I know nothing about phono stages but what is that ugly plug/ hole above the right hand RCAs and why does it look like something I might have butchered with a soldering iron?

 

[staticV3]

I would pay $2,100 for the Lehmannaudio Decade

I feel like something is missing

Thanks for the review, Amir!

 

[rodrigaj]

I know nothing about phono stages but what is that ugly plug/ hole above the right hand RCAs and why does it look like something I might have butchered with a soldering iron?

Grounding screw. Necessary in phono stages.

 

[Endibol]

This is a review and detailed measurements of the Lehmann audio (one word?) Decade Moving Coil and Moving Magnet phono preamplifier. It is on kind loan from a member and costs US $2099.
View attachment 351393
As you see, it comes in two boxes with the one on the left being the power supply and on the right, the preamp. A high pass filter is provided as well as four gain settings. The two boxes are interconnected using a 4-pin XLR connector:
View attachment 351394
I was disappointed to not see labels on the RCA connector. They are under the unit as well as switches to select loading. Otherwise, the two box solution looks nice.

The Decade is the mid-level unit and I think came out some 10 years ago but still being manufactured.

Lehmannaudio Decade Measurements
I measured the Decade in three gain settings:
View attachment 351395
View attachment 351396
View attachment 351397

This is good performance going by our rankings of noise+distortion as expressed in SINAD:
View attachment 351398

RIAA equalization is passive and looks nice other than a slope down toward low frequencies:
View attachment 351399
I don't understand the usefulness of the high-pass filter (dashed green). It seems more like a subwoofer crossover than rumble filter for a phono stage. Company even documents it as such saying corner frequency is 50 Hz.

Despite having an external power supply of their design, the headroom is not sufficient to deal with loud clicks and pops:
View attachment 351400
Such noises will clip, accentuating their impact. I would like to see performance twice as good.

Sweeping frequencies, we see that the headroom shrinks even more at higher frequencies:
View attachment 351401
Ticks and pops are liable to have high frequency energy making it even more important to do well here.

Back to distortion, we see that is very low:
View attachment 351402
View attachment 351404

Conclusions
I like the look and feel of the Decade although one could argue it is not $2,100 good. Noise and distortion performance is very good to excellent. Headroom is limited however.

I would pay $2,100 for the Lehmannaudio Decade but putting aside the cost, it would go on my recommended list. You could say I have a soft spot for German engineered hardware.
------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Great review Amir, and I can’t wait to see where Michael Fidler’s MM Pro would end up in the ranking.. hope Michael will send you one.

 

[AdamG]

Manufacturer Specifications:

 

[Mikig]

Hi Amirm, thanks as always!
I had experiences with Lehmann audio, when I used the turntable. Very good products, solid and with good performance. Mine was Black Cube SE II. Then little by little I sold almost everything. However, if I were to get back into vinyl, I would still go for the basic Lehmann model...

 

[Deleted member 71725]

Hi. New here not as technical as many of you. I continue to hold on to my LP collection and TT, but am hard pressed to answer why I do so. Pretty sure my next system iteration/upgrade involves liquidating both along with the other stuff being replaced. I might even end up with net cash inflow when all is said and done, to go along with pristine performance. That’s the dream, anyway. Cheers.

 

[DonR]

At this price a phono stage has to be technically perfect. Lack of headroom means this one isn't. Close but no cigar.

 

[Hipster Doofus]

AH RECORDS AND YOUTH..... rem when you had all the time in the world and could play a record all the way through.

 

[charlielaub]

I don't understand the confusion about the rumble filter, @amirm. The 3dB down frequency is exactly at 50Hz, just like the MFG advertises. For a Butterworth second order filter this is exactly what one would expect. The MFG specs mention a first order 6dB/oct filter but it doesn't look like it to me. There might be a very small effect (droop) at higher frequencies, but for a passive network I would not be too concerned. It could simply be a result of the tolerances of the component used in the filter causing the response to deviate from exactly what is designed/intended.

 

[amirm]

I don't understand the confusion about the rumble filter, @amirm. The 3dB down frequency is exactly at 50Hz, just like the MFG advertises.

That's not the confusion. The confusion is why anyone playing an LP would want to lose their low frequencies. The purpose of such rumble filters is to eliminate infrasonic frequencies that cause extra work for the amplifier and speaker. It is NOT to get rid of audible band frequencies. As such, the proper filter would have a much lower cut off frequency and have a sharp roll off.

 

[subframe]

Thanks Amir. The clipping is unfortunate, and puzzling given the effort put into building a separate power supply. The ‘rumble’ filter is effectively useless, just a very strange design decision.

 

[MacClintock]

Finally a Lehmann product, the measurement outcome is what I would have expected. I had once a headphone amplifier from Lehmann, it was kind of expensive and very hyped in the community. That was about 10 years ago, before I really knew a lot of things about hifi and SMSL and Topping dominated the market measurementwise. I tested this headphone amp against the built in one of my integrated amp and couldn't hear any difference, so I sold it. Summary, decent gear, but overpriced and nothing special, even less so nowadays.

 

[JSmith]

...costs US $2099.

Ouch... cheers for the testing though;

JSmith

 

[DrCWO]

The ProJect phono box has literally the same performance for less than half the price
In Addition it offer symmetric in- and outputs on XLR
In my eyes in any case a better choice...

 

[AndreaT]

And yet more acolytes of an old source, the LP, with orders of magnitude lower Sinad. No reasons to have a poorly optimized headroom for both MM and MC and a wrong design of the rumble filter. Thank you Amir for an impeccable review. I am so happy with FLAC files from my red book CD collection that I might choose healthier food and habits to prolong the time left to me to listen, listen and listen to Music.

 

[flor]

The ProJect phono box has literally the same performance for less than half the price
In Addition it offer symmetric in- and outputs on XLR
In my eyes in any case a better choice...

One could even call the ProJect a two box device as well, because of the wall-wart power supply.

 

[tagomago1979]

400$ would be a fair price

 

[Michael Fidler]

Quite a strange approach to subsonic filtering, to say the least. I wonder if they decided how many db of attenuation they wanted at 10Hz (say 14 or so/5 times) and then worked out what kind of cutoff they'd need with a first order filter to get it (50Hz or so).

Some of the ICs look interesting, though (THAT corp). The overload behaviour reminds me of heavy loading/current limiting on an active filter rather than the usual passive sort that we see. Purely speculation, though... Unfortunately, despite quite a complicated power supply arrangement, which will doubtless have plenty of audiophile appeal, we're not seeing enough voltage output to give us an overload margin of 20dB against 5mV in the final analysis.