Classic Audio MC Pro Phonostage Review

[cgallery]

My Panasonic SL-N15 (same as Technics SL-N3) runs the ground over the left (or right, I don't know, could be both) signal return, perfectly silent.

 

[EJ3]

TVS + polyfuse on the input side, shunt diodes across first caps in the voltage-doubler "but how does my 24V AC Rega power adaptor SOUND with this unit". Usually I can "best of luck with your next choice" those guys before it comes to payment, but occasionally one will get through, or some predatory little reptile (almost always in the UK) will try and foist some dubious 'upgrade' upon them that results in destruction + it's still remotely possible to connect the wrong power adaptor by accident.

Also, strong RF filters on input and output. I designed the original to withstand about 5 times what you might expect from marginal EMC-passing equipment in the near vicinity, but it's still not quite enough for about 3% of cases, especially using exotic cartridges of the very low output type. In close enough proximity (60cm or so), dodgy LED lights from Aliexpress and ethernet-over-power adapters can yield enough RF at the input to provoke detection, especially if exotic cables are being used. Having a massively high gain doesn't help much, either. This does also affect the vast majority of contemporary preamps, but it would be good to make it much more resilient.

It would be good if we quite importing dodgy anything from anywhere. The fact that it gets through to us is what keeps people making the dodgy anything's anyway.
If they couldn't sell mass quantities of it to unsuspecting people, it wouldn't be worth it to them to make it to begin with.
But: that's a separate conversation.
Unfortunately it has an effect on this conversation: And it needn't be so.

 

[Palmer]

Forgive me if I don't interpret this charitably . The internet is littered with furious forum users and people who've tried the product and have given ample feedback that the company needs to change its ways. Personally, when I've dealt with clients who have Rega setups, it causes an issue half of the time, all for a tiny little wire...

Rega: Just say anything, make anything up, say you've changed the electrical alignment of the design or some other BS, but fit the ground wire!

Regrettably, Fidelity Research FR 24S was guilty of this in the past as well - lovely arm, impossible to find cable, and no ground wire...

 

[Michael Fidler]

My Panasonic SL-N15 (same as Technics SL-N3) runs the ground over the left (or right, I don't know, could be both) signal return, perfectly silent.

My advice (unsolicited), would be not to change anything in the setup if you're not experiencing any issues.

It would be good if we quite importing dodgy anything from anywhere. The fact that it gets through to us is what keeps people making the dodgy anything's anyway.
If they couldn't sell mass quantities of it to unsuspecting people, it wouldn't be worth it to them to make it to begin with.
But: that's a separate conversation.
Unfortunately it has an effect on this conversation: And it needn't be so.

Indeed, but it does pose an interesting design challenge, and also a market advantage if the problem can be solved in some way that doesn't require brute force/hideous compromises.

 

[mackat]

Regrettably, Fidelity Research FR 24S was guilty of this in the past as well - lovely arm, impossible to find cable, and no ground wire...

View attachment 415159

Some were fitted with DIN connectors - I’m guessing later in production. They are harder to find.

 

[Palmer]

Some were fitted with DIN connectors - I’m guessing later in production. They are harder to find.

I don't know enough about Fidelity arms to be able to name which was which, certainly the FR-54, or the FR-64 came with 5-pin DIN Style connectors. The 24S cable with the threaded connector can be an expensive afterthought, if one would find a nice example that's missing the original cable.

 

[mackat]

I don't know enough about Fidelity arms to be able to name which was which, certainly the FR-54, or the FR-64 came with 5-pin DIN Style connectors. The 24S cable with the threaded connector can be an expensive afterthought, if one would find a nice example that's missing the original cable.

Yes, most FR-24S have the strange connector but there are some specimens out there with a DIN connector. Unfortunately, they are less common. I have owned 3 FR-24S, and I believe only one had it. All later FR arms did, AFAIK.

 

[Newman]

The subsonic filter deals with cutting out tone-arm resonances/record warps/surface effects below 20Hz, while the LF XFEED function reduces stereo field noise below 100Hz or so. They both do different things: one operates outside the audio band, the other within it.

Michael, what's your view on filters for reducing LP noises including pops and scratches and hiss? There are one or two phono stages that attempt this. I can't help but feel that they will fail to avoid any deleterious impact on the music signal.

 

[Michael Fidler]

Michael, what's your view on filters for reducing LP noises including pops and scratches and hiss? There are one or two phono stages that attempt this. I can't help but feel that they will fail to avoid any deleterious impact on the music signal.

While noise reduction, especially impulse noise reduction, can be very effective for restoration, it's very difficult to implement this to a satisfactory degree for general playback.

Wideband noise reduction (hiss) can create unpleasant artefacts, and the threshold point is nigh on impossible to set correctly on the fly. For discs in restoration, the thresholds can be tuned, and the level of reduction modified to mask artefact, but for direct playback it's pretty bad. If the threshold is too low, a lot of watery artefacts are generated by granular nosie.

Impulse noise reduction, click detection and interpolation, is generally much better, although it is still important to set the threshold of detection high enough so that certain recorded waveforms and transients do not trigger false positive and hence distortion. For a very high detection threshold, it can certainly work with DSP, but will only be able to remove the worst clicks. There are also questions of overload margin that come into play when DSP is implemented.

I own a few thousand 78s, and find limiting the bandwidth to be most useful for playback/off-disc listening. Switching to mono also greatly helps.

 

[welwynnick]

Could I respectfully suggest that this test / thread is moved to join most of the other phono amplifier reviews in the Turntables, Phono Amplifier, Cartridges Review forum?

I noticed this review (and maybe a few others) was missing from the phono preamps comparison chart.

 

[Michael Fidler]

Could I respectfully suggest that this test / thread is moved to join most of the other phono amplifier reviews in the Turntables, Phono Amplifier, Cartridges Review forum?

I noticed this review (and maybe a few others) was missing from the phono preamps comparison chart.

View attachment 420506

This is because we are talking about an MC input: all of those measured devices are MM, and there is yet to appear a graph that compiles the results of MC phono preamplifiers.

 

[welwynnick]

........ there is yet to appear a graph that compiles the results of MC phono preamplifiers.

I was thinking of putting one together myself, it would show the MC Pro in a very good light.
Phono preamps have varying gains, but I noticed a pattern. If you add gain + SNR a good head amp gives you around 120dB no-matter what sort.
It doesn't vary enormously, so it's quite a good figure of merit. The MC Pro stands clear of the rest though - at 140dB - but it takes some digging.
I have a Luxman PD300, Alphason HR100S and AT OC7, so definitely need an MC head-amp (preferably with balanced output, though not sure if I can buy one any more).

 

[welwynnick]

Here we go, arranged in order of MC SINAD+gain, then MM SINAD+gain:

Brand	Model	Price USD	SINAD	GAIN	TOT	SINAD	GAIN	TOT	Rec'd	Review Date	Review Link
			MM	MM	MM	MC	MC	MC
Classic Audio	MC Pro	$850				73​	69​	142​	Yes	8/13/23	Review Link
eXemplar Audio	Exception Phono	$6,950	64​	43​	107​	54​	73​	127​	No	3/25/19	Review Link
SOTA	Pyxi	$300	80​	46​	126​	65​	59​	124​	Yes	5/27/23	Review Link
Cambridge Audio	Alva Duo	$300	84​	39​	123​	63​	60​	123​	Yes	7/24/23	Review Link
Schiit	Skoll	$399	81​	41​	122​	64​	59​	123​	Yes	10/14/23	Review Link
Parasound	Zphono	$200	76​	47​	123​	56​	59​	115​	Yes	09/08/20	Review Link
ART Pro Audio	Precision Phono Pre	$81	78​	34​	112​	60​	52​	112​	Yes	6/13/22	Review Link
PS Audio	Stellar	$2,499	65​	44​	109​	51​	61​	112​	Yes	9/24/21	Review Link
Vincent	PHO-8	$250	73​	40​	113​	51​	58​	109​	No	3/25/20	Review Link
Graham Slee	Reflex C	$900			0​	59​	50​	109​	No	01/09/21	Review Link
Six Acoustics	York	$437	67​	40​	107​	48​	60​	108​	No	04/12/22	Review Link
Cambridge Audio	Alva Solo	$180	86​	39​	125​			0​	No	11/01/19	Review Link
Schiit	Mani 2	$149	81​	44​	125​			0​	Yes	2/23/22	Review Link
Emotiva Audio	XPS-1	$200	82​	42​	124​			0​	Yes	5/16/19	Review Link
Musical Fidelity	MX-VYNL	$1,000	79​	42​	121​			0​	Yes	06/07/19	Review Link
Pro-Ject Audio Systems	Phono Box DS2 USB	$600	80​	40​	120​			0​	Yes	07/12/20	Review Link
Rega	Fono Mk3	$400	78​	41​	119​			0​	No	11/04/20	Review Link
U-Turn Audio	Pluto 2	$99	78​	40​	118​			0​	Yes	6/23/21	Review Link
Schiit	Mani	$130	74​	43​	117​			0​	Yes	07/11/19	Review Link
U-Turn Audio	Pluto	$100	80​	36​	116​			0​	No	06/10/18	Review Link
Pro-Ject Audio Systems	Phono Box MM	$89	76​	40​	116​			0​	No	07/08/23	Review Link
Rek O Kut Ultra	Ultra	$159	76​	39​	115​			0​	No	5/17/22	Review Link
Hagerman Audio Labs	Bugle3	$199	74​	40​	114​			0​	N/A	3/18/23	Review Link
Parks Audio	Puffin	$400	73​	40​	113​			0​	Yes	1/25/21	Review Link
Parasound	200 Pre	$895	69​	43​	112​			0​	N/A	09/11/21	Review Link
Musical Surroundings	Nova 3	$1,500	69​	43​	112​			0​	N/A	12/29/20	Review Link
Rane	PS1	$50	75​	36​	111​			0​	No	5/16/19	Review Link
Pro-Ject Audio Systems	Optical Box E Phono	$200	76​	34​	110​			0​	No	12/13/20	Review Link
Pro-Ject Audio Systems	Tube Box S2	$400	69​	40​	109​			0​	No	4/26/20	Review Link
Graham Slee	Gram Amp 2 Comm'tr	$299	69​	39​	108​			0​	No	04/11/22	Review Link
Darlington Labs	MM-5	$199	64​	41​	105​			0​	No	7/24/21	Review Link
ART Pro Audio	USB Phono Plus	$99.99	59​	45​	104​			0​	No	08/03/23	Review Link
Hagerman Audio Labs	Bugle2	$150	61​	40​	101​			0​	No	8/14/20	Review Link
Realistic	42-2101A	$20	58​	38​	96​			0​	No	1/22/21	Review Link
NAD	PP 4	$229	54​	42​	96​			0​	No	04/06/21	Review Link
Lounge Audio	LCR Mk3	$300	53​	40​	93​			0​	No	04/07/19	Review Link
Chord Electronics	Huei	$1,500	44​	49​	93​			0​	No	11/07/20	Review Link
Rolls	VP29	$50	49​	41​	90​			0​	No	1/22/21	Review Link
Pyle Audio	Pro PP444	$13	48​	35​	83​			0​	No	10/15/19	Review Link
Furutech	Alpha Des Labs GT40	$525	40​	41​	81​			0​	No	10/05/19	Review Link

There were nine MM + MC head amps, and one other MC only - the Graham Slee Reflex C.

I changed the SINAD figure for several amps, either because the Review Index figure was for the ADC or DAC, or quoted MM instead of MC.

Its interesting reading, though. Congratulations Michael!

 

[Soniclife]

Here we go, arranged in order of MC noise+gain, then MM noise+gain:

Brand	Model	Price USD	SINAD	GAIN	TOT	SINAD	GAIN	TOT	Rec'd	Review Date	Review Link
			MM	MM	MM	MC	MC	MC
Classic Audio	MC Pro	$850				73​	69​	142​	Yes	8/13/23	Review Link
eXemplar Audio	Exception Phono	$6,950	64​	43​	107​	54​	73​	127​	No	3/25/19	Review Link
SOTA	Pyxi	$300	80​	46​	126​	65​	59​	124​	Yes	5/27/23	Review Link
Cambridge Audio	Alva Duo	$300	84​	39​	123​	63​	60​	123​	Yes	7/24/23	Review Link
Schiit	Skoll	$399	81​	41​	122​	64​	59​	123​	Yes	10/14/23	Review Link
Parasound	Zphono	$200	76​	47​	123​	56​	59​	115​	Yes	09/08/20	Review Link
ART Pro Audio	Precision Phono Pre	$81	78​	34​	112​	60​	52​	112​	Yes	6/13/22	Review Link
PS Audio	Stellar	$2,499	65​	44​	109​	51​	61​	112​	Yes	9/24/21	Review Link
Vincent	PHO-8	$250	73​	40​	113​	51​	58​	109​	No	3/25/20	Review Link
Graham Slee	Reflex C	$900			0​	59​	50​	109​	No	01/09/21	Review Link
Six Acoustics	York	$437	67​	40​	107​	48​	60​	108​	No	04/12/22	Review Link
Cambridge Audio	Alva Solo	$180	86​	39​	125​			0​	No	11/01/19	Review Link
Schiit	Mani 2	$149	81​	44​	125​			0​	Yes	2/23/22	Review Link
Emotiva Audio	XPS-1	$200	82​	42​	124​			0​	Yes	5/16/19	Review Link
Musical Fidelity	MX-VYNL	$1,000	79​	42​	121​			0​	Yes	06/07/19	Review Link
Pro-Ject Audio Systems	Phono Box DS2 USB	$600	80​	40​	120​			0​	Yes	07/12/20	Review Link
Rega	Fono Mk3	$400	78​	41​	119​			0​	No	11/04/20	Review Link
U-Turn Audio	Pluto 2	$99	78​	40​	118​			0​	Yes	6/23/21	Review Link
Schiit	Mani	$130	74​	43​	117​			0​	Yes	07/11/19	Review Link
U-Turn Audio	Pluto	$100	80​	36​	116​			0​	No	06/10/18	Review Link
Pro-Ject Audio Systems	Phono Box MM	$89	76​	40​	116​			0​	No	07/08/23	Review Link
Rek O Kut Ultra	Ultra	$159	76​	39​	115​			0​	No	5/17/22	Review Link
Hagerman Audio Labs	Bugle3	$199	74​	40​	114​			0​	N/A	3/18/23	Review Link
Parks Audio	Puffin	$400	73​	40​	113​			0​	Yes	1/25/21	Review Link
Parasound	200 Pre	$895	69​	43​	112​			0​	N/A	09/11/21	Review Link
Musical Surroundings	Nova 3	$1,500	69​	43​	112​			0​	N/A	12/29/20	Review Link
Rane	PS1	$50	75​	36​	111​			0​	No	5/16/19	Review Link
Pro-Ject Audio Systems	Optical Box E Phono	$200	76​	34​	110​			0​	No	12/13/20	Review Link
Pro-Ject Audio Systems	Tube Box S2	$400	69​	40​	109​			0​	No	4/26/20	Review Link
Graham Slee	Gram Amp 2 Comm'tr	$299	69​	39​	108​			0​	No	04/11/22	Review Link
Darlington Labs	MM-5	$199	64​	41​	105​			0​	No	7/24/21	Review Link
ART Pro Audio	USB Phono Plus	$99.99	59​	45​	104​			0​	No	08/03/23	Review Link
Hagerman Audio Labs	Bugle2	$150	61​	40​	101​			0​	No	8/14/20	Review Link
Realistic	42-2101A	$20	58​	38​	96​			0​	No	1/22/21	Review Link
NAD	PP 4	$229	54​	42​	96​			0​	No	04/06/21	Review Link
Lounge Audio	LCR Mk3	$300	53​	40​	93​			0​	No	04/07/19	Review Link
Chord Electronics	Huei	$1,500	44​	49​	93​			0​	No	11/07/20	Review Link
Rolls	VP29	$50	49​	41​	90​			0​	No	1/22/21	Review Link
Pyle Audio	Pro PP444	$13	48​	35​	83​			0​	No	10/15/19	Review Link
Furutech	Alpha Des Labs GT40	$525	40​	41​	81​			0​	No	10/05/19	Review Link

There were nine MM + MC head amps, and one other MC only - the Graham Slee Reflex C.

I changed the SINAD figure for several amps, either because the Review Index figure was for the ADC or DAC, or quoted MM instead of MC.

Its interesting reading, though. Congratulations Michael!

Great work.

Isn't the price of the MC pro now a little bit higher now .

Would be great to see the Spartan 20 tested, I'm guessing it would be in 2nd place.

 

[Michael Fidler]

Great work.

Isn't the price of the MC pro now a little bit higher now .

Would be great to see the Spartan 20 tested, I'm guessing it would be in 2nd place.

I would hope so. I'm working on a new generation of stuff that can be built using automated methods, so perhaps the price situation could change to the advantage of the buyer.

 

[welwynnick]

I would hope so. I'm working on a new generation of stuff that can be built using automated methods, so perhaps the price situation could change to the advantage of the buyer.

Intrigued.
Surface mount components?

 

[Michael Fidler]

Intrigued.
Surface mount components?

Highly likely! I've got a few working prototypes now.

 

[Soniclife]

Highly likely! I've got a few working prototypes now.

Is performance likely to change?

 

[Michael Fidler]

Almost certainly only for the better. I'm not prepared to release anything that doesn't improve on the previous version. Designing this for automation is a little tricky, though, but not necessarily impossible.

 

[NoxPlague]

@Michael Fidler I feel incredibly fortunate that I snagged one of your last MC Pros this summer when I did!

It's an excellent MC phono stage, it's connected to a Denon DP 3000NE and I regularly rotate between three different cartridges, a Hana SL, a Denon DL-103, and an AT33PTG/2. The mono switch is so nice for the my small collection of mono records, much more practical than investing in a mono cartridge.

The MC Pro replaced a Schiit Skoll that caused excessive speaker cone movement and an aging Creek Audio OBH 15mk2

I don't know how one could setup a blind A B with different cartridges to verify the MC versus MM differences without two completely identical systems, but I believe that I notice fuller or less distorted sound in the <200Hz range with my MC carts versus my remaining MM cart, the Nagaoka MP 150. Of course this is sighted and biased.