Classic Audio MC Pro Phonostage Review

[ban25]

I did think about this a while ago, and it is possible to source EMI shielded custom glass pieces for surprisingly little as long as the quantity is in the triple digits. However, it seems that this would have to be at the top of the product to give a good view (maybe some space on a full-size enclosure on the front panel), which would probably get broken very easily when stacking units on top of each other. At the moment, dropping the cases just dents the corners a little, but doesn't render the units inoperable.

For the time being, it doesn't seem like a great idea to devote time to, but perhaps in the future, with a new enclosure style, it might be worth looking into again. At the moment, I'm just trying to concentrate on the electronics and keep the enclosure design relatively simple. For a 'high end' type of product it's probably a very good idea with a few strategically placed LEDs, but I'm not selling things for four figures (yet).

Makes sense. If and when you do get around to designing that premium product in the future with the fancy enclosure and all the trimmings, count me in for one!

 

[lamda18]

Πιθανώς στην περιοχή των 2-2,5 χιλ., καθώς θα διαθέτει 4 εισόδους RCA, 4 εισόδους XLR, νικηφόρα χειριστήρια τόνου, περίβλημα πλήρους μεγέθους, έλεγχο έντασης ρελέ, μετρητές στάθμης, ισχυρότερο ενισχυτή ακουστικών...

Sub out?

 

[Michael Fidler]

Sub out?

Like a mono mixer?

 

[Angsty]

There is now a HP/pre-amp, the Spartan 30 <https://michaelfidler.com/products/spartan/spartan-30-headphone-amplifier/>. I'd prefer remote volume control for pre-amp use, but even just for the HP amp it's good value for SOTA performance.

After checking it out, it looks impressive. I have two old Bryston pre-amps that will never die. But if I were looking for a new, compact high-performance pre-amp, this one would be at the top of my list to try.

At first look, it’s preferable to me versus the stream of competitors coming out of China.

 

[Angsty]

Because once a suitably low noise input amplifier with a noise figure of less than 6dB against 10 ohms is selected, the coils' thermal noise dominates as it increases past 20 ohms, so insertion loss doesn't degrade SNR as much as you would think (effective degradation would be 3dB by 120 ohms of coil impedance). The penalty is negligible for coil impedances in the 30 ohm range although I believe such cartridges are sub-optimal for noise performance, pushing the effective SNR below 80dB (220Hz to 22kHz). Generally the 10 times rule assumes that impedance bridging is desirable because if the input amplifier has a very poor noise figure it will be the main source of noise in the system.

Additionally the loading network has an important function in preventing RF peaking and also shunting away as much RF interference to ground. Increasing the resistance without reducing the load capacitance peaks the frequency response around 3MHz. Reducing the capacitance increases the RF cutoff point which is undesirable.

In all honesty moving coil cartridge loading is an extremely dull subject and I get more e-mails about it than I care to have about this subject, particularly the 'zero-impedance'/'current input' marketing scam that's currently doing the rounds. I'm writing all of this up for a new article for the website so I can just reference it in future.

There may be a shot in Stereophile. The first article in the January 2024 issue is about dispelling “a myth about phono-cartridge loading”.

The article poses that loading variation does not change the frequency response in a real world cartridge, as positioned by Peter Moncrieff 43 years ago in International Audio Review (IAR) #5. “Proper” loading is said to perhaps reduce distortion - but I did not see any evidence to support this in the article.

The editor invites anyone who has “solved the mystery of MC cartridge loading” to write-in.

Edit: The same issue features a glowing review of the new MoFi phono preamp with both variable-loaded voltage and current amplification techniques.

 

[manisandher]

I finally got around to setting my old turntable (Technics SP10 with SME 309) up and giving my MM Pro (not MC Pro) a go. I took some digital captures from the outputs of the MM Pro and of my hyper-expensive valve phono preamp using my E1DA Scaler/Cosmos. The MM Pro trounces the valve phono preamp.

Well done Michael!

Mani.

 

[keiron99]

I'm still toying with the idea of "upgrading" from my Lehmann to this Classic Audio MC stage, especially now it's available in black, but can't get over the nervousness of making yet another change to my hifi that will make zero audible difference (to wit: every change of CD player, DAC, amp over the last 25 years)!

 

[AudioSceptic]

I finally got around to setting my old turntable (Technics SP10 with SME 309) up and giving my MM Pro (not MC Pro) a go. I took some digital captures from the outputs of the MM Pro and of my hyper-expensive valve phono preamp using my E1DA Scaler/Cosmos. The MM Pro trounces the valve phono preamp.

Well done Michael!

Mani.

You must have expected this question: what is the hyper-expensive item?

 

[manisandher]

You must have expected this question: what is the hyper-expensive item?

Haha... Can I try to sell it first?

It was 14k Sterling retail. I paid 6.5k for it ex-demo.

Mani.

 

[AudioSceptic]

Haha... Can I try to sell it first?

It was 14k Sterling retail. I paid 6.5k for it ex-demo.

Mani.

That's a serious investment, even at the price you paid. Good luck!

 

[Angsty]

I'm still toying with the idea of "upgrading" from my Lehmann to this Classic Audio MC stage, especially now it's available in black, but can't get over the nervousness of making yet another change to my hifi that will make zero audible difference (to wit: every change of CD player, DAC, amp over the last 25 years)!

It’s funny that my phonostages are where I have heard the most differences in my system. My two last amps and my three last DACs had no meaningful audible differences. But there were definitely audible differences between my last three phonos and my last three turntables.

I’m parked on my “end-game” turntable and phono now, but I don’t doubt that I could potentially hear differences in other kit. The design philosophies and measurements of phonos seem to vary widely.

 

[AudioSceptic]

It’s funny that my phonostages are where I have heard the most differences in my system. My two last amps and my three last DACs had no meaningful audible differences. But there were definitely audible differences between my last three phonos and my last three turntables.

I’m parked on my “end-game” turntable and phono now, but I don’t doubt that I could potentially hear differences in other kit. The design philosophies and measurements of phonos seem to vary widely.

I think that's well accepted. The RIAA compliance and hence FR can vary a lot. Factor in "rumble" filters, distortion, and inevitable noise because of the high gain, and it's no surprise that phono stages often sound very different.

 

[MaxwellsEq]

I think that's well accepted. The RIAA compliance and hence FR can vary a lot. Factor in "rumble" filters, distortion, and inevitable noise because of the high gain, and it's no surprise that phono stages often sound very different.

There are so many compromises to decide on. With MC cartridges the gain is sufficiently high to make low self-noise measurements genuinely challenging, whilst handling the impact of RIAA on gain and SNR is another challenge. One observation I would make is that in general phono stages seem to have trended towards improved noise behaviour.

 

[levimax]

There are so many compromises to decide on. With MC cartridges the gain is sufficiently high to make low self-noise measurements genuinely challenging,

Which is why some people like to use a SUT with MC carts... ~20 dB gain with virtually no noise.

 

[AudioSceptic]

There are so many compromises to decide on. With MC cartridges the gain is sufficiently high to make low self-noise measurements genuinely challenging, whilst handling the impact of RIAA on gain and SNR is another challenge. One observation I would make is that in general phono stages seem to have trended towards improved noise behaviour.

What we can say is that the maker of the DUT has pretty much nailed it. I almost wish I could find an excuse to buy one.

 

[manisandher]

What we can say is that the maker of the DUT has pretty much nailed it. I almost wish I could find an excuse to buy one.

I didn't really need another phonostage, but am really glad I went for this one. Of course, it performs superbly. But buying it also helps out a new audio outfit in the UK, which makes me feel... well, good, I suppose.

Mani.

 

[ban25]

I didn't really need another phonostage, but am really glad I went for this one. Of course, it performs superbly. But buying it also helps out a new audio outfit in the UK, which makes me feel... well, good, I suppose.

Mani.

I'm quite happy with mine. Almost tempted to order a 2nd to have one in black....

 

[Angsty]

I was tempted to get the MC Pro but stopped short. I’m happy with my current phono; “better” might not make me happier.

 

[AudioSceptic]

I'm quite happy with mine. Almost tempted to order a 2nd to have one in black....

I'm tempted by the headphone/preamp. <https://michaelfidler.com/products/spartan/spartan-30-headphone-amplifier/>

 

[Angsty]

The Spartan 20 is the one I’m anxiously waiting to see reviewed. Although I have suggested the Spartan 15 to several, the lack of both MM and MC capability is a stumbling block.