Schiit Skoll Balanced Phono Stage Review

[mike70]

Ive seen a few people write this phono stage pre off over the measured performance of the high pass filter...can anyone explain the reasoning?

i think is simple .... the filter have -1dB at 70dB and -2dB at 50Hz.
Do you want your bass response attenuated by 2dB at 50Hz ... and then more and more? Yes, question answered. You don't.

Normally, high pass filters for phono preamps only attenuates more lower octaves. I would not use that filter, for sure.

 

[JP]

but because they tend to have lower moving mass, they can be better at detail retrieval and high frequency response.

They don’t though, and I’ve never seen an actual correlation to “detail retrieval“ or FR. It tracks or it doesn’t.

 

[Angsty]

They don’t though, and I’ve never seen an actual correlation to “detail retrieval“ or FR. It tracks or it doesn’t.

“The lower effective tip mass of the MC stylus assembly gives it some significant advantages over the MM-type assembly.

This may not appear to be desirable at first, but this very lightweight assembly allows for much wider frequency response, improved transient response, more detailed reproduction overall and, in particular, the reproduction of signals that are low in level, which a heavier moving magnet assembly may miss.”

Audio Technica makes both types of cartridges.

Audio-Solutions Question of the Week: What Are the Differences Between Moving Magnet and Moving Coil Phono Cartridges?

Find out the difference between moving magnet (MM) and moving coil (MC) phono cartridges and the best applications for each type of turntable cartridge.

www.audio-technica.com

 

[JP]

“The lower effective tip mass of the MC stylus assembly gives it some significant advantages over the MM-type assembly.

This may not appear to be desirable at first, but this very lightweight assembly allows for much wider frequency response, improved transient response, more detailed reproduction overall and, in particular, the reproduction of signals that are low in level, which a heavier moving magnet assembly may miss.”

Audio Technica makes both types of cartridges.

Audio-Solutions Question of the Week: What Are the Differences Between Moving Magnet and Moving Coil Phono Cartridges?

Find out the difference between moving magnet (MM) and moving coil (MC) phono cartridges and the best applications for each type of turntable cartridge.

www.audio-technica.com

Marketing literature as evidence? Come on.

 

[GXAlan]

They don’t though, and I’ve never seen an actual correlation to “detail retrieval“ or FR. It tracks or it doesn’t.

Introducing the Phono Cartridge Measurement Library

After years of development we are finally launching our phono cartridge measurement library. These measurements were created using the brilliant cartridge response python script written by @scott wurcer and @JP. Information about its origins can be found in the following threads...

www.audiosciencereview.com

If you go through this, most MC cartridges have a treble boost. I don’t know if this is beneficial since most regular LPs (as opposed to test disc pressings) have a treble roll off and the MC is restoring what’s lost or if the detail is just FR.

I like the sound of my MC cartridges even though I also have the Shure V15 VMR which is flat in the CBS test disc.

 

[JP]

Introducing the Phono Cartridge Measurement Library

After years of development we are finally launching our phono cartridge measurement library. These measurements were created using the brilliant cartridge response python script written by @scott wurcer and @JP. Information about its origins can be found in the following threads...

www.audiosciencereview.com

If you go through this, most MC cartridges have a treble boost. I don’t know if this is beneficial since most regular LPs (as opposed to test disc pressings) have a treble roll off and the MC is restoring what’s lost or if the detail is just FR.

I like the sound of my MC cartridges even though I also have the Shure V15 VMR which is flat in the CBS test disc.

You’re aware who enhances and maintains that tool?

 

[GXAlan]

You’re aware who enhances and maintains that tool?

Of course

I meant to reply to Angsty. You are too humble when making your comments about “never seeing” something.

 

[Angsty]

Marketing literature as evidence? Come on.

Actually, I cannot find any source that does not corroborate that MCs tend to have lower moving mass than MMs. That does not inherently make MCs better than MMs.

There is a general tendency for MMs to track better than MCs, although that is not universally true, either. It’s more common now to see MC carts track 80µm grooves successfully in testing.

According to Julian Hirsch, “the shape and dimensional tolerances of the diamond stylus are far more important than the generating system [MM vs. MC] employed in the cartridge.” If the choice of MM or MC matters less than the diamond profile choice, that could influence which preamp to buy.

Paul Miller at HiFi News tests cartridges on occasion. It is easy to see the boost in high frequency response for MCs across multiple models, sometimes as high as 4 dB. That HF boost may be what gets attributed as “greater detail”.

Back to the Skoll preamp, I would look elsewhere for a LOMC pairing but this one looks fine for MM. You could put a SUT ahead of the preamp for additional MC low noise gain, but the SUT could cost more than the Skoll itself.

 

[JP]

Actually, I cannot find any source that does not corroborate that MCs tend to have lower moving mass than MMs. That does not inherently make MCs better than MMs.

Data: https://www.audiosciencereview.com/...ctive-tip-mass-master-list.41783/post-1477540

It was true when MCs first came out, but the use of stronger magnets allowed for smaller magnets. Technical literature shows that in most cases the cantilever is the greatest contribution to moving mass. The sample set were MM with Alu cantilevers, though the numbers would hold up directionally for other materials.

Paul Miller at HiFi News tests cartridges on occasion. It is easy to see the boost in high frequency response for MCs across multiple models, sometimes as high as 4 dB. That HF boost may be what gets attributed as “greater detail”.

Then it’s not actually greater detail, and exaggerated HF response is not better HF response.

 

[JP]

Of course

I meant to reply to Angsty. You are too humble when making your comments about “never seeing” something.

The more I know the less I know.

 

[mike70]

Vinyl measurements are really hard ... even more with MC cartridges.

A decent SUT is a must, and many (many) times I hear about "everything is the same" they have a standard preamp with tons of noise at 60dB, a bad compliance between tonearm/cartridge, turntable without proper isolation, etc etc.

Vinyl is mechanical ... not a "plug and play" chip with some cables inside. So, you only can have some trust on really serious tests, not on the open internet and not certainly from 50 years ago.

With digital devices and amplifiers, measurements have some care to be trusty and I trust ASR ... with cartridges ... is much harder.

 

[Angsty]

Data: https://www.audiosciencereview.com/...ctive-tip-mass-master-list.41783/post-1477540

It was true when MCs first came out, but the use of stronger magnets allowed for smaller magnets. Technical literature shows that in most cases the cantilever is the greatest contribution to moving mass. The sample set were MM with Alu cantilevers, though the numbers would hold up directionally for other materials.



Then it’s not actually greater detail, and exaggerated HF response is not better HF response.

Thank you - it’s good to have a new reference data source.

Regarding HF response, I think it is very easy to slip from FR to preference among vinyl users. There could very well be a bias in the MC crowd to the HF boost given other factors that may dampen HF response in other parts of the acoustic chain.

For potential buyers of the Skoll, I would advise thinking about your current and anticipated cartridge use cases before making the leap. Ensure you have the right match.

 

[4D_Coaxial_Cube]

Thank you - it’s good to have a new reference data source.

Regarding HF response, I think it is very easy to slip from FR to preference among vinyl users. There could very well be a bias in the MC crowd to the HF boost given other factors that may dampen HF response in other parts of the acoustic chain.

For potential buyers of the Skoll, I would advise thinking about your current and anticipated cartridge use cases before making the leap. Ensure you have the right match.

For me the high pass filter seems like a complete deal breaker as I do not want a linearity problem with frequency response. I suspect this HPF issue is applicable to both types of carts, right?

 

[Angsty]

For me the high pass filter seems like a complete deal breaker as I do not want a linearity problem with frequency response. I suspect this HPF issue is applicable to both types of carts, right?

The Skoll could be a perfect preamp for a user with small, LF-limited “bookshelf” speakers, say a Wharfedale Denton. The filter will prevent overloading the woofer while keeping a flat FR in the important midrange frequencies.

For a full range speaker with flat response to 40 Hz, the rolloff could be noticeable and I’d advise that user to look elsewhere.

 

[gxleetw]

The Skoll could be a perfect preamp for a user with small, LF-limited “bookshelf” speakers, say a Wharfedale Denton. The filter will prevent overloading the woofer while keeping a flat FR in the important midrange frequencies.

For a full range speaker with flat response to 40 Hz, the rolloff could be noticeable and I’d advise that user to look elsewhere.

Skoll’s HPF is defeatable; once turned off the FR is perfectly flat per Amir’s measurement.
I turn the filter off with main speakers, but turn it on with headphones in late night listening, which noticeably lowers the rumbles even though most of my records are pretty flat.

 

[ban25]

FWIW, if you're looking for a high-quality balanced phono pre-amp with no noise issues and willing to spend a bit more to buy from a low-volume (1-man) operation, I can highly recommend Michael Fidler's MC PRO, well reviewed on this site:

Classic Audio MC Pro Phonostage Review

This is a review and measurements of the Classic Audio MC Pro by Michael Fidler. It was sent to me by the company and costs US $850 (£650/€750). As non-fancy enclosures go, this is pretty nice looking and with some unusual features such as low frequency blending to reduce noise, mono switch and...

www.audiosciencereview.com

Mine is noise free in both channels at reference volume.

 

[Angsty]

Skoll’s HPF is defeatable; once turned off the FR is perfectly flat per Amir’s measurement.
I turn the filter off with main speakers, but turn it on with headphones in late night listening, which noticeably lowers the rumbles even though most of my records are pretty flat.

I do believe one can get better performance from a system with a “rumble filter” than without one. Getting rid of subsonic information is worthwhile with vinyl, if not always available on phono amps. I just object to the high “knee frequency” on this particular model for use with full range systems.

A flat frequency response to the lowest frequencies can create its own problems.

 

[dzerig]

For potential buyers of the Skoll, I would advise thinking about your current and anticipated cartridge use cases before making the leap. Ensure you have the right match.

Skoll works for just about any cartridge that doesn't cost twice or more than it's price, and pretty much ANY mm type.

i think is simple .... the filter have -1dB at 70dB and -2dB at 50Hz.
Do you want your bass response attenuated by 2dB at 50Hz ... and then more and more? Yes, question answered. You don't.

Normally, high pass filters for phono preamps only attenuates more lower octaves. I would not use that filter, for sure.

Actually, people who are using a rumble filter for the right reason have pumping woofers, so more is better than less in that situation.

 

[4D_Coaxial_Cube]

I still havent ordered a phono stage yet. One one hand the Michael Fidler design approach seems very encompassing to have done what he did with making the lower frequencies mono and working out a filter for them as to compensate for rumble. I do believe it would cost more though, and doesnt have the flexibility the Skoll has if a different cartridge is ever pondered. The Skoll has a remote as well as balanced out. Choices...

I really wish someone with experience with both would chime in.

 

[ban25]

I still havent ordered a phono stage yet. One one hand the Michael Fidler design approach seems very encompassing to have done what he did with making the lower frequencies mono and working out a filter for them as to compensate for rumble. I do believe it would cost more though, and doesnt have the flexibility the Skoll has if a different cartridge is ever pondered. The Skoll has a remote as well as balanced out. Choices...

I really wish someone with experience with both would chime in.

There are roughly half a dozen unique reports in this thread of buzzing in the left-channel on the Skoll. If you decide to order one, just be prepared to return it if the issue manifests and you can't tolerate it.