Saturday, July 21, 2018

Phono Cartridge Comparison - Audio Technica CN5625AL vs Numark/Ion Groove Tool

At $30 the  Audio Technica CN5625AL and the Numark/Ion Groove Tool are about the cheapest phono cartridges you can buy. But I suspect few people buy either of them, they mostly come mounted as freebies on relatively inexpensive turntables. That in and of itself however does not make them bad phono carts.

I wanted to do a comparison between these two carts, and it's the start of a series of posts I've planned comparing various phono carts. After this comparison I'll move up the price chain a little bit to help you determine if it's worth upgrading the cart that came with your table.

I'm not so much interested in declaring winners and losers as helping people find the phono cart that's right for them. I've augmented the discussion with YouTube videos that allow you to listen and compare the carts yourself. I'll also discuss a few things that phono cartridge reviews rarely mention but that are important. I suspect I'm not alone in having read some flowery prose praising a cartridge's "buttery highs" and "creamy midrange" only to get it home and realize it can't track worth a damn.

It may be unfashionably objectivist to say so, but tracking ability matters. So for each cart I will give a report of how it fares on the bias tracks of the Hi-Fi News Test Record. I'll also present frequency response charts, something that was common in cartridge reviews years ago, but seems rare now. Frequency response matters too. My own personal preference is for frequency response to be as flat as possible, but you don't have to share that bias. Listen to the clips for yourself and make up your own mind.

With all that said...let's go!

First up is the Audio Technica CN5625AL. As I mentioned above, it is often included installed on many turntables. There are other variants of the cart with a carbon fiber cantilever, and sometimes it is rebadged under a different brand (the Rega Carbon for example).

Let's listen. Here's Stan Getz and João Gilberto performing "The Girl From Ipanema." I picked this cut because: A. I like it, B. It's familiar to many, and C. The LP has a bit of surface noise and I want you to hear how each cart handles surface noise. The Audio Technica CN5625A gives us a nice mellow sound that many associate with vinyl playback. Take a listen (you do not have to listen to these recordings all the way through, listen as little or as much as you want):

Now let's hear the same track from the Numark/Ion Groove Tool, which as far as I can tell is a re-badged Sanyo ST09D, another cart with a long history that has travelled under many different names.

Here's a third video where you can listen as I switch back and forth between the two carts every 30 seconds. I try very hard to match volume levels on all these comparisons, as even a minor difference in amplitude can effect our perception of sound. Because audio memory is very short, I find this method very helpful in getting a handle on how carts sound with respect to one another.

The first thing I noticed was that the Groove Tool picks up more of the surface noise on the record than the CN5625AL, but it also extracts more detail from the grooves (listen for the difference in the cymbals).

The tonal balance between these carts is very different with the Groove Tool emphasizing the upper midrange and treble region much more than the CN5625AL. Here's another cut, The Cure's "In Between Days" from an 1980s US Elektra pressing of 'Head On The Door':

The brighter tonal balance of the Groove Tool is especially evident on this treble heavy 80s cut!

So which one is right and which one is wrong? Let's take a look at the frequency response plots:

As you can see the Groove Tool is relatively flat out to about 5 kHz, then there is a big peak leading up to 10 kHz followed by a steep drop off. The CN-5625AL in contrast is dished out from around 2 to 10 kHz, which explains its more mellow tonal balance and also why it's better at rejecting surface noise (which lives in that region of the audio band).

So which is better? I'd go with the Groove Tool. A $30 cartridge that is razor flat out to 5 kHz is pretty extraordinary. The 6.5 dB peak around 12 kHz does result in an overall bright tonal balance, but personally I would take that over the scooped out midrange of the Audio Technica which sounds dull and muffled in comparison. But that's just me. I'm almost 49 and so I've lost some of my ability to hear in the upper frequencies. That brightness might bother a younger person a lot more than me.

The CN-5625AL performed well on the Hi-Fi News Test Record's bias tracks, suggesting it should be a good tracker. It passed the first three cuts and only "failed" the final "torture track." This is actually excellent performance as we'll see later when looking at some more expensive carts. The Groove Tool on the other hand is another story. It is an EXCELLENT tracker. It passed all four bias tracks. It even played the final "torture track" with no distortion. I was shocked by this, as it was the first cart (of many) I've had in my system to ever pull that off. Nice.

It's funny because the Groove Tool does not have a appear to have a good reputation for tracking among online commentators. In fact, there's already a comment on the Cure video from someone saying his Groove Tool tracks inner grooves very poorly. I can't explain that. I can only report what I find. The result is counter-intuitive, conical styli are not supposed to track that well. But there it is.

Is it possible the Groove Tool is a good tracker on test records, but not with real music? Here's a comparison between the CN-5625AL and the Groove Tool on an inner groove cut, "Freedom of Choice" the last cut on DEVO's album of the same name. This is also a fairly bright cut, and I'd expect a cart that tracks inner grooves poorly to have trouble with it. You can make up your own mind about how these carts perform on inner grooves:

The Groove Tool also demonstrated better stereo separation, measuring 17.5 dB of separation at 1 kHz, whereas the CN-5625AL only managed 12.5 dB of channel separation. The Groove Tool's channel balance was also superior with the left channel measuring +1.5 dB on the pink noise track and the Audio Technica left channel measuring +2.5 dB, so the Numark badged cart should have a wider and more balanced stereo image. There are some important objective respects in which the Groove Tool is simply the superior cartridge, in other respects it's a judgement call between the two and will depend on personal preferences.

In short, if you have an inexpensive table that came fitted with the Groove Tool I wouldn't bother upgrading the your cartridge. If you are looking for better sound, buy a better turntable and put the Groove Tool on it! Next time I'll compare these carts to something more expensive to see if it performs better and is worth the price difference.

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