I would translate "super-low internal impedance" to mean below 1 Ohm and preferably well below. 5.4 Ohm is well outside the ballpark and 8.2 Ohm is far enough away that the ballpark is only visible in the far distance.
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Compatible Phono CartridgesTransimpedance preamplifiers require a low impedance MC cartridge. A certain few MC cartridges may have trouble driving a transimpedance phono stage, and a closed-down upper octave response will result. The general rule of thumb in choosing a compatible cartridge is: the manufacturer's suggested load resistance is 100 ohms or less (e.g., 100, 50, 25, 10 ohms, etc.). Another specification is the cartridge internal impedance (which is related to, but different than the load resistance): 10 ohms or less, and the lower (e.g., 5 ohms, 2 ohms) the better. If either or both of these are true, it's likely that the cartridge will be an optimal match. If you have any questions feel free to contact us via email or phone and we'll be able to tell you if your cartridge is suitable.
I've used cartridges with internal impedances ranging from 4-14 ohms with no problems with my Aqvox, and think that all worked well.
I've also used an AT MONO3/LP with an internal impedance of 40 ohms and thought it worked reasonably well with my stage, although it was not a great match in terms of output/gain, having a bit too much output for the Aqvox to really dial it in; the review of the Loco I saw on line stated it would not work at all with that phono stage delivering only a loud hum, so there may be some other slightly odd compatibility issues with certain cartridges and the Loco because of other elements of its design. The Aqvox is fully balanced in and out so perhaps that is why I was still able to get that AT to work with it.
The Lyras are in the middle to upper range of output (as far as low output MC's are concerned) with .5 mV and .6 mV respectively with Kleos and Delos and the issue with the Delos may have had more to do with proper gain matching/setup than the internal impedance of the Lyra at 8.2 ohms which is still relatively low.
Most current mode stages should perform reasonably well with cartridges with internal impedances of 1-10 ohms I would think.
The Lino is a great preamp. Team it up with Pure Vinyl and something like an Apple Mini and you have an unbelievable record playing system. You can record records to your hard drive. You type in the record's PL # and all the data will pull down automatically. If you want to compare cartridges and you can record a sample of each then AB them. The RIAA correction is done in the digital domain with accuracy and a lack of various distortions not possible in the analog domain. Everything is done in very high resolution. You can also use the Pure Music part of the program to download digital files to your hard drive and the program includes a stream through option. Your Apple becomes a music server, actually a media server as you can also stream movies. The program automatically up samples everything to 24/192 pushing the anti aliasing
filter up away from the audio spectrum. Check out Channel d's web site http://www.channld.com/
Less than 10 ohms is a good rule of thumb. But not all "current-driven" phono stages are created equal, as they all have an input impedance that is in reality greater than zero. The one Chakster uses comes the closest to zero input impedance of any I know about. But most present an impedance of from 2 to as high as 12 ohms. Therefore, it’s a case by case question of whether you will get a great result or just a very good result, depending upon both the cartridge and the phono stage. The Kleos is well suited to trying. I’m using an Ortofon MC2000 (internal impedance 2 ohms) with a one-off product made by EMIA for me. Its input impedance is higher than average, yet the combo sounds excellent. It’s the first set-up that allows me to hear what the MC2000 can really do. (MC2000 has super low voltage output = .05mV, and I did not want to try an SUT.)