2. analog
  3. 133274-5236

How to pick a COMPATIBLE phono cartridge

As follow-up to my recent post titled "Da Benz", I'm trying to better educate myself on how to pick a phono cartridge. There are many to choose from but I don't know which "type(s)" (i.e., output, etc.) will work well with my setup. Not considering price or characteristics at this point, but simply compatibility . Once I know that I can research options to make a selection. Looking through some past forums I see this can get complicated, so I'll provide some info on my setup:

Conrad Johnson EF-1 Phono Stage
    Gain: 40, 46, 52 db
    Phono Overload: 70 mV (40 db gain setting)
    Hum and Noise: 88 db below 10mV input

Conrad Johnson Premier 16LS Pre Amp
    Gain: 25 db
    Maximum input: 15 vrms
    Output impedance: under 700 ohms
    Hum and noise: 96 db below 1.0 mV

Conrad Johnson Premier 12 mono block Amps
    140 watts per channel
    Input Sensitivity: 0.90 volts to full power
    Input Impedance: 100k ohms

SME IV Arm
    Cartridge weight range: 5 - 16 grams
    Weight: 700 grams

And my leading cartridge candidate is the Benz Micro Wood (available in low, medium, and high versions), specs as follows:
    Output voltage: 0.4 (Low) 0.8 (Medium) 2.5 (High)
    Internal ohms: 12 (Low) 24 (Medium) 90 (High)
    Loading Range: >100 (Low) >1000 (Medium) 47k (High) 
    Weight: 9 grams
    Compliance: 15 (Low) 14 (Medium) 14 (High)
    Tracking 1.6 - 1.9 grams

The high output has been suggested. 

However, what cartridge specs should I be looking at for compatibility sake with my equipment and why? I have no idea!!!!   

Thank you to anyone who's willing to take the time to read and respond to a posting like this! :-)

Randy


rbschauman
hdm
1,062 posts
 
" One last question: If a system can accommodate both medium and high output versions of a cartridge, why choose medium (i.e., why choose a lower output version)? What do lower output cartridges do better than higher? Thinking that's the case..."

With moving coil cartridges the theory is that the lower output version will have smaller coils with fewer turns which can reduce mass and impedance thus improving performance. 

That is the theory as I said but one also has to consider that the lower output cartridge will require a higher gain in the phono stage; higher gain,
higher quality amplification, though, also becomes more expensive so it can sometimes be more difficult and costly to realize that better performance. 

rbschauman OP
138 posts
 
hdm,

Thank you for explaining the difference between low and higher output MC cartridges and what low may lead to. Been waiting for this...

Thanks,Randy
terry9
2,354 posts
 
Consider a step up transformer, which allows you to choose a low output cartridge. The thing about sut's is that they don't wear out - you buy them once, for life. That makes them a very cost-effective purchase.

Building a pair of sut's is dead easy. All you need is a box, four RCA connectors, and two transformers. Solder them together as indicated, and you've got yourself a really fine item. K&K audio is where I bought the Lundahl transformers for my Koetsu platinum, and I could not be happier.

As was noted above, lower output MC cartridges have lower mass weighing down the cantilever. Therefore, these tend to be more resolving and just plain musical. IMO.
almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
hdm 1-1-2018
Unless you are running a very unusual system (passive pre-amplfier, flea type amplifiers with extreme hi-efficiency speakers, etc.), I think you will find it [the KAB calculator] will give you a very accurate read on the type of gain optimization you need to do with the cartridge/phono stage interface.
This is a good point, which emphasizes that an online calculator should not be applied blindly.

Specifically, the KAB calculator indicates the gain that would result in the cartridge’s rated output being boosted to 0.325 volts. As indicated in its description that value was chosen based on what is appropriate for driving a CD recorder. However power amplifiers will typically require inputs in the vicinity of 1 to 2 volts to drive them to full power, for single-ended inputs, and twice that for balanced inputs. Which means that the gain of a typical active line stage, perhaps 6 to 15 db or so, will be required to assure that the phono stage gain specified by the calculator will make it possible to drive the power amp to full power.

On the other hand, like most CJ preamps Randy’s 16LS provides unusually high gain (25 db) for a line stage. So if a gain problem were to arise it would most likely be in the other direction, resulting in the volume control having to be used at undesirably low settings. That is very unlikely to occur with a cartridge/phono stage combination, but is certainly a possibility with a CD player or other digital source depending on the gain of the power amp and the sensitivity of the speakers.

Regards,
-- Al

robd2
45 posts
 
Great thread and info guys. Al could you expand on this item a little further with another example or two? Maybe a good and bad senario?

"4)The relation between cartridge output and phono stage signal-to-noise ratio is what primarily determines the amount of hiss that will be present when playing a record. Adding gain further downstream will not improve that; it will just result in using the volume control at lower settings."
More to discover