Does it improve the sound of a MM or MI cartridge by playing it through a phono stage?

presumably you are asking "sparate dedicated box vs built in RIAA & amplifier".
And (drum roll please) it depends on which one is better designed and executed. I happen to be working on one right now. The circuit, PCB etc will be identical whether in its own box or plugged into a motherboard. Same card. What will differ is:

• isolation (nothing like having its own box around it
• Power supply (more money can be spent due to expectations and price point)
• packaging
• price
  

Its like the integrated amp vs pre and power amp. In theory the integrated is better. In practice they are bought for the convenience, package and value, so they rarely aspire to the highest of high end.

You might infer that I’m working on one of those too. :-) In the end as noted, and i think you know this, every cartridge needs an extra 30-65 dB of gain ( and that’s a LOT) and the inverse equalization to what is done during mastering so that it is flat and accurate. No RIAA EQ, no bass. Pretty simple.
G

Dear Raul, While I yield to your generally superior experience to mine, I must say that all the information at my disposal would indicate that the 300 series of Acutex cartridges were induced magnet types.  However, the 400 series are conventional MMs.  I do see that on the Bluz Bros website, they say that BOTH series are MM, which we both know for sure is incorrect with respect to the 300 series, which makes me all the more ready to disregard anything they have to say on Acutex, especially since they have none to sell.  On the other hand, I will grant you that the 400 series LOOK a lot like the 300 series in terms of shape, which would fit the idea that the 400s are also IM types.  However, I also found this quote from a website much like this one, and surely not the last word any more than this one is the last word.  Nevertheless, "while the 420 (full name 420 STR) is a very good cartridge, it's not in the same league as the 320 (full name M320III STR). The STR refers to the "Special Tri-Radial" stylus tip, a line contact type developed by Toshiba, so the 320 and 420 have that in common but that's about it.The 420STR and M320III STR were the top of the line in their respective series but the 300 Series had things going for it that were dispensed with when the 400 Series came along. Whereas the 300 Series were an induced magnet design, the 400 Series were of the more typical moving magnet type. They also abandoned the tri-pole design which is where the magic is in these cartridges and also in the boxy "Brick" types. The stereo chain responsible for the Acutex brand of cartridges, speakers and headphones (interestingly, all transducers) was Atlantis Sound in Falls Church, VA in suburban DC."

All cartridges, MM, MI or MC require a phono stage.  The MC phono stage always needs more gain than the others hence makes it much more critical (and expensive).
You can get a VERY decent combination with the following:

MM cartridges: 2M Black, Nagaoka MP 300/500, Goldring 2500 etc. (about $500)
phono stage: Schiit Mani (about $120)
or going all out:
Avid Pulsare II (about $7000)

Dear @wolfie62 :  ""  The Acutex carts are just unauthorized copies of run-of-the-Mill AT carts. Instead of V magnets, it has mumetal “Mickey Mouse” ears. It uses the identical cantilever suspension as used on AT carts .""

"  Cheaper just to buy an AT cart. They sound and perform the same ."


Perhaps what you posted could be that way and at the end I don't care to much about because the quality level performance of AT vintage cartridges ( I own or owned all top models as the Acutex models too. ) against Acutex is certainly different and certainly does not sounds the same as you stateted. No way my friend.

Next and " old " Acutex cartridge review compared against top vintage cartridges including top AT:

https://forum.audiogon.com/discussions/review-acutex-lpm-315-iii-str-cartridge

Anyway, if for you sounds the same fine with me.

R.

Sutherland has several in the lowish price points - $900, $1400, and $2200 (and several higher end up to I think $15K). All are considered great values compared to the competition and the $1400 and $2200 ones have reasonable priced options for a linear power supply. The $1400 insight can have a board swapped internally (and the power bridge) for only $350 - typically done when configured/built, but can be upgraded after the fact as I did after buying a used one (did it myself with the help of Ron Sutherland himself), and the 20/20 has an optional external LPS for $450. It is probably $100 more because of the extra box.

Most of all, Ron Sutherland is a great guy, willing to do anything to make his customers happy. Very down to earth and generous with his time. He spent time on the phone with me before, during and after the purchase (probably well over an hour in total, plus a few emails) for a $350 sale! -which was shocking and refreshing. I believe he is the only PS designer in the market with any kind of market share that is talked about by high end dealers. I heard in the past he has designed high end amps that are still sought after. He also was one of the founders of Martin Logan. He probably just does it for the fun of it now....