ZYX "House" Sound

Primarily better tonearm - new, much higher quality bearings. The better the tonearm the more you get out of your cartridge. I am familiar with the 505 - I was a high end distributor for a few years and personally owned some of the micro TT's and arms including the 505. Very good arm, but everything wears out, particularly bearings.

The early DD micros are quite grainy sounding to my ears. If you prefer DD then get a new one with more advanced speed control systems than what was used on the 70's & 80's.

Basically a $500 cartridge on a top level TT will outperform a top level cartridge on an average TT. doesn't have to be a Rega - I just suggested that as a starting point. There are plenty of others such as SOTA, Feickert, Kuzma at various price points.

From 30 years of distributing high end audio and setting up 100's of high end TT's my advice - start with a better TT. Both of your existing cartridges, unless they are worn out, are capable of much more. I've also owned and or set up both of your existing cartridges.

The ZYX, if it has a family sound tends to neutral and resolving. On of my personal favourites is the Omega, it does sound a little fuller through the midrange compared to models above and below.

Why don't you find a dealer and ask them to demonstrate a very good TT ( $4k up ) with one of your cartridges mounted - the Shelter would be best since the Koetsu is less neutral. Find out for yourself. 

I don't have the audio reviewers vocabulary to do justice in describing my ZYX Ultimate Exceed 100 cartridge. My table is a highly Hot Rodded VPI Prime Prototype with a TriPlaner tonearm. I have to say that the ZYX is highly resolving with just enough warmth to still be open and natural. I think my arm and table combo are "high quality" enough to let this cart sing without being hindered. Detail, speed, bass, accuracy, are on the mark. I always get a sense of hearing what's in the grooves, nothing more, nothing less. I have no doubt that moving up the ZYX line will give incremental improvements, but that doesn't interest me, my listening isn't super critical. I already feel like I have "arrived". Good luck in your audio journey.

This is disturbing and confusing.

I have thoroughly tested the MA-505 and the DD-40. Both are functioning very well. I have an MS in Physics and have spent my entire career developing very high end medical and communications equipment. I thoroughly understand the mechanics and electronics of TT and cartridge behavior.

I have tested the bearings on the MA-505 arms using my own techniques and using the WallySkater. Very fluid, no rough spots both vertically and horizontally.

I've recapped the TT. The rotation speed is rock solid. Test records indicates a very stable speed.

I have listened to the Koetsu on my WOW XXL table using a brand new Audiomods 6 arm. Both are very modern products. I very much prefer the sound from the DD-40 and MA-505. The arm that came with the table (Acoustic Signature TA-2000) has been removed because it is so difficult to use.

What arm and table did the people who purchased a Koetsu in the 80s use? Were all arms and tables insufficient then?

What else should I look for in the DD-40 and MA-505 that will  tell me that they're  not good enough for the higher end cartridges? I test every piece of equipment that I put in my system with a spectrum analyzer and an oscilloscope. I can measure and optimize distortion, anti-skate, tracking force, speed stability, and frequency and time domain response. Performance is very important to me.

In summary, what tests can I perform that will show me that the DD-40 and MA-505 are inadequate for higher end cartridges? I need to see some data before I am convinced that my older tables are insufficient.

Dover’s advise is usually spot on, but in this case I believe he’s a little too stern. Many folks here seem to believe that the new stuff is always better. Obviously technological progress does exist, but in the case of turntables, tonearms and cartridges this is much exaggerated. I’ve owned pretty high level modern turntables and tonearms, but have come to prefer the old school Japanese analog devices from the ’80’s and ’90’s. I use old and new cartridges side by side and there’s no fundamental performance jump with the newer stuff. There are incremental improvements as more advanced manufacturing techniques and new materials have become available. But more often than not it’s just changing tastes, like the rather loud ’extreme detail retrieval’ crowd which still dominates the audio scene.

In short I see no reason why the MA-505 would fail to deliver a satisfying performance from ZYX cartridges, provided they are a good match in terms of effective mass. Nakatsuka’s designs are fairly traditional Japanese cartridges with a medium compliance, so I don’t see any reason to be disturbed or confused. 

@kevemaher, It sounds to me like you have a speaker/room problem. Changing cartridges is only going to make marginal differences. The frequencies causing your problem are in the 3 kHz to 4 kHz region and these frequencies love to bounce around the room creating that "white noise" you mentioned. Makes you want to squint. While it is true that cartridges that lean on the bright side will make this worse the cartridge is not the primary problem. 

Systems that are tuned correctly will initially sound dull until you realize that the high frequencies are there right where they should be, over with the cymbals. Voices and violins sound natural without any sibilance. Acoustic foam tiles are dirt cheap. Buy a box of them and use double sided carpet tape  to tape them to the walls and ceiling at the early reflection sites. You will be shocked at how your sound improves. If you do not know how to find them message me and I will go over it with you.