tonearm upgrade, how far up the food chain?

Dear Lloydc: IMHO you have a " so so " tonearm and a " so so " phono stage when you have a top rated Grado cartridge that is a great performer and a one that deserve the very best you can get on tonearm/phono stage if you want that the cartridge show you how good is in reality and that today IMHO it can't do it even if you change the TT.

The cartridge/tonearm IMHO is one product not two independent products, a cartridge must be mounted with a matching tonearm not with any tonearm but with the best match for it.
In the other side the phono stage is very critical link in the analog audio chain because is inside this " box " where the cartridge signal must pass to be processed not only to increment its output but to mate the inverse RIAA eq ncesary for a even frequency response, is in this phono stage where the cartridge signal " suffer " in true and where that signal is degraded maybe the most.

The Thorens 850 is a very " decent " TT and for the moment could makes a very good job.

Try to find a removable headshhel tonearm design and a phono stage that can handle ( with out setp up transformers. ) the 0.5mv of your Grado.

Regards and enjoy the music,
Raul.

Agree with Raul, he hit the nail on the head.

Aiming for some cost ratio is largely pointless, since the performance and compatibility of components cannot be judged just from their cost. OTOH, good lessons can be learned by looking at the ratios of systems that work vs. systems that don't. In that vein, here's my system with either of two carts:

Phono stage...........8
Turntable...............7
Tonearm................5
Cart 1 (LOMC).....4
Cart 2 (MM).........0.1

This favors the phono stage, TT and arm over the cartridge more than NickT's list, extremely so in the case of the MM (thanks, Raul!).

The sound with either cart is phenomenal. You'd expect that from the $4,000 LOMC and it's certainly the better of the two, but the real lesson is how great that little MM sounds. No one would guess they were listening to a $100 cartridge in a $20,000 front end. This crazy cost ratio (top class components, throwaway cartridge) works remarkably well.

OTOH, every time I plug my world class LOMC into a system with a lower quality tonearm, turntable or phono stage the results range from boring to terrible. Very revealing cartridges reveal system weaknesses just as well as they reveal music. Do not make this mistake.

Get your other components above the level of your cartridge or you'll never hear what it can do.

Regarding the Rega 300 I agree with Stanwal and disagree,
logicaly, with Raul (sorry Raul). I.e. the 'so-so' qualification applys for the original wiring but the Rega is easy to rewire. I bought this tonearm for my son and deed riwiring myself. BTW my son is also reading this forum
so such 'so-so' qualification my 'disturb' our relation.
Regards,

Dear Doug, Your argumentation looks very 'sound' but presupposes much knowlege about,say, analog 'experience'.
I,for example, know that Van den Hul 'swears' by Technics
EPA-100. I would never dream to pretend to know beter. But I bought the Triplanar VII wich is ,say, 4 x more expensive because I regard this tonearm as the most beautiful ever made. But your 'cost-ratio'argument
have some other support. One Dutch firm bought an very expensive 'machine' ($ 20 million) but this machine 'refused' to work. So they asked for an specilist
who give an rap to the macine in 'some place' and the machine was working. But he made expenses claim for $ 4000.
To the questin:'$ 4000 for an rap?' his answer was:'the
rap is $50 but the knowlege where to apply the rap is the
rest'.
Regards,

Thanks so much for the thoughtful comments. I am largely persuaded that upgrading the arm should be a priority, and probably the phono stage, too (which I suspected.) Unfortunately, the Thorens is not the best platform to "build on", as it is limited in the arms it will accommodate, only Rega-type or SME (with a different arm mounting plate, which takes almost 6 months and $200 to get from Thorens.) fwiw, the low output Grado Ref was described as a "budget" cartridge by a knowledgable distributor, and it exhibits slight sibilance in my system; it is good to know it is probably not the most limiting factor in this setup.