What cartridge to use....Rega RB25 Structural Mod

I agree (sort of) with TWL – keep the cart and upgrade the arm. If you do have some money to invest, get a better arm and you will be shocked to see how much the Red can deliver.

IMHO you are already running into diminishing marginal returns by trying to upgrade from Koetsu Red on your RB250. The RB250 bearings are not up to scratch to extract the most out of said cart, even less so from a better cart.

(I am being kind by saying the RB250 bearings not being up to scratch – the bearings are total shyte)

Regards
Paul

Oh bother …

The DL103 is a fine cart for the price – I use one to listen to my old (read very worn) jazz LP’s. However, compared to a Koetsu Red, it can only be described as vulgar, edgy with an exaggerated top end. I have not heard the Shelter 901, but the having lived with both a 501 and DL103 for a while, you would have to be quite deaf not to recognize the 501 as being the more musical of the two.

I am not going to make a comment about your choice of tables other than to say if you used a half decent turntable for your comparisons, you would recognize the shortcoming of the DL103 and RB250/300 in a heartbeat.

Clearly idler wheels suffer from so much noise contamination that the subtleties in the music are lost, and quality cartridges and arms are a waste of time (and money).

Regards
Paul

Ps. As a DIYer myself, I applaud other folks who take the time and effort in this hobby to roll their own. That includes people who resurrect old tables. However, one should avoid the trap of evaluating your own handiwork with those rose tinted glasses.

"no less a critic than Art Dudley in Stereophile has stated that they [RB 250/300] are extremely good value for the money"

Yes, I agree. That is what I said in my post no? In fact, they are probably the best value for money arms out there. They are however, not very good. (In the same way $200 is a lot less than $3000)

"they all fell into the range of 1P-3P"

Agreed. 1P is the very worst ABEC grade and 3P is the second worst grade. 1P and 3P are not sufficient to reproduce music with any level of accuracy. All you will get is a blunted and smeared mess; which is what the RB250/300 deliver in spades.

BTW - I have not heard the RB1000, but have heard the 600 and 700. I heard the same bluntness and smearing from both. So I have no problem with your statement that 250/300 bearing spec the same as the so called ‘better’ models in the RB range.

"is a tolerance you cannot feel"

Agreed, you cannot feel it but you can most certainly hear it. Personally I listen to music – touching my tone arm does very little for me.

"I have had literally hundreds of Rega arms (of all models) in my hands and have never had a single one with excessive play."

That is a lot of arms to have owned (you must be very wealthy), but since they spec at 1P to 3P they all have excessive play. Your inability to discern that is hardly contrary to the fact.

Regards
Paul

Stefan

I know who Garth is. Garth sells Rega/OEM arms. He has a lot of experience but nobody lies more than a salesman. I believe that in the industry, lying to the public is known as marketing, no?

My setup is very good and more than adequate to come to an objective conclusion as to which arm is better. (I can send a photos and description off line if you want – email me) Also, I have no reason to like or dislike Rega arms. I am only interested in having good sound – I do not have to sell anything to anybody.

My RB's (I had 3) were all modified with Incognito(2) and Discovery. I loved them till I mounted my Morch – the difference was nothing other than dramatic. Even some arms that are less expensive than a modified RB (Scheu Classic/Bel Canto Unipivot and Graham Robin) are significantly better. Yes, I tried them both and now own a Scheu also. At one time I had two Morch's mounted on my table.

A good friend who is a Rega fan lent me his RB600 to compare against my Morch. It was a joke – the RB was blown out of the water. He now is running a Morch UP4 also.

I think Jeff would be well advised to consider upgrading to an arm like a Morch UP or Hadcock and keeping his Koetsu Red.

Regards
Paul

“All unipivot arms are pushed to their limits of stability with low compliance cartridges”

Rubbish. That sweeping statement is simply not true. I have never ever had any stability issues with any properly set up unipivot in more than a decade that I have used unipvots.

“I wouln't recommend the use of something like a Koetsu, DL103R, or Shelter in most unipivot arms(although there are a few exceptions), especially any light weight unipivot arms.”

Since the carts you mention are low compliance carts, it would be rather dumb to use them on a lightweight arm, unipivot or not.

I have used all the carts you mention (Koetsu Rosewood, Shelter 501 and DL103) on a Morch UP4 (blue dot arm wand – 14 grams) and 12 inch Scheu Classic II (also 14 grams) with great results. I tried the same carts (on same table) on a modified R250 and it compared badly to the Morch and Scheu.

“Matching is critical, and proper matching goes beyond simple mass/resonance calcs.”

It goes way beyond that and includes the choice of turntable and the stand/isolation employed..

And again I feel the need to emphasize that I have no motive to prefer one arm over another other than for purposes of sound quality. I do not sell arms (or promote tweaks) for any audio equipment.

Regards
Paul

“I am not su[r]prised that you preferred the Moerch and Scheu over just a rewired RB 250 because you have to do more than just a rewire”

Sigh ...

I used a number of stubs different stubs – brass stub & weight (from Brit Audio) a Michell stub & weight and a custom-made brass counter weight. They did improve the sound (especially on the 250’s) but did not bring it even close to the sound of a top-flight arm. In fact I would say the structural mod seems to be a bigger improvement that the rewire itself

I also tried it with spacers, Easy Rizer VTA, Pete Riggle VTA on the fly and the VPI VTA adjuster. The best sounding to my ear was with using the VPI adjuster, but again it was very disappointing compared to Morch.

The modified RB250/300 was on par with the RB600 I tried. Your posting indicating the level of quality (or should I say lack there of) pertaining to the bearings, fall in with my observations.

“A form of VTA adjustment is also required and then all your attention must be given to adjusting the base-nut to EXACTLY the right tension(Usually Finger-Tight with just a Nip).This is critical and quite labourious at first but the Rega literally "sings" when it comes together”

If you are eluding the poor performance is due to bad setup you are sorely mistaken. And no, the Rega only sings when you are not used to anything better – and there are many better arms out there.

Don't get me wrong, I think and RB250 is good value for money. If you happen like it, that is cool. Hifi is about enjoying what you listen to, no?

Ultimately though, you get what you pay for. Running a Koetsu on a RB is casting pearls to the swine.

Regards
Paul

Hi Jeff

Just remember to tighten your arm by a single "NIP" - no less no more ok? ;-)

Regards
Paul

Ps. If you are interested in the zyx, have a look at http://www.high-endaudio.com/RC-Cartridges.html. Arthur S makes some interesting comments which you may find of interest