Upgrading Rega P9 + RB1000

As a CAT SL1 Sig. Mk 3 owner, I thought that I should add my comments here.

The CAT phono stage is an excellent phono stage acknowledged by many worldwide. I reasonably sure that Yhyun's problem is *not* the CAT. The phono section has 47dB of gain - higher than the usual 40dB MM but less than the 60dB MC. It is a "compromise" in gain as explained to me by the chief designer @ CAT in a personal phone call with him. The input sens. of the CAT phono is 0.12mV & so the it is very possible that a 0.8mV Ruby H does not have sufficient output. Usually, if the cart. has an approx. 1mV output, it should be sufficient for the CAT phono.
As Yhyun mentioned a parallel pair of RCA female connectors is provided to change the cart. loading. It is very possible that CAT did not provide the exact load desired for the Ruby H - tough to anticipate which cart. the user's going to use when the CAT leaves the factory.
When using a low output cart., I have had the CAT volume cranked up to 11 o'clock to get decent level of sound. I can testify that the phono stage is dead quiet - no tube rush at all. However, the dynamics were lacking & there is no bass heft, atleast in my case.
A 1:5 step-up should do the trick real well as this will boost the cart. signal to 0.8mV * 5 = 4mV, which is nearly like the Clearaudio Aurum Beta S MM output level. It should be plenty of drive.
The CAT line stage has 26dB of gain (this is true!) so the grand total of gain from stylus tip to pre out = 14dB+47dB+26dB=87dB.
I have no experience with the Bent Audio step-up but I know that it is a mu-metal xformer core.
There is another, excellent step-up available for half the cost ($225 as kit & $300 custom built): the K & K Audio Lundahl xformer step-up. The Lundahl xformer is used in Art Audio's Phono 1 unit, which has received many, many glowing reviews by now. It also can be configured for 1:5, 1:10 or 1:20 gains. It uses an amorphous core xformer core. This material yields a much more natural sound delivery than any other xformer core material (mu metal & permalloy). The very best Japanese step-ups use *only* amorphous core xformers. I have heard this step-up & the music thru it is absolutely fantastic. I sincerely recommend that you listen to this step-up before spending $800 on the Bent step-up. Disclaimer: I have *NO* association with K&K Audio or Bent Audio.

Lastly, here are some recent Ruby 2 threads:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1031749078&read&keyw&zzruby+2
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1065811086&read&3&4&
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1048003449&read&keyw&zzruby+2

Yhyun, your ears are not deceiving you. Something's wrong with the music and it's not the tonearm, cartridge, wiring nor phonostage. It's the turntable that's not keeping up with your Audio Aero. The woody sound is the result of vibrations and the lack of details comes from substandard speed/rotational stability. It's easy to corroborate the latter. Just get a couple of LP and CD versions of the same album--one with a lot of fast percussion and one with piano/orchestral work. Listen for the attack and decay of percussion instruments and horns. You will find out that the Audio Aero will attack faster, tighter and the decay of the harmonics will be linear and not wobbling, with more detail and richness. On orchestral passages you will find that the Audio Aero plows through them while on the Rega the sound will become congested and the stereo image will shift.

Yhun- I have found away to reduce the lumpy bass to almost imperceptable levels with most LP's-- with the stock wire. I advise that you do not use the expressimo heavyweight. My listening has revealed the the low slung weight will increase the bass level but not the definition. I will not get into why the "low-slung" design is wrong. What you need to do with your Ruby is get the concentric counterweight within 1/4" of the rear of the arm. You need to get the Rega "extra-heavy-tungsten" counterweight- available from the importer. This will still however-leave you too far away though- although you will hear an improvement. Go to the hardware store and purchase (2) non-magnetic 1-1/4" flat washers and two sided carpet tape. What you want to do is adhere (1) washer on each side of the heavy Rega weight- centered around the central hole. This will make the weight heavy enough with the Ruby to bring you about 1/4" from arm rear. I gaurantee you will hear a startling improvement in bass. You should also be aware that the very newest versions of the ruby have a much more controlled bass response. I don't know how old yours is. (I have a brand new ruby2- if your wondering where my knowledge comes from)- at this time with the counterweight mod and ground wire mod- the arm is sounding very transparent and musical. So, perhaps the lumpy bass is really not caused by the coax leadout but rather cartridge-arm synergy.
good luck

There is an interesting Phono FAQ on the Van den Hul website.Specifically no.147 on direct wiring to your phono stage.There are about 4(or more) rewire kits for Rega arms available.Without getting too complicated, regarded opinion seems to favour copper over silver wire.A review of the benefits of modding your basic RB 250/300 by Paul Szadaby in Stereo Times is good reading as is the Origin Live site.stefanl

Yhun, I didn't know you had the MC board. Sorry for the slight diversion, although 47dB gain still sounds like MM territory to me. How much gain in the line stage?

I have the Mu feeding the MM phono stage in my c-j PVll preamp, which has 47dB gain + 19 in the line stage. My cart puts out a "solid sounding" .5mv but 66dB of total gain is not nearly enough. Without the stepups I have to crank the c-j's gain control to nearly 2 o'clock, compared to 9 o'clock for line sources. This pushes the line stage tubes too hard, raises the noise floor and, well, the sound just sucks! :)

If you have to push your gain significantly more for phono than for line then I'd investigate a SU device. I haven't heard anything but the Mu so I can't offer comparisons. People who have A/B'd trannies (Arthur Salvatore) say the Mu is the best in today's market.

I know it has admirably flat frequency response, down only .5db at 20Hz, dead flat to well above 20kHz. That's probably as good as any transformer anywhere. It's dead quiet of course. I haven't heard any phasing problems, but my speakers are probably worse in that regard so it's hard to say. The Mu's integrated leadout wire and easy load resistor changing did it for me. If you're having a slow day you can read my cartridge load test results on a thread called "Shelter + BentAudio Load Test" or something like that. Have the coffee ready. :)

It sounds like your arm wire issues are bigger, but why not try the different load plugins on the CAT? Can't hurt to experiment a little.

Thanks to all.

Doug, my CAT SL1 Ultimate preamp has an MC phono board. Its phono gain is 46db. So mid to high output cartridges (0.35~0.8 mV) can be used. The CAT also supplies the impedence load plugs (probably 50, 100, 150, 300). But as the Ruby's recommended load is 1000~47k, I do not use the plugs. So the impedence is currently matched to 47k.

For the head amp or the stepup transformer, I agree with your opinion. They may improve the base weight and the presence of music. Thanks for your information about the Mu stepup transformer. Could you give me more comments about Mu's sound characteristics?

For the phono cable, is there anyone having experiences of rewiring of Rega's stock ones? Any significant improvement? Any risk in the modifications? My P9 + RB1000 combo has a so-called 'golden midrange glow', but the bass is lumpy and 'folded' under as Reb described.

Soldering direct to the stage is only for the most "adventureous". This past weekend I opened up the base plug and did the ground mod- this took care of the distortion in the highs. I am not looking foward to doing more surgery. Attaching a din to the internal wire at the bass is like a 3hr nerve wrenching tourture session. If I go back in it must be the best proven option. Was thinking of drilling the arm tube near the back to let the wire come out like the VPI and Basis arms. But I decided that having these wires exposed to airborne vibration is a no-no.

I believe that if you put a DIN plug on the Rega arm you can then use some tonearm grade pure silver wire(Audio Note U.K) and solder a direct connection to your phono stage,without using RCA plugs.This is the best thing to do apart from a complete rewire.stefanl

Reb1208, good insights. I've never seen an RB100 and had no idea it was wired so poorly. Coax lead out??? ...

I have the RB-1000. You must atleast disconnect the ground from the left channel lead and run a seperate ground wire. Also get the rega extra heavy weight (from rega) so you can place it closer to the arm pivot. That said, the arm is still compromised with the stock wiring as the bass is lumpy and 'folded' under. I do not like the Incognito kit for many reasons. And the Discovery wire is too high a gauge. So for now I am contemplating putting a Din plug attached to the stock internal tonearm wire. In summary the main culprit on the 1000 is the ground scheme and use of coaxial cable lead out. Internal arm wire is acceptable.

You have a fundamental mismatch between cartridge and phono stage. The CAT SL1 has a MM phono stage. It lacks sufficient gain for even the "H" version of the Micro Ruby, which outputs less than 1/6th the voltage of an MM cartridge. The CAT also does not provide the loading the Benz wants to see.

Inadequate gain will make music sound thin, distant and lifeless. It also buries low level details beneath the system's noise floor. Any decent LP has more low level detail than a CD. You'll hear them once you solve this problem.

The loading of the CAT is much too high for the Benz, or any other MC cartridge. This will suck bass weight and "prescence" out of the music. You'll still hear bass, but no meat on the bones and images will be diffused.

Short of downgrading to a MM cartridge (not recommended) there are two ways you could address these issues. Properly implemented, either approach will solve them both.

Solution #1 is to change to an MC phono stage. Variable gain and loading would be nice, to avoid tying yourself to one particular cartridge forever. (Every MC cartridge has it's own gain and loading requirements.) You could do this with an outboard phono stage or by replacing the CAT altogether. This is not what I would do, though some would.

Solution #2 is to add stepup transformers between cartridge and pre. If you like the CAT then I'd recommend this approach. Take a look at the Mu trannies at www.bentaudio.com. Just $750 or so, and they include easily variable cartridge loading. This means they'll work with the Benz today and just about any conceivable MC cartridge tomorrow.

Fixing your gain/loading mismatch should pretty nearly maximize performance from that TT/arm/cart. They're not the last word but they should be able to outplay any CDP, even one as nice as the AA. Right now you're not hearing everything they can do.