Upgrading Rega P9 + RB1000

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

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.

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