Zyx Universe. O.24 mv vs .48 mv with low eff spkrs

Tom,

Many thoughts and questions...

Can you give a bit more info? Has this need to crank up the gain come on gradually over time? Or is this suddenly out of nowhere?

Are you sure some tubes aren't going? Have you tried swapping in new phono stage or power amp tubes? Much cheaper than buying a new UNIverse.

I don't know anything about your Salk speakers or power amps, but your Doshi pre has oodles of gain, so the problem "shouldn't" be there. I know you had it modded by Nick. You might check with him to see if he has any insights. Gain and impedance matching between amplifier stages is one of his specialties.

If your supposition about faulty/sticky arm bearings wearing out the suspension is correct, then clearly the first thing to do is remedy that (duh).

Once you've got a properly functioning tonearm then presumably there's no risk of wearing out your next cartridge early. In that case, if a new cartridge is needed and the .24mv UNIverse gave you sufficient output before, I can't recommend going with the .48mv. I've heard both, as you know, and there's really no comparison. It's not just detail that's lost with the HO version. Dynamics and speed suffer greatly too. The music sounds (comparatively) dead and dull. Read Arthur Salvatore's original (.48mv) and followup (.24mv) UNIverse reviews for detailed comparisons. I discouraged him from bothering with the .48mv but he wanted to try it first. He wasn't that impressed, finding it only slightly better than his LO Airy 3. When he switched to the .24mv UNIverse... bingo!

If you go for another UNIverse, DO order the UNIverse II. It's head and shoulders better than the original. One of the improvements is increased dynamics and punch, which should help ameliorate any need to crank it up.

Amplification is a chain to your speakers. And it is useful when you realized that Volume and Gain (internal amplification) are 2 different things.
I think you will have a proper Amp to drive your speakers, then the next critical detail is the matching between Preamp output to Input Amp. When the amp needs a stronger input signal than your preamp can deliver, you will have a loss in Gain and you can only compensate it with the volume poti. But this is something you can check on your own. When they match then you are normally with the volume poti at 09.00....
Same is for your Phonostage connected to your Preamp, they should match, too. A 0.24mV cartridge needs normally Phono Gain in the area of 62-65dB. When this is not sufficient then you can only compensate that with a better Preamp, or with a higher Gain setting in your Phonostage.
When your phono gain is probably at 55dB max, a 0.24mV Cartridge is too weak (or your Phonostage is too weak), this means, all the advantages of a low output MC Cartridge are useless because you will never hear it.
That is the reason why a lot of carts are offered with higher outputs, 0.5mV+
When you made this controlling, you will know what you can do to improve that. Normally it is the cheapest way to switch to a cartridge with higher output (a different Preamp or Phonoamp is generally more expensive when you look for something serious).
No matter what will be, a Preamp (and a connected Phonostage) are the brain of the System. They are responsible for a lively or a static performance). Amplifier power is cheap and there are a lot of good units out there. But good Preamps are much harder to find. But, when you made the right decision and only the internal Phono gain is too weak, So, go for a higher output MC when you don't want to change parts of the hardware...
0.24mV carts are better BUT you need the right working area for these.

To summarize what I think Doug and Syntax are saying, don't do it. If your phono stage had sufficient gain for the 0.24 version of the UNI in the first place, then you will gain nothing by switching to the 0.48 version, and the latter is not as good sounding. If the phono gain was never sufficient, by criteria described by Syntax, then you may need to have it modified or replaced. If you really think you have a bad bearing in your tonearm, then first and foremost you need to have it fixed or replaced.

Lewm, that's exactly what I was saying.

Further, I'm confident that Tom's Doshi Alaap (phono + line preamp) has (or at least had) ample gain for a .24mv ZYX. You heard the UNIverse/Alaap combo at the home of our mutual friend and your neighbor, Michael K****. I'd wager that inadequate gain and dynamic compression were the furthest things from your mind.

Something's clearly amiss, but we need more info.

***

@Audiotomb,

Try this experiment: reduce your VTF drastically... like to 1.30-1.50g. If the cartridge tracks cleanly and dynamics open up, your supposition that the cartridge suspension is giving out is confirmed.

thanks guys for the insights

here is what happened and why I was questioning my options
Do I choose more volume (but less resolution in the zyx) or higher output stage?

How much less of a cartridge is the .48? thanks for your comments and experiences

I didn't know just how big of a difference the .24 and .48 would be musically and really appreciate your insight. I love the resolving power of the .24, can't give that up

the more volume part of the equation is that the Salk Soundscape 10s are 84db efficient and I have to have my Doshi in the top several clicks to get sufficient driving volume where you really separate out things. It wasn't a problem till I switched to the lower efficiency speakers. The Doshi is a step down attenuator so it isn't clipping being near the top end of it's range.

In addition woofer pumping takes a lot of wattage away from the music and makes a hard load to drive

The cartridge is on a triplaner arm - I was fighting woofer pumping for a while. With help from Richard Gray locally, Doug Deacon, Mehran and Thom Mackris of Galibier we were able to isolate this with a feather test. A feather should be able to lift a properly functioning arm. The arm bearing wasn't working and so the cantilever was doing all the up down motion and causing subsonic woofer pumping and damage to the suspension.

Tri totally reworked my arm and all was well the last year. The pumping has returned but the arm is tracking correctly vertically.

I believe the cartridge issue is one of two things
The suspension has finally given way from all the arm rigidity abuse or I was not properly using my magic eraser, just barely lightly rubbing slowly from back to front (Richard Gray freaked out). He showed my how to dip the cartridge in the eraser a few times instead.

Universe II - tis tempting - ouch on the price. I've read all your reviews on it Doug and I listen to a broad range of music from the period piece chamber ensembles we both love so well, symphonies, acoustic jazz, rock, folk, everything really. Especially acoustic instruments in space. I play upright bass and my son is in several symphonic groups

Tell me more about Andy Kim. Does he work on ZYX?
Maybe the cartridge can be salvaged.
Perhaps sending this back to Mehran is in the cards