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Looking for ideas on Lyra Delos - muddy middle

I realize I'm opening up any number of Pandora's boxes here, but given that the cartridge designer is a regular visitor/contributor, I'm hoping to get some great feedback in addition to the great feedback I'll be getting from all of you.

Here's the dilemma - I recently bought a used Lyra Delos (claimed to have less than 400 hours on it) cartridge to mount on my current rig.  Details on that setup later in this post.  After some serious VTA adjustment/validation, Azimuth adjustment/validation and verifying the rake angle is accurate, I get what I think is the best sound I can get out of the setup of the cartridge. And, with 200ohms loading, I've sanded off the highs while keeping the lows and everything there is in check - detailed and musical.  Yet on a number of recordings (Rock mostly, but some jazz and psych with large transient swings or lots of instrumentation in the moment) the 'music in the middle' sounds muddy and congested especially on faster passages - almost smearing like I'd expect on the highs except the highs (for the most part) are detailed and cymbal decay, for example sounds right and not smeared or slushy.

Great channel separation, great soundstage, just a clogged middle.  Am I missing something obvious?  I feel like I've been back and forth and over and over and I'm just not finding anything.  I haven't gone back to my previous cartridge to check if it's something else in the signal path, but that would be the next thing if there isn't anything that comes from this discussion.  And, of course, if I go back and find that it's not the case with the old cartridge, then what?

My reference recordings to test are:

Arne Domerus - Jazz at the Pawnshop (German Pressing)
Beach Boys - Pet Sounds (Mono Reissue)
Dead Can Dance - Into the Labyrinth (MoFi Master Reecording)
Deep Purple - The Book of Taliesyn (EMI/Harvest)

and yes, the records are cleaned before playing.  


My rig:

Table: Thorens TD-124 Mk I with Mk II upgraded motor supports, custom dual-tonearm plinth
Cartridge: Lyra Delos (used, but no rebuild to my knowledge) w/Boron Cantilever/Microridge stylus
Old Reference Cartridge: ParadoxPulse modified Denon103R w/Sapphire cantilever/Microridge stylus

Tonearm: Esoteric Sound S320 Mk II
*Type: Static balance, tubular, S-shaped, with removable headshell
*Effective Length: 9.02 inches (229 mm)
*Effective Mass: 13.4 Grams
*Resonance: 8.5 Hz
*Spindle to Pivot Distance: 8.43inches (214 mm)
*Mounting Hole: 1-3/16 inches
*Arm mounting pillar diameter: 0.703 inches
*Overhang: 0.59 inches (15 mm)
*Offset Angle: 22 degrees
*Tracking Error: +1.9/ -1.1 degrees
*Bearings: Steel ball bearings
*Material: Aluminum, Magnesium
*Dampening: Rubber
*Finish: Matte Black
*Horizontal and Vertical Sensitivity: 20 mg
*Height Adjustment: 1.5 to 2.4 inches (38 - 60 mm)
*Tracking Force Calibration Range: 0 to 3 gm (for more force, turn
  weight past "0")
*Counterweight: 140 gms
*Anti Skating Range: 0 to 3 gm
*Cartridge Weight Range: 4.0 to 12 gms
*Headshell: Magnesium with oxygen-free copper Litz wire, adjustable azimuth

 Phono Preamp - Paradox Pulse Phono 70 w/200ohm loading

Headphone Amp - SRM-007I w/Mullard/Brimar tubes (6gc7)
Headphones - Stax Lambda Nova Signature (Serial - S00966)


The only thing I can think of is to further tweak cartridge loading, but that may cross the line of diminishing returns.

Thoughts?  

Thank you in advance for any advice you can give.
128x128dducat
dducat's avatar
dducat OP
40 posts
 
@lewm  - Yup, that's why I started with the 100Ohm load based on the various forums here, other forums, etc.  The kick up to 750Ohms was definitely a positive change.

WRT to the TD124 - I recently installed the MK II motor mounts and re-plinthed it, so I'm fairly confident that part if working correctly.  And, as I stated earlier, the Denon 103R worked fine after that as well, and the rest of the signal chain is something that I also need to look at and I will.

Given the significant change in SQ with the load change, I'm fairly confident that loading is the largest opportunity for improvement.

catcher10's avatar
catcher10
77 posts
 
@dducat what phono cable are you using and do you know its capacitance spec? Lyra carts really like to see a low cap cable so you can load at the phono stage. I used to run a very high cap phono cable with my Delos loading at 121 ohms. Pretty nice. Then bought a low cap AQ cable and loading at 475 ohms based on the Lyra mathematical settings and the cart opened up and the sound is glorious across the whole musical freq range.
Also if you are at 70dB gain that is huge, you could be overloading your preamp section depending on its input sensitivity. I run my Delos with 56dB gain from my Nova II phono preamp which gets me about 350mV out to the preamp.
All of these things can affect the sound of your Delos.
dducat's avatar
dducat OP
40 posts
 
@catcher10 - I'm using a cable that I bought from the company that sold me the tonearm (Estoteric sound - premium cable based on the Mogami Neglex 2534) and it's roughly 100pF for 1m.  The cable is a hair over 1M long.  I was running it at 660Ohms, but going back and looking at the Lyra docs, it appears I should be between 200 and 390 ohms.  So, I'm starting at 396 (it's what I had on hand) and I'll work my way down.  When I was at 200 before it was where I started hearing mud in the middle, so I'm probably going to stay closer to the high end.

Right now, I'm not running a true preamp - I'm running out to a Stax SRM-007tII to Stax Lambda Nova Signature (404) Headphones which are VERY detailed and very fast.  Given what I've known about Stax Tube Energizers/Headphone Amps, they need higher than usual signal gain to be most effective, so I don't think that's it.  I haven't actually measured the voltage so I can do that, but as I said earlier, I'm convinced it's just a matter of tweaking the loading and being patient which, of course, I'm not. ;)

Thanks for your input and suggestions.
catcher10's avatar
catcher10
77 posts
 
I can't recall exactly I think my AQ is around 60pF as a 1.5mt cable. I suspect you have it dialed in as best you can....Enjoy it, the Delos punches miles above its price point.
avanti1960
1,471 posts
 
unfortunately your turntable and most suspended tables have a warm imprint on the sound.  
as others have suggested try different cables, i really like the nordost purple flare between table and phono preamp, will be very neutral and detailed.  also experiment with increasing load resistance. 
but the other thing you can do is to try different mats.  your congested middle might be caused by undamped tonearm to record resonance in the midbass region that definitely affects midrange clarity.  the one that always works for me is the herbies way excellent ii, minimum 4mm thick if that fits.  
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