2. analog
  3. 188637-89448

VPI Prime Sig/Lyra Delos / Feedback ...help!

Hello all, strange one here...just picked up a VPI Prime Signature Rosewood and a Lyra Delos with about 20-40 hours on it...sounded great at low volume with my sacred Steely Dan - Aja Cisco pressing . Later that night at higher volumes I'm getting a midrange-low feedback . 

Here's my rig : 

VPI Prime Sig with Unipvot / Lyra Delos 0.6m output voltage / 1.75 tracking force

Allnic 1202 Phono Pre (variable DB boost  +22, +24 , +28, +32) 

Manley Snappers / Jumbo Shrimp Pre 

Harbeth 40.3XD 

So I A/B'd w the old turntable VPI Prime Scout / Unipivot / Hana ML 0.4 Output and all was fine 🤔 I then swapped arms moving the Hana to the Prime Sig , no feedback ....🤔

I've tried adjusting the Allnic (all 4 levels mentioned above) and get feedback with the Lyra on every setting...

The hifi business I purchased from said they had tested thoroughly and had 0 problem with it ...so I'm perplexed , this doesn't seem to be any vibration feedback , is the Lyra just not jiving with my Phonostage for some reason? 

Any help appreciated ...

 

128x128tommypenngotti
tommypenngotti's avatar
tommypenngotti OP
217 posts
 

This just in - VPI recommended a continuity test on all headshell wires with multimeter...the white wire seems intermittent...not sure that is the culprit though , I think that's a ground..

Ag insider logo xs@2x
drrsutliff
834 posts
 

White is the left channel “hot” wire.  White (hot L), Red (hot R) so it could be an issue in the arm wiring…

lewm
12,522 posts
 

No way this has anything to do with tonearm wires. And yes, white is L channel hot, if it mattered.

larryi
3,739 posts
 

The Lyra cartridge is NOT prone to resonating and causing feedback problems.  It is most likely the combination of the arm/cartridge/table suspension that is unfortunately tuned to a resonant frequency that is causing the feedback.  You could try adding a small amount of weight to the headshell to see if it moves the resonance to a less sensitive frequency, or you can try tuning the table to change its resonant behavior (put it on a different platform, add weights to the plinth, etc.  

It probably makes sense to reduce the overall tendency of the platform the table is sitting on shake--if it is on a rack, can you make the rack more rigid?  If the rack is close to the wall, the best way to make it more rigid is to somehow attach it to the wall.  I did this by putting a cleat on the wall near the top of the rack and then using angle braces to attach the rack to the cleat.  This made the stand MUCH more rigid.

mijostyn's avatar
mijostyn
8,223 posts
 

Tommy, you have several problems that lead to issues like this. Your turntable is not adequately isolated and Lyra cartridges do not like unipivot arms. You need an isolation platform tuned to 3 Hz or below and a gimbal pivoted arm, then the Delos will work fine. Lyra cartridges are relatively compliant and that arm is also too heavy for it. 

More to discover