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

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.

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. 

@mijostyn l

@larryi

Thanks for the help , however my unipivot w Hana ML never feeds back in exact same position with same isolation feet 🤷

VPI seems to think the tone arm white wire shorting is the culprit 

Mijostin's comments make sense.  If the arm is already too heavy (meant for a low compliance cartridge) there is nothing much that can help.  You have a basic incompatibility, and perhaps a beef with the dealer who sold you the cartridge.  It is not the fault of the cartridge--it is like putting the wrong kind of tires on a car and blaming either the car maker or the tire maker for the poor performance.

While you might not be able to cure the problems that result from this incompatibility, you might be able to reduce the feedback by changing the isolation and tuning of the table's suspension (try different platforms, different feet, try making the platform the table is sitting on more rigid, etc. If your unipivot has provisions for damping its motion you can change the amount of damping.  

@larryi 

yeah I get it, I’m gonna try moving around the table today,…

funny how VPI and also Lyra recommend this cartridge with the table and the arm I have 🤔