Help - Phono stages dying!!


Greetings,

I have a bewildering and unfortunately expensive issue that has come up with my turntable set up. I currently have a VPI prime with Hana ML cartridge [both purchased new October 2020] connected to Audia flight FL3S integrated amplifier. My original phono stage was an older Rega aria which was the 1st victim of my current predicament.

Just prior to Christmas - two months after the VPI was purchased new - I lost right channel sound. After a process of elimination I suspected it was the aria, which was confirmed by our local AV repair guy that indeed the Rega did have a blown right channel. I thought nothing of it, bad luck as there were no needle drops, lightning storms, etc.  

Fast-forward then about one month, while awaiting the Aria repair, I made use of the internal phono on my integrated. Definitely not on par with the aria, but serviceable. By then as well I had upgraded all my cords to Blue Jeans cables from cheap amazon cables. Remarkably, while listening quietly the right channel goes out on the Audia Flight internal phono. I take this apart and can clearly see a blown resistor (I think)! At this point I have no idea what is going on. Prior to the second phono blowing, everything seemed to be playing flawlessly. No sound changes. No hum. No static issues that I could detect. Nothing. So, I take my turntable to our local vinyl guru here in Vancouver, Nick at the turntable shop. I would have taken it to my dealer, but I bought the tt/cart as a package for a remarkable deal from a reputable vendor in Eastern Canada... I could not get a local store to match the price. Anyways, he tests the tonearm and cart and he can find nothing wrong with either. Speaking with my repair technician handling the aria, he has never seen 2 phono stages die in such short succession. He as well feels the turntable/cart are unlikely culprits although I did not bring to him to inspect.

By this time I had already swapped out all my cables, bought a furman power conditioner, and was hoping to get my aria back in action. I thought perhaps simply bad luck x 2 as the turntable inspection passed muster and I could not think of any plausible deficiency with the TT. Again simply bad luck x 2. Unfortunately with Covid, parts are very difficult to find for the Aria and so with the delay I decided to upgrade my phono stage and purchased an avid pulsus lightly used.
2 weeks now with the avid, I like it very much. Last night though while washing dishes suddenly our speakers began to hum dreadfully. Nothing was playing at the time, but the platter was still spinning as I forgot to turn it off. However, the tonearm was safely parked. I race over, turn everything off quickly. Nasty smell. I popped off the case of the avid with dread and confirmed the smell of electronic death, one the little resistors black colored and clearly fried.

At this point I think I may need a priest for an exorcism. Obviously I am not going to be connecting anything to my turntable. CD player, stream box, everything play nicely so I am going to park my vinyl until I can sort this out.

I did email both VPI customer service and my dealer initially when the aria blew, and they assured me that is was likely the aria. Thereafter I have been in touch with both as well after the integrated phono blew...but they too were puzzled by the issues. I am awaiting their responses now after my latest debacle.  

I would be most grateful for any shared similar experiences or theories. Thankfully the TT and cart were purchased new so boxing it up and returning both may simply be my best option. I have been combing through forum after forum, and have some theories but I am hopeful that the vast experience on these forums will help me solve this puzzle. Again thanks in advance your help.
slashsmil

Showing 7 responses by lewm

It just occurred to me that solid-state devices are more susceptible to static discharge than are tubes, as a rule. If I read the OP correctly, all three phono stages that have failed are solid state. It might be interesting to try a tube-based phono stage as a replacement. Of course, as well, one should do an analysis for the source of a potential static discharge.
Mijo, And....?
I think the static discharge hypothesis makes some sense here. But why the turntable is uniquely held responsible, I do not know. I don’t know how a turntable, especially a belt drive turntable with an outboard motor that is displaced from the phono pick up could likely be the cause. Static discharge can be a local phenomenon, really having nothing to do with the equipment.As to the idea that the downstream component is complicit in this problem, please give me an idea how that could be. Then I will believe in it more avidly.
Based on the very limited information, I have the impression that the failure is occurring somewhere at the phono stage input, if for no other reason than the fact that the OP needs to play a record in order for something to blow.  Because apparently the same failure has occurred with 3 different phono stages, that indicts something upstream from the phono stage, anything right up to the input to phono.  So I guessed that there may be an intermittent hot to ground short on the R channel input upstream from the phono input.  But now I think of it more, that would just be like a mute switch.  Signal would disappear but no damage necessarily.  Seems like you are thinking about something on the phono output side, between phono and linestage. Again, given the limited info, that certainly is possible.  RFI doing this seems far-fetched; RFI can sure mess up listening pleasure but does not normally destroy audio components.  We'll probably never know.
Shorting the grid of a tube or the gate of a transistor to ground would eventually blow the device. Could be anywhere from cartridge itself to phono input. Because this problem has recurred with three different phono stages, that tends to make me think the problem is extraneous to the phono stage. What do you mean by an out of band signal? Are you talking about R FI? Then you’d have to think why is it only affecting the right channel? 
I am forgetting the fine details of your story. Is this problem occurring always with the same cartridge and the same wiring from cartridge to phono input? If so, I am wondering whether you are experiencing an intermittent short between the hot and ground on the right channel of your cartridge or anywhere in the wiring up to the phono input. Why this would blow the load resistor, I have not yet worked out,But it would not be good for the gain device that comes at the input. Intermittent wiring failures are very difficult to find, for the very reason that they are intermittent and may not be in effect when troubleshooting.
As the late great Roseanne Rosannadana said, “It’s always something.”
Never let your speakers wash the dishes.  (Sorry, could not resist. It's a matter of syntax.)

Seriously, it would help to know WHICH resistors are failing and whether in all 3 cases the failed resistors have a common function.  For example, is it the phono load resistor for the R channel that is failing in all cases?  You should be able to get that information from the guy who does your repairs.  Also, in all cases, were you correct in visually identifying failed resistors; you tell us that this or that resistor looked like it was blown, but I wonder just what the problem(s) actually were. If a resistor blows, you usually think it was passing too much current, which increased the power handling required above the resistor rating (in Watts) and overloaded the resistor.  Since the phono load resistor handles only a tiny current, many times the builder will use resistors with a very low power rating, which is easily exceeded.  But not much can happen in that position in a phono circuit that would lead to that kind of failure.  It's puzzling.  But, if it's always the phono load resistor, that at least would narrow one's thinking.