Concerningly loud pops in vinyl playback


I have a problem I've been unable to diagnose yet, so I thought I'd gather some ideas. This is for a 2nd vinyl system in my girlfriend's home, not my main system. I've never had any issue like this in the main rig. 

We're all used to annoyingly loud isolated "pops" from surface defects or perhaps static discharge during vinyl playback, but usually these are only truly annoying during quiet passages and tend to become relatively "outgunned" during heavy loud music. However, very occasionally (once every several records) I will get a POP so loud it is concerningly startling, even during loud playback of rock music. I don't like the tweeters being subjected to that, though they're fine so far. And it hasn't tripped the VAC 200iQ's protection circuitry yet, so there's that. Still, I don't like this. It's happened on the left and on the right speakers, so it's not isolated to one channel. Once it occurs, it is more likely to occur again within several seconds (and again), until I take the record off and start over. It seems to occur only starting at a certain high volume level on my ARC Reference 6 preamp (40 and above). The records and stylus are clean, and it's now occurred on multiple different records that I KNOW aren't the problem. So my suspicions are down to: 

  • Static discharge (I have a  record brush with conductive fibers and use anti-static sleeves)
  • Really bad overload reaction in phono and/or preamp, possibly prompted by static discharges and possibly because the gain is set too high in phono stages (I have the Hagerman set to 60dB for 0.8mV which I thought would be OK)
  • Power line noise issue of some kind / EMI / RFI
  • Tubes in the ARC Ref 6 going bad. Maybe PSU tubes? But it really seems to be instigated by a volume level on the Ref 6 going above 40.

This rig is kind of like my playground, so I have lots of gear at my disposal, much from the main rig. I've already swapped out many different components and had the problem reoccur on each of:

  • Different Speakers (Tannoy TD10, Tannoy Glenair 10)
  • Speaker cables (AQ Rocket 88, AQ KE-4/CV-8 biwire)
  • Power amps (VAC 200iQ, Phison A2.120SE)
  • Phono stages (Hagerman Trumpet MC, Herron VTPH-2A)

The consistent gear I haven't swapped out yet has been:

  • Clearaudio Innovation Compact turntable, Universal arm
  • Benz Wood SM cartridge 0.8mV
  • Audio Research Reference 6 preamp

What do you think is most likely the cause, and how to fix it? I'm not real eager to "try" to reproduce the issue, for obvious reasons. But other than this issue, the rig sounds great - really enjoyable. 
 

128x128mulveling

 

Regards mulveling:

mbmi may be on the right "track".

There is no recording standard for the maximum allowable value common for cutting LPs. An owners’ setting which is fine on one LP may clip when playing another.

Set up a Goldring 1042 (6.5mv output) for my sons’ Denon DP-60L into a Kyosera A-710 integrated amp. On loud passages there would be a startlingly loud "pop". Checked grounding, added an additional ground from the Denons’ chassis directly to the receptacle, no luck. Swapped cartridges to a Signet TK-5ea (5.0mv) and all was good.

 

Peace,

Thanks again all, really good ideas here!

Replaced the 2 regulator tubes in Ref 6. Greatly enjoyed my music yesterday with no incident, though I didn't budge the Ref 6's volume past 40 max (if I'm in the mood I might like to go up to ~ 42 :)). Other than this issue the small room system has really exceeded my expectations; so nice. 

I did order an AQ Niagara 3000 from TMR; the gear in here deserves it, even if this isn't a power issue. 

Also have the Hudson Hifi brush/wand thing on the way - these devices never really appealed to me, but it's cheap enough to buy & try. Got a humidifier too; just need to hook it up. 

I hooked up the "optional" bearing ground wire to my Clearaudio, but it's not clear to me where the other end (small spade) goes. I've put it on the phono stage for now (along with tonearm ground) BUT being a Hagerman Trumpet, it takes DC from a SMPS wall wart that's 2 prongs. So there's no connection to earth ground. So I guess that's kind of a bummer if the intention of this bearing ground is to earth it? Any ideas what else I can do with this ground wire, or whether it might actually help at all? The Herron has a linear PSU with 3-prong cord, but quite frankly the Hagerman is the better sonic match here so I want to use that. 

Any ideas if clamp and mat can affect the static issue? I have a Synergistic Research UEF mat I can retrieve from the loft. When I've had the POP issue I'd been using the bare delrin platter with a Stillpoints LPI weight that fits loosely over the spindle. I've started using a Clearaudio Twister clamp that gives a tight grip on the spindle and should be conductively connected to the metal tightening knob. 

I've put it on the phono stage for now (along with tonearm ground) BUT being a Hagerman Trumpet, it takes DC from a SMPS wall wart that's 2 prongs. So there's no connection to earth ground. So I guess that's kind of a bummer if the intention of this bearing ground is to earth it? Any ideas what else I can do with this ground wire, or whether it might actually help at all? The Herron has a linear PSU with 3-prong cord, but quite frankly the Hagerman is the better sonic match here so I want to use that. 

Its OK that the phono section isn't grounded to the wall. What is important is that the ground of the 'table is the same as that of the phono section.

IME the platter pad can have a big effect on static. I've never used a delrin platter though.

Its OK that the phono section isn’t grounded to the wall. What is important is that the ground of the ’table is the same as that of the phono section.

IME the platter pad can have a big effect on static. I’ve never used a delrin platter though.

Thanks for the info, @atmasphere - I went ahead and connected it that way.

So certainly, this case appears to be a complex problem with a lot of variables. I got the Hudson Hifi arm brush for static dissipation - easy to use, and a nice product for cheap. I’ve been very careful to eliminate any sources of static - and yet the problem still persists (on average once every several records or so). So I think we can eliminate static discharge itself being the primary factor. The common point here is the preamp (as Ralph surmised earlier).

So I dug up my Rogue Athena preamp and subbed it in. This is a more traditional design with analog attenuator up front (motorized stepped attenuator), and it also uses Jensen line transformers for I/O conversions (SE to balanced). I swear the surface noise & pops/ticks seem a bit quieter, and no "mega POP" has occurred yet. If this holds, then perhaps it points to the Ref 6’s digital attenuation not fully blocking the circuitry from overload conditions in all cases (I’m no circuits engineer, just stretching here)? I didn’t face the issue with this same Ref preamp in my main rig - but yeah there are a lot of variables at play - for one, the main rig speakers are 6dB more efficient. Thinking back I’ve certainly noticed that the Ref preamps in general (I’ve had two now) do seem to "enhance" the record surface noise a bit versus traditional attenuator-based designs like VAC. Other than that, they sound absolutely specular with vinyl...but I just can’t keep subjecting my tweeters to this when Tannoy doesn’t supply the parts anymore...catch 22 :-/

** Again thinking back a few years, I remember a humble little system I put together with NAD C368 integrated used as the preamp (digital volume control) that also faced the mega POPs issue with vinyl. Is this a general issue of using digital volume controls with vinyl for loud playback?

So I’ll enjoy the Athena preamp for a while, hopefully get used to its sound (some pros, some cons versus the Ref 6), hopefully not experience a mega-POP again, and report back :)

Thinking back I’ve certainly noticed that the Ref preamps in general (I’ve had two now) do seem to "enhance" the record surface noise a bit versus traditional attenuator-based designs like VAC.

@mulveling 

If the preamp seems to enhance surface noise, the volume control likely has nothing to do with it. This problem is usually caused by high frequency (in the case of LOMC cartridge, Radio Frequency energy) overloading the input of the phono section.

Sounds for all the world like a noisy LP surface. But swap in a different phono section and its gone or noticeably reduced.

I've written about this a lot in the context of 'cartridge loading'.

Its one thing to read about it though; quite another when you encounter it.