2. analog
  3. 182753-3032

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

Showing 3 responses by atmasphere

atmasphere's avatar
atmasphere
11,604 posts
 

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.

atmasphere's avatar
atmasphere
11,604 posts
 

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.

atmasphere's avatar
atmasphere
11,604 posts
 

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.

@mulveling If this only happens when the volume is turned up then the turntable and phono section are off the hook. Since it seems to occur with different amplifiers, suspicion is case upon the line stage.

If a ground wire from the phono isn't connected all bets are off. Connect it to the chassis of the phono preamp.

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