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Phono preamp headroom - why?
- Thread starter Multicore
- Start date
yet in this case Magic is well implemented engineering, and works pretty well.
It has never held water for me. Vinyl noise I’ve experienced is the same across cartridges and phono stages - like nearly identical when comparing laybacks.
Vinyl noise is built up by friction, stylus dance with warps/eccentricity, resonance... (and of course follows the RIAA curve).
So if you want to reduce noise, reduce the factors above. If your RIAA pre amp shows below -75 dB noise and is hum-free, it is not a factor. Headroom needs to be adequate but not excessive.
So if you want to reduce noise, reduce the factors above. If your RIAA pre amp shows below -75 dB noise and is hum-free, it is not a factor. Headroom needs to be adequate but not excessive.
Maybe you always have had good quality well behaved phono stages
. You do bring up a good point though as I have never done a "capture" of different phono stages to compare the same record level matched for noise. The problem now is I use an ADC and digital RIAA in a PC as my phono preamp so it is hard to compare.
kemmler3D
Master Contributor
This is pure speculation on my part, I think that a pop on a record will be biased toward low frequency... a lowpassed impulse. If it clips, it spreads the energy up into higher harmonics which will be louder (psychoacoustically, not in sheer level) and impact more of the music.
I recently listened to a friend's cheap record player with a built-in Phono preamp... the crackling from the dust on the record was INTENSE. On my on player (schiit mani 2) it's not objectionable at all in comparison. I actually assumed that it was due to lack of headroom.
restorer-john
Grand Contributor
Maybe you always have had good quality well behaved phono stages
And that's the key.
Overload margin is an indicator of high performance design, high voltage designs are generally much lower noise (residual), lower distortion and the massive overloads mean there is no likelihood of the stage latching up, oscillating or prolonging and distorting transient aberrations.
Most people are running phono stages these days with abominable overload margins due to pratically every stage being based on a cheap off-the-shelf opamp with +/-12V, +/-15V or maybe, if you're lucky +/-18V rails. Work backwards from those numbers and you'll see why phono overload is way worse today than it was in 1972. We are talking ~100mV if you're lucky.
Phono stages were discrete, using the highest quality parts and running on high voltage carefully regulated rails. Front end noise was down to 0.1uV in the mid 70s, overloads over 350mV and S/N ratios achieved were impressive. This is a high quality preamp's actual S/N on both MM and MC carts. Circa 1977/8.
I also have my share of damaged records but most are due to poor handling, improper cleaning and poor inner sleeves. 40 years ago I thought carbon fibre brush was the only cleaning device. Wet cleaning was assumed to give more damage than it would gain and some tests I made back then confiirmed that. Just horrible pops and clicks after cleaning. But it was just because the methods used were wrong. Now we have both manual cleaning methods and cheap machines that works. And both noise and clicks gets reduced from those old records. And also real-time click repair digitally.
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This is a mini review of the HumminGuru ultrasonic cleaner for vinyl records. The following procedure was used for cleaning. 5 minutes of ultrasonic using alkaline water (≈pH 10) followed by 2 minutes ultrasonic in demineralised water and 5 minutes of drying cycle. Both solutions contained 2...
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Not for me. Until recently, the pre I was using was the cheapest I'd been able to get at a local store - Project Phono Box.
In July I got the waxwing - and even with the "Magic" feature turned off noise (particularly pop/crackle) is (seems) much lower - or at least much less intrusive. To the point after 6 sides of vinyl last night, I hadn't noticed any outside of the lead out.
Now this is perceptive and sighted listening - Id have to try to measure it to be totally certain there is a real difference.
Rumble filter on? Your example of the Billie Jean shows quite a difference on and off having both rumble filter and HP filter below 20 Hz. Even if 8 Hz is not audible per se, you are effectively improving headroom downstream of the DSP function.
(Better still is to reduce the LF noise at the source as much as possible...and then apply rumble filters. Having the cartridge working with less dance around resonance gives less noise and more cartridge/stylus headroom...)
MaxwellsEq
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I'm a relative newcomer to the idea that some phono preamplifiers do not have enough headroom. I'd not thought about it much, principally considering RIAA accuracy and noise figures to be key determinants of what works and what doesn't. But I don't recall ever seeing the Shure and other "hot cut" analyses during the days when domestic high resolution was only commercially available on LPs and where I spent real money on turntable, arm, cartridge and preamplifier.
I do find some of the points raised by @restorer-john to be quite compelling. I also think: "why have limited headroom, when you can have more" (assuming noise is not compromised).
Subjectively, having a turntable/arm where there is a lot of damping (e.g. the Cranfield research) certainly seemed to reduce surface noise as did a preamplifier with more headroom.
I had access to studio sound and master tape quality. During the heyday of turntables, much of what I heard domestically seemed too "lively" and overwrought and I wonder if people were unknowingly pursuing resonance and compression!
I do find some of the points raised by @restorer-john to be quite compelling. I also think: "why have limited headroom, when you can have more" (assuming noise is not compromised).
Subjectively, having a turntable/arm where there is a lot of damping (e.g. the Cranfield research) certainly seemed to reduce surface noise as did a preamplifier with more headroom.
I had access to studio sound and master tape quality. During the heyday of turntables, much of what I heard domestically seemed too "lively" and overwrought and I wonder if people were unknowingly pursuing resonance and compression!
I would agree - but I've no idea what I would need to do to achieve that.
Bake flat records using Pi flattener or similar/vacuum hold-down, centering of records... and a tonearm with damping...shure brush. And of course clean records and clean stylii. Those pops and clicks are usually broad-band and clean records reduce that friction that cause noise. Wet playing is another method but I don’t want to go there or recommend it.I would agree - but I've no idea what I would need to do to achieve that.
yeah - what I thought. None of that is going to happen - except the cleaning which I already do.
Ok I'm fine with that.yeah - what I thought. None of that is going to happen - except the cleaning which I already do.
Clean is really good. I have tried the manual method according Neil Antin just to get the acidic step, but the lack of Alconox and Citranox made me try the method of "liquid wash power sensitive" + "distilled white vinegar". I just wanted to try the acidic step to remove any potential salts embedded in the groove. However, I actually found that my method with multiple rounds of Humminguru ultrasonics was better for noisy records; it removes/reduce clicks and pops for every round. So my suspicions is that there are things really hard stuck dirt in the grooves in some records that is not easily removed neither manually or by machines.
As mentioned, if you are using rumble filter and HP filter, you will probably reduce level of pops and clicks since they are broadband and may contain out-of-phase components. It may have a bigger impact of the clicks and pops than "headroom".
Not to mention the "Magic" real time click removal.
In what way, I'm sure I have records I used to DJ with 20 years ago that still play essentially as new. The interesting thing is I never cleaned them and they were always kept in a relatively low humidity environment. Aside from getting scratched, I think unless records are dirty with a filthy contaminant (not fingerprints from clean hands), maybe cleaning can do more harm than good?
Sure, I've used the real-time click removal (RTclickrepair) since 2018. On some records however, the removal is going with the music beats, so it is not bullet-proof for retaining music content. I don't know if the Magic is better or worse.
That said, I am a bit perplexed regarding cleaning. Even if the records get better with respect to noise/clicks/pops after a round in my Humminguru Ultrasound, I get further improvement if I repeat the procedure. So how dirty are the records, really? Or is it something else happening with the surface that lowers friction and noise? Like wet play?
Before cleaning, clicks and pops, and a rather "thick" background noise line:
After two rounds of cleaning, clicks/pops gone, and a the background noise has been lowered, seen as a thinner line. Though now visible several smaller peaks - so does it mean that most but not all "dirt" has been removed and there is a need for many rounds to get clean?
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