Problem with phono stage

So the low capacitance cable as the first step is now, a page and a half later, shown to be correct.

You can easily hear a peak at 17KHz as it influences an envelope of frequencies about it, going down to about 10KHz.

A gentleman with deep knowledge levels way higher than you and ovbiously than me says about:
" Clicks don’t inherently have a frequency because there is no repetition in the signal. That would be like asking "what is the frequency of an impulse? ""

Raul made this comment earlier which is mysterious, as its obvious that whoever he’s referring to here has no idea of what he was talking about. Obviously you can hear ticks and pops in the tweeter of a speaker; so you want that resonance to be well above the audio band so it becomes inaudible and not acting as a treble control. This is why there are low capacitance cables meant for phonograph use :)

The actual inductance is not listed on the Nagaoka website. Naturally I looked there first, but since Raul suggested the value first, I used his numbers (600mH) but sensing that was probably too high gave him the benefit of the doubt and went with 500mH. The thing is here that in order to generate 5mV, you're going to have an associated inductance that is going to have to be in that area, generally speaking so its a safe value to assume, and it gave Raul the benefit of the doubt.

Now Raul made some other comments that were so ridiculous that I wondered if they were even worth addressing. But since there are many who might read this that don't have an engineering background, I probably should address at least one:

October 16 of 2020 year and are you talking in a high end analog forum of op-amps? really? when several years ago no one use op-amps in any decent today SS electronics: decent unit design.

This statement is all at once laughable, ridiculous and patently false. To those that don't know, 'opamp' is a reduction of the phrase 'operational amplifier' and refers to a circuit that has exceptional if not nearly infinite gain- so much in fact that in order to operate linearly it has to employ feedback. Feedback is the act of taking a signal at the output of a circuit and sending it back in a reduced form to the input to act as a correction voltage. In this way distortion is reduced. Opamps are commonly available in small plastic packages with 8 pins containing a pair of opamp circuits. They have been in use in audio since the late 1960s and have seen dramatic performance improvements over the succeeding decades and make no mistake, are very much in use in high end audio today in preamps, DACs, tape machines, power amplifiers, tuners and so on. They are used in servo circuits (including servo-controlled subwoofers), power supply regulators and of course as gain blocks in audio circuits. 


With regards to phono sections, there's a kind of phono section made by a variety of companies, Krell, 47 Labs and so on that are current rather than voltage amplifiers; these phono sections (which get nice reviews) absolutely *have* to use opamps in order to work- they are intrinsic in the design and this is no secret. But you can google this stuff easily enough, by googling almost any solid state preamp with a phono section, look for the interior shots (try John Curl's Blowtorch preamp) and the opamps are clearly visible in the photos.


But there is a particular phono preamp with which Raul claims to have some association, one which he claims is the best (its obvious at this point he was not part of the design team) and it too employs opamps! Res ispa loquteur...

Speaking of capacitance, phono cable single ended and balanced, will capacitance of the cable affect the same on either case?

@luisma31   Yes.

It looks like Raul is on a roll again. There is some possibility a post of his will be removed, so I will not quote it. Instead I will generally address some of his benighted comments.

The calculator I linked to demonstrates that an electrical resonant peak exists with any cartridge. But it is a mistaken idea to assume that the peak has an influence at only one frequency. As you can see from the graphs, there is a rise in the frequency response curve prior to the peak; this is true of *any* resonance; the slope of the curve is defined by a value known as 'Q' (Quality) in radio terms (and is caused by how tightly the windings of the inductance are wound). The higher the Q value, the higher the peak and the steeper the curves on either side of it. From this we can see that the Q associated with MM cartridges is considerably lower than that for LOMC cartridges. This also means that its influence is spread out over a wider range of frequencies- the lower the Q the wider range of frequencies it influences. Here is the Wikipedia page regarding Q:
https://en.wikipedia.org/wiki/Inductor

Any signal that exists in the envelope is boosted. In addition, phase shift will exist below the cutoff of the resonance (this is basic filter theory); the ear perceives this as brightness since this is a peak rather than a dip. So the result is the brightness will enhance ticks and pops. Ticks and pops are high frequency in nature; this is why a 'scratch filter' seen in older audio gear rolls off the highs. This stuff should be pretty easy to understand.


I've seen the idea that a tick or a pop is not a repetitive signal; that its an impulse. We can see easily that this idea is false and quite laughable! This is because of the very simple fact that audio circuits amplify signals inside the audio band, and ticks and pops exist in the audio band as well (hence scratch filters affect them...). This means by definition that they **are** repetitive in nature albeit quite short. Further, its important to understand that not all ticks and pops have their origin on the LP surface as I've pointed out earlier: many phono preamps generate them due to poor high frequency overload margins in the front end of the phono circuit. This is common with opamp-based preamps as quite often where the overload is occurring is outside of the feedback loop of the circuit so it can't be corrected by feedback. Regardless of their source, ticks and pops are an audio frequency artifact, but if the playback apparatus is set up properly they can be minimized. To this point (also as I mentioned earlier) I am very used to playing entire album sides without any ticks or pops (so long as there are no actual scratches on the LP surface) and I don't clean my LPs with anything more than a carbon fiber dust brush.


Raul appears so willing to attack me that he's actually contradicting himself in order to do so. In this quote, which is from a post of his that has not been reported he says this:

No one approach 500mH.

But I only used that example in my prior post because Raul said this:

first than all Nagaoka is not MM design but IM similar to MI and the like where normally internal inductance is not really high ( say over 600. )

-In that prior post of mine I even quoted the part above! In general, when you see someone engaging in this sort of behavior its not about fact anymore, its about making someone else 'wrong', often at any cost. Its my feeling this is the phenomena we are seeing here. 

where normally internal inductance is not really high ( say over 600. ) so with that 150/200 capacitance in the Lehmann and due that has a high overload design seems to me that that is not the problem but Lehmann overall set up.

Let's drop these values into the calculator and see what pops up shall we? Giving Raul the benefit of the doubt we'll use 500mH for the cartridge inductance, but the Lehmann has a 100pf input capacitance; if we assume another 40pf for the Audioquest cable mentioned above:http://www.hagtech.com/loading.html

-we got a peak at 19KHz. BTW that's a 10dB peak; its going to be audible. The slope of the peak is there at 15KHz and there will be phase shift elements easily down to 10KHz, which will be perceived as brightness. Clearly keeping the cable capacitance down is paramount.

Don't worry about clicks and pops because there are more critical issues for the cartridges shows it at the best.

Increased audibility of ticks and pops is a clear sign of a problem. If the obvious problems of setup are overcome (VTA, HTA, tracking pressure and so on) and the ticks and pops are worse, then with any high output cartridge (which will have a higher inductance in order to produce that high output) the loading needs to be addressed. To that end, you start by minimizing the capacitive load on the cartridge, as the more capacitance the lower the electrical resonant peak (hence a low capacitance cable). After that then you look into reducing the load resistance. For example with many Grado high output cartridges, a load in the neighborhood of 10K takes out the brightness that you might otherwise hear with the stock 47K load of the phono preamp input.


But all cartridges are electrical generators, meaning that the lower the resistance of the load, the more work the cartridge has to do to make its voltage.

This causes the cartridge cantilever to become harder to move. For this reason alone, its worth it to start by having the capacitive load minimized first!

Btw, problems with capacitance normally will be at a frequency range that even stays says at 17-18khz can't we perceived and again today phono stages comes with pretty decent designs.

Its easy to see that this statement is false.

How in the world are pops and tics not normal in vinyl playback? It’s part of the medium as it is a contact sport so to speak.

@audioguy84

Many phono stages generate ticks and pops on their own, caused by poor high frequency overload margin, related to the excitation of that resonant peak I described earlier. Plus its useful to keep in mind that on any LP project a test pressing is made and the producer has to sign off on it prior to the pressing run. One of the things he’s signing off on is the surface quality.


I’m very used to not hearing any ticks and pops on entire record sides as the phono section I use deals with the pesky electrical resonance issue by having a good HF overload margin. This has nothing to do with bandwidth BTW!

I thought capacitance for cables didn't matter with a MM Cartridge , only MC.

@vinylvin ,  @emilin
Actually it matters quite a lot!


With a high output MM cartridge the inductance tends to be rather high. This in tandem with the capacitance of the tone arm interconnect cable connecting into the phono preamp results in a resonant peak. If the cable capacitance is high (as is often the case with many regular audio cables) the peak will be forced down in frequency, and can easily be somewhere at the top of the audio band.

This will make the system brighter and more susceptible to ticks and pops which tend to have a high frequency nature.


The suggestions about checking loading and overall gain were good ones. But we now know that the gain is 41dB which is fine. With regards to loading though, the cable capacitance plays right into that. Take a look at this page:http://www.hagtech.com/loading.html
Play with the numbers in the calculator, including the default. The link I provided earlier for the tonearm/phono cable from Blue Jeans has about 12pf/foot; you can see by dropping in 36pf for a 3 foot run that the resonance is pushed up higher, outside of the audio band. So that is where you start; after that you work on whatever loading is needed.


It is also a good idea to contact Lehmann: I think you will find that they confirm everything I've said on this thread so far.

Do I need a special cable for the phono stage?

@emilm    Yes! Most regular cables have too much capacitance. This causes a high frequency peak and certainly can emphasize ticks and pops.


A proper phono cable will have a capacitance of about 20pf (picofarads) per foot and you won't be running more than about 1 meter, or else you'll want to find a cable with lower capacitance.
This is the sort of thing you're looking for:
https://www.bluejeanscable.com/store/audio/index.htm

Is this a common problem with added phono stages as opposed to integrated ones

No. So let's start with what cartridge do you have? Also, what kind of cable (phono cartridge cables should be low capacitance)?