RME ADI-2/4 Pro SE - RIAA mode measurements

[levimax]

This a balanced receiver. Since the RME is already balanced two simple impedance converters would be sufficient. However I prefer not to worsen the great SINAD of the RME by putting something in front.

@MC_RME himself wrote to me here long ago that I could replace the two 9 kOhm resistors inside the ADI2 with 100 kOhm each which would be the perfect solution for me. I just did not find the guts to open the ADI2 and do it. Although I've built my own analog preamp and digital patchbay I've only had bad experience soldering SMD parts so far. Well warranty has run out so maybe ...

I agree I would not mess around with a beautiful RME trying to change SMD resistors.

Regarding the "balanced transmitter" to match impedance and capacitance with the cart, I don't think most MM carts are inherently "balanced". By keeping the balanced transmitter close to the cart you not only get a proper cart load (impedance and capacitance) you also get the Common mode rejection of a true balanced connection. In my case it made a huge noise difference but of course it depends. I am not worried about a little SINAD loss of the transmitter when talking about TT SINAD of ~40

 

[LTig]

Regarding the "balanced transmitter" to match impedance and capacitance with the cart, I don't think most MM carts are inherently "balanced".

The carts themselves are all balanced, but not the wiring leaving the TT.

By keeping the balanced transmitter close to the cart you not only get a proper cart load (impedance and capacitance) you also get the Common mode rejection of a true balanced connection. In my case it made a huge noise difference but of course it depends. I am not worried about a little SINAD loss of the transmitter when talking about TT SINAD of ~40

Yep, but I could do the same with those 2 impedance converters above, and it should be even better because then any noise induced into the balanced cable between converter and RME gets cancelled at its balanced input.

 

[dlaloum]

Please explain why the explanation from RMI is false. To me it appears that the 20 dB or even 34 dB headroom requirement is nothing but a "myth". Engineers have always done as told by marketing and 40 years ago if 20 dB of headroom was "good" then 34 dB must be better. To me RMI is challenging one of the oldest and hardest to understand Hi-Fi myths of all time and I think they should be applauded if correct and corrected if wrong. So far their explanation makes sense to me but I would be very interested in the "other side" if there is one.

For digital archiving purposes, when you need to take a sometimes imperfect record, and convert it to digital... you need to provide headroom not only for the recording itself, but also for the imperfections that cannot be physically removed, pops and clicks caused by actual damage to the vinyl that no amount of cleaning can remove.

So to resolve the problem you need to have sufficient headroom to cleanly record the peak of a pop or click... while still also recording the full dynamic range of the recording - thereby allowing you to use various mechanisms to eliminate the pop/click digitally - without artifacts that would be caused by ADC clipping.

So you are highly unlike to require even 20db of dynamic headroom for the recording itself... you may well require 30db or more of headroom to CLEANLY record the flaws, so you can optimally edit them out afterwards.

That's also why ADC's with SN of 130db+ are highly desirable - it just makes it a heck of a lot easier to "position" the signal being recorded within the available signal range - the lower the SN, the more you need to get that signal positioning/gain just right, so as to avoid ADC clipping at the top end, and detail being lost in the noise floor at the bottom end.

But if we are talking about "just" playing records at home - this is well into OCD excessive territory.

 

[dlaloum]

Yeah I still need to to set the TT up properly, I have a test record I use with Pink Noise, so I can work out the corresponding EQ to get it back flat again. That'll be as easy as storing a preset on the 2/4.

Make sure you use one of the "good" pink noise test records - the HFNRR test record, has pink noise that is wrong above 10kHz (from memory)...

 

[dlaloum]

My MC pickup is specced for 50 kHz (Van den Hul MC One Special) and although there are no +/- dB limits mentioned I'd expect it to reach 20 kHz with ease. Yes, you cannot do much to improve FR but I think you don't need to.

Any of the micro ridge styli (regardless of cantilever type) will be able to trace out to beyond 40kHz - they were originally designed for it as part of the development for Vinyl based Quad records.... (Shibata was the stylus designed for it at the time)

But the effective tip mass will drive the cantilever resonance - as an example - the Shure V15V's used a Beryllium Tube cantilever - the end result was a resonance at 32Khz (with some variation based on manufacturing variability)

A Solid boron cantilever is highly unlikely to ever achieve as low a tip mass - and therefore the resonance will come in at a lower frequency - typically at around 19kHz or 20kHz - heavily dependent on the design of the mounting system and its impact on overall mass.

My 10 year old Boron cantilevered Jico SAS needles, measure the resonance at 14kHz and 16kHz respectively (much lower than I expected)

And yes - they can track and provide good quality signal well into the ultrasonic (I have measured out to 48Khz) - but that doesn't tell you about the rise and falls in that response.

It has to be measured - and with MC - typically you will see a rise in the top end - as it rises up to the resonant peak - a bell curve... even on the Shure V15V's you can see the start of the rise to the 32kHz peak at around 19kHz.

Technics did manage to manufacture some ultra light Boron pipe (hollow) cantilevers with resonance at around 50kHz - as fitted to the EPC205 and EPC100 cartridges.... unfortunately long gone, and no one is manufacturing this type of cantilever (to the best of my knowledge - would love to be corrected!!) - their response out to 20kHz as a result was ruler flat... the beginning of the resonance rise was already in the ultrasonic range.

So yes - reaching 20kHz with ease... I'm sure it can and does - reaching it with a flat F/R - I seriously doubt.

P.S. I have a near cousin to that cartridge, the Empire MC1 - exact same body, but with a much more ordinary cantilever/needle - Empire at the time partnered with VdH - not sure which member of the partnership manufactured the cartridges, as they look identical with the exception of colour and labelling.

 

[LTig]

For digital archiving purposes, when you need to take a sometimes imperfect record, and convert it to digital... you need to provide headroom not only for the recording itself, but also for the imperfections that cannot be physically removed, pops and clicks caused by actual damage to the vinyl that no amount of cleaning can remove.

So to resolve the problem you need to have sufficient headroom to cleanly record the peak of a pop or click... while still also recording the full dynamic range of the recording - thereby allowing you to use various mechanisms to eliminate the pop/click digitally - without artifacts that would be caused by ADC clipping.

I'd like to disagree. To be able to remove pop/klicks you don't need to record them in full volume. They can be hard limited because the removal process replaces them by interpolated data.

Much more Important than extraneous headroom is that the preamp recovers immediately from being driven into clipping, otherwise the pop/click becomes longer which makes it (a) more audible and (b) more difficult to remove. I have experienced significant differences regarding this behaviour. Where my former preamp produced a loud tock my new one produces a much quieter dig.

 

[dlaloum]

I'd like to disagree. To be able to remove pop/klicks you don't need to record them in full volume. They can be hard limited because the removal process replaces them by interpolated data.

Much more Important than extraneous headroom is that the preamp recovers immediately from being driven into clipping, otherwise the pop/click becomes longer which makes it (a) more audible and (b) more difficult to remove. I have experienced significant differences regarding this behaviour. Where my former preamp produced a loud tock my new one produces a much quieter dig.

The issue is not just the pop / click - but the overload and its recovery... which takes much longer...

You can relatively easily zoom in and edit out a pop/click with readily available digital tools, but the artifacts of the overload (analogue) or hard clip (digital) - are practically impossible to remove... hence the need to totally avoid clipping OR overload.

We can cleanly remove the click/pop - and have a result which is well nigh indistinguishable from a pristine recording - but ONLY if the recording of that pop/click was totally clean.... and for that you need a heck of a lot of headroom.

(if I have time later, I might see if I can dig up some recordings where I was experimenting with this - I may have some relevant examples)

 

[levimax]

The issue is not just the pop / click - but the overload and its recovery... which takes much longer...

You can relatively easily zoom in and edit out a pop/click with readily available digital tools, but the artifacts of the overload (analogue) or hard clip (digital) - are practically impossible to remove... hence the need to totally avoid clipping OR overload.

We can cleanly remove the click/pop - and have a result which is well nigh indistinguishable from a pristine recording - but ONLY if the recording of that pop/click was totally clean.... and for that you need a heck of a lot of headroom.

(if I have time later, I might see if I can dig up some recordings where I was experimenting with this - I may have some relevant examples)

The 20 dB headroom adage has been around decades before digital existed and it was said to make the pops and clicks less noticeable. I understand about clipping and poor overload behavior but why is it better to "not clip" the phono stage but then clip the pre-amp or power amp? I also agree with RME that I have seldom if ever heard a pop or click play much louder than music in the loud sections of an LP.... if I do I throw the LP away as it is severely damaged. I have plenty of fairly noisy LP's unfortunately but only noticeable in the quiet parts. I think 6 dB of headroom (over the peak music playback level) may plenty for listening to LPs (vs digital archiving) especially if coupled with good overload behavior. I am surprised there is so much folklore on this subject and so little actual testing and data.

 

[dlaloum]

I am talking about a mastering process... not playing straigh to output - any listening would most likely be via Headphones.

You record with huge headroom to allow a clean capture of the click/pop - remove the click/pop, and then adjust the levels so the recording is at a more normal level... which once in digital and cleaned up, can be determined very quickly by finding the peak level, then setting the overall track level so the peak ends up at betwen -1 and -4db no higher... possibly lower, depending on where you want the average level to be.

Some DAC's can start overloading as early as -4db - although most DAC's have no issues until you go beyond -1db.

After doing all that - then you listen to the archived form of the track on a proper speaker/amp system.

The end result will not need 20db of headroom.

And yes poor overload behaviour is a key reason why all this is done - both in digital and in analogue domains.

 

[sarumbear]

I am surprised there is so much folklore on this subject and so little actual testing and data.

It is folklore because the tests were done 75+ years ago and as Internet was not a thing records were left in paper form in some storage facility at best. Mainly because Vinyl was not a thing until a few years ago and nobody was interested on their playback. However, if you are old like me (72) you do remember those tests and the discussions about it.

 

[Gregg Hermetech]

Make sure you use one of the "good" pink noise test records - the HFNRR test record, has pink noise that is wrong above 10kHz (from memory)...

Thanks, that's the one I have though. Can you recommend one which has proper Pink Noise?

 

[morillon]

correctly respect the riaa curve ( dsp or classic)... of course
do not have an overload situation .. certainly ...

use the measurement to finely adjust the cell arm the load...subject mastered from the end of the 60s...easy now...

but when you see the limits of all the elements of the "analog chain" ... the orders of magnitude ..
fine correction via dsp of the response curve, at""" 0.1db""..
personnely..makes me more than smile...
(there's a pretty filiary right here on the "fun" vinyl)
;-)

 

[restorer-john]

The 20 dB headroom adage has been around decades before digital existed and it was said to make the pops and clicks less noticeable. I understand about clipping and poor overload behavior but why is it better to "not clip" the phono stage but then clip the pre-amp or power amp? I also agree with RME that I have seldom if ever heard a pop or click play much louder than music in the loud sections of an LP.... if I do I throw the LP away as it is severely damaged. I have plenty of fairly noisy LP's unfortunately but only noticeable in the quiet parts. I think 6 dB of headroom (over the peak music playback level) may plenty for listening to LPs (vs digital archiving) especially if coupled with good overload behavior. I am surprised there is so much folklore on this subject and so little actual testing and data.

I typed a long reply to your previous post to me yesterday and saved the draft, sadly it has disappeared.

Don't assume the rest of the chain is wide open. Nobody listens to vinyl with all the level controls at flat out at 0dB (unlike a whole bunch of silly digital 'gain stagers').

Immediately after the phono stage, you have a balance control and a volume potentiometer in most preamplifiers. And your power amplifiers may be attenuated (like mine by about 12dB to give me a good range on the volume control).

 

[restorer-john]

what is the relationship with a possible overload that you are announcing at the level of the phono amplifier...?
""that you denounce"""

Are you using an online translator because I can't make sense of your post? Sorry.

 

[morillon]

sorry
delete

 

[Gregg Hermetech]

Thanks, that's the one I have though. Can you recommend one which has proper Pink Noise?

Actually I think I'll just get my friend to do me a 7" lathe cut of Pink Noise, mono on one side and uncorrelated stereo on the other. At least then I know it'll be good! Before that I'll record the pink noise from the HFNRR just to see how bad it is.

 

[dlaloum]

Thanks, that's the one I have though. Can you recommend one which has proper Pink Noise?

Hmm I started searching for the references.... here is a thread where the topic came up:

Pink noise test tracks- Vinyl Engine

www.vinylengine.com

Seems as if the HFNRR track is OK if averaged

also:

HiFi news vs Elipson test record comparison for measuring use

In another thread I said I was waiting for the Elipson test record and would post some comparisons with the HFN record when I received it. I have now got it, so here we go! I am measuring my 10 year old VPI scout (acrylic platter) and a Dynavector DV20X low, into a Project DS2 preamp and...

www.audiosciencereview.com

I have used the HFNRR pink noise track myself ... part of the reason being it is readily available and if I wear it out, I can get another easily!

The issues according to some threads - were in the high frequencies and when measuring there - I run at 45rpm (and adjust RIAA EQ accordingly!) that way the shift resolves potential issues (as the problem area ends up at beyond 20kHz...)

 

[levimax]

I typed a long reply to your previous post to me yesterday and saved the draft, sadly it has disappeared.

Don't assume the rest of the chain is wide open. Nobody listens to vinyl with all the level controls at flat out at 0dB (unlike a whole bunch of silly digital 'gain stagers').

Immediately after the phono stage, you have a balance control and a volume potentiometer in most preamplifiers. And your power amplifiers may be attenuated (like mine by about 12dB to give me a good range on the volume control).

Thanks. If your draft shows up I would be very interested in reading it. I assumed it had something to do with "gain staging" which gets a little hard to follow especially when mixing "analogue and digital gain and headroom". I am still interested in RME's take on phono stage headroom as well as how to best quantify "overload recovery" of any type of amplifier.

 

[sarumbear]

The above is said with no reference to any tests. If they are rumours around prove otherwise by testing. Why would I trust you?

I can't believe that this is written by a company who is obviously competent in engineering. They assume the crest factor of music is 0db or just one! @levimax I like to see the reference to the text on the image if I may.

Gob smacked!

 

[levimax]

View attachment 249942

The above is said with no reference to any tests. If they are rumours around prove otherwise by testing. Why would I trust you?

View attachment 249943

I can't believe that this is written by a company who is obviously competent in engineering. They assume the crest factor of music is 0db or just one! @levimax I like to see the reference to the text on the image if I may.

Gob smacked!

Hello, I copied and pasted the RME information from a previous post but see below is the entire TT section of the manual available online.