I'm not familiar with REW, but can you catch a long enough recording of this 0dB 1Khz signal in a .wav file and send it to me ?
Hans
Hi, that's just smoothing so we can see something, this is without smoothing. The bins are the same on both.. same measurement as above
Still don't know. At your record it is 10db, don't know why is it on mine as it is.... Ill see if I do something wrong, Just to check I put digital sweep from soundcard into the same preamplifier input where the chart is plugged, all settings the same to compare: Same preamp, same input and output, but instead of cart+LP it is generated sweep, no smooothing,
Again not so simple.
My soundcard uses ASIO driver, REW sees it , but nothing else in windows allows to select it as an input....
While not MC, here is my experience with a MM balanced preamp. Record play back with a stylus has high distortion. At 1kHz expect 0.5% up to 5% depending on the stylus. The distortion rises with frequency from there. The distortion measurement results posted earlier look correct to me. You would have to build a very very bad preamp to exceed the distortion from the record playback itself. I spent months building a flat response differential input preamp earlier this year. I made measurements using a new and pristine Ortofon record. The record playback distortion is dominated by the geometric tracing error due to the radius of the stylus. I tested with four different radii. With my preamp and line noise more than 70 dB below this signal level, I'm pretty confident in the results. As you can see in the table below the distortion at 1 kHz tracks with stylus radius.
I used the LT1037 op amp with good results for a moving magnet cartridge. I only built the first stage of the preamp below. I connected it into the balanced line level inputs of my Motu M4. The LT1037 has low voltage noise, good for high impedance input, the LT1028 has low current noise, good for low input impedance. The noise calculated using LTSpice was about 80 dB below the expected signal level. The assembled circuit performed a bit better than predicted.
Low noise balanced preamp buffer.
From StereoLab website and video
From a youTube video => Comparison and detailed measurements of Audio-Technica AT95E and Nagaoka MP-110 phono cartridges.
| 1 kHz 5 cm/s level and distortion measurements | 2nd Harmonic Distortion | ||||
| radius Mil | radius um | Left % | Right % | ||
| Conical | Grado EC | 0.6 | 15.2 | 3.5 | |
| Bi-radial | AT 85 EP | 0.3 | 7.6 | 1.5 | 1.8 |
| Shibata | AT 85 SHIB | 0.26 | 6.6 | 1.7 | 1.2 |
| Vivid Line | AT Series V | 0.2 | 5.1 | 1.3 | 0.9 |
I used the LT1037 op amp with good results for a moving magnet cartridge. I only built the first stage of the preamp below. I connected it into the balanced line level inputs of my Motu M4. The LT1037 has low voltage noise, good for high impedance input, the LT1028 has low current noise, good for low input impedance. The noise calculated using LTSpice was about 80 dB below the expected signal level. The assembled circuit performed a bit better than predicted.
Low noise balanced preamp buffer.
From StereoLab website and video
From a youTube video => Comparison and detailed measurements of Audio-Technica AT95E and Nagaoka MP-110 phono cartridges.
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Good observation, thanks for contributing.
My Benz Micro has only 5um radius, Still 3 to 5% THD @1khz...... Need to work on this more to explain...
PS, nice and logical preamp (without checking opamps specs) you made. Why did you use 2 x LT1128 as 2x "differential line receiver" configuration and not just as first stage of INA amp, with just 3 feedback resistors?
What Asio driver did you use, is it a specific Asio driver that REW supplied ?
You could try the universal ASIO4ALL.
Hans
It is normally RME FX total mix, but I also have asio4all installed. Windows, or Audacy don't see any of it . But dont break your head over it on remote, Ill figure out. So far I did not need it, now ill look closer.
I'm not much of a preamp designer and simply adapted a balanced phono stage design I found on the web (see below). I wanted a flat response preamp, so I could use the Stereo Lab distortion reduction software. So I just removed the filtering parts from this schematic. I played with resistor values to get the lowest possible predicted noise from the LTSpice simulation. As it turned out I had sufficient gain only using the first stage with the LT1037 op amps, as that worked well with the balanced line level inputs (channels 3 & 4) on my sound card. I may rebuild it at some point with the second stage. It could be the INA input structure you mentioned would be better. I don't have sufficient experience to know without trying it.
https://www.tubecad.com/2018/09/blog0440.htm
Me neither, I built only 2 own designs for MC that actually worked well, here we explore more together with great members.
John Brosky has very nice site and excellent ideas. This one skipped my attention as it's more MM than MC, but that could be fixed with couple of transistors more at input to accommodate MC
Hi Hans,
This small issue is solved, just digging a bit in RME fantastic free software offer and support. Now I have some 16 inputs to choose for recording.
So waw-s,
1khz test tone
3 dynamic songs
Anything else?
PS, will not manage today, not at home
Your head amplifiers are nice units Hans. I see your point.
XLR's just seem a more robust and cleaner connection with less dielectrics to consider than in compacted RCA's, not that it has any sonic advantage necessarily. I have several DIN cables with RCA ends that came with mostly Linn tonearms. No turntables with fixed cables though. RCA's are mostly all I ever used in the past, with the plan to gradually change over. Balanced seems the trend of the industry anyway, with the "hi-end" needing to "keep up" with the likes of Topping and SMSL.
Project sells numerous phono cables that seem very good. In particular the ds line that includes a 5 pin din to mini-XLR (or normal paired XLR's). It uses low capacitance cell polyethylene dielectric material that is sometimes used in some large RG-8 coaxial cables to extend frequency response out to the GHz region. In other words a low capacitance, low dielectric loss material (something that is viewed important). The low capacitance of these cables may be more important for MM cartridges than MC's though.
https://www.project-audio.com/en/product/connect-it-ds/
Your Benz LP looks like a fine cartridge, one that seems I would like. What table are you running it on?
I am currently using a somewhat modified Linn LP12 with ITTOK arm with a DIN to XLR cable inherited from a friend. I also have a Goldmund Studio with what I believe is a heavy Delrin platter containing 6 perimeter lead pucks embedded in it, being directly driven by a DC motor. The main platter and drive appears reasonably good and easy to extract from the plinth along with the control electronics. It uses pots for the 33/45 rpm control. The balancing, suspension and isolation of the rest (including the plinth), is very solid but poorly done in my opinion, something that I want to work on at some later time. I used a linear tracking air bearing arm on this with a Linn Asaka. Besides the Denon 103R (that I have gained considerable respect for), I also have Linn Troika and Ortofon Contrapoint that I haven't had time to try yet. I also used a Sumiko Blue Point EVO 3 on a Project table, a good cartridge that (unlike yours) needs considerably more physical weight behind it to begin to work in my opinion. Also a Dynavector Ruby, more Ortofon's some interesting Decca's and various MM's.
Wow, you have a nice collection of TT’s and Carts.
I have a VPI scout with an LP clamp ring to keep the disk flat.
But the 90 degrees phase for the motor is poverly created with a simple cap.
This is not a perfect solution.
So I have made Xtal oscilator that delivers two 50Hz sinewave phases exactly 90 degrees apart. A Quad 303 stereo amp fed with these signals drives two toroids giving two perfect 220Volt sinewaves.
As a matter of fact, Linn is doing the same with their motor drive unit but of course with their own high voltage amps.
Much better as the cheap cap that VPI uses.
When making a Lissajous figure of the two motor phases, the image is a dented oval with the cap but shows a perfect circle with the two separate phases
Result is 3-6dB less rumble.
Hans
I have a VPI scout with an LP clamp ring to keep the disk flat.
But the 90 degrees phase for the motor is poverly created with a simple cap.
This is not a perfect solution.
So I have made Xtal oscilator that delivers two 50Hz sinewave phases exactly 90 degrees apart. A Quad 303 stereo amp fed with these signals drives two toroids giving two perfect 220Volt sinewaves.
As a matter of fact, Linn is doing the same with their motor drive unit but of course with their own high voltage amps.
Much better as the cheap cap that VPI uses.
When making a Lissajous figure of the two motor phases, the image is a dented oval with the cap but shows a perfect circle with the two separate phases
Result is 3-6dB less rumble.
Hans
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The VPI is a nice table. And nice work on the motor drive. Years ago I also designed my own motor drive unit for the Linn, this with push button selectable 33/45 using some design that I can't recall, this along with some high voltage amps inside the table. Functionally it worked great but sonically inferior to the Linn Lingo. So this was abandoned and am just using some simple capacitive phase shifting network at the moment. I haven't noticed any rumble, though I expect the drive could be improved.
I recently repaired the electronic drive in my first turntable, a Thorens TD125 MK 2, a table my wife gave me as a Christmas gift years ago when she really liked me... seemingly more than she does now. It creates variant frequencies in a purely analog way... though crudely and unreliably in my view. This table was for my pseudo son in law... someone that my daughter seems still careless to engage to marry after 22 years or so. I suspect the electronics and mechanics inside the Thorens hinders its performance somewhat, but because of its weight still works well enough, particularly in the low end.
The Linn is an exceptional table, but is highly problematic to set up. It was first tuned by a local Linn expert, someone alleged having being touched by the hand of Ivor Tiefenbrun... apparently in a spiritual gathering amongst numerous of his singing disciples in a since modified version to "How great thou wert" ... since Ivor passed away. Notwithstanding my trepidation of a skill set ethereally enhanced by such formal engagement the Linn table was very well set up by this expert.. actually a good friend.
The mechanics of the LP12 can be considered elegant and horrific. I once changed two arm boards on the Linn, those containing two different Linn arms. When changed back to the original arm the sonics collapsed... leading to the conclusion that the phono cable itself and the manner of its attachment to plinth was critical to its sonic performance. Suggesting that in any inadvertent bouncing or pulling on the cable, as upsetting the clamping critically undermines the sonics. Using the dressing of the phono cable of questionable composition as part of the mechanical damping/control of the totality seems horrific in its mechanical implementation, despite that if properly adjusted yields exceptional performance.
What is uncanny about the Linn is in the manner the sonics can be upset with the slightest of alterations. This isn't necessarily good or bad, rather can lead to a greater understanding of the mechanics of turntables in general if engaged in the modifications to it.
I'm gone for Nick Cave concert now, Wild God tour is in Zagreb tonight... Bit of live enjoyment and PA sound enforcement suffer... So much miss times when musicians played unplugged, or with decent PA, As you see I'm already biased that PA will be mediocre as usual... hope to be proven wrong....
Well, my pessimism was completely unfounded, concert was magnificent
I am not sure if this bootleg photo is legal and allowed, admins please check if this is ok?
Anyway, (if it is ok to post) , the King & Seeds did not save themself , he gave all he had for fantastic performance. They brought their own PA (I counted 8 40foot trucks) and it had no flaw (3 line arrays per side hanging + 2 in the middle for back seats (2x mid tweeters and one midbass) + I think 10 enormous subwoofers on the floor) . Since most of us here are not in mid of youth, might be better to sell or our gear and save money and time for live happenings while these artists and us are still alive and kicking 🙂 PS, the photo is actually made by a friend, not me , but I post it as it is the best of what we have.
Anyway, (if it is ok to post) , the King & Seeds did not save themself , he gave all he had for fantastic performance. They brought their own PA (I counted 8 40foot trucks) and it had no flaw (3 line arrays per side hanging + 2 in the middle for back seats (2x mid tweeters and one midbass) + I think 10 enormous subwoofers on the floor) . Since most of us here are not in mid of youth, might be better to sell or our gear and save money and time for live happenings while these artists and us are still alive and kicking 🙂 PS, the photo is actually made by a friend, not me , but I post it as it is the best of what we have.