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I just saw this new Hagerman headamp (link below) mentioned over at Michael Fremer's Tracking Angle website and thought about the recent discussion of the Audio Technica ART9XA and ART9XI versions. But the 12 Ohms internal impedance of the cartridges (which probably isn't considered low) may not work well with the Zero. Have to learn some more about transimpedance stages.This new transimpedance headamp from Jim Hagerman might be a very reasonably priced solution for the low output of the ART9XA.Another mention at Analog Planet
Edits: 01/28/24 01/28/24 01/28/24 01/28/24 01/28/24 01/29/24Follow Ups:
I played some more music using the Piccolo Zero last night trying to get a sense of how it sounds compared to not having it in the system. The Zero may have had some promise with the ART9 but unfortunately there were problems that showed up. There were occasional passages that would excite the Zero headamp > phono preamp > preamp chain somewhere along the line and create what sounded like loud crackling and popping sounds. At first I thought that maybe the record was much noisier than I remembered but I played back the digital recording and there wasn't any noise. The problem showed up on another LP I played so it wasn't limited to the one LP.Not sure what the specific incompatibility is between the ART9 and the Zero in my system but it's enough of a problem for me to just take the Zero out of the system and go back to using the phono preamp alone for gain and loading. Not sure if the Zero would work better with the lower output of the ART9XA or not but I'm not going to get one to find out. :-)
Edits: 02/08/24
I shut the stereo down and removed the Piccolo Zero from the signal path and reconnected the phono preamp and turned everything back on. I played a record that I'd listened to the night before with the Zero for comparison. But when I lowered the tonearm I quickly realized that I'd forgotten to reset the phono preamp gain and add the custom loading resistor. It was still set at 42dB gain and 47K Ohms loading. So I thought what the heck let's give this a try. I had to reduce preamp attenuation by quite a bit to get the loudness right; from around 12:00 on the volume knob to about 2:30 or so. It sounded similar to the Zero being there but without the sense of being overdriven; still not the sound I prefer.Today I'm going to increase gain back to 61.5dB and try a 604 Ohm resistor, lowering the load somewhat from the 300 Ohm resistor I'd been using. I think the ART9 needs a bit of loading to sound its best in my setup but I did like some of the free spirited response I was hearing at 47K Ohms loading.
Edits: 02/09/24
Well, I installed the Piccolo Zero and gave it a spin so to speak. First impressions using it with an Audio-Technica ART9 cartridge? Not sure what to think yet. Part of the problem is that I was trying to reduce the gain of the Zero and instead it seemed to be getting louder (and harsh). Turns out the labeling on the DIP switch module is a bit nonconventional in that up is OFF and down is ON in reference to the switch numbers. I was inadvertently increasing gain and probably pushing the input sensitivity of the phono preamp and perhaps even the preamp.Note: I emailed Jim Hagerman and he replied that yes, the switch settings are kind of backwards but there's a small arrow that points towards the ON (closed) position.
Once I got the Zero's gain set to a more reasonable level, 0dB (83uV/uA) feeding a phono preamp with 41.5dB gain and 47K resistance, the sound improved greatly. For reference, the ART9 has 0.3mV output with 12 Ohms internal impedance. The result was quite a lively and energetic sound. Compared to running the ART9 straight into the phono preamp with 61.5dB gain and 300 Ohms resistance there was a 2-3dB increase in output using the Zero. That's based on the input levels used for digital recording to keep the signal from clipping.
I played a few LPs that I'd recently recorded and tried to compare the digital playback with the spinning LP but because the output levels were 2-3dB different I couldn't easily level match and make quick comparisons. At times the differences were not all that noticeable but other times the Zero seemed to bring out a liveliness and additional definition that wasn't there otherwise. Bass frequencies seemed to be fairly similar but I haven't had sufficient time listening to really say what differences I was hearing.
Now that I have the gain problem worked out I can hear some potential benefits using the Piccolo Zero with the ART9, especially with simple recordings of vocals and guitar work (Steve Earle "Townes-The Basics"). With more energetic recordings (Omar & The Howlers, early Kinks) the verdict is still out. So I'm going to do some more listening and try to compare what I'm hearing with the Zero to LP recordings I've done with the ART9 running straight into the phono preamp.
This has been a fun experiment so far...
Edits: 02/06/24
Mine's on order, about 2 weeks out. Eager to try w/Miyabi, Koetsu, etc.
I've got a new Piccolo Zero, and love it already :)
It works extremely well with Koetsu Blue Lace (5 ohms), as expected. Compares very well to a good SUT, which was my favored approach over various JFET voltage mode stages (ARC Ref 3SE, Herron VTPH-2A, various earlier Piccolos). Maybe better! There are some things I may like about its sound even more than a SUT. Very transparent and vivid, without sacrificing musicality. Jim made a comment about it perhaps not being his choice for "Earth Wind and Fire" but so far I find no need to qualify its performance by genre or complexity of music.
I also tried it with 2 Van den Huls. Works wonderfully with Crimson XGR Strad. Its coils are listed at 12 ohms for 0.65mV on Van den Hul's site. Mine is a 0.75mV version, so maybe it's more like 15 ohms? Anyways, this combo works very well with exceptional sound quality. I may even prefer it over my EAR MC-4 SUT (my usual reference). So I wouldn't worry about 12 ohm coils. On my Crimson I'd estimate the gain at its +6dB setting (this is how it ships) is roughly like that of a 10x - 15x SUT. In theory that would put the highest +12dB setting at 20x - 30x.
Unfortunately the Colibri seems like a much tougher match. These coils are spec'd at 36 ohms for 0.38mV and you can really tell the drop in gain through Piccolo Zero. I think if you do the math (assuming I did it right) it's like a 4x or 5x SUT at the +6dB setting. From what I heard when I tried this - yeah that's about what I'm hearing. It's too low in gain due to the high coil impedance, so you'll be fighting noise after you crank up volume to compensate. I need to try the +12dB setting again and see if I can get some reasonable performance out of it.
People seem to think Van den Hul's Grail phono is current mode, and I just don't see how that works for a Colibri (which you'd think would be their recommended pairing), though in theory the "dynamic breaking" could be of great benefit to the sibilance range where Colibri tends to be more problematic! I know I've fought with sibilance during its break-in period.
Good to hear about the Van den Hul cartridges working well with the Zero. I'm really curious to see how the gain settings in the Zero correspond to the 12 Ohm impedance of the ART9 feeding my phono preamp set to 42dB or 52dB of gain.
The transimpedance gain is specified as 83uV/uA. For the ART9XI that has an output of 0.5mV at 5cm/s and 12 ohms internal resistance it will source 42uA of current at 5cm/s into the 0 ohm input resistance of the Piccolo. That will create 3.5mV at the output, which should be enough for an MM phono stage. The ART9XA output is 60% less so you'd get 1.4mV, which may still be OK.
FWIW, I use an OC9, same specs as the ART9XI, into a transimpedance phono stage (Channel-D Lino C) and then into an ADC. The ADC full scale input is 4V balanced/ 2V single-ended and with the Lino C set to maximum gain I get good signal levels at the ADC input. Of course, it depends a lot on cut of each LP but I generally stay closer to full-scale without clipping (except for a couple of 12" singles). If I was to upgrade to the ART9XI I would expect the same performance but with an ART9XA I'd lose 8dB of signal and I'd be cautious about that. If I was using a preamp with input sensitivity of 2V balanced/1V single-ended then I could live with 6dB less gain overall and the ART9XA would probably work fine in that situation.
Thanks for the information.
Sutherland did not publish input sensitivity for the AcousTech PH-1P phono preamp but I used to run a Dynavector KARAT 17D3 with 0.3mV of output and it did fine. The Piccolo Zero provides up to 12dB of additional gain so I'm expecting that I'll have sufficient voltage using the ART9XA at 0.2mV output.
I would double check any equipment facts mentioned by a guy who recommends buying an expensive product to demagnetize vinyl. the guy is a good story teller of vast experience , a quality I always enjoy.
although not my opinion, I recently read someone saying he embodies everything wrong with the audio industry.
I don't take it that far, although I used to, reflectively. Now, I just chalk it up to the New York City culture, which is very nice, and has admirable social values , but where hyperbole is not regarded in the same way as where I am from , where it can be considered rude because of the potential to mislead. Where in New York ,if you believe everything someone might say, you are a rube, it's understood.
Fremer didn't say anything about the Zero headamp, it was just a heads up about a new product, but there were some interesting comments about it. Did you read those?
Dave Slagle provided a link to a discussion at Stereophile (shown below) that is a worthwhile read. That's if you're interested in transimpedance phono preamps.
I think it is awesome that Jim came out with this product and I have one on the way.
Dave
I ordered one myself. Out of curiosity more than anything but if it works well with my ART9 I just may trade for an ART9XA. I'm assuming that my Acoustech PH-1P phono preamp will cooperate with the Zero.Thanks for the link to the discussion. I'm not an engineer but do find these discussions interesting. It's part of the fun of using a cartridge, tonearm, turntable, and phono preamp to play music embedded in a disc of vinyl.
Edits: 01/29/24
This thread over at Steve Hoffman forums mentions the Audio-Technica ART7 not working well with a Sutherland Loco transimpedance phono stage. Wonder if that's true with similar transimpedance preamps?
The discussion I have been trying to have about these types of stages is in relation to loading. As far as I know most cartridge manufactures specify some "maximum load" which is many multiples of the cartridge internal impedance. How does one reconcile this with the load of at or below the cartridge internal impedance presented by transimpedance stages?
For this discussion it is important to note that a cartridge is a two terminal device and ground plays no part in the discussion of cartridge loading. The load seen by the cartridge is simply the external impedance presented across those two terminals. It is also critical to consider the following stage to be a simple ideal black box that provides gain.
dave
If the low impedance load (zero ohms) damps the movement of the cantilever (Dynamic Braking, Hagerman) then the performance of the cartridge can't be anything like the specs.
For one thing the measured dynamic compliance would go way down.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I agree with the dynamic compliance changing but isn't this the nature of the beast?
My disconnect here is; by presumably giving a maximum load for a cartridge a manufacturer must have determined this value in a meaningful way. This suggests going below that value somehow harms the cartridge performance. It is unclear how this maximum load number is determined and people take it as gospel until a transimpedance stage shows up and loading suddenly gets tossed out the window. I fancy myself a scientist and arbitrarily applied rules bother me.
dave
"I agree with the dynamic compliance changing but isn't this the nature of the beast? "To the best of my understanding, not until now.
Loading a 10 ohm cartridge at 100 ohms (or even 50 ohms) won't do much, if anything, to damp the physical movement of the cantilever (and is only intended to damp the electrical self resonance of the windings). But loading a 10 ohm cartridge at 1 ohm gives a damping factor of 10 and .5 ohms would be a damping factor of 20 so the actual movements of the cantilever would be pretty well damped at that point. I would think loading the same at zero ohms would dramatically stiffen the compliance. (I am thinking in terms of speaker damping here)
The user would need a tonearm with a much higher effective mass or end up with a very high tonearm/cartridge resonant frequency excitable by the music in the groove.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 01/30/24
Hi Tre'
according to Lenz's Law, if a conductor moves within a magnetic field it will induce a current in the conductor and that induced current will create its own magnetic field that opposes the motion that created the current in the first place. IMHO, that will act to dynamically reduce compliance. I am not sure if, or why, reducing dynamic compliance would be advantageous and it is not clear how small the coil resistance needs to be for Lenz's Law to actually make a difference. Electromagnetism is not my speciality, I once posed this very question to one of my EM-savvy colleagues who had no answer!
In 'normal' voltage mode, very little current flows in the coils as the total resistance is usually > 100R. If you took things to the extreme and had zero coil resistance and a true virtual earth transimpedance input then a very large current would flow and generate its own magnetic field that would completely oppose the cantilever movement! Probably, you don't need much resistance to get any benefit while still allowing the thing to work (?).
I had never equated this effect with amplifier damping factor before. In that case the amplifier output voltage creates a field that moves the voice coil and the speaker moves. Considering what I wrote above, in moving a current will be created in the voice coil that opposes the movement - I've never seen that commented on before (at least not explicitly). What I thought advantageous about high damping was if the speaker overshoots and is no longer following the driving signal any 'error' current created due to that extraneous movement will create a magnetic field to compensate for the overshoot. But if there is effective opposition to an overshoot why not effective opposition to the voice coil moving in the first place? Maybe, the current sourced into the voice coil by the driving amplifier swamps out any back emf but when there is overshoot that ratio of back emf to driving current is much higher (because the amplifier isn't driving at that point)?
Enough musing for now, I have some non-EM technical problems to attend to and after that enjoy some LPs without thinking about how they work :)
Take a floppy woofer without a box and move the cone by hand. Now short across the voice coil leads with a .1 ohm resistor. Assuming an 8 ohm speaker, that .1 ohms represents an amplifier with a damping factor of 80. The cone will not move nearly as freely for the reasons you have described.
When the speaker is connected to an amplifier that is playing, the cone has to move to follow the signal provided by the amplifier but any movements, as you have described, that are outside of the signal that amplifier is feeding to the speaker will be damped out due to the low output impedance of the amplifier. Speakers are also mechanically damped. In fact, some speakers do not require electrical damping but I believe all woofers do.
With a cartridge loaded into zero ohms the movement of the cantilever, other than the movement caused by the undulations in the groove that the stylus is following, will be damped out by, not only the built in mechanical damping (that gives us the compliance number given in the specs), but now, and in addition to that, we have the electrical damping, do to the extremely low load impedance, damping the movement further.
The question I have is how much will the compliance be lowered by this electrical damping on top of the mechanical damping built into the cartridge's suspension?
So much so that a heavier tonearm will be needed to keep the cartridge compliance/tonearm mass resonance at 10Hz? And how much heavier?
I am a little disturbed that Hagerman didn't say anything about this.
He has to know that the compliance is lower. He says as much in the text while talking about Dynamic Braking. "Hence, the lower the resistive loading, the more effort it takes to move the cantilever."
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
It is s slippery slope to attempt to quantify the concept of "dynamic braking". A few key general thoughts:
-With your shorted woofer example, it is impossible to tell if the driver is shorted or not from gently pushing it in and out. It takes an abrupt blow to see the effects of Lenz Law. It can be thought of as a velocity sensitive effect.
-the nature of the riaa curve typically has the highest measured velocities occurring in the 4kHz-12kHz range and Holman found measured dynamic peaks in music in the 80-100cm/sec range.
-I contend that under 'normal' conditions the change in compliance (dynamic braking) is minimal but on the dynamic peaks where mistracking occurs it can clamp down and reduce the negative effects of the needle attempting to be kicked from the groove wall.
dave
.
Have Fun and Enjoy the Music
"Still Working the Problem"
Sadly, I don't understand EM well enough to be authoritative. However, it is not obvious to me that Mr. Hagerman understands it any better.
At the link see the section Current-mode design improves cartridge tracking through superior damping. The picture shows better tracking when an MC is loaded into a transimpedance input due to 'simple physics' but not simple enough to actually describe :)
I have often mused that the 'unique' sound of the transimpedance approach has little to do with the nature of the amplification or the mythos surrounding the coil as a current generator and everything to do with the aggressive load improving the dynamic tracing ability of the cartridge. It is good to see Lino say the 'quiet part' out loud.
A must read for anyone interested in this is:
Audio Fallacies Exposed
Low impedance Loads for MC Cartridges
J. Peter Moncrief
International Audio Review #5
1980
dave
"The user would need a tonearm with a much higher effective mass or end up with a very high tonearm/cartridge resonant frequency excitable by the music in the groove."
I guess that's what I'm going to find out. The SME 309 that I'm using is only 9.5g effective mass.
you will be able to measure the tonearm/cartridge resonant frequency loading your cartridge in a conventional way vs. this low impedance way and report your findings.I see your cartridge is 18x10-6 cm/dyn compliance (100Hz). Do you know, or have you measured, what it is a 10Hz?
18 times 1.7 is 30.6. At 9.5 grams your tonearm is heavy for your cartridge so less compliance might be a good thing in your case as long as it's not too much less.
According to the chart on the Vinyl Engine you would be better off with half the compliance giving you a resonance of 10Hz vs. 7Hz.
Thanks
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 01/30/24
When I purchased the ART9 to use with the SME 309, the resonance calculations didn't look ideal. But after nearly 800 hours of play I never noticed any problems with distortion or rumble. I think the higher compliance actually works in my favor, despite what the chart says. I ran a Dynavector Karat 17D3 which has that short (1.7mm), lower compliance cantilever and had some problems with that cartridge getting thrown around with high energy passages or deep bass. There were times it would overemphasize vocal sibilance and sound harsh. I ended up using some heavier stainless steel cartridge mounting screws to dampen the resonances. Seems to have worked because I ran that cartridge up to 800 plus hours before I switched to the ART9.I'll have to re-read about testing/measuring resonance frequencies. It's not something I've ever done.
Edits: 02/01/24
Interesting musings, and experimentation here (part 1 or 4):
I've read some of his posts and he often has an interesting take on things. I'll give these a read, thanks.
The Hi-Fi News and Record Review test record HFN 001 has tones on it. When you hit the frequency that matches your resonance frequency you can see the tonearm shake.
10Hz is one octave above from the warp tones and one octave down from 20Hz, which should be the lowest tone cut in the groove. So that is why 10Hz is the target frequency. It all about placing the resonance where it will be the lease apt to be excited.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
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I'm not the right person to discuss moving coil cartridge loading other than my experience with a few phono stages that had the ability to change the impedance values by way of resistors. I've never tried a SUT but had thought about it in the past. My perhaps misplaced enthusiasm for the Piccolo Zero comes from reading reviews of a couple of transimpedance phono stages and how the reviewers thought it was a good way to boost the output of low output moving coil cartridges. But the 12 Ohms internal impedance of the ART9XA may be too high for the Piccolo Zero to be effective.
You can always just buy it and try it out. After all, it's not very expensive compared to a topnotch SUT. If it sounds good, then you're good to go!
Anyway, that's what I'd do if I were still into vinyl. I just love to buy inexpensive components that have a reputation for top quality sound, and Jim Hagerman's designs definitely have that reputation.
I recently bought a Topping preamp that sounds as good as any preamp I've ever owned, and it cost only $600. It's one of the best purchases I've ever made. I bought it after reading Kal Rubinson's review in Stereophile where he compared it to the $18,000 Pas Labs XP-32.
Happy listening!
John Elison
I might just try a Zero out with the ART9. If it works well then the Zero may be a reasonably inexpensive way to give an ART9XA a try. Either that or it won't and I'll end up having to buy a new phono preamp with plenty of gain. Or a SUT. :-)
Edits: 01/28/24 01/28/24
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