Moving Iron Adventures

Excellent post and very well written. I enjoyed it, thank you. 

@dogberry 

It is exceedingly rare to read a well-written post on this Board. I am also one who tends to throw in little unnecessary details such as your account of supplying weed. I wish you the best and thanks for the thought-provoking post. 

@dogberry Super post. Had to laugh out loud at the Hawkwind no-show. They were one of my teen favorites with the consequent accumulation of twenty plus albums including many original gatefolds. Joe Banks book is well worth a read. Feel well, man.

I’m hoping against hope that someone steps in to fill John Wright’s shoes. There IS no replacement for the London Reference! Or the Jubilee, or even the Super Gold. If I were you @dogberry, I would just buy a couple/few more London’s, enough to last you whatever time you think you have left. I’m planning on doing exactly that myself.

It probably doesn't belong here, but my involvement in the weed thing was entirely accidental (yes, your Honour, it was an accident, I swear...) A funny story and one I'm happy to relate elsewhere. Believe it or not, I have never touched the stuff! It's legal here now, and I suppose I may end up with a good excuse if there has to be more chemo.

I was only 17 at the time and I can tell you I was much, much more interested in the fact there were naked women walking around the disused airfield where it took place that hot summer. We were told Hawkwind would be arriving by helicopter, but I don't even know if they were actually booked, or whether the idiots organising (to be generous) the whole affair were just using the name to attract visitors.

If I could buy another Reference it would solve a lot of problems. But there's none to be had, and it probably won't hurt me to have some variety in the way my vinyl plays.

Sorry to hear about your health issues; I truly hope everything starts turning in your favor!

I know the Kontra C - it’s a super fun sound with sweet warm midrange, rich bass response, sparkling treble, and just generally tons of PRaT. It has a good helping of a higher-end MC’s detail and refinement, but with heaps of fun factor too. It has an output of almost 0.5mV, and is an easygoing partner with almost any decent MC stage. As I said before, I’m sorry I sold mine.

I did not find the higher end Ortofon MC’s to be in this vein. They will be progressively more refined & detailed, but also drier, and quite frankly less fun. I’ve owned Jubilee MC (Cadenza Black’s predecessor), Cadenza Bronze (Kontra C’s successor), Windfeld MC, Windfeld Ti, and A90. Of these, the Cadenza Bronze is quite similar to Kontra C (being its successor), but even here (going on memory) it seems to lack a little of the C’s fun factor. Perhaps I prefer the C’s silver wire (gold plated copper on Cadenza Bronze), and perhaps the plastic inner chassis (versus aluminum for Cadenza) wasn’t all bad. The Jubilee didn’t thrill me at all. The Windfelds are very technical, and that can be thrilling, but their voicing is more matter-of-fact dry. No warmth in the midrange. Now, the A90 I like! That seems to better marry some (not all) of the fun & warm beautiful voice of Kontra C with technicalities (and beyond) of Windfeld.

So in short, I would probably stick with the Kontra C for Ortofons - or maybe try out an A90 if a good one comes up for sale. If you retip the Kontra C you should keep the cantilever (tapered/conical aluminum), as I think that’s a big part of its sound. It uses a Fritz Gyger "FG80" stylus.

In moving on from Kontra C, I eventually found true love with Koetsu cartridges. Paired with a good SUT, they have even more of a brilliant "technicolor" sound than the Kontra C. Plus better technicalities too. But the Kontra C was just a rockin’ cart for the money! Wish it were still in production.

Thank you for your kind thoughts! It's hard to remember now exactly why I bought the Kontrapunkt C. I had gone from a Shure V15VxMR on a Rega P3, to the SME 10 initially with an M10 arm, then a Series V arm, then a Benz Micro Wood H2 and then the Ruby 3. Why was I unhappy with the Ruby 3? I suspect I was seduced by enthusiastic reviews, and simply got lucky that the reviews, on this occasion, were telling the truth. At that time though, I remember regarding the Kontrapunkt C as being just a bit over-detailed, and perhaps that was just a comparison to the admittedly lush Ruby 3. It seemed to me then as if it were a bit of a guilty pleasure, maybe making my records sound like the CDs that had replaced vinyl for me for around ten years, and upon which I had spent rather silly amounts of money chasing decent sound, when all the time it was under my nose in all the LPs I never threw away. I was using an all Quad tube system then, along with their electrostatic speakers. I still do, although the 24p phono stage has been swapped out for the NuVista Vinyl. I have no desire to change anything there: it may not be perfect but after all these years it makes the sound I regard as 'right'. I have discovered how to take apart my 2905 speakers and keep the failing panels alive a bit longer with hot glue. It's a relief on one hand to have a system that I feel content to live with for as long as I can, but on the other hand it is a responsibility to maintain those parts like cartridges and speaker panels that wear out. Listening again to the Ruby 3 recently, I was pleased to find it competitive to the Deccas. Not as close as the Ortofon, but nonetheless, pretty good. I haven't seen fit yet to dig out the Wood H2, but maybe I shall once I have carts on the Rega RB330 arms and have 309 headshells to spare. Just for fun. It was a high output MC, and I have no reason to think it would be better than the Ruby 3 that replaced it, but you never know!

To get a bit fanciful, I see a consistent thread in the cartridges I like. Cutting the mass that has to be moved by the stylus/groove engine right down to the bone. The Deccas do it by taking the signal from the armature just above the stylus. (I've never heard one, but I dream about the old Ikeda MC designs that did the same.) The current MI designs have a cantilever but claim to have as little mass on the proximal end as possible. Lederman gets quite poetic describing that, and I think he is right in principal, but not all the way there in execution. I haven't heard a Hyperion, though. Now to take that as far as we can, there are new cartridge technologies that look promising: the strain gauge, where the proximal end of the cantilever doesn't have to move, just press against the gauge, and the the DS optical system that needs no mass on the cantilever other than wafers that block more or less light from internal LEDs in the body. Finally, with a nod to those old Ikedas, there's the AT ART1000 with the coils mounted on the cantilever right next to the stylus (like an old Neuman DST 62). I'd give my eye teeth to have the chance to compare those three in my system. For good or ill, it seems my canines are safe!

@dogberry 

I really like Benzes a lot too (and the current line with Zebra and Ebony woods is better than the prior lineup with Bruyere wood like Ruby 3), but they don't have quite as "juicy" a sound as a Kontra C or a Koetsu. The Ruby and LPS models are also harder to match to phono stages (versus the lower iron-cross models), as they don't mix super well with SUTs in my experience. But I do quite enjoy the Zebrawood L and Ebony L in my collection too :)

I was at first super interested in the Decca London Reference.

But finding it no longer available, I turned to the Grado Epoch3.

I have been using it now for a couple of months. It blew away my Lyra Atlas SL.

The Lyra is sold. And the Epoch3 is now my destination cartridge.

The Statement3 Grado is a different world from the Epoch.

I can’t say that it blows away the Decca, but comparing it to the similarly priced Lyra says a lot about the SQ.

I understand the Statement 3 belonged to the lower tier of Grado cartridges, but they felt it was sounding good enough to be promoted to the Lineage series along with the Epoch 3 and the Aeon 3. I'm very pleased to hear that the Epoch 3 does so much for you, and I assume it is very different to the Statement 3.

There really isn't anything wrong with the Statement 3, if you value neutrality above all else. But I don't hear any excitement in the music. Perhaps I'm accustomed to a highly corrupted sound from the Deccas, and I interpret that as excitement. Who knows? But that's what I'm looking to find again.

@dogberry  - You said: "I have discovered how to take apart my 2905 speakers and keep the failing panels alive a bit longer with hot glue."

Really? I'd love to learn more about what you're doing. I have a pair of 2805s that have been rebuilt. 98% of the time they sound superb. But there are some frequencies that cause buzzing. I expect that one day they will require another service but if there's a way to prolong their life with hot glue, I'd love to hear about it. Your comment was the first reference I've ever read about this...

Thanks,

Markus the (used to be) Naimnut

Markus,

This is what I wrote about it:

I spent three hours today looking over the shoulder of a skillful repairman as he dissected a Quad 2905. It takes about 20 minutes to get the speaker stripped down to the point where you can see and test the panels. There are six separate panels, two bass at the bottom, two mid/high range in the middle, and two more bass panels at the top. For those who don't know, each panel is a sandwich, with a plastic grid of 2cm squares on the outside front and back. Inside this is a copper panel perforated by a grid of small circular holes, resting against a phenolic board like a PCB (again, front and rear). Between the phenolic boards is a Mylar membrane, glued at the edge to the rear plastic grid's outer edge. There is a 2-3mm gap between the Mylar and the PCB in front of, and behind it. The Mylar has a graphite coating all over except for the very edges. High voltage is fed into the copper stator on each side of the Mylar, and the graphite responds by by being drawn to or repelled from the stators. The stators are solid single pieces of copper for the bass panels as low sounds are non-directional. The mid range/treble panels have the classic Quad arrangements of concentric circles of the copper mesh, each part circle connected separately through delay lines so that the two treble panels act like one large concave/convex panel, simulating a point source.

All the delay lines must be unsoldered to remove panels, and reconnected afterwards.

My faulty panel, this time, was the lowest bass panel, and the phenolic board at the front of the sandwich with the copper stator on it was detached from the plastic frame at one side. Originally, it was glued in place. Careful probing with an insulated tool makes the loose part of the stator arc noisily as it is pushed towards the Mylar. So that panel was removed and replaced with a new one ordered from Mo-Fi some weeks ago.

However, the four original panels in that speaker (two now being replaced with new ones) all have the same problem developing, and all on the same side of the front face. They have come loose from the frame, but are not yet loose enough to cause arcing. Comparing old and new panels one can see some differences. The glue on the originals is slopped around a bit, but is extremely sparse or absent where the phenolic board is loose. The new panels have a visible bead of glue connecting the stator to the plastic grid.

So we scratched our heads for a bit, and discussed various glues. We don't want water based glue, and we don't want it to penetrate through the phenolic board. We decided to place a blob of industrial hot glue at each cross of the grid, and then used a dental pick to pull the copper stator back up against the glue as it set. We used one of the old panels as a test first to ensure the Mylar would not be hurt by the heat of the glue - it wasn't. Then I remembered the roasting bags for poultry, which I think are made of Mylar, so it should resist heat OK. At the end, all the stators on the front are well-affixed to their frame. None of the stators on the back of the panels were loose at all. Looks like a poor manufacturing process led to insufficient glue, and I'm guessing Quad became aware of it since the new panels have lots more glue on them. Then the speaker was reassembled and we set off home.
It works just fine now. So what was the point of the hot glue? As the end of the stator starts to flap in the breeze it gradually detaches for more of its length, and at some point it can move enough to touch the Mylar and it arcs. After a short (pun intended) while there is a hole burned right through the Mylar. By fixing the stators firmly with glue I hope we have reset the clock on those panels, or at least at that end of them, as the other end had no looseness, and nor did the rear stator as I said above. Time will tell.

As for doing it myself if needed, I think I can. There are airtight dust screens that look like Saran wrap on the front and rear of the speaker, to keep dust out (!) - because an accumulation of dust would increase the risk of arcing. The PCB with the delay coils and circuitry on it is coated in wax, probably beeswax, as it is outside of the sealed dust screens, and again any dust gathering between the terminals that the delay lines are soldered onto will encourage the terminals to arc. So after re-soldering the delay lines we dripped a beeswax candle onto the terminals. Not as pretty as the factory finish, but it should work.

Now the other speaker hasn't had a problem at all, so far. I could take it apart now and go at it with the glue gun if needed, but I think I'll wait until it starts to cause trouble, replace the panel that goes, and apply glue to all the others if showing signs of loosening. Fingers crossed, it won't happen...

@dogberry , Mylar will shrink when heated with a heat gun. After final assembly Acoustat panels were run under an infrared heater to tighten the Mylar. If the speakers were not crossed to a subwoofer, with age the diaphragms would loosen a bit, and they could rap against the stators with loud bass or a bad warp. A heat gun fixes the problem. Jim Strickland, the brain behind Acoustat, discovered that by using a certain type of insulation on that stators you could prevent dangerous arching altogether. Roger West of Sound Labs uses a similar construct but smaller individual panel sizes. They never get lose enough to rattle even if you require them to make bass.

In regards to cartridge design, it is the effective mass that matters, the distance of the mass from the fulcrum along with it's size. 

I have heard both the Strain Gauge and Hyperion. Peter spells his name with two Ns, Ledermann. The Strain Gauge immediately gets your attention with fast transients and a brightness that does not increase sibilance, so it is easily tolerated, and harder to identify. The Hyperion sounds rather boring on first listen. Turn up the volume to more realistic levels, and it becomes apparent that the Hyperion is the more accurate cartridge. It is also a fabulous tracker, the Strain Gauge is not. I could live with an Hyperion had I a phono stage that could mate with it. I did have The Voice for about 1 year. It is the most accurate high output cartridge I have ever heard, and a terrific value matching cartridges twice the price. The ART 1000 is a scary design. My instinct, right or wrong, tells me to steer clear.

Small point: Sound Lab panels are a single large sheet of Mylar that is sandwiched between a pair of egg crate grill-like hard plastic  dividers, resulting in small rectangular divisions of the Mylar that are variously sized to spread out their respective resonant peaks. SL like to bias their panels at very high voltages compared to most other commercial ESLs, and possibly as a result they had problems with arcing for many years. The combination of high voltage and inadequate stator insulation were culprits. SL used to endorse having customers “kill” any of those individual rectangles that were arcing, by injecting silicone caulk across the space between the Mylar and the static where arcing was occurring. The affected Mylar would also develop holes, eventually. The whole problem was a nightmare for owners like me, until eventually after killing so many rectangles, you sent the whole panel back to the factory for total rebuild. About 10 or more years ago, they seem to have solved the insulation problem. My 845PXs , purchased back then, are doing fine.

Autocorrect made when one of its usual blunders.  In the phrase "...the space between the Mylar and the static where arcing was occurring...", the word "static" should be replaced by the word "stator".  ESL enthusiasts would have figured that out.

 I wasn't really aware of moving iron cartridges until I bought used TT with one mounted. I have no complaints with the sound, but yes, they certainly are prone to induced hum. I still have the cartridge but have replaced it with a MM which is in the ballpark sonically. 

The older Deccas often required some special voodoo to tame or obviate their hum. Some of it was related to the common ground of the three-pin versions, some because of the thin pressed metal shell. So trying various ground configurations and doing brave things like potting the innards with bees wak was tried. The Deccapod mount was made to tame the resonance too, as were some third party efforts to encase them in wood.The recent models have much less resonant shells, and have come from Mr Wright ready potted.

I see some of what you are saying. What I am referring to is electrically induced (EMI) hum. And you addressed a possible cause by referring to the ’extra ground’ used in many cabling systems in phono. No doubt there is a preferred way for each situation. however, I tried working with that and it did not matter. Interestingly the hum increased a bit when the tonearm neared the center of the album. The TT motor was DC and so I discounted it as a source. Come to think of it, I have moved the TT since then and it would be interesting to hear any difference with that cartridge. I would readily do that if I had another tonearm for SOL TT, as it is incredibly simple for the uni-pivot design.

I'm no expert on the older Deccas, but there is as much or more information than anyone might need in this 290 page thread:

Moving iron cartridges are not particularly prone to inducing hum, compared to other types. Decca cartridges are notorious for generating hum in concert with nearby TT motors. This is due to their atypical grounding scheme.

A DD TT with an AC motor being rather awkward. Some people have tried shielding the motor with mu-metal.

Oddly, I have never heard any hum with my Deccas, but they are of the newer type, with proper bodies and four pins. They don't seem to mind me connecting both ground leads either (though I do connect one to the phono and one to the pre-amp.

I would make a guess that the higher output Deccas (5mV typical) with more windings on their coils, would be more sensitive than lower output MI designs. I never hear complaints of hum about Grado, Soundsmith or Nagaoka.

Most all DD turntables use AC motors. Typically the motor itself is encased in a metal that shields. The platter itself usually enhances shielding. There is no hum problem. I’ve had 5 different DD turntables in my home system, used them with a wide variety of MM, MI, and MC cartridges. No hum ever. Some Decca cartridges used a common ground for both channels which made or makes them more likely to induce a hum in certain turntables of any drive type, depends on proximity of the motor and its EMI. At least that’s how I recall the Decca issue. This is in no way to say the Decca London is not excellent. It is. Wish I still had mine.

Yap @lewm, Deccas could be a problem with some tables. The first time I heard a Decca---the Blue---was at the only high end dealer in San Jose in the early-70’s, who had tried it in the Thorens TD-125. Too much hum, so they put it on a Sony (don’t remember the model but it was pre-direct drive). Yet the next time I heard the Blue it was mounted on a prototype Audio Research arm which never made it into production (it looked like the 1950’s Grado arm) on Bill Johnson’s own TD-125. Sample-to-sample variation? No two Deccas sounded the same!

Most all DD turntables use AC motors. 

@lewm 

Are you sure about this ?

L07D - DC servo motor

SP10 - brushless DC motor

Pioneer - P3 DC hall motor

Victor TT101 - coreless dc motor

Having heard the Sussurro MkII transformed by treating it as an MC and playing with the resistive loading, I had to do the same with the Grado Statement 3. This has an output of 1mV, which could be treated as MM or MC. I have used it as an MM, but my phono amp lets me do pretty much what I want, so...I mounted the Statement 3 on a 309 headshell and fitted it to the second SME table and aligned it with the Feickert (Baerwald). Set the VTF to 1.8g and the VTA as dead level. I like to use Elgar's Sea Pictures for the next bit, as Dame Janet Baker has a powerful contralto voice for the top end, and the tympani provide some deep bass behind her voice. So I listened to the first track, the Sea Slumber Song repeatedly while altering the resistive loading. I kept the volume comfortable with an SPL app, between 50-60dB. I have the options of 10, 25, 50, 100, 400, 800, 1200 and 47kΩ. Starting with 47k, it was rather thin with her voice a bit much for me. Coming down to 1.2k she was tamed a bit, and more so at 800Ω. I think 400 is the first loading that sounds like a real voice, and maybe I prefer the 100Ω loading. The tympani got a bit more prominent at first as I came down from 47k, but after that stayed much the same. Having done that I moved on to the next section of my torture test, conveniently on the other side of the same LP (EMI ASD655, Barbirolli, DuPré, Baker, LSO, Elgar Cello Conc and Sea Pictures). Not the world's finest audiophile LP, but the best I know of that expresses both music and sound in luscious detail). The cello is not only a wonderfully expressive instrument, but it produces some of the richest of natural timbres. If I describe the rosined horsehair bow drawn slowly over the Cats Go strings (Cats Go Down Alleys - C, G, D, A yes?) you can feel shivers down your spine as you imagine the horsehair grab and slip many times in the duration of each note. If you don't feel what I mean you should stop both reading and listening and go and watch football.
The cartridge is dramatically better than when set as an MM, and is probably more refined than the Sussurro, which has a bit of the bouncy liveliness that makes me enjoy the MP-500. I think it is now just in the lead for one the remaining seats on my tonearms. The last seat will become a Sussurro vs MP-500 showdown. Price-wise, that should be a foregone conclusion, but it seems to me that price is not a reliable guide here in the upper troposphere of cartridges (I'd place the Reference in the lower stratosphere, but beyond that I have no experience).

And after all that......GOOD NEWS!

Don't know who that is, nor if armatures are to be made again, but this is excellent news!

Dover, your information is correct. I was incorrect, regarding DC motors. But the potential noise issue with DD TTs is there regardless, because all motors can radiate EMI and also reflect EMI back on the AC power source, which is why it’s best to isolate the AC line from the rest of the system. As far as radiated EMI, any good DD turntable will have addressed that issue in its basic design, mentioned elsewhere. I tried to measure EMI at the platter surface for two of my DD TTs using a sensitive meter and got zero, but I suppose you could argue the meter was not sensitive enough. Practically speaking, there’s no audible noise with any of my 4 DDs. I haven’t owned a Decca cartridge in decades but those are particularly sensitive due to the odd grounding scheme and how it mated to ancillary equipment.