New Lyra Delos Cartridge

Didn't edit the previous post - accidentally submitted it. This brilliant tablet has a mind of its own when it comes to offering alternative spellings and word without asking me first...

apologies.

I have been fighting with loading the Delos. In my setup the only way that I could get it to sound right (meaning neutral spectral balance and tamed transients) was as follows: 1x10 setup ratio, and a 0.5k - 1.5k loading paralleled to the 47k on the tube preamp. The resultant 5 -15 ohm load works. But I had never loaded a cartridge this low before. For that reason I did not trust what I was hearing. I finally stumbled on this thread after I had convinced myself that this was the right answer for my setup.

Reassuring to come to the same numbers and same questions that restock mentioned.

I talked to the Lyra guys who were very helpful. I was all wrong with what I was doing.

They clarified their instructions. The load that you use with the Delos should be the same regardless of whether you use a SUT or a MC phono preamp - that is, > 90 Ohms. The note about SUTs in the instructions does NOT refer to loading. It refers to the kind of SUT that you use. The SUT should be one that is designed for cartridges with an internal impedance from 5 - 15 ohms. The Delos is about 8.

The 10x SUT that I was using was designed for 20 - 40 ohms cartridges, not low impedance cartridges. I don't know how low and high impedance SUTs differ, but apparently they do. The other SUT is designed for low impedance cartridges but has 16x and 32x taps. Without loading these down significantly, my MM input was overloading - too much gain.

So bottom line is that the specified load for the Delos is > 91 ohms, regardless of what sort of step up method that you choose. If you choose a SUT make sure that you don't overload the MM input.

Actually, I am wondering if the settings I mentioned above make sense. It seems that the instruction suggest that 91 ohms is the minimum setting with the Delos. That does not work for me. Too aggressive on the transients, a glare on the natural timbre of instruments. So why am I finding that I need to use these low settings?

I will note that on a solid state phono preamp (a prototype which allows for 67dB of gain) -same arm, wiring and table, the Delos seems pretty insensitive to load. With that preamp (no transformers) anything from 100 to 47k works pretty well.

The setup I am using is a Denon AU-340 SUT (40 ohms setting which is 1x10) into a Audio Innovations P2 phono preamp with a 47k input load. The phono cable is a straight shot of Discovery tone arm wire from the cartridge to the SUT - no other junctions - about three feet.

One thing that I should also mention is that the greater the load, the lower the output from the cartridge. So if you load the cartridge as much I seem to have to do, the input to the preamp drops significantly. This means that with more loading you can actually use a 1x20 ratio without having to worry about overloading the phono preamp.

I use the 1x10 though. But with the P2 phono preamp I can use a 12AX7 instead of a 12AU7 in the second gain stage to make up for the signal loss due to loading.

Any ideas as to why this amount of loading is necessary for me to get accurate timbre and non-aggressive transients?

I am very confused then. With the solid state phono pre that sounds right to me. But with my 1x10 sut into my 47000 tube phono pre it sounds bad. In the SUT situation l need 5-15 ohms to make it sound natural. And it does not seem to effect dynamics or high end detail. I was listening to a Chandos recording of Respighi's Church Windows last night and it was powerful enough to make me sit up straight in spots. Triangles, tubular bells, and celestre were very well represented. Timpani was wonderfully pitched and the organ was quite powerful.

Maybe I am mis-understanding what the actual impedance is somehow. I am just soldering resistors in parallel to the 47000 resistor at the phono pre input though.

Syntax did warn that this cartridge would show up all kinds of things about the down stream system. I have found that to be true. I have changed the tubes around in the phono pre. It didn't sound very good with Telefunken 12ax7s or other old stock tubes (I have a lot of them to try). The Sovtek 12ax7lps sounded very good (and I have only found one other application for this tubes in the past). I also re-cabled between the sut and phono pre and between the phono pre and the amp. I haven't messed with cables in years.

The end result sounds pretty good, but I might not be done yet...

RTFM!!!

I didn't see that in the manual. Well, it is reassuring that what I arrived at empirically is exactly that same as the manual. BTW, 15 ohms still seems a little hot to me. 8 ohms seems to sound better.

I wish I understood the theory behind the differences when loading with a tranny -vs- a mc phono pre. My intuition (for what it is worth) suggests that the loading impedance should be the same. How does the cartridge know that it is driving a mc phono pre or a SUT if the loads are identical?

To reiterate, I am loading the secondary with an 820 ohm resistor in parallel with the 47k. That gives 805 ohms. Divide the the square of the turns ratio (10x10) and I get 8 ohms.

I finally got it dialed in. Seems that 15 ohms is good.

I first went back to no parallel resistors, 1x10 tranny, 47k at the secondary for a 470 ohm load. In my system that is positively brutal. I had a friend over because I was getting confused with what I was hearing. He is a musician with very good ears (classically trained pianist). He agreed that that setup was unobtainable.

We were listening to Van Morrison's 'Poetic Champions Compose'. Van's studio work is, for the most part, exemplary. But at 470 ohms, while you could hear detail (too much transient attack) you could not tell that on a number of cuts he was using a string section as opposed to a synth. The string timbres were that poor. I changed to 15 ohms, and the string section became obvious to the point that you could actually discern individual instruments.

Listening to Respighi ('Church Windows' - Geoffrey Simon, Chandos digital, 'The Birds' - Dorati, Mercury Living Presence) the worldwide were very ambiguous at 470 ohms. At 15 ohms, there is no doubt which instruments you are hearing.

Finally, all you tube rollers, DO NOT overlook the Sovtek 12ax7lps. I figured that it would not work in the phono pre with the Delos, since the Delos is so sensitive. Wrong. I am using two of them into pair of RCA cleartop 12au7 buffer tubes. They sound far and away better, than the Telefunkens, Mullard long plates, GE long plates, or anything else that I tried. They are the icing on the cake in this setup. What ever ambiguities in sonic definition that remained after the loading experiment were completely cleared up with the Sovteks.

Great sound but a pain in the a** to get there...

Well, I am mightly confused. The Lyra guys say >91 ohms. I can't tolerate listening to it at that loading in my setup. I have to load it down to 5-10 ohms using a SUT, and then it sounds very good. With a solid state phono-pre it doesn't seem to matter so much (100 ohms sound ok), but the solid state rig is not working at the same level as my SUT/tube rig. So it is kind of hard to tell anything from the comparison.

I am not yet convinced that the reason that my SUT/tube rig sounds bad at 100 ohms is that the SUT is overloading the tube MM input. At 16x and 100 ohms the input is about 9mV. But even during soft passages, the transients don't seem to sound right. There could be something wrong elsewhere in my system. However, I am tempted to send the Delos back for an inspection, just to be sure that it is performing correctly. I bought it used, so it will have to be at my expense.

I like the sound when loading between 5-10 ohms; but since this is radically different from what the manufacturer suggests, I have to assume that something is not right in my rig, or with the cartridge. (Or maybe the Delos is just hotter than I can tolerate... but no one else seems to have this experience, or maybe blah, blah, blah).

I find it interesting that Manitunc likes 10 ohms even with a SS preamp. But I am curious what settings others are using with SUTs and what the turns ratio is on the SUTs.

I did not want to leave this discussion hanging with a lot of ambiguity as regards my experience with the Delos. So here is how it all shook out for me.

I am using a K&K Lundahl 1941 sut with an Audio Innovations P2 (modded) phono pre. The K&K was new and the Delos had very few hours on it. Over about six weeks time the sound changed considerably. Basically the wierd timbre and the aggressive transients gradually cleared up. Over that period of time I gradually reduced the load until I am now using no extra load resistors. I have 16x sut into a 47k phono pre for an effective load of about 180 ohms.

It sounds great. I do not know why this gradual change occurred. I have read discussions of the Lundahl 1931 and 1941 which both use some kind of amorphous cobalt core. Some people said they preferred the mu-metal versions (1933 and 1943) because they felt that the timbre was off with the 1931 and 1941. I had the same experience initially. Now I can find nothing to criticize about the 1941 in this regard. I have been listening to the cellist Christine Walevska's recordings lately, and the tone she gets is absolutely beautiful. All instruments sound accurate now, and the cartridge sounds neutral and balanced from top to bottom.

So bottom line is that this setup now sounds great without having to resort to load resistors and/or unusual cartridge alignment. And no, I am not overloading my phono-pre. I have never been one to pay a lot of attention to 'break-in', but that is the only explanation that I am left with.

One more thing. After everything settled out I revisited the tubes. While the Sovtek 12ax7lps is a good tube, I ended up using a Telefunken 12ax7 smooth-plate at the input, Telefunken 12au7 smooth-plate at the second gain stage, and two RCA 12au7 cleartops at the buffered output. The Telefunkens just have a more refined sound - to my ears.