Ortofon Per Windfeld Load Impedance?

Jonathan Carr,

Thanks for your explanation. I thought Mr. Karsten's comments about there being one right loading, in terms of proper electrical dampening of the cartridge made sense, but, it did not exactly square with my experience that the best loading of any particular cartridge seems to differ depending on the phonostage. I can see how both comments are not incompatible.

Mr. Karsten,

How, in layman's terms, would one go about "ringing" a cartridge with a square wave and observing the waveform? Are you talking about a special test record and an oscilloscope, or feeding an electrical signal (square wave)into the cartridge and viewing the returning signal?

Is this something that the manufacturer could do to give a precise recommended loading? I ask this because some manufacturers recommendations fall into a huge range (I believe my Lyra Titan came with a recommendation of 100 ohms to 47k ohms) while others give an incredibly precise figure, such as the loading recommendation for Allaerte cartridges.

Jloveys,

I will have an opportunity this weekend to play around with a friends Tron Seven. Another mutual friend has it while the owner is out of town. The "agenda" for this weekend is tube rolling. My friend has a big selection of 12AX7s as well as the other tube (can't recall the exact type) which is roughly the equivalent of a 12AU7. I will be able to contribute a Telefunken ECC803S to the experiment. The friend who is now playing with the phonostage has had it in his possession before and really likes this phonostage (used with either a Lyra Helikon or Transfiguration Orpheus)>

I read your comment, above, about loading for the Allaerte cartridge. I can understand that the manufacturer has loaded the secondary of the transformer feeding the active stages of his phonostage optimally (one needs to dampen the transformer ringing), but, to me, there is room to optimize the loading of the cartridge by choice of the proper resistor in parallel across the primary. My own phonostage (Viva Fono) also has a transformer at the input. I have experimented with loading across the primary and have found that it makes a difference. The difference is not as dramatic as changes in loading in my solid state phonostages, but, there is a difference. The high numberic value specified by Allaerte suggests that it should not be loaded down very much (good thing given its extremely low output), so I can see how no loading of the primary works for you, but, I am a bit skeptical about the universal claim that loading would not make a difference with this phonostage.

The owner of the Tron Seven is also an owner of a Tron Jubilate amp. The designer has also said a lot of things to this owner about how performance of the amp has been optimized, but frankly, the amp sounded like crap to me in several different systems. It was only after we did some tube rolling, discouraged by the designer, that the amp sounded pretty good. I am just a bit skeptical about things the designer of this gear says (he also had a lot of excuses for the amps multiple power supply failures).

Jloveys,

Perhaps you should ask Allaerte about the right resistor to achieve proper dampening of the cartridge. I bet the value is different from the 845 ohms specified, given that the primary of the transformer represents a load different from that of other types of phonostages so the proper value might be different. If Tron supplies you information on the turn ratio, etc. of the transformer, I bet Allaerte can give you some suggestions.

The other alternative is to just experiment with different values. This should be relatively easy to implement. Just solder in a resistor between the hot and ground tabs on the back side of the RCA jack going into the Tron.

By the way, if the Mullards sound too lean in your setup, I would bet that the ECC803S would be EXTREMELY lean to you (a good thing, perhaps, given the CRAZY price for 803S' these days).

Jloveys,

I did not get a chance to hear the Tron 7 in my own system, but in my friend's system, I got to hear it with two different sets of 12AX7s. I did not find the Mullards too lean, as you found them, but, they were extremely phasey sounding, particularly so with reproducing the piano. It was so phasey sounding that it almost sounded like the phasing of the two channels was off (except the center information was reasonably coherent).

I much preferred the Amperex Bugle Boys that were substituted for the Mullards. My friend thought that Telefunken 12AX7/EEC83 was a bit too lean in his setup. I did not get to hear that tube, nor some of the substitutions he tried with the other tubes in the unit.

With the Amperex, I thought that this was a very good phono stage -- musical, reasonably dynamic, and dead quiet (my friend's speakers are 105 db/w efficient so noise is easy to hear).

Jloveys,

The friend borrowing the Tron Seven has a system cobbled together from an ElectroVoice system (15" woofer with a folded horn, horn tweeter) and a huge multicellular midrange horn and compression driver of different manufacture. He has a big range of amplifiers. I heard the Tron mated to a custom-made tube linestage feeding a custom-made pushpull 45 amp, and on a different day, the Tron feeding a Levinson No. 32 linestage and a customized commercial solidstate amplifier. The phono cartridge was a Transfiguration Orpheus.

The owner of the Tron Seven has an older pair of JBL speakers and the Tron Jubilate amp and the Ortofon Per Windfeld cartridge.