Anyone try the replica B-60 Fidelity Research VTA?

Dear Lew:

I specifically replied to your statement:

>The load resistor might affect frequency response but not gain.

This is exactly backwards. The load resistance attenuates the cartridge output - the lower the load resistance value, the greater the attenuation. The load resistance _equally_ affects all frequencies that are not part of the electrically reactive area, and as my graphs from the What's Best link show, that electrically reactive area will be in the hundreds of kHz to some MHz.

Ergo, the load resistance value will not affect the amplitude of any frequency that you can hear directly. The exception would if the source inductance is so big that the electrically reactive frequency region is dragged down (by the cable capacitance) into the tens of kHz, but this calls for a MM or MI, while the post directly above your post (the post that you responded to) spelled out LOMCs. One other exception would be if your phono stage designer likes to add huge amounts of capacitance (nF rather than pF) at the phono stage input.

>were you inferring that my statement (essentially, low load resistances that get into the range of less than a multiple of the internal resistance can affect FR of some cartridges) was correct or incorrect

I was pointing out that your statement is incorrect. Due to its operation as an attenuator, using a very low load resistance affects the output level more significantly than the frequency response, unless electrical resonances form a fundamental part of the cartridge's audible frequency response (which again describes MMs or MIs rather than LOMCs).

>I said nothing about capacitance.

Neither did I (at least not on this thread so far).

Although the What's Best link shows that the interaction between cable capacitance and coil inductance is the mechanism causing varying degrees of frequency peaking (reactive resonances), and that resistive damping of this peaking is why you would on occasion want to use a lower-value rather than higher-value load resistance, it also graphically showed what kinds of frequency ranges will be affected by the load resistance value. Hundreds of kHz to some MHz.

Please keep in mind that the quote of yours that I responded to did say:

>The load resistor might affect frequency response but not gain.

Incidentally, it should be stated that although the ultrasonic frequency peaking is caused by the cartridge (and tonearm cable capacitance), it is never part of the cartridge's own frequency response. No phono cartridge that I am aware of has any output in the MHz region. The highest frequencies emanating from the cartridge itself will be when it encounters a cut in the groove, or a raised particle. Such physical damage is not subject to the limitations of groove cutting lathes, and can give rise to large impulses with frequency content extending as high as 150kHz (according to John Curl, some extreme cases may reach 300kHz). Still, some way off from the MHz region affected by the load resistance value.

What the frequency peaking will do is boost any environmental or local noise that is present in the affected frequency region by the amplitude of the peak. Many radio broadcasts occur in the same region (from 500kHz to some MHz) as that affected by the interaction between cartridge inductance and cable capacitance.

If your phono stage is simultaneously asked to amplify the output of your LOMC along with a local AM broadcast which has been boosted by 30dB due to the frequency peaking action between cartridge inductance and cable capacitance and an improperly chosen load resistance value, it is no surprise that you may hear a skewed energy balance, or audible distortion. But that is a phono stage issue. It is not caused by an alteration of the phono cartridge frequency response.

hope that this clarifies sufficiently.

kind regards, jonathan

PS. BTW, the frequency response of a phono cartridge will vary according to the room temperature, and the LP groove radius (upper frequencies fall as the cartridge gets closer to the label). There are various reasons why I consider the frequency response of a transducer (microphone, cartridge, speaker) to be of merely token interest.

The Ikeda Sound IT-VTA-06 is a modern version of the FR B-60 elevation base, and made by the same guys who made the original.

Although I have handled the IT-VTA-06, I haven't had the chance to try it out or compare it to the original. What I do know that the machinery that the IT-VTA-06 is made on is far more accurate than what FR had at their disposal back in the 1980s.

If what Nandric had problems with was the IT-VTA-06, I strongly recommend that he describes exactly what the problem is to the seller, so that feedback can be provided to the manufacturer and improvements can be made.

kind regards, jonathan

Dear Nandric: You are the first person who has ever requested that I give them a heart attack (grin).

>some old-fashioned machinist still swear by the old lathes and categorically claim that the talent of the machinist is more imortant then the used kind of lathe (grin).

I fully agree about the talent of the machinist, but I think that we can agree that superior equipment will enable even experienced machinists to do more precise and consistent work.

The person machining the Ikeda Sound IT-VTA-06 is the same person who machines all of the components for the Ikeda tonearms, and FWIW, the Lyra cartridges. He has over 35 years of experience in machining medical / surgical components where any lack of precision is unacceptable. He is not cheap (as you can see by the prices that his work commands), but his quality is truly excellent.

kind regards, jonathan

Dear Lew:

We are talking about low impedance MC cartridges, right?

>The load resistor might affect frequency response but not gain.

If so, wouldn't the MC cartridge frequency curves published in various magazines be non-comparable and essentially meaningless unless there was an industry-standard load resistor value that all magazines adhered to?

kind regards, jonathan

Hi Lew: Since I have already written about this topic on the What's best forum, and a kind soul there was willing to convert my charts into gifs, I recommend that you read the following thread on the SME 30/2 turntable, from pages 3 to the end. The charts are on page 6, and they will show you what kinds of frequencies are affected when the load resistor value is changed.

http://www.whatsbestforum.com/showthread.php?14082-Sme-30-2/page3

kind regards, jonathan

Hi Nandric:

>What is your opinion about the difference between the 'old-fashioned' FR-64 S and the (new) Ikeda IT-345?

The FR-64S has a bit of extra resonant energy, a bit of extra spiciness that has been engineered out of the IT-345 (which was developed with full knowledge and understanding of the FR-64S). In some systems and for some ears, the extra spiciness works well, in other systems and for other ears, this upsets the balance of the sound.

But do keep in mind that while there is such a thing as intelligent engineering and unquestioning (not-thinking) engineering, when it comes to subjective listening preferences, there is no correct or incorrect. Like food, or the opposite sex, or sports, not everyone shares the same subjective preferences as you or I.

Decades of listening to audio systems at shows, reviewers, dealers and audiophiles all around the world have shown me that likes and dislikes come in all flavors; what one listener loves, another may abhor. If someone prefers the sound from a telephone made from two tin cans and a length of hemp, I do not have the right to say "you are wrong" (although I may make a mental note to avoid taking that person's opinion seriously).

My advice to you is listen to both tonearms, then try to appreciate each for what it is, rather than disrespecting either for what it isn't.

kind regards, jonathan

Dear Lou:

IMHO, analog audio today is saddled by more than a few unjustified myths and misbeliefs. These unfounded beliefs are fettering the progess that audio engineers are able to make, and are also preventing audiophiles from extracting the full performance potential of the components that they pay good money for.

AFAICS, MC cartridge loading is one of the problematic areas. Allowing the old myths to continue unchallenged causes audiophiles to wrongly evaluate the cartridges that they listen to, in addition to holding back progress in phono stage design.

Dispelling the unfounded beliefs by provoking understanding of the fundamental mechanisms and issues will hopefully allow both audiophiles and audio design engineers to take some good steps forward.

BTW, that's a roundabout way of saying that I apologize - it was never my intent to beat up on you.

kind regards, jonathan