Lyra Delos Settings

Hi Agiaccio: How much capacitance does your tonearm cable have? Also, how much capacitance does the internal wiring inside your tonearm have?

It would be nice if you could disable the capacitance at the phono stage completely, is this possible?

I suspect that you will have better dynamics with the MC gain set to 64dB, but if you have very efficient loudspeakers, you may try 54dB.

kind regards, jonathan

Hi Agiaccio: The loading resistance for a low-impedance MC cartridge is related to the values of the capacitances between cartridge and phono stage (plus whatever amount is present at the phono stage input). The general rule of thumb is that, the lower the capacitance value, the higher the resistive loading value can be (which is beneficial for dynamics and resolution).

If you are willing to give me a few days, I could run a set of loading simulations for you. Please be aware that without knowing some of the key capacitance values, a certain amount of guesswork will be involved.

These days you can buy a digital multimeter (DMM) which can easily measure capacitance for not a lot of money, and this would eliminate the guesswork (hint, hint).

The Nordost Heimdall 2 will likewise be one meter long (3.28 feet)? FWIW, 1.2m is more common for bespoke tonearm cable.

How long would you estimate the signal wiring inside the JMW-9 tonearm to be (including the leads to the junction box)?

kind regards, jonathan carr

Hi and hope that everyone is doing well:

According to a member of the Phonogram mailing list who recently contacted Harry Weisfeld, the total capacitance for a Classic tonearm with standard tonearm wiring and the standard RCA junction is 143 +/- 2 picofarards (for the arm and box).

He also asked about the Valhalla version, and I am not entirely sure which version Harry's reply addressed. Still, at least 143 can be a starting point.

kind regards, jonathan

I was finally able to set aside some time to put together an electrical model that reflects Agiaccios's particular situation, and start running simulations. Over the next days, I will make a series of posts, one for each capacitance setting on the Uphorik. Today's post will be for the Uphorik's lowest-capacitance setting, 470pF. 23 simulations (a decent amount of work!) were run in order to obtain the results below.

First let me set forth the parameters of the electrical model.
Delos internal resistance is 6.3ohms, coil inductance is 9.5uH.
VPI tonearm internal cable capacitance is 143pF
Since VPI internal resistance and inductance are unknown, I will use values taken from AWG25 50cm zip cable, which are 0.3117uH, 0.106ohm
Tonearm external cable Nordost Heimdall 120cm, capacitance 98.4252pF
Since Nordost resistance and inductance are unknown, I will use values taken from AWG20 120cm, which are 0.748087uH, 0.0798ohm
Phono stage Linn Uphorik capacitance settings 470pF, 1000pF, 1500pF, 2000pF
Phono stage Linn Uphorik resistance settings 31, 37, 42, 53, 70, 100 170, 580, 670, 810, 1000ohms

Today's net capacitance will be 143pF (tonearm) + 98 (Nordost) + 470 (Uphorik minimum setting) = 711pf.

Load__________Peak magnitude_____Peak frequency
1000ohm:_____15.1847dB_____1.8394MHz
810ohm:_____13.8811dB_____1.8356MHz
670ohm:_____12.6458dB_____1.8305MHz
580ohm:_____11.6723dB_____1.8254MHz
170ohm:_____3.1484dB_____1.5957MHz
100ohm:_____0.2680147dB_____944.8883kHz

From 70ohm and lower there is no high-frequency peak, so I changed the table to show at what frequency the response drops to -3dB, which is a standard way of speccing audio components. The small differences in amplitude simply reflect how closely I was able to get to -3dB.

Load____________________Frequency
70ohm:_____-2.9923dB_____1.5423MHz
53ohm:_____-3.0008dB_____1.0860MHz
42ohm:_____-3.0040dB_____825.7936kHz
37ohm:_____-2.9968dB_____719.1689kHz
31ohm:_____-2.9969dB_____602.3495kHz

Below are 3 resistive values that the Uphorik does not have, but in conjunction with a net capacitance of 711pF, would yield a rise of +6dB, +3dB, and +0dB, respectively.

Load resistance for a +6dB rise would be
256ohm:_____6.0009dB_____1.7402MHz

Load resistance for a +3dB rise would be
166ohm:_____2.9907dB_____1.5825MHz

Load resistance for a +0dB rise would be
89.8ohm:_____0.0244404dB_____524.9368kHz

Hope this was of interest. jonathan carr

BTW, the Linn forums have a thread which is for Uphorik users and loading of various cartridges. It treats cartridge loading from Linn's own perspective, which is to load MC cartridges not only resistively (per standard MC phono stage design practice), but capacitively as well (a practice which AFAIK is seldom found on MC phono stages, at least those designed in the US or Japan).

http://forums.linn.co.uk/bb/showthread.php?tid=10332

When defining the resistive load recommendations for the Delos, the assumed maximum load capacitance was 600pF, so I find it interesting to analyze MC cartridge behavior with phono stages that allow significantly higher capacitance values.

kind regards, jonathan carr

Hi Kinara:

It would be interesting to see what is going on in your tonearm(s), because 2 out of three is highly unusual.

I would be happy to send you an email, to either discuss what may be going on. or set the corrective wheels in action (smile).

Wonder why I haven't seen your emails?

kind regards, jonathan