WV5 and WV9 Custom Loading Values for MC Loading Plugs
MC Loading Plugs provided by Alta Vista for the Aria WV preamps can be ordered in several build levels.
Type C loading plugs are the least-expensive, and use Neutrik gold RCA plugs and good quality E96-value resistors (smooth-sounding, some loss of detail which is normal for all resistor types except the more expensive ones used in the Type A, B, or Z plugs). Type B loading plugs are somewhat more expensive and use and Caddock TF020 resistors at E96 value. These resistors are very transparent with great detail with no smearing, but do thin the sound slightly, but they are about the only choice when higher values of resistance are needed. Type A loading plugs use Cardas GRMO RCA plugs "naked" Vishay TX2352 S-foil resistors (custom-built to "Ideal" value ). The TX2352 resistors used in the Type A plugs are every bit as transparent as the TF020 with almost no thinning of the sound. In the highest loading values, TX2352 are not available. Type Z loading plugs (added July 2008)
use Cardas GRMO RCA plugs "naked" Vishay TX2575 Z-foil resistors (custom-built to "Ideal" value ). These are, without a doubt, the most transparent, most neutral resistors ever. A breakthrough in sound quality.
If you have some other RCA plug you'd like us to use, please advise.
Prices are for pairs (one plug per channel).
MC Load (ohm)
Ideal resistor value (ohm)
Closest E96
resistor value
Closest E24
resistor value
Type C
Type B
Type A
Type Z
(For the man
who wants the best)
1000
(none needed)
--
--
--
--
--
900
1.2Meg
1.18 Meg
1 Meg
$45
$70
Not available
Not available
800
440K
442K
430K
$45
$70
Not available
Not available
700
220K
221K
220K
$45
$70
$140
Not available
600
149K
147K
150K
$45
$70
$100
$180 (1)
500
100K
100K
100K
$45
$70
$100
$150
400
68K
68.1K
68K
$45
$70
$100
$150
300
45K
45.3K
43K
$45
$70
$90
$140
200
27K
27.4K
27K
$45
$70
$85
$135
150 (recommended for Linn cartridges)
17.3K
17.4K
18K
$45
$70
$85
$135
100
13.5K
13.3K
13K
$45
$70
$85
$135
50
8.05K
8.06K
8.2K
$45
$70
$85
$135
Notes
Maximum single resistor value for TX2575 is 100K. To make 600 ohm load, which uses 149K of resistance, two 74.5K resistive elements connected in series are assembled at the factory.
Construction "Z" is GRMO plug with Naked Vishay TX2575 0.1% resistor inside plug body.
Construction "A" is GRMO plug with Naked Vishay TX2352 0.1% resistor inside plug body.
Construction "B" is GRMO plug with Caddock TF020 1% resistor. Resistor is too big to fit inside plug body, handle carefully.
Construction "C" is Neutrik gold plug with 0.5% Draloric or PRP metal-film resistors inside plug body.
These values apply only to WV5 or WV9 which use the Sowter 8055 MC Step-up Transformer (standard). For WV built with other transformers, contact Alta Vista Audio.
You can build your own loading plugs by soldering the resistor from the hot to the ground of an RCA plug.
Values not shown above can be found by interpolating from the above table, or view this chart ( PDF, 12kb).
