Sonics
That, in the final analysis, is what counts.
While Apt can provide you with what is perhaps the most thorough technical explanation of any as to why the Holman Preamplifier actually sounds better in a high-fidelity system, what matters in the end is how it sounds.
The differences between preamps are not mysterious, and they are clearly audible. Apt seminars have demonstrated this to hundreds of people coast-to-coast. Interfacing problems account for most of the differences between otherwise fine equipment, and the Holman Preamp has been designed to be especially free from interaction.
Thus it sounds better in the wide range of conditions encountered in a high-fidelity music system.
If you would like more information about the Holman Preamplifier or the technical considerations underlying its design, please check the appropriate box(es) on the coupon and send to:
Apt Corporation
Box 512 Cambridge, MA 02139.
Thank you.
For a brochure and the name of your local dealer.
For reprints of reviews.
For a set of 5 technical papers by Tom Holman, send $2 ( Canada $3).
For an Owner's Manual, send $4 ( Canada $5) refundable with purchase.
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The problem of Cartridge Impedance Interaction
Most phonograph cartridges are designed with a particular electrical load in mind to yield a smooth, overall flat response.
If the cartridge is not terminated in its intended load, response errors up to plus or minus 5 dB may arise, and such errors are clearly audible to practically everyone.
This potential interface problem can be averted only by properly terminating the cartridge. The optimum load must be supplied by the connecting cables in combination with the input resistance and capacitance of the preamplifier.
Hence the preamp must present a known, well-defined input impedance, completely free of interactions.
The Apt/Holman Preamplifier provides a range of resistive and capacitive terminations, and information accompanying the unit allows optimum setting. The values given on the terminators accurately define the input impedance. Few units provide both non-interacting as well as adjustable input impedance.
Input characteristics are one important part of the story of how a system sounds. Many more are dealt with in the Apt/Holman Preamplifier.
For additional information, check the appropriate box(es) and send to:
Apt Corporation Box 512 Cambridge, Massachusetts 02139
(Source: Audio magazine, May 1979 )
Also see:
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