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B.
Hybrid filters (use of both CR and negative feedback types):
In this method, both types of filters applied separately; an active filter is applied to
the low frequencies and a passive filter to the high frequencies. Unfortunately, both
the advantages and disadvantages of each of these two types of filters, already
discussed, affect the playback system at the same time.
C.
LCR filters, which are used in the H-6500:
Two pieces of a linear reactor (a kind of choke coil) comprise the main part of these
filters, assisted by precise CR filters, to lower impedances and insertion loss. In
vacuum tube circuits, active and passive filters usually are operated on one hundred
plus kilo ohms of impedance. An LCR RIAA filter's impedance is a constant 600 ohms.
Furthermore, an LCR RIAA filter's series resistance is less than 13 ohms (as a
comparative, some famous ones are 31 ohms). The lower the impedance, the more
dynamic is the sound reproduction, with better bass response and speed.
But LCR RIAA units have drawbacks as well. These drawbacks are high cost and the
difficulty of impedance matching; the latter has been the primary hindrance to the
commercialization of this superb method in the construction of phono-stage
amplifiers. However, Allnic Audio manufactures a high quality LCR RIAA unit and has
developed a 600 ohms impedance matching method.
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For superior signal to noise ratios, the H-6500 is equipped with pure vacuum tube,
high voltage regulation for each channel
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power supply unit separate from the phono-stage itself
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High quality MC Step-up Transformers with Permalloy cores are used for the H-6500’s
dual MC inputs
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Pure Class A operation
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As are all Allnic Audio products, the H-6500 is fully RoHS (EU Reduction of Hazardous
Substances regulation) compliant in construction and materials
