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Custom Equipment |
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Two versions of built-to-order linear-regulated power supplies are now available for UREi 1620 and Bozak CMA 10-2-DL /DLA / DLB / DLC / DLO mixer-preamplifiers. A Bozak CMA-10-2-DL-series with Isonoe LRPS improves its signal-to-noise ratio from 67 dB to 94 dB *. This puts the CMA10's phono preamp noise performance on a par with much newer hi-fi preamps. The UREi 1620 with Isonoe LRPS increases its maximum signal-to-noise ratio from 66.9 dB to 83 dB * * 20hz - 20khz / A-weighted / Phono Input to Master Output @ < 0.1% THD |
Bozak CMA10-2-DLA Noise Comparison |
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The above plot shows a converted DLA, measured from via a single Phono channel, with all others muted. Note the presence of a large spike at 100hz (this will be 120hz in the USA). This is due to the Bozak's PSRR (power supply ripple rejection), enabling rectified AC to find its way into the signal path. Simply fitting an external transformer, or a power supply with lesser filtering, will not improve the Bozak's ability to reject this rectified AC. By fitting an Isonoe LRPS, one sees the 100hz spike reduce by around 40dB. The highly audible 150hz spike's amplitude drops by a jaw-dropping 60dB (this also drops by around 50dB when using the Line Inputs). 50/60hz mains hum is reduced by around 44dB. As can be seen, a Bozak CMA 10-series with original power supply has mains harmonics extending all the way into the crucial midrange, potentially masking low-level information. The difference in sound quality and detail is so dramatic that one could say that a person has never truly heard a Bozak CMA 10-2-DL-series until it's been fitted with an Isonoe LRPS. If you think the figures on paper are impressive, wait until you hear the difference. All data presented is taken from Bozak units that have been fitted with brand-new electrolytic capacitors in all circuits. Note that we are only too happy to personally demonstrate the improvements to clients who wish to present their mixers in person to us for conversion. If truth be told, we were surprised to see how radical the improvement was, and were reluctant to publish any figures until numerous mixers had been fitted with the LRPS, and it could be seen that the benefits were the same regardless of model. |
UREi 1620 Noise Comparison |
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The upper plot shows the noise trace of a standard UREi 1620 mixer with its original power supply, measured from Phono Input to Master Output. The lower plot shows the noise trace of the same 1620 mixer having been fitted with an Isonoe power supply. Note that the highly audible 100hz rectified AC frequency (120Hz in the USA) is attenuated by nearly 40dB. |
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Specifications:
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