The Wire - Low Power Ultra High Perfromance (LPUHP) 16W Power Amplifier

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Joined 2004
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SMD is nice and all, but I'm a sucker for sausage shaped low tempco resistors.

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More to come.
 
Member
Joined 2004
Paid Member
Took a while, but I managed to complete my LPUHP build.



As you can see, I have used RN55C/D resistors instead of SMD parts, which made for some fun soldering. For the onboard regulators I have used the LT1033 and LT1085. Again, fun soldering.



I have also opted for an offboard power supply with a 2x18VAC 300VA toroid, MUR860 rectifiers and 33mF 25V capacitors, supplying 24VDC to the LPUHP pcbs. Classic chipamp PSU. The circuit itself runs on +/-18VDC.



Coming from beefy class A amplifiers built with great care and exotic parts, it really bothers me how good the LPUHP sounds. There’s so much clarity up top and such control in the bass, with just the right amount, it very much makes me question amp topology. My speakers have 91 dB/2.8V/1m sensitivity and their impedance dips down to 3.7 Ohm. The puny LPUHP has no problem driving them past comfortable SPL.



I’m using the LPUHP with a BA-3 pre that intentionally injects some negative phase 2nd harmonic, so there’s some sweetness that’s probably not coming from the main amp. Still, even after hours of listening, the setup remains a pleasure to listen to.



The amp will surely remain in the system over the hot summer months. Come next fall/winter, I may have to reevaluate class A amplification…
 

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