Good to see it´s up and running!
I just finished my LU1014 prototype but I´m gonna get some sleep before I turn the power on.
I wish I could find/afford fancy transistors like 2SK180 but I guess LU1014 (cascoded with a mosfet) will do fine too.
I´s a but funny though, I usually hang out in the tube section and the first thing I see in the Pass section is a bunch of threads where people are discussing obsolete, unobtainable devices that has triode-like transfer curves and requires output transformers...😀
I just finished my LU1014 prototype but I´m gonna get some sleep before I turn the power on.
I wish I could find/afford fancy transistors like 2SK180 but I guess LU1014 (cascoded with a mosfet) will do fine too.
I´s a but funny though, I usually hang out in the tube section and the first thing I see in the Pass section is a bunch of threads where people are discussing obsolete, unobtainable devices that has triode-like transfer curves and requires output transformers...😀
The SITs were less expensive when they were first called to the attention of this board, but they weren't cheap either, something like $150 or so for a pair. I don't think I would buy any now, personally. The LU1014 is a neat device, my favorite amp, the F3, uses them.
A resurrection!
I recently acquired and built an ACP+, my one and only preamp with voltage gain, which totally changed my perception of what was possible with source follower topology like ZM's "Redneck DEFiSIT". I couldn't help myself, I had to hear the Arch Nemesis when driven with some voltage gain. So I made monoblocks in the style of M. Rothacher's MoFo, repurposing the heat sinks, the IRFP240's, and the salvaged ~19.5V IBM laptop power bricks I'd used in my MoFo build. The rest was filled out using leftover & salvage save for a pair of 1R 40W power resistors from a local electronics shop. I bent mounting brackets for the power resistors from scrap steel at a local maker space.
I needed a simple and dumb mechanismus for gate bias. It's a mere voltage divider between rail and ground, with the FET's gate taken off the midpoint of two 10K resistors, and a pot in parallel with the 10k resistor to ground, for tuning purposes. I fried the wiper on a 5k pot with a miswire so I turned to some 500k bourns pots in swappable pin sockets, in case it happened again. A gate bias of 6.12V and 6.22V respectively draws about 1.7A, but if those dumb pots fall out or go open circuit the gate will be slammed to half of rail, and those bricks will likely dump most of the 4A+ they're capable of. A fixed resistor may be in order.
These things sound really good, better honestly than they have a right to. They're full of bass and plenty smooth whether playing through full-range horn loaded drivers or 2-ways with series crossovers, whether electronica through bluetooth or jazz from an antique CD & player. I guess the lesson here is, if you've got a special project requiring a weird output transformer, don't be afraid to roll your own. You may be surprised with how good they sound.
I recently acquired and built an ACP+, my one and only preamp with voltage gain, which totally changed my perception of what was possible with source follower topology like ZM's "Redneck DEFiSIT". I couldn't help myself, I had to hear the Arch Nemesis when driven with some voltage gain. So I made monoblocks in the style of M. Rothacher's MoFo, repurposing the heat sinks, the IRFP240's, and the salvaged ~19.5V IBM laptop power bricks I'd used in my MoFo build. The rest was filled out using leftover & salvage save for a pair of 1R 40W power resistors from a local electronics shop. I bent mounting brackets for the power resistors from scrap steel at a local maker space.
I needed a simple and dumb mechanismus for gate bias. It's a mere voltage divider between rail and ground, with the FET's gate taken off the midpoint of two 10K resistors, and a pot in parallel with the 10k resistor to ground, for tuning purposes. I fried the wiper on a 5k pot with a miswire so I turned to some 500k bourns pots in swappable pin sockets, in case it happened again. A gate bias of 6.12V and 6.22V respectively draws about 1.7A, but if those dumb pots fall out or go open circuit the gate will be slammed to half of rail, and those bricks will likely dump most of the 4A+ they're capable of. A fixed resistor may be in order.
These things sound really good, better honestly than they have a right to. They're full of bass and plenty smooth whether playing through full-range horn loaded drivers or 2-ways with series crossovers, whether electronica through bluetooth or jazz from an antique CD & player. I guess the lesson here is, if you've got a special project requiring a weird output transformer, don't be afraid to roll your own. You may be surprised with how good they sound.
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I always have affection for anything that sounds better than it has a right to.
Thank you for your kind encouragement, Mr. Pass! I appreciate it!I always have affection for anything that sounds better than it has a right to.