I simply cannot afford this product I want. I'm wondering if there is anyone I could pay to help me design a clone of this? Or if there is a DIY product on the Forum like this with plans I could build one from? If you scroll down the page you can see a photo with the top off.
DECWARE all tube gain stage / purist preamp model ZSTAGE
DECWARE all tube gain stage / purist preamp model ZSTAGE
A 12AU7 gain stage with 4 vac output is nothing special. Look at V304a V304b of a hammond H100 organ. Those have a 7 vac output. 250 v source, 10 k plate resistor, 560 ohm cathode resistor to negative bypassed by 50 uf. 1 meg ohm to ground input attenuator pot. Change ratio of plate resistor & cathode resistor for different gains.
Why you would want 4 vac output is beyond me. You'd have to have a PA amp with input attenuator to get away from standard 1.6 vac full volume. Hammond wanted 7 vac because they were running the signal 100 feet in a cable with 120 vac. They produced a differential signal with two opposite phases for noise reduction.
the whole tube fascination thing is beyond me. Yes, they will take a mile away lightning strike without damage, if the transformer is wound with insulation as good as a hammond. We have MOS suppressors now to take the hit. Sound? My PAS2 preamp lost its pure sound when the paper dielectric general instrument cap went bad & I replaced it with polyester. My RA-88a op amp mixer sounds better, now, at 1/100th the electricity burned. After I modified it for ST33078 op amps instead of 4558. The only thing unique about vacuum tubes is the ability to flatten sine waves sweetly if you run them red plate. And 12AU7 is no good for that. You need 6L6 or something similar.
Why you would want 4 vac output is beyond me. You'd have to have a PA amp with input attenuator to get away from standard 1.6 vac full volume. Hammond wanted 7 vac because they were running the signal 100 feet in a cable with 120 vac. They produced a differential signal with two opposite phases for noise reduction.
the whole tube fascination thing is beyond me. Yes, they will take a mile away lightning strike without damage, if the transformer is wound with insulation as good as a hammond. We have MOS suppressors now to take the hit. Sound? My PAS2 preamp lost its pure sound when the paper dielectric general instrument cap went bad & I replaced it with polyester. My RA-88a op amp mixer sounds better, now, at 1/100th the electricity burned. After I modified it for ST33078 op amps instead of 4558. The only thing unique about vacuum tubes is the ability to flatten sine waves sweetly if you run them red plate. And 12AU7 is no good for that. You need 6L6 or something similar.
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