@Stupidbirdis probably charging on his station atm, but I’m sure he’ll be glad to help soon.
Well...a perfect preamp takes the the input and makes it bigger without modifying it in any other way - that's the basic definition of an amp, so if you're modifying the sound in some way that's your preference. Filtering of any sort is per the listener - if it sounds good to you, use it.
And a pre-amp, what are you driving that needs a low-impedance output? A preamp is supposed to feed the signal into your main amp, so while it can convert hi to lower (think a phono amp) it's still "hi impedance" for the most part - a tube amp reaches low impedance at the final output drive (your speaker) and does so with a transformer. That's really the only way you're going to get low impedance out because a tube by nature is hi impedance. I'm sure there are some circuits out there that can bridge it down, but you're trying to not use the tube like it's designed at that point. A transistor is going to be your choice if you want to direct drive a low impedance system.
(What are you considering low impedance here? 100 ohms?)
I'm not familiar with class AD amplifiers, that seems to violate itself because they're two different animals...Class A is all the power all the time while class D is no power until needed. What sources are you looking at for this one?
Ok, fair enough - let's take one question at a time.
If I understand correctly, you want to take two speaker level outputs and convert that to nine line-level signals to feed that into other amps?
yes my left and right front speaker lines will turn into multiple RCA outputs
I'm curious to the application myself, RF is vastly different than a guitar amp vs car sub amp. Low impedence in car is .5 ohm, low impedance for guitar or home audio is 4 ohm.
Tubes indicate a desired coloring the sound for guitar and bass, while the rest seem car audio.
this is for a car audio setup. I want to build a Line-Out that uses tube technology to convert the speaker line impedance to RCA's while also getting finer voltage adjustment and can increase voltage from factory 4v to a crisp 7.5v without distorting as my last 5 LOC's would distort the signal if I increased the voltage above 4.5 volts. if I increase RCA voltage my amps will best realize rated power and produce a cleaner signal if RCA voltage is maximum amp can input which mine are 6v which gives a cleaner signal since you don't need much gain at all to realize power.
Tubes add noise when improperly run. If you bias it correctly, it outputs exactly what goes in, except bigger.
If you starve them or overdrive them, they start to add "color" as it's called. Great when you want a fuzz pedal, terrible when you want Bach to sound like Bach.
exactly why I'm asking for help lol. I don't want to add color only to use them to keep signal HiFi as its converted and let me increase voltage on the outputs by 3.5v maximum.
100% agree, that's why knowing the intended application is critical.
i dont run low impedance speakers like .5, 1 ohm speakers I like 4/8 ohm DVC subs and svc 4/8 ohm for other speakers. higher impedance produces much better sounding and responsive drivers. those that use low impedance for subs is for daisy chaining 12 18"s in a TAHOE or some other dumb shit you can think of. I like studio quality but at much stronger levels. I don't want it concert loud anymore but a nice small gig or dive venue is respectable. I'm going full IB with my Subs and Mid-Bass woofers, rear subwoofer will be set in rear right corner of truck cone firing through cabin, along with all equipment so I still have 60% of rear cabin. front sub bass will be a 8' mounted cone through floor on passenger side. will be 1 6.5" mid-bass woofer on each side in floor kicks with cone through floor, tweeters and 4" Mid-range will be mounted in dash with midrange 30% on axis and tweeter same.
also class AD hybrids accept signal wheter high or low impedance and run it through tubes to amplify signal which then the signal if fed through a mosfet nchannel output circuit which in theory lets you obtain a more clean output. butler audio th2150 uses this technology
forgot to respond to ya sorry. i did get a few things capable from it after examining butler audio tube amps but in all couldn't agree to the price to build it. alot of things made it a challenge and mostly to me that was needing digital means to controll voltage as simple resistor networks or small cap banks wouldnt let me get the ideal configurations to accomplish my goal and the transformer was huge
transformer was huge
Yep. Welcome to yesterday, it's why we live in today instead.
still prefer the clarity of tubes anyday. might try to source out a butler audio tube amp and just use a dc to 110 converter and enjoy. however i have decided which way im going to go with my trucks sub bass and will just build a 3d polygon which cuts through truck bed header and cabin then i can start with one sub and as i buy more add them to the polygon unbtil i have 4 18's in free-air. will retain both my read seats and gain all my space back.
ill probably grab a raspberry pi 5 and add to ADC hats and found 2 4 channel output DAC hats so i can also enjoy the dsp featues of the RPI5 plus i have a radio dash kit for my truck to install a 9" screen for a nice multimedia setup. i think ill even be able to use the harness i have to retain swc functions