That's easy enough, there are plenty of speaker-level to line-level converters out there. If you want to go from two to nine, you'll need to first determine how you're going to mix the two channels down, unless you want 18 total outputs. After you get the line levels, then it's simply a matter of buffering it and feeding it into the requisite number of amplifiers. For the most part, line is high impedance so putting a blocking capacitor after the plate and feeding your signal into the appropriate resistor will give you the impedance you're looking for.t
In regards to the comment you posted on mine about noise and tubes -
Tubes are fun to use and they're a cool thing. But they're also power hungry, generate a lot of heat, and require higher voltages than you're going to find in a car. For most common applications, say a 12AX7 triode line-level amp, you're going to need 200mA of regulated 12V for the filaments (needs to be regulated, your alternator floating all over the place will burn them out quickly) and 180-250VDC of plate voltage.
So not only are you now concerning yourself with a relatively fragile heater in a glass bottle, you need two more circuits to generate the appropriate voltages. Using solid-state supplies here can generate a lot of what's called hash noise, so you're going to struggle getting a clean voltage to not make your tubes whine.
Don't buy into the hype that tubes are somehow better - a simple good quality op-amp circuit will do the same thing, be cleaner, and work better.
you don't really see tube amplifiers in car audio but look what has popped up as of late. https://www.nonsolospeakers.com/4-channel-amplifiers/9944-nakamichi-n40t-450wx4-tube-amplifier.html
they are a new company and everyone who acquires their products see to be extremely satisfied. though I'm not trying to design a tube amplifier like they have yet lol I was just curious on building a well I guess 2ch x 9ch tube amplifier that converts speaker line impedance and outputs an adjustable RCA signal that can amplified so I can send super clean signals as uneffienct as possible hahaha. now i found that amplifier i might even go as uneffienct as possible to seek crispy clear. i have done basic sound deadening now the sealing and sound insulation comes
That amp isn't using tube finals, it's solid state. They've simply stuck a couple of triodes in there as a pre-amp. Looks like they use 1/2 of a 12AX7 for each channel.
thanks for input ill avoid it until I find or can design build what I want. why I posted it I knew you could see it for what it is.
My main objective was focusing on signal conversion and using a tube to let me amplify signal enough to meet amplifier's max input voltage gain needing no more than 25% and producing far more rated output with one crisp ass input signal outputting clean tonality, and musically blissful tubes are known for. I personal think they are better but that is my opinion.
So what I gather off your last post ill have to put a Low Pass before or after speaker line impedance is changed to remove any frequencies above say 120hz, then using a voltage regulator, smoothing filter and some capacitors, I can properly power the tubes preamp, run signal through to a Class D output modified to be RCA.
To answer the other question about the outputs I would need 8 channels for the front and 3 channels in rear maybe more as not sure on how many channels that depends on if I run a 3way component or just a set of 2/3 way coaxial's in doors for fill. I prefer doing a complete rear sound stage like the front so passengers can enjoy the same music as the front so possibly 7 channels in rear so between 11-15 channels when completed and depending on how far I got in rear. super complexity would come if I wanted to make each channel seperate which I taking a wild guess would require a High/Low pass filter network for each channel so they were define for a purpose. if I have to do that I would need up front 1 Mono, 3 Stereo Channels Mid-Bass, Mid-Range and Tweeter, Rear would need 1 Mono and 1-3 stereo channels. i would place outputs like so
|front-left | front-right | | front-sub | | rear-left | rear-right | | rear-sub |
In theory I suppose I'm trying to do similar as that "Nama" amp. they are using high and/or low level running through tube preamp and using the class d solid state eff to boost speakers.
I'm trying to convert the high level input into a signal to run through a tube preamp then through a Class D amplifier that outputs a RCA signal instead of outputs for speakers where I want to build a amplifier tube Line-Out Converter for the amplifiers that will power the speakers. might be far fetched but it is a interesting idea and I'd like to see how it affects the performance of amplifier classes. I know there are plenty of Converters but they are tubed and if something and be tubed then lets tube it
regarding the tube voltage issue I think that can be overcome by I can place a capacitor bank or a Voltage Stabilizer between alternator and battery when will drastically improve voltage smoothness.
I am fixing to build a battery Isolator probably diode based, which is going to insure my main system is safe from draining with the secondary.
I found a bunch of super capacitors that ranged from 100F-3400F and voltage ranged 2.7-5.5v for $6-$45 each. I can wire how every many in series to obtain a needed voltage in the rear along with either a XS Power battery or a sodium ion power bank that has plenty of reserve. I can probably find a DC - DC booster that can handle the voltage difference the tube will need.
I might be a gleam idea but I really would like to design one and make it for enjoyment and the learning aspect. never got to play with tubes and now I'm older I want to experiment while I can and stuff a knowledge deep in my sons brain. he is always building paper robots. im going teach him to build speakers then we are going to try to build a rotary speaker for my truck that will be infinte baffle so should be absolutely bonkers in there.
based on your comment with my intended goal truly what I'd be trying to accomplish is a Class A tube amplifier that used Speaker Line inputs, change speaker line impedance, signal through gain adjustable amplifier circuit, output signal to RCA's, RCA connects to amplifier connected to speaker
so based on that would it be possible to then connect a simple opamp circuit for the impedance change and feed that to a Class A Tube amp input for the HiFi signal and do the biasing and switching with a Class D output and just output the signal to RCA's that will be used for the inputs of the amplifiers which then in theory if all Class D amps are used to amplify the signal system should be Eff but also crisp clean and breath taking all done with the desire to obtain it through non-dsp means just good ol circuit designing
It's not smoothness that you're worried about here. It's 12.6VDC. Period.
Your car's electrical system is rated for 13.8VDC. Your tubes want 12.6 (or 6.3 or 3 or 5 or 1 or whatever tube you've chosen.) Going above that range by too much will burn out the filament or stress it to the point where your expensive tube is now a glass bottle with some metal in it. Yes, a 12.6VDC tube can handle 13.8VDC, but that's the absolute upper limit. You're still short the plate voltages which you'll need to invert to get to the higher voltage. You can get inverters to do that, but solid-state stuff can induce noise. Your car's electrical system can induce a lot of noise as well, especially stuff with a lot of modern electronics. You're going to need a lot of filtering and shielding to do this right.
A word about what line-level means, when you say that it refers to a very specific thing. 1V @ 600Ω is typical line output, 10k is typical line input. You don't need more than that - I would usually limit my stuff to 2V when I did some audio work. I'd also usually tie the output of the preamp to 20k - that seemed to work well. Get too much of a mismatch and you get noise.
Are you looking to use 9 monoblocks for your finals? I assume you want mono output, and not stereo?
the sub amps are mono but my current door amps I have one is a Timpano tpt500.4d and my rockford is a 300x4.ab and I plan to grab a 3@ class d 4 channels one for front/rear Mid-Bass, one front front/rear Mid-Range and one for front/rear Tweeters ill use 2 class d mono blocks for subs. im just pondering how to make a lineout converter that has a amplifier attached to the signal raising the voltage to 6v preferably but upto 7.5 cleanily as i am seeing alot more amplifers with much higher input headroom then ever before. im basically dreaming up a super nice ass LOC and rca voltage amplifier all in one.
now i think on it the lineout converter can be the high level input of a amplifer, use the tube for the preamp of the amplifier boosting the rca signal outputs it powers.