I will first start out by saying that I am a completely new to this subject matter, which is why I am here. My only experience is in guitar pedal making and preamp pedal design. But I have been dreaming about making my own class D guitar amp with a preamp. I know something like this would be better tooled towards bass but taking a quick look at the market it looks like some companies are already making high wattage guitar/bass class D amplifiers (example Verellen amps).
My end goal is to design a amplifier that is capable of handling 4x12 16 ohm 150W speakers using a tube preamplifer, which I will probably base around the Sunn Model-T so I could also use it for bass guitar. The reason I am doing this is I just like DIY projects and learning new things along the way.
My question is if you know of any good threads or articles that could help me reach this goal. I have tried looking in the class D forum and I am either missing a concept or searching to broadly. I have also watched the youtube video made by petey twofinger on class D guitar amplifiers. Seems like people find the correct class D module, a power supply, and then a preamp and then box it up?
Appreciate the help!
My end goal is to design a amplifier that is capable of handling 4x12 16 ohm 150W speakers using a tube preamplifer, which I will probably base around the Sunn Model-T so I could also use it for bass guitar. The reason I am doing this is I just like DIY projects and learning new things along the way.
My question is if you know of any good threads or articles that could help me reach this goal. I have tried looking in the class D forum and I am either missing a concept or searching to broadly. I have also watched the youtube video made by petey twofinger on class D guitar amplifiers. Seems like people find the correct class D module, a power supply, and then a preamp and then box it up?
Appreciate the help!
Might be a better idea to end up with a 4 ohm cab - that way, you could get away with a lower power supply voltage for the same output power / SPL.
To push 150w into 16 ohms (i'm guessing four series-parallel 16 ohm drivers), you'd be looking at an amp working off of a +/-75V-ish supply, assuming it's single-ended.
150w into 4 ohms (same four 16 ohm drivers, but all in parallel) is well within the range of class-D chip-amps, like some of the bigger TAS-series chips from Texas Instruments, or TDA chips from NXP or ST. Most of those work in "bridge-tied load" mode, so you'd only need a single 35V supply, able to provide enough current (8-10A or so).
Or if you insist on going with discrete-component amplifiers, lower-voltage FETs for the amp are cheaper and faster (lower gate charge) than higher-voltage ones. Class-D amps are better(?) at pushing out large currents, than large voltages 🙂
To push 150w into 16 ohms (i'm guessing four series-parallel 16 ohm drivers), you'd be looking at an amp working off of a +/-75V-ish supply, assuming it's single-ended.
150w into 4 ohms (same four 16 ohm drivers, but all in parallel) is well within the range of class-D chip-amps, like some of the bigger TAS-series chips from Texas Instruments, or TDA chips from NXP or ST. Most of those work in "bridge-tied load" mode, so you'd only need a single 35V supply, able to provide enough current (8-10A or so).
Or if you insist on going with discrete-component amplifiers, lower-voltage FETs for the amp are cheaper and faster (lower gate charge) than higher-voltage ones. Class-D amps are better(?) at pushing out large currents, than large voltages 🙂
Thanks Khron this has given me a lot to think about. I could really design it for any speaker I just have limited space and only currently have a 8x10 4 ohm bass cab (not a space saver) which may be a better cab to design an amp for or the 4x12 guitar cab. I am going to have to read up on a lot of what you said if I have more question I may shoot you a message. Thanks again.
For what it's worth, i've seen a few 4x12 guitar cabs with dual input jacks, one wired for 4ohm, the other for 16ohm.
IcePower modules are used by some guitar amp manufacturers and are excellent. However, this is mostly for bass guitar and steel guitar where you want clean clean clean. Six string guitars need tubes!!
Class D amps have come a long way over the years.
You will need a decent amount of gain before the amp.
I have designed guitar amps and found them pretty flat.
I have always added tone controls and a soft limiter to make the sound more interesting.
You will need a decent amount of gain before the amp.
I have designed guitar amps and found them pretty flat.
I have always added tone controls and a soft limiter to make the sound more interesting.
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For this application, I would aim for the class d amp to be capable of 300 watts at 4 ohms. Still not a big deal to build, still not terribly expensive. +/- 30 to 35 volts unregulated or 50 volts regulated will supply this to a full bridge class D module. You do not want the amp to clip or limit - you want whatever emulation or processing ahead of the clean amp to do that. Set the gain ahead of the clean amp so that you get 150 watts when your preamp is limiting and providing whatever "sound" you are aiming for. You will get more than 150 watts of average power when simulating an overdriven 150 watt tube amp, and the 300 watt clean class D amp will faithfully reproduce it. You could even use a small (10 to 15 watt) tube amp, complete with transformer and network emulating a guitar speaker as the front end. Or do it digitally, or whatever.
This. Do not clip your (feedback based) solid state stuff.
And as others have said, guitar and bass are two completely different (ok, five or six completely different) applications. I have a 10W guitar amp that is "too loud" compared to a 120W of bass amp. Hint: they're trying to do different things and are doing them differently.
Pretty much everything that needs to be said on this topic is in the Tube Emulation Thread. Go read it.
If I read your post correctly, most replies are not answering your question.
If your goal is to learn to design and build the Class D power section of your amp then this thread is a good starting point: Class D Design Issues
Hate to say it but the Class D forum is a better place to post such questions.
If your goal is to learn to design and build the Class D power section of your amp then this thread is a good starting point: Class D Design Issues
Hate to say it but the Class D forum is a better place to post such questions.
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