Hi all!
So I already built two LA4440 guitar amps but both sound too sterile (clean, but not warm clean) and washed off of warm sounds.
So I thought why not build a transistor preamp for it, but I don't have enough knowledge to build a good preamp, so I wanted to ask for help, and I want it to have dirty, crunchy Hendrix sound, but also very warm Bassman cleans.
Is it possible?
So the bridged schematic under the first one that has 19W needs to be corrected, and it has to have its own preamp.
Thanks for helping in forward!
So I already built two LA4440 guitar amps but both sound too sterile (clean, but not warm clean) and washed off of warm sounds.
So I thought why not build a transistor preamp for it, but I don't have enough knowledge to build a good preamp, so I wanted to ask for help, and I want it to have dirty, crunchy Hendrix sound, but also very warm Bassman cleans.
Is it possible?
So the bridged schematic under the first one that has 19W needs to be corrected, and it has to have its own preamp.
Thanks for helping in forward!
Anybody?
Akward, I feel like I wrote something wrong.
Or is it just that LA4440 is not meant for guitar...
Maybe a little of both.
But in actuality there are maybe a dozen people here to any great extent and there are times we are waiting just like fish in a pond below a branch with tasty bugs that might fall into the water (use waiting for a request for help on an obscure amplifier). It is easiest if you say to yourself, 'It is not about me, maybe they work for a living.'
Looks like you could use a good preamp, are you going directly into the chip with your guitar? So you want a 6W amp (probably more like 4W) to give you dirty, crunchy Hendrix sound and very warm Bassman cleans? A tall order. Have you listened to any pedals that you find appealing. Speaking of making a big influence on the sound, what are you using as a speaker?
Me misunderstanding is not unusual, no more than wondering where my glasses are. Have you thought of the pedal thing?
Yeah... But I want the amp to be all built in, with dirt input, clean input, and a mic input...
And what is stopping you from building a pedal into your amp, or at least portions of it? At least you will have an idea what kind of sound you want and the circuitry that can do it. The diy pedal community is quite strong and have a good handle on what can be done with solid state at low voltages. Other than that you can pick a solid state amplifier that you think will give you what you want and then copy its circuit. Since you do not have the knowledge to develop your own preamp and do not want to put in the time to get that knowledge, what are your other options?
Here's a well-documented project that also shows a guitar-preamp schem and wiring etc. Which may be - or may not be - useful to your build.
100W Guitar Amplifier (Mk II)
100W Guitar Amplifier (Mk II)
I want knowledge, and I study electronics regularly, because I'm interested in it, but amp needs to be built for 3 days cause I am going to give it to a friend who needs it immidiately to go somewhere with it and play with batteries.
And that is my point, you can't re-invent the wheel without a lot of effort so that gives you a few choices. Again, you have to grab an already working design or at least something you can cobble together. You do not say what parts are available to you, how you are going to construct it. The only thing you throw out you want the sound of two iconic tube guitar amps.
So how are you going to do that without tubes? Have other people gotten close to what you want with a circuit running on batteries? Now we have two more constraints, you need it in three days and it has to run on batteries. How many volts? You say you will be achieving 19W. I think the big question next is your part supply. What electronics have you to use? No sense giving you a circuit when you do not have the parts for it.
YouTube
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Then forget it, you just turned a somewhat difficult task into an impossible one. Sorry.
As reference: I *commercially* design and build amplifiers, am fully setup, besides a complete Carpentry shop I can cut/bend/punch/paint/silkscreen chassis, already have a stock of sheet aluminum, paint, raw copperclad boartd, heated acid bath, make my own speakers, design prints and process my own PCBs, wind my own transformers, in sum am fully setup as far as machinery (not only tools) , have made some 14000 amplifiers in almost 50 years, including battery powered ones, always have a couple 12V 7A batteries in stock, ... and even so would be hard pressed to make a new design out of the blue and have it "deliverable" in 3 days.
You might recycle some wooden box or attache case, get and mount some speaker, etch/drill/process some PCBs (IF somebody gave you the ready to transfer designs that is) , you might get parts, including a battery, adapt/ludge a charger, just to have "something which sounds if you plug a guitar" in a week or so.
And you want it to do the Bassman thing?
Sorry, not a realistic goal.
Have your friend buy a Roland Micro Blues Cube which does all that except it´s only 2 W out, you can connect it to a 15/16W bridged amp (fed from a 12.6V battery) if you need more power.
Or buy/clone a Sansamp Classic pedal which again does it (and very well) and feed it into the bridged amp.
If you have everything needed (although I doubt you stock rail to rail Op Amps and they are needed) , included some case, the battery, speaker, etc. then you *might* do it in 3 days ... but drop that keyboard and start NOW.
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But that is doing it the right way. To slap something together there are some veroboard designs you could get together and have a C shaped chassis bent and everything mounted to it. A few holes for jack and pots, switch, it is doable. Won't be pretty.
veroboard pedal plexi - Google Search
One IC but it is going into a preamp which has tone controla and I am guessing a little scoop out of the midrange. Seems no one goes directly into the power amp. Needs a LM386.
Guitar FX Layouts: Lovepedal Purple Plexi 800
YouTube
veroboard pedal plexi - Google Search
One IC but it is going into a preamp which has tone controla and I am guessing a little scoop out of the midrange. Seems no one goes directly into the power amp. Needs a LM386.
Guitar FX Layouts: Lovepedal Purple Plexi 800
YouTube
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This is exactly the problem with 99% of solid-state guitar amps. They are too clean when clean, and abruptly too dirty when overdriven. They tend to go directly from cold and sterile to wasp-in-a-tin-can buzz.
This is not just a subjective opinion - there are good technical reasons for this behaviour, and they come from the fundamental differences between solid-state devices and vacuum triodes.
People have been trying for many decades to make solid-state guitar amps that sound like valve amps, and even today, very few have come anywhere close to succeeding.
I myself have tried to to do this many, many times, and never succeeded. I've made some amps that were less-bad than others, but none that were as good as a real (good) valve guitar amp.
One Russian engineer who has come pretty close is known as KMG on several audio forums. You can find out more about his really amazingly good work here: Главная страница
-Gnobuddy
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