LM386 amps: LM386 serves as power amp?

[add4]

Just being curious here:
i just built the noisy cricket, but also looked at the schematic of the ruby and i saw the JFET in front of it.
I wonder if the LM386 could be seen as a kind of 'power amp' on these circuits.
if yes, would that make sense to add a kind of 'preamp' section in front of it to control/flavor the sound entering the LM386?

[R.G.]

The LM386 *is* a power amp, albeit a small, low powered one.

[PRR]

> control/flavor the sound entering the LM386?

You could.

> would that make sense...

The big deal about LM386 is 5 wires and you can drive a loud speaker. Very Easy.

Just adding a buffer and volume control, like the Ruby, triples the amount of work.

Multiple stages of distortion, bass/treble, vibrato, reverb mean hundreds of connections.

Now you look at a $100 preamp with a $1 power amp with <1 Watt of output, and wonder if you should up-size to TDA2002 or 2*6L6 power stage so it can be heard more than 20 feet away.

[Earthscum]

I'll give you 3 guesses what chip these use, and the first 2 are wrong... 

http://www.smokeyamps.com/

[add4]

OK i don't know the first thing about how amp works so i might say something stupid here, but i have that question in mind so, i'd love to die a with a little more knowledge..
How much sense does it have to think about using Doug Hammond /runofgroove trick of replacing tubes by JFETS to  emulate the preamp / amp of idk .. a fender,box,insertanynicesoundingamphere and add a small transparent solid state power amp section behind it, say 20 watts..
is it possible ? would it sound like the original (at least a bit like the original... :p )
just being curious about it as it seems like an appealing idea to me
thanks

[bcalder]

Hey add4,
I don't know squat about amps either, but the low-wattage SE amps I like are even too loud for home practice. I'm making one using a Tiny Giant (http://musicpcb.com/pcbs/tiny-giant-amp/) as the power amp, a ROG Supreaux Deux as the front end "flavoring" and a 6x9 oval speaker to make a budget Supro. Though lately I've been thinking a Valvecaster might make a nice front end ...

I should be done soon, and I'll let you know how it turns out.

[petemoore]

  To oversimplify: a recommendation to use the components and circuits you prefer the sounds from.
   386's have a 15v max on power supply...enough to 'wiggle' a speaker, not enough current to support much bass response or volume.
  As an amp at very low volume the signal can remain soemwhat linear, quickly turning into '386 distortion' if volume or bass is increased [the effeciency of the speaker matters greatly with 'power' being a scarce commodity].
  Very easy to experiment with, and can power some small speakers or headphones..enough to 'get them going', but easily outperformed by pretty much anything with a higher supply voltage, the only loss being the '386' sound.

[add4]

ok about the 386, but well let's imagine things.. using another power amp solution? would that be possible?
theres the tiny giant and other solutions at the solid state amp forum ..

[teemuk]

How much sense does it have to think about using Doug Hammond /runofgroove trick of replacing tubes by JFETS to  emulate the preamp / amp of idk .. a fender,box,insertanynicesoundingamphere and add a small transparent solid state power amp section behind it, say 20 watts..

For "emulation" it doesn't really make much sense at all. The "add 9V power supply, replace triode with FET + drain trimmer" -recipe will result into circuits that perform pretty much entirely unlike the tube circuit they try to copy. Gain is way off, frequency response is way off, clipping characteristics are way off. Triode and pentode circuits can be very accurately modelled with JFETs or any other solid-state componewnts but that method is not one of those accurate ones. It's totally way off.

Most of that sort of stuff also entirely fails or even neglects to model power amp in any way so you have a colouring tube power amp vs. transparent solid-state power amp. It can be a very big difference. The end result of everything combined is usually that these circuits sound entirely different from the stuff they try to "model". They can sound nice though - in their own way.

is it possible ? would it sound like the original (at least a bit like the original... :p )

No, not as simply as that. No, it won't sound like the original. Perhaps a bit like it, at least on clean tones, but that's all.

ok about the 386, but well let's imagine things.. using another power amp solution?

Even if you're talking about chip-based solutions there's more than several handfuls to choose from, ranging from low power class AB and class D stuff to high power class AB and high power class D stuff. What output power range are we actually even discussing about? Does the topology matter? Are there any other details that could actually limit the gigantic amount of possible chip solutions to a more sane number e.g. supply voltage limits, battery powering and so on....  

[add4]

hmmmm
i guess pedals are great at the moment .. that was an 'out of nowhere idea' and i understand why it's not been done before ...
i'll go back at it when i'll have more than 2 months experience in practical electronics i guess:)
i'm still interested to know more about the power possibilities for solid state amps, not battery powered,
i made the noisy cricket .. it's not bad .. but you're very fast at volume 11 with this thing . and i'm not a loud player