Low wattage amplifier for a small vintage PA speaker

[thomasha]

I got a small PA speaker that looks like a lunch box

and was thinking about building a mini amplifier with it.
When I opened it up I noticed that it uses a 50 ohm speaker, and not 8 ohms as I am used to.
So, the class D amplifier I was going to use got shelved again and I tried something with the well known LM386.


The schematic is the basic configuration, with a gain of 20, without any other stage.
The IC alone has enough gain to reach its maximum output before distorting.
Using a 12V power supply the maximum output before distorting is something like 10V peak-to-peak for the 50 Ohm speaker. The datasheet shows that the output before distorting is considerably higher, than at 8 ohms.

With a gain of 20, the +-5V (10Vpp) is only 0.25V (0.5 Vpp) at the input. So, no other stage is required, IMHO, unless one would reduce the amount of signal coming from the guitar.

I also added an overload meter, as in the DMM, using a 2N5087 transistor, 22k resistor bias to Vcc and 180K resistor to base. Falstad simulation here. It lights up when the output is at the +-5V (10Vpp). So I have an Idea when this thing is actually reaching distortion. The 180k ohms is quite high though...

The sound is quite OK, but I thought it could use a cabinet simulator in front of it.

For testing purposes I used my Astrosim Cab. sim. and it improved considerably. I mean, why don't we always use cab. sims in front of such mini amplifiers? It takes away a lot of the high frequencies making the sound considerably better.

What is your opinion? Anyone tried using cabinet simulators with other mini amplifiers?

In the age of digital stuff, I see that much of what we think sounds good is actually created by software, like the fake bass, our brain hears when all the other frequencies are there. Could one achieve something similar without going full digital?

I found some info about the blackstar mini amp, which uses a gyrator?
Has anyone tried something like this? It should, theoretically, make the box sound less like a small box.