What is that blue thing and why did I install it?

[mmagliaro]

Most of contemporary sound decoders use Class-D amps (which use PWM to drive speakers directly).  They are also very efficient, so they do not run hot.

Bus some low-end sound decoders (MRC is one, and probably only-one), still use old-school analog audio amp chip (SMD version of LM386), and an analog voltage regulator (both of which generate heat).

By the way.... this made me chuckle,
" In the vacuum tube days they used inductive coupling (transformer) to drive the speaker, "
You betcha!  Just like my Fender Twin Reverb all-tube guitar amp,  where a lot of the weight is that big ol' output transformer.

[peteski]

By the way.... this made me chuckle,
" In the vacuum tube days they used inductive coupling (transformer) to drive the speaker, "
You betcha!  Just like my Fender Twin Reverb all-tube guitar amp,  where a lot of the weight is that big ol' output transformer.

I'm glad I was able to amuse you.  We go way back!  Transformers were/are excellent for impedance matching: The primary having high impedance needed for the high voltage tube output stage, and the secondary having low impedance matched to the voice coil of the speaker.  It was a beautiful thing!  Have you ever wound your own transformer?

[Cajonpassfan]

Yes we have come a long way..but talk about a thread drift!
My new toy... the Spark😎
Wow. A “practice “ amp. Google it if you have questions.
Otto

[peteski]

LOL!  A "smart" guitar amp that connects to a smart phone app, and a ToneCloud!!  A 1-man band!  Where will the technology take us?   

I don't know much about electric guitars but yours looks to me like a Les Paul.

. . . just keeping on drifting  . . .

[Cajonpassfan]

Lol, Peteskí, no, I wish: it’s an Aria Pro, good enough for this amateur.
But there are eight others in the house, all different styles and types (my other habit)
Now back to regularly scheduled programming...
Otto

[mmagliaro]

Actually, it looked like a Gibson ES-335 style and so when Otto said "Aria", I looked it up.  It looks like an Aria TA Classic, are you sure of what you have there, Otto?  They are very well reviewed.  I've always wanted an ES-335, but they cost way too much $$$.

[Cajonpassfan]

Ha, you got me Max, I bought it new about 35 years ago, I think before the “classic” moniker was used and paid about $400 for it (seemed like an ungodly sum then). But yea, it’s a very good instrument. But, I also have a very old Gibson “stereo” after which tha Arias were patterned. We should start a new site, he “stringwire”?
Otto

[MarkInLA]

When you get around to the upgrade don't forget to squeeze in a keep-alive circuit as well !!! Yuk yuk !! M