Metropoulos Forum

Hi. This is my first post. I have a question regarding an amp phenomenon, but I don't know the proper terminology. I'll try to describe things as best I can:

I'm wondering what factor (or combination) results in an amp being "smooth" (with notes blending into each other), as opposed to being more "defined" (with a harder edge to the notes).

I see the timbre of a jtm45, or a blackface fender as being "smooth", whereas Marshall jmp and jcm amps are more "defined". When playing a clean passage on a jtm45 vs a jcm800, the notes on the jtm seem to "blend together" more than those played on the jcm800.

Is this phenomenon a question of compression?
If this is a result of compression, can something defined (like the jcm) be made less defined?

can an amp be made with a switch that will allow smoothness and definition, depending on the switch position?


Thanks

Different amps (specs, models) sound different. You hear differences between shared and split cathode, bass spec vs lead spec, tube rectifier vs ss, non cascade vs cascaded pre amps, iron, tubes etc...
Welcome to the forum

That along with filtering. Split cathode with high filtering, vs shared cathode with lower filtering makes a huge difference in feel and sound. Throw in a mixture of the two and you're basically in '68 with the 12 series Super Lead and the 1987 (50 watt).
Those amps are amazing and so versatile.
That said, a JTM-45 is still such an incredible amp, like the 45-100 and the '67 100's with EL-34's.

Thanks for the replies. By "filtering", you're referring to filtering done by capacitors within the power supply, right?

Hi,

and don't forget the JTM 45's much stronger NFB (27K / 16 Ohm tap v.s. 47K / 8 Ohm tap v.s. 100K / 4 Ohm tap) of the JTM45)!

This makes also a huge difference in Sound, e.g. 100K / 4 Ohms sounds really sharp / shrill / aggressive.

Regards

Robert