Some Discussion on Amp EQs

Ah, OK. For some reason that didn't pop out at me when I first read it, but it could have been that I'm extremely tired but can't sleep Thanks Charlie.

 

I think post #1 in this thread is possibly the most epic opening post I have ever seen in any discussion on the forum.

It's this sort of stuff that really makes TalkBass what it is. Thanks for taking the time and trouble to share this expert info.

 

Incredible thread.

 

Really awesome thread. Thanks for sharing.

 

This really makes my understanding of the different stacks much deeper and more easily related to how I practice using them. Wonderful and useful thread!

The thought of a Hiwatt clone amp with a mid control like the SVT seems like it would make a holy grail combination. Has no one done this before?

 

Hiwatt one would be appreciated.

 

Very good...thanks for the further explanation. And thanks for a really interesting discussion.

 

Here's another nice discussion of these tone stacks from an old friend of mine, done back when ASCII diagrams were still uptown. Kind of the Cliffs Notes version of Nicks dissertation.

 

Here's a discussion of the Hiwatt tone stack:

http://www.ampbooks.com/home/classic-circuits/cp103-tonestack-analysis/

There's some other decent stuff on this website as well.

 

I played around with the one in the link a long time ago. I would say it was very "glassy" sounding. I've never heard the new ones.

 

Yep, and you'd need to measure the transformers yourself in most cases too. You can find a few Fender guitar amp LTspice models online that attempt to model everything, including the speaker in an open-back cab in one case.

Bass Gear Magazine posted SVT graphs that show frequency response at the output, both with controls at noon and also set to "nominal flat." It's well worth comparing those to the basic tone stack models.

 

And then there's the room, of course.

 

These AB763 Twin Reverb sims (courtesy of the Yahoo Groups LTspice forum) include the power amp section and an output transformer model. I'm showing the curves both pre-phase inverter and post-output transformer, with a resistive dummy load.

Normal Channel:




Vibrato Channel:

 

Here's a cool little video that advertises a line of A-Designs preamps but gets into a discussion about output transformers and the different tonal properties using different metals for them. Aimed at the layman, probably not quite as useful to the techies.