Let's talk advanced amp parameters

[Ledvedder]

I come from an amp building background, where I've learned a ton about the various ins and outs related to a tube amp's guts. I'm curious to hear about the different advanced amp parameters everyone likes to use.

Ive been cutting the input gain to around 80-100hz, messing with the output compression. Also the speaker impedance curves. I haven't really messed with any of the other stuff.

 

[Tonedeaf]

I always wondered if people like yourself who come from an amp building background have used all the advanced parameters to basically design an original amp.

 

[Randalljax]

I come from an amp building background, where I've learned a ton about the various ins and outs related to a tube amp's guts. I'm curious to hear about the different advanced amp parameters everyone likes to use.

Ive been cutting the input gain to around 80-100hz, messing with the output compression. Also the speaker impedance curves. I haven't really messed with any of the other stuff.

Hmm there are a few
The Negative Feedback
Changing tone stacks
Power tubes , bias
The B+ , the bright cap
Input dynamics , the Amp block boost

 

[Therickyjones]

Transformer drive
Speaker impedance
Supply sag for the ghosties
Input eq, usually increased definition
Tubes surprisingly don’t usually make a huge difference in sound to me

 

[rcm78]

Great topic! I've read on this forum that there's a way to change the power amp in an amp block. How is that done?

What parameter sets the power tube bias?

 

[Rex Rox]

Great topic! I've read on this forum that there's a way to change the power amp in an amp block. How is that done?

What parameter sets the power tube bias?

As far as I know Power Tube Bias is set under the Pwr Tubes + CF tab. Besides all the other params under Power Amp tab, you can change the Power Amp's Master Vol Location - which certainly changes the nature of the Power Amp in a big way. But I don't mess with the Power Amp tab stuff since I don't know enough of what I am doing yet. I do play a little with Tube Bias since I know just enough to be dangerous about that.

Since newb advice generally sucks - I am sure someone else will know much more fabulous information than I.

 

[Rajnar]

For me, the main principle is that everything is interdependent, and after changing, say, settings in Cathode Follower section (which I almost always do), Snapshots are your best friend for quick comparisons. The new Dyna-cabs, are as many of us suspected, a major game-improver but I also suspect that most of their potential still lies ahead.

 

[Dave Merrill]

Negative feedback makes a really big difference, for better or worse it really changes the character of the amp and how it feels.

 

[Sixstring]

Negative feedback makes a really big difference, for better or worse it really changes the character of the amp and how it feels.

This^^^, and the Cap value especially if you want to get a hold of the fizzy stuff.

 

[Lettuce]

Been playing around with the Cathode Follower Compression which seems to open up the sound above 50%. Another one which affects the eq a bunch is the Triode 1 Plate Frequency. Dropping the frequency mellows out the tone. Took this last tip from the Fractal Wiki page, discussing the IIC+, which compiles a wealth of info and ideas. If you haven’t already done so, check out the AMP block page toward the bottom of the Fractal Wiki.

If you want the sound of the non-SimulClass version set Triode 1 Plate Freq to 1350 Hz.

 

[peteri]

Don't forget changing the tone stack - another massive difference between how things sound and react

 

[skolacki]

I try all kinds of adjustments and many are like splitting hairs, hard to tell if there’s a real difference. I like the master bias excursion, and usually lower it from the default 100%. Occasionally I’ll adjust triode hf response. Might have the name wrong and not at home right now. But those are the plate resistor bypass caps you see on modern amps. Variac sometimes both up and down. I wish there were 2 of those, one for both pre and power amps. Amp bias I play with, usually go up since no tubes will get baked and sounds better to my ears. Sag is useful. NFB for sure you can really hear that one. Biggest bang for your buck are the speaker curve and IR. I’ve had this thing awhile now and still a lot of things I haven’t tried yet. The advanced parameters aren’t necessary for a great tone but they can be fun.

 

[Will Schut]

Speaker Imp. Curve and Tonestack Type. I tend to switch these to 1x12 G12-T75 and Brit Silver for most Brit and FAS amptypes. (Cabs are Factory 1 323 and/or 234, 1x12 G12T 57 A and B.)
Input EQ gain. Pushing 800 Hz with as much as 7 db sometimes.
Output EQ, taming the 250Hz a bit.

And I'm off........