Swanky Amp (release 1.4.0)

[guitarzan]

The amp model has also been re-worked to have better dynamic behviour, and I did extend the drive range somewhat so that guitarazan can try to make it sound like someone is destroying the amp.

It's not a lack of drive — Neil Young uses nothing but "clean" boost from his tube Echoplex into a tweed Deluxe that is unmodified except it is biased to run 6L6 output tubes. It centers around the output transformer, speaker, and power supply / power amp interaction.

That Tweed Deluxe video I linked to was by Oscar Isaksson who built that entire Neil Young based rig as documented in this thread:

https://www.thegearpage.net/board/index ... r.1795107/

To get the Neil tone I think there are a few keypoints in this rig…
… A tweed deluxe with a ceramic speaker and the combination of a 5y3 rectifier and 6L6 tubes. I have tried it with a GZ34, that would be more common sense with 6L6:s, but it gets way to stiff and clean. With a 5y3 it's sag deluxe and you get that amp about to break down, starved voltage sound…

Also, I linked to this thread before but I don't know if you ever read to the part about sag (B Ingram, post #27, Re: Voltage Sag, Voltage/Current Waveforms):

https://www.lespaulforum.com/forum/show ... ost2722430

…Class AB amps don't draw big current all the time. If the amp is idling, there is no big drain on the power supply. If we're playing softly, the drain on the supply will be small. If we're playing at the limit of amp's clean output power, the drain will be high. So we have a power-output-dependent drain on the power supply, and we'll have the most sag when we're playing the loudest…

Pretty much describes a form of compression, right?

Another interesting point brought up in that thread is the practice of "tolerance hollowing" in manufacturing back then:

…So now, even though the resistor is marked "100kΩ" there won't be any resistors actually measuring 100kΩ…

https://www.lespaulforum.com/forum/show ... ost2722023

I'll try my best to check out the new update sometime this weekend.

[jbraner]

I like the new interface!
I'm getting some nice clean sounds and "crunch" - but harder work keeping the fizz at bay on higher gain sounds. I'm getting best results keeping "touch" way down around 2 (whether pre or power amp) when the drive goes over 5 or 6.
Filter and tone stack don't help - but keeping "touch" down does.

This amp also takes real pedals very nicely. I would typically use a dirt pedal or two going into a clean or a little crunchy amp.

I'll let the others get in to the intricacies of sag and note bloom - but as far as dialling in a good sound pretty quickly - on single coil Strats and a Tele - this amp is doing a great job.

[garrinm]

I'm getting some nice clean sounds and "crunch" - but harder work keeping the fizz at bay on higher gain sounds. I'm getting best results keeping "touch" way down around 2 (whether pre or power amp) when the drive goes over 5 or 6.

Hi John, glad to see you're back at it. I had noted an issue with the pre amp distortion coming on very suddenly, and generally keeping a buzzing sound in the back when you're playing near breakup. I've got a solution to this in the form of a "grit" parameter, I'll be pushing that update out today. Hopefully this resolves at least part of the fizz you're hearing.

I'll have to do the same treatment on the power amp section eventually, but for now I think that one sounds good within the available parameter range. If you're still hearing that fizz though after the next update let me know and I'll know to look into the power amp more closely.

Thanks,
Garri

[DaveClark]

Hi all,

On SPICE: A SPICE developer at a major semiconductor manufacturing company once said to me, after I was commiserating with him about some poor results I had obtained, something approximately like, "SPICE is only as good as the models you use." In other words, he and other developers had done all they could do. It was up to me to find better models or to develop new ones if I expected more accurate results. He was absolutely right.

The folks who develop models are often different and outside of the groups that work on the core parts of SPICE. The typical SPICE developer's expertise certainly does not include modelling of pentodes or transformers, etc. The disclaimer is part of the name of SPICE, "Integrated Circuit Emphasis." Included models should be considered a courtesy. Of course, great pressure is often put upon SPICE developers to include various poplular models, but again, not for pentodes, transformers, or other neolithic circuit elements that some of us are very fond of, nor do they usually develop these poplular models themselves.

Perhaps I should also say that if there is a group of people amongst us who could possibly develop a good transfomer model, that group would undoubtedly include Garrin.

Regards,
Dave Clark

[garrinm]

Version 0.2.0 is out. The main feature here is the addition of a "grit" control for the pre amp, largely put in place to address the feedback from jbraner.

[jbraner]

Version 0.2.0 is out. The main feature here is the addition of a "grit" control for the pre amp, largely put in place to address the feedback from jbraner.

Thanks Garrin - I'll have a play with it tomorrow

[guitarzan]

Perhaps I should also say that if there is a group of people amongst us who could possibly develop a good transfomer model, that group would undoubtedly include Garrin.

That is my hope — I have spent years just trying to get somebody to look beyond the existing output models — they are obviously quite static right where the dynamics should be cooking the hottest. It works OK for modern high gain amp models because they get most of their gain dynamics from the pre amp anyway, but all models would benefit from improved output section modeling — vintage class AB amps (like the tweed Deluxe) most of all. Also, I hope I'm not coming off as insulting anybody — the SPICE guys or especially Garrin, but improvement in output dynamics modeling is way overdue, and I hope this can be a beginning.

[guitarzan]

I just checked out 0.2.0 and the overdrive in Resonant Amp really does react to picking dynamics extremely well and it does guitar volume knob cleanup as well as a good overdrive pedal or maybe even some amps. It opened with some overly blown-out settings that really didn't show off those abilities, but that may be from the previous version's settings or something.

Still missing that overt compression bit (sag, bloom, etc.) though. Even clean Fender silverfaces have it to some extent when cranked up to volume. Should be able to feel the threshold point trigger the envelope, sustain then release, just like some kind of compressor.

Thinking now about why I ditched vst's altogether for so long though, and part of it was not only the missing compression feel in amp sims, but also the missing compression feel from compressor plugins (at least the ones I had 8 or 10 years ago). It's like digital just cannot pump or breath enough to even feel [insufficient audible compression artifact cues to set muscle memory], so it's possible that I may never be satisfied with purely digital processing.

It does seem like I was making some progress with ADSR Generators and Envelope Followers and stuff in energyXT, but placed before the amp sim wasn't quite right and neither was after — it needs to go inside the amp sim… Use Envelope Follower/VCA as the basis of the entire power-amp!! The ADSR Generator [sidechained into VCA] could be set to simulate different plausible power drain and recovery envelopes [invert the ADSR envelope] depending on desired traits (tight, loose, vintage, modern, class a, class ab, whatever). Your existing overdrive characteristics should be fairly easy to incorporate… There's your sag and bloom!

…maybe… it was easy in energyXT to just try stuff until it worked, so don't remember exactly how it was all routed. Seems like the signal was split into the Envelope Follower / VCA and into the ADSR which was then sidechained to the Envelope Follower/VCA? — I wasn't using midi gate or anything, it was all audio. It was pretty much a compressor, but with total control of the envelope. The ADSR envelope wasn't totally imposed over the signal, but it influenced the nature of the compression… Oh, and ndc Amplitude Imposer too, somehow… yeah, I need to find a new modular host — Kushview Element sort of reminds me of energyXT, think I'll give it a try.

EDIT: It would be helpful to me if an updated version of the controls description from earlier in this thread could be accessed from the GUI somehow… are tooltips still a thing? Just a readme or "about" kind of thing or whatever, but only if it doesn't take time away from further development… not a big deal.

[jbraner]

Ok, I had a play with 0.2.0 today.
Yes, the grit control really helps! I'm still keeping the touch way down - but I got some good higher gain sounds today (clean and crunchy have always been easy to dial in).
I could get rid of the "fizz" that I was hearing.

I plugged in my '66 strat today - and i just "got" your vision. Today, I finally heard the cranked up Fender sound that you're working on

Here's a setting that's working for me today.


PS - I don't know how much a "grit" control will work in the power section - but it probably wouldn't hurt

[acousticglue]

I get just a bit of noise from it in the in out stage. Very slight but the other knobs make no diff

[acousticglue]

I really like though I mean really really like these two amps.

[acousticglue]

I have had to fiddle with my levels coming in to balance everything as there isnt a master volume for overall output. I can turn up output a bit but not a lot. Input distorts very quickly past plus 2 for me.

[acousticglue]

An IR loader w stereo, dual mono and mono would,make this a fantastic piece

[garrinm]

An IR loader w stereo, dual mono and mono would,make this a fantastic piece

Hi acousticglue,

Glad you gave it a try, and thanks for the feedback! IR loader is something I've thought a bit about. I think seeing someone ask for it directly is making me inclined to prioritize this a bit more. I still have a small backlog to clear but I'll throw that on the roadmap.

I have had to fiddle with my levels coming in to balance everything as there isnt a master volume for overall output. I can turn up output a bit but not a lot. Input distorts very quickly past plus 2 for me.

The output level should act as the master volume, it's just applied directly before the output, so changing it should just change the volume without affecting any of the distortion. Maybe I'm misunderstanding your comment, but if you're having issues with it (range is wrong or it causes some changes to the sound quality) I will need to look into that.

I get just a bit of noise from it in the in out stage. Very slight but the other knobs make no diff

I'll shortly be adding another knob to control the "grit" of the output stage. It *might* allow you to make it more or less buzzy. I think a lot of guitarists prefer to lean on the pre-amp distortion, so no problem just turning down the power amp drive.

It's great to hear this kind of feedback, I appreciate it.

Thanks,
Garrin

[garrinm]

I could get rid of the "fizz" that I was hearing.

Hi John,

I'm glad to hear that fizz is gone for you, I know how annoying that is, dialing in a sound, and then strumming a chord just a bit louder and just hearing buzz buzz buzz in the back.

PS - I don't know how much a "grit" control will work in the power section - but it probably wouldn't hurt

I'll play around with a grit control, but it might take second seat to trying to get rectifier sag into the model, so no specific timeline on that just yet.

As always, thanks for the comments,
Garrin

EDIT: as for the "touch" controls, I think for lots of users the preferred setting will be low. And it occurs to me that 1) the first thing you want to know with hardware (or well, hardware emulation in this case) is to turn up the knobs an 2) it seems touch sensitivity is desirable so turning it down feels kind of wrong. So as a pure user experience thing I'm contemplating renaming those knobs to "tighten" and switching the way they work. I think it'll be clearer this way, when you crank the drive the sound gets sloppy, so you want to turn up those knobs to tighten the sound.