The Big Guitar Amp Sim Roundup + Review

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audiojunkie
KVRAF
2912 posts since 19 Apr, 2002 from Utah

Post Tue Oct 15, 2019 9:42 am

audiojunkie wrote:
Tue Oct 15, 2019 8:10 am
Anderton wrote:
Mon Oct 14, 2019 11:48 pm
audiojunkie wrote:
Mon Oct 14, 2019 3:27 pm
So, what would be the difference between using a physical/hardware limiter prior to I/O hardware vs putting a software limiter (from within the I/O hardware--like a brickwall limiter vst)? Would it be intent or what one is trying to achieve?
Anything in the software is post-A/D converter, so it doesn't solve the problem of sending spiky transients into the A/D converter....which requires you to turn down the input level, and thus sacrifice input level. But there's much more to the story than that:

* The LED has no overshoot, nobreathing, and nopumping. No active electronic circuit based on gain control can do that.
* The reaction time is instantaneous, so there's no need for look-ahead. The circuit lives in real time.
* The LED has junction capacitance, which increases with voltage. So the more level you put into it, the more capacitance there is (figure about 70 pF max, although that’s not an exact science). This not only shaves off the top, but does soft-, not hard-, clipping above the frequency of the guitar (i.e., where the spikes live).
* You can select an LED with a breakdown voltage to match your pickups. This is why the Gibson circuit worked so well - the pickups levels were a known entity. Luthier Jim DeCola went through a bunch of LEDs to find ones with the ideal breakdown voltage to shave off only the peaks. This is also why you have to use red LEDs. Other colors have too high a breakdown voltage.

Anyone who reads the Guitar Player article can see before-and-after waveforms, with and without the transient control circuit, as well as a chart showing the difference in average level that can go into an audio interface. The most dramatic difference was with the bridge pickup, which without the transient control circuit would peak out at 13.4V RMS before clipping the A/D converter. With the transient control circuit, it could peak out at 8.2V RMS. The neck and bridge pickups could deliver about 2 dB higher average level with the transient control circuit. It’s not as much, but still, 2 dB isn’t trivial.

It’s also not just about the A/D conversion. Eliminating that spike makes compressor and limiter gain control circuits soooo much happier. One of the people at Planet Waves who tested the cable said it made some amp sims sound better because they weren’t trying to deal with the spikes – similarly to how tubes “absorb” spikes.

Tom Scholz (the guitar player for Boston) is another red LED fan. We had quite a discussion about their distortion properties, when used instead of conventional silicon or germanium diodes in op amp feedback circuits. That was the secret of my hardware Quadrafuzz circuit (the one both Steinberg and MOTU virtualized).

I know, TMI...sorry. Back to the reviews.
Fascinating information!! This has been very useful! I've lived under the false impression that a brickwall limiter would work just fine to prevent all clipping. It makes complete sense that clipping at the A/D converter input wouldn't work with a software limiter, but I guess I never even thought about it. I know that a brick wall limiter is great to prevent clipping in-track, but always assumed any clipping took place after the A/D converter. This discussion has corrected a 20+ year false impression! Very useful!!
Another question about all of this. What if the user is using 24bit or higher in their A/D converter? Doesn't that make this all moot? Doesn't the added headroom prevent clipping and allow software limiters and compressors to work their magic without needing an extra hardware device at input? I'm still having a hard time adjusting to the idea that I'm going to have to be unlearning what I've learned over the last 20 years. :?

To quote:
Note: Important part Bolded for easy reference.

https://www.tested.com/tech/1905-the-re ... bit-audio/
24-bit sound is a tricky thing to gauge. Does it provide for a greater resolution of sound? Definitively. It has room for 256 times the data, remember. Are you going to be able to hear that difference? Harder to judge. Human hearing supposedly tops out at 20kHz, but that doesn't make higher sample rates useless. According to the Nyquist rate, to fully capture a wave, it should be sampled at twice its highest frequency. In other words, a higher sample rate, and a greater bit depth, gives your sound more wiggle room, meaning sound peaks are less likely to be truncated and the subtleties of the music are less likely to be drowned out.
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guitarzan
KVRian
1162 posts since 3 Sep, 2005 from Outer Bongolia

Re: The Big Guitar Amp Sim Roundup + Review

Post Tue Oct 15, 2019 11:06 am

This Transient Tamer idea seems golden to me — must try!

To have a Transient Tamer that was adjustable for different pickups would you need to switch between different LED pairs or would there be an alternative way to dial in the perfect transient response?

To judge the best LED for a given pickup, would the most practical way be to just go by ear (keeping in mind the info offered in the article: "For passive pickups, 2.2 volts is a good compromise value, but if you use lower-output pickups or have them further away from the strings than usual, you’ll want the lowest possible forward voltage") or is there some other relatively simple way to zero in on the best LEDs?

Would the Transient Tamer change impedance, like would it mess with the cleanup interaction between the guitar circuit and a fuzz face if it was placed before the fuzz (like in the cable)?
Last edited by guitarzan on Tue Oct 15, 2019 11:18 am, edited 1 time in total.

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Anderton
KVR Expert
137 posts since 4 Mar, 2004
KVR Expert

Re: The Big Guitar Amp Sim Roundup + Review

Post Tue Oct 15, 2019 11:17 am

guitarzan wrote:
Tue Oct 15, 2019 11:06 am
To have a Transient Tamer that was adjustable for different pickups would you need to switch between different LED pairs or would there be an alternative way to dial in the perfect transient response?
I've found it's not really all that critical, but I use humbuckers 90% of the time, so I'm in a "one size fits all" situation. Jim at Gibson just figured hey, why not optimize the circuit...so I don't know how much you'd need to change things around for different pickups. I guess the best way to find out would be to use cables that had LEDs with different breakdown voltages (i.e., 1.8, 2.0, 2.2, 2.4) and see if you can hear a difference.
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guitarzan
KVRian
1162 posts since 3 Sep, 2005 from Outer Bongolia

Re: The Big Guitar Amp Sim Roundup + Review

Post Tue Oct 15, 2019 11:19 am

I was editing again while you were responding, sorry... Would the Transient Tamer change impedance, like would it mess with the cleanup interaction between the guitar circuit and a fuzz face if it was placed before the fuzz (like in the cable)?

Dewdman42
KVRAF
1712 posts since 14 Mar, 2006

Re: The Big Guitar Amp Sim Roundup + Review

Post Tue Oct 15, 2019 11:22 am

or build it into the guitar itself..ideally with a switch...
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Anderton
KVR Expert
137 posts since 4 Mar, 2004
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Re: The Big Guitar Amp Sim Roundup + Review

Post Tue Oct 15, 2019 1:07 pm

Dewdman42 wrote:
Tue Oct 15, 2019 11:22 am
or build it into the guitar itself..ideally with a switch...
That's what Gibson did, but it was on a DIP switch along with some other options, like treble bleed for the volume controls. I never thought of transient control as something you'd switch on or off a lot - you'd either find the concept useful and leave it on, or not want to shave off the initial transients, and leave it off.
My educational website has launched! Read articles, see videos, read reviews, and more at https://craiganderton.org. Check out my music at YouTube.com/thecraiganderton, and visit my digital storefront at https://craiganderton.com. Thanks!

mmann
KVRist
35 posts since 22 Nov, 2015

Re: The Big Guitar Amp Sim Roundup + Review

Post Tue Oct 15, 2019 7:00 pm

I'm going to change my format a bit as I found my mini reviews too distracting (large and/or bold fonts) from the main and more relevant reviews by Craig. Which brings me to my next candidate; Scuffham S-Gear.

My experience with S-Gear is almost the opposite of Craig's in that I was initially blown away by the sound but as time progressed (and S-Gear didn't) I found it surpassed by other amp sims. The interface is very Guitar Rig like, with all the pedals looking like rack effects, but unfortunately the user can't manually increase the window size.

I thinks it is interesting that my favourite amp in S-Gear was also the last one that got added; the Custom '57 introduced in v2.4 back in 2014. I remember thinking at the time, that things were certainly looking good and I was eager to see what would come next.

The effects are stellar if limited and actually still hold up well to this day. It's just a pity they are not available separately, like Waves GTR3 or AcmeBarGig Head Case.

Remember; everyone has their own preferences in amp sims and the only important one is your own. Try the free 15 day trial and see (hear) if S-Gear is for you; I would certainly be using it much more frequently if I didn't have such a sizeable collection of plugins to choose from (not that I'm complaining).

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Anderton
KVR Expert
137 posts since 4 Mar, 2004
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Re: The Big Guitar Amp Sim Roundup + Review

Post Tue Oct 15, 2019 7:28 pm

Thanks for the comments! No real need to change formats, the more the merrier. This is a forum, after all :) But do whatever feels right.

I agree that there are a lot of plug-ins out there, and S-Gear may seem limited by comparison. But, it does what it does well, and I give them credit for that. After seeing the review, Mike wrote me and said he's working on more stuff...but no specifics...

In a way, I was judging S-Gear by the standard of "real" amps. After all, if you like a Fender Twin, you don't like it less because Orange makes cool amps. On the other hand, $ is $. If you can pay a little more and get a lot more options, then S-Gear may look much less attractive - unless you find the S-Gear sounds compelling. In that case, all that matters is getting the tone you want.

I really appreciate your contributions. I'd be interested to hear what you think about TH-U. It's kind of like going to a smorgasbord with 46 tables - you know you can't eat everything, so you hope you hit the stuff that's good!
My educational website has launched! Read articles, see videos, read reviews, and more at https://craiganderton.org. Check out my music at YouTube.com/thecraiganderton, and visit my digital storefront at https://craiganderton.com. Thanks!

jzero
KVRist
201 posts since 24 Jul, 2002 from Tennessee

Re: The Big Guitar Amp Sim Roundup + Review

Post Wed Oct 16, 2019 9:23 am

I'm interested in your red led transient limiting technique, Craig. Are you aware of any inexpensive red-led overdrive pedals that could be set conservatively and placed in front of my audio interface to have similar effect. Are there any commercial cable sellers that are incorporating your design? Soldering is an unpleasant ordeal for me.

Mats Eriksson
KVRist
128 posts since 4 Sep, 2016

Re: The Big Guitar Amp Sim Roundup + Review

Post Wed Oct 16, 2019 11:47 am

Anderton wrote:
Tue Oct 15, 2019 8:59 am
The transient of a guitar, the initial peak, is huge compared to the average level that it settles into shortly after the peak.
No, that's where you and I differ. Because it depends. You can't say that generally speaking, regardless of pickups, strings, and so on. Not even say "in most normal cases". And even if it would/should, well then, any tube guitar amp input can take it. What it does is compress it, distorts it, both, or completely ignores it. But anyway I'll quote legendary pickup designer Seth Lover once again, regarding all these things, what's heard and not heard, in an interview with Seymour Duncan:

" I’ve heard musicians talking about things that are just bothering the hell out of them – complaining and so forth – and I’d listen and listen and I couldn’t hear. At the same time I could hear things in there that were bothering the hell out of me and they’d pay no attention to them. I hear something they don’t and they hear something I don’t.

What are you going to do?"


https://www.seymourduncan.com/blog/the- ... seth-lover

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Anderton
KVR Expert
137 posts since 4 Mar, 2004
KVR Expert

Re: The Big Guitar Amp Sim Roundup + Review

Post Wed Oct 16, 2019 11:51 am

jzero wrote:
Wed Oct 16, 2019 9:23 am
I'm interested in your red led transient limiting technique, Craig. Are you aware of any inexpensive red-led overdrive pedals that could be set conservatively and placed in front of my audio interface to have similar effect. Are there any commercial cable sellers that are incorporating your design? Soldering is an unpleasant ordeal for me.
I don't really know if anyone has incorporated this in their designs, sorry.
My educational website has launched! Read articles, see videos, read reviews, and more at https://craiganderton.org. Check out my music at YouTube.com/thecraiganderton, and visit my digital storefront at https://craiganderton.com. Thanks!

Mats Eriksson
KVRist
128 posts since 4 Sep, 2016

Re: The Big Guitar Amp Sim Roundup + Review

Post Wed Oct 16, 2019 12:01 pm

mmann wrote:
Tue Oct 15, 2019 7:00 pm
My experience with S-Gear is almost the opposite of Craig's in that I was initially blown away by the sound but as time progressed (and S-Gear didn't) I found it surpassed by other amp sims. The interface is very Guitar Rig like, with all the pedals looking like rack effects, but unfortunately the user can't manually increase the window size.

I thinks it is interesting that my favourite amp in S-Gear was also the last one that got added; the Custom '57 introduced in v2.4 back in 2014.
Completely agree with you on that one. It's the only amp in there I use now. I do have objections to the "retro" GUI in that the delay unit has a knob that changes between short/medium/long delays. In a digital world who cares, it's all delay and these days they can be as long or as short as you like. Don't like that you have to flick/click another switch to go past a certain millisecond reading. And some other things too, but too nit picky to go into here.

Dewdman42
KVRAF
1712 posts since 14 Mar, 2006

Re: The Big Guitar Amp Sim Roundup + Review

Post Wed Oct 16, 2019 12:18 pm

I have tried to like S-Gear for a while now, but it just doesn't work well for me at all. So many great reviews about it, but something about it is "too smooth" or something for my tastes. Granted I should spend a lot more time with it. It doesn't have a million amp options like some others, but I don't view that as a negative. Most people today want one of maybe 4 or 5 different basic amp tones.. (Marshall, Fender, MesaBoogie, Vox), with a few metal guys wanting a few other newer offerings. S-Gear clearly is meant more for classic vintage style of amps, as opposed to Engl, Peavey, etc..

I think S-Gear does cover Marshall, Fender, MesaBoogie quite well, maybe not Vox so much. But I just find the tones to be kind of too smooth for my tastes. In order to a add a bit of teeth you need to insert a treble booster pedal, or perhaps a tube screamer in front, etc...and since it doesn't include any pedals that means futzing around in your host signal chain...and also means none of the presets are designed around that... I have wanted to like S-gear for a long time, bought it right away when it came out and got so many great reviews, but most of the time it just hasn't inspired me.. sorry to say. Granted I haven't tried to use it in recorded tracks yet and maybe it would sit perfectly in mixes in some way I haven't discovered yet. I haven't spent much time with its Custom 57 yet either and I will after reading your comments.

Craig, did you review Thermionik? Its severely lacking in presets, but I do have to say the tone is pretty great and raw sounding..not so smooth like S-gear. Its rough around the edges.. touchy with gain staging, etc..but I have to say I love the tone.

My favorite at the moment is hands down Mercurial Reaxis.

I'd also love to see JamVox brought more into mainstream conversation, I don't know why nobody ever talks about it, I still think its one of the best, especially in terms of feel...and it does have the Vox sound nailed, among other things...
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Soundwise
KVRist
111 posts since 17 Nov, 2015

Re: The Big Guitar Amp Sim Roundup + Review

Post Wed Oct 16, 2019 12:56 pm

I don't hang around the KVR forum, just saw a link to this discussion on another forum so am a little late to the party. Please, bear with me if posts that I'll comment on have already been fully discussed and the questions answered. This topic stirs up too much interest in me to quietly pass it by. :)

Soundwise
KVRist
111 posts since 17 Nov, 2015

Re: The Big Amp Sim Roundup + Review

Post Wed Oct 16, 2019 1:02 pm

Aloysius wrote:
Tue Aug 06, 2019 12:23 pm

You may as well look at Nembrini Audio too. As far as I know, they do a lot of work for PA.
Kudos for mentioning Nembrini. Have recently acquired their BST100 and can't tell it from the real amp in tone and feel. But I also use Celestion IRs with Melda Mcabinet (more on it later) and these two play a huge role in making the amp sim sound real.

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