Agree.
The premise seems strange, because anything through a guitar amp is gonna be “slower” in transient…
DI if you want “fast”…

The preamps drastically change the sound. Even clean ones produce different distortion. Vintage type preamps can sound incredibly different. API slews. Neve 1073 type circuits are class a, have a ton of distortion, and the transformer has dc running through it. To say it sounds the same as the chip pre on your interface or that the chip pre sounds the same as a Grace or Millenia is to ignore the physical reality that they are all different circuits and impose your ignorance upon others perceptions of the multiplicity of the physical world that you pretend does not exist.

If you want to accurately record how it slews, you need a pre that doesn’t slew or distort. You’re listening to distortion from the guitar cab. Something like a dull Behringer pre or similar preamp designs from more respected manufacturers will neither record it accurately nor sound particularly punchy compared to modern clean Pres.

Punchy mic pres provide additional distortion in the midrange without adding distortion in the lower midrange and bass. The whole thing is perceived as punchy. API and Trident A range type circuits like Daking both do this when pushed. That is why they are perceived as punchy. The API signal will even be slewed on transients often but sound punchier. The distortion sounds good and can make the distortion of the instrument sound better.

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Just for clarity:

You're using "slew" pretty much oppositely to how I would use it. Slewing is a rapid change in amplitude and the slew rate of the amplifier tells you whether it can change amplitude that fast, and follow the steep bits of a waveform.

If an amplifier fails to slew fast enough, and slew-rate-limits the signal, then fast-rising (or -falling) edges are not followed correctly, and the output is more gradually sloped than the input in those places. That means that any amplifier following it in a signal chain doesn't have to slew any faster, because the steep bits just aren't there anymore. (So even a slow preamp should be fine if it's following an even slower guitar amp.)

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As I understand it, inexpensive solid state preamp circuits generally haven't had a hard time slewing plenty fast for audio signals since the 1970s. (And there were fast-slewing tube op amp circuits used in analog computers long before that.)

Also AIUI modern solid state preamps aren't slew-rate limited for audio signals, unless they're designed to be, for intentional distortion. (My impression is that it's uncommon for them to be designed for distortion by slew rate limiting, because most designers don't think it sounds as good as amplitude saturation for harmonic distortion.)

If that's right, I'd think that any decent normal preamp generally wouldn't have a problem following the output of a guitar amp, played through a big slow speaker.

(I could be missing something, though. Maybe when you distort the signal enough to resemble a square wave, you get really steep front edges and even a big slow speaker manages to catch up with them at some point before they're clipped?)

I'm skeptical. What makes you think modern Behringer preamps (like in the UMC404HD) are slow? Not super quiet maybe (but fine for normal purposes), and not entirely clean if you drive them hard (tending to saturate a bit a couple of dB before full scale; leave a couple of dB on the table and you're good)... but are they slow? I've never heard that. (I seem to recall somebody scoped them with a square wave and didn't complain about the rise times, but I don't recall where that was.)

Trident S20. Fast and detailed.

Drastically? Not usually. Perceptibly, sometimes, sure.

Blind tests usually show that the differences between preamps are generally wildly overstated, sometimes hilariously so. (Even Neve preamps, which are admittedly pretty weird.)

https://www.soundonsound.com/reviews...ake-difference
https://www.soundonsound.com/reviews/preamp-post-mortem

Can You Tell The Difference? ART vs. Great River!

If you're not pushing them hard, preamps are usually very linear and the least audible part of the signal chain, with nothing like the drastic effects of, say, transducers like speakers or microphones.

IIRC, they're also usually close to minimum phase, too, so their phase shift properties are predictable from their frequency response, which is usually close to flat. (And straightforwardly matchable with minimum phase EQ, automatically along with the frequency response.)

See the Sound on Sound results. They don't show that the preamps all sound exactly the same, but they do show pretty clearly that in a blind test, many people can't hear a clear difference, and most people who think they hear a definite difference can't tell which are the cheap chip pres and which are the expensive discrete amps or whatever.

(Even when people can definitely hear a difference, it's often not clearly a difference in quality; it can be something trivial like a difference of a fraction of a dB in frequency response across the midrange, or a FR bump due to transformer inductance coupling with cable capacitance to create a resonance. Whether that's good or bad is a matter of taste and whether it suits the source.)

And as I understand it, there are some very good IC preamps these days, with laser-trimmed resistors and so on for a few bucks a pop.

Some veteran studio gear designers will tell you that... if they're not trying to sell you expensive vintage-style all-discrete transformer-coupled preamps.

(IIRC, we recently had a designer of classic SSL gear explain that even Neve preamps don't easily saturate their transformers, despite having DC running through them. So even with Neve type pres, the differences are usually subtle, as in the SOS results, not "drastic.")

Another vote for the Pacifica/P-1. Great pre.

Chandler TG2 would be my second choice. First, if it would be cheaper. Gives the sound "chest" like nothing else.

This is so valid, I was having a a conversation with a fellow engineer the other day about this very thing, what even is "fast" . I think a lot of engineers use the word fast to describe the combination of qualities you mentioned. a weightier preamp like a 1073 with marinair input and output transformers and a Class A amp circuit adds some weight in the lower mids that generally makes things sound a little smoother and less in your face (not to say you can't get some in your face sounds out of a 1073). something about that circuit changes the frequency response and harmonic content in a distinct way. I think a simpler circuit like an API 312 based on an OpAmp and completely different transformer design usually has a quality to the high mids that feels more open and slightly emphasized in a way that makes transient information feel more apparent (maybe more apparent transients means faster?).

so to your point, I agree that harmonic characteristics and frequency response would be some of the major contributors to what "fast" means. i'm too stupid to know how slew rate would contribute to something sounding "fast" or "slow" . also preamps being pushed into saturation will round the corners off of transients in different ways that would affect how those transients are presented. a transformerless circuit for example when pushed would have different saturation characteristic than an opamp based circuit with an output tranny. so maybe "fast" or "slow" is also to do with the quality of those harmonics and the inherent transient shaping that comes from the different points of saturation within these circuits being pushed.

Here's what happens in an unusally simple and unusually extreme case with a preamp that is actually slow in terms of slew rate. It can only change amplitude slowly, so it can't accurately follow a very loud sine wave, which has steep rising and falling parts. Instead it just rises at its maximum slew rate until it intersects the sinewave as it is descending again, then descends at its maximum slew rate until it intersects the sinewave as it is ascending again.

That turns a pure tone into something close to a (symmetrical) triangle wave, with LOTS of odd harmonics.

More generally, though, when you start with a complex waveform, what you get is intermodulation noise, generating all sorts of weird frequencies, including some lower frequencies than any in the original signal. (IIRC, as the waveform mutates due to beating of frequencies it does contain, the effect of slew rate limiting generates harmonics of the lower beat frequencies.)

That is usually not a good thing at all, for most normal signals. It makes a mess.

(It might not be terrible for quick transients like the attack of a snare hit, though. They tend to contain a lot of fairly broadband noise anyhow, and replacing one chiff of noise with another, different chiff of noise can sometimes be okay, or even desirable. Similarly, clipping a sharp attack may be OK, hence the popularity of "clipper" plugins. That's a different way of replacing one chiff of noise with a different chiff of noise.)

Anyway, from this picture you should be able to see why following a slow amp with a faster one is fine... the signal coming out of the slow amp doesn't change as quickly, so any faster amp should be able to follow it without being slew rate-limited.

...and vary between a slow dynamic mic and a fast sdc if 'speed' is what really bugs you: their different frequency response and transient behaviour most likely will be more noticeable than varying between preamps (unless they are of a very specific design).

anyway, i find the attribution of 'speed' (or lack thereof) to preamps not very helpful (and neither 'punch', 'colour', 'versatility' etc.)...

A short update.
Well, in the end....I got a VP28! I thought about it for a long time, but it has everything I was looking for: separate output and gain, pad, a variable HPF which is welcome. The only thing I miss is the DI input, but I have it on both my 73jr and 610 Solo.
I used it in these last month with the electric guitars and it's exactly what I needed, a nice fast pre that colors pleasantly but not over the top.
I also had the idea of buying a SSL VHD+, but you told me SSL pre's are on the clean side of things. I also remembered an old message I read here on the forum that sounded something like: "You always see Neve and API pres into SSL consoles, but never an SSL pre into a Neve or API console".

My setup is very traditional, a Neve clone (Heritage 73 Jr) and an API clone (CAPI VP28) that sometimes take turns with a UAD 610 Solo, but considering that I prefer to spend my time creating music rather than testing preamps in series, I'm fine with that. Then I like the sound I get, the gain pot is there to be used so I can have more or less "sauce" depending on the need. I can make them sound super clean or super distorted.
Anyway, I must admit that today the offer is wide and covers all needs and budgets, from the entry-level GAP and Warm Audio till to A-Designs, Shadow Hill, H2 Audio, and many others. What a time to be alive!
In the future I'd like to try my pres with a pair of Rupert neve 542 tape simulators, but one step at a time...

Good plan - I always have 542’s in the chain when recording guitars and love em! Usually @ 30ips, 50% mix, and red silk at 12 o’ clock.

The Portico 542 is a nice toy, I've been thinking about it for a long time, but it's a toy that costs almost €2000 since I would need two of them.
I've listened to it on YouTube and I like it with both red silk and blue silk, depending on the source. If I understand correctly how the 542 works, red is more extreme and "in your face", while blue is softer and rounder. Do you use the red silk for both distorted and clean guitars?

I have a pair and use them a lot. They are very useful.

Soyuz Lakeside pre is really good on electric guitar,

Man, the prices have really gone up since I purchased these! I’d look for some used units if you want a pair - they’re built to last, so I personally wouldn’t worry about buying used.

I use the red silk on just about anything that needs a little bite, brightness without sounding eq’d, or a bit of character to distinguish it from other elements. It’s fairly rare that i’ll use blue, and if I do it’s usually at lower settings and combined with red from my Neve MBP to retain the spectral balance (blue seems to roll of the highs and can muddy things up quickly).

To make up for derailing the thread - I really like the Burl B1D’s for guitar, specifically distorted guitar. Currently, i’m liking:

-Royer 121>Soyuz Launcher>AEA TRP

-SM57 with TAB Funkenwerk T58 mod >Soyuz Launcher>Silver Bullet A>N

-Soyuz 017 Fet>Audioscape D.AM 27

I’m usually inserting a bunch of hardware after the preamp as well. Currently loving the Overstayer MAS, Neve 542, LMI Prime, Bereich Density, and the Zahl eq1 for cutting resonances on the way in. Sometimes i’ll hit the Zod IDDI’s pretty hard if I’m going for glassy, but big punchy cleans. By the time I hit the AD+ with the Hammond transformers engaged (and a touch of emphasis), I have a tone that’s ready to go without much work in the box.

Seeing your posts in multiple threads I appreciate your grounding in electrical design. My day job involves software and hardware engineering and I can appreciate how you explain technical concepts in simple language.

In my hobby world I still use Spectrasonics 110/110A as my go to preamps which I think have impressive specs on frequency range and slew rate.

KB

You might want to check out also the Bereich 03 Density.. it’s different from the rnd.. but serves a similar purpose.. and it’s much less expensive.

Also, I know you got the capi, but maybe you might want to test the Avedis MD7 at some point, and its stellar DI (among the preamp which is Avedis take on the api opamp design pres).

howdy

Cheu

In the GS shootout some years ago, the Shadow Hills GAMA (nickel) and A-Designs EM Red caught my attention, then the API 512c.

I didn't know the Bereich or the Avedis MD7, although I did know the Avedis MA5, and not even "Howdy" which I read is a typical greeting from the southern United States
The Bereich costs half the price of the Portico 542...let's hope it doesn't sound half as good. I'll go listen to it. Thanks for the tip!

Avedis fa solo cose spettacolari..Consigliatissimo! Check on its website and on the PYE website.. (pyeaudio.com)
only very high quality, at a very reasonable price for what you get! (We’re speaking of some of the very best stuff around).

Anyway.. you can listen the bereich on their website, there’s a pretty good and long video that shows what it does.

ciao

Cheu

Back in 2015, I asked here what is a good preamp for recording blues guitar, and was told one with cigarette burns and beer rings. I don't remember who said that but it was probably gravy.