Sound Quality: Preamp vs. Direct to Mixer

[schinckley]

There seems to be a consensus that using a preamp results in better sound quality then plugging directly into a mixer when amplifying an acoustic guitar. I want to know why, but read on for more specifics before answering.

In a separate thread asking for advice about DIY solutions for powering an internal mic so as to avoid having to use a blending preamp, I was given advice to just get a preamp. However, from what I can tell, if I can power the mic and get the two signals (separately) to my Mackie DL16s digital mixer, then the main features of a blending preamp are redundant. The Mackie has all the EQ/HPF any blending preamp has, and usually more.

Yet many players (running dual-source or not) swear by some particular preamp, saying they get better sound. For example, people rave about the Pendulum Audio SPS-1. What makes it so magical? While it’s cool (in a 1990s analog kind of way) that it has 3 bands of parametric EQ per channel, my digital mixer has four bands (plus or minus 12db of gain), two of which are switchable to high or low shelves, plus a separate HPF, (plus gate and compression) times 16 channels. I also have two hi-Z channels on the mixer, so no impedance matching issues. So the Mackie has more features. Is the sound quality really that much better on an SPS-1? Are the components really that much higher quality? And if I were to use an SPS-1, I still have to run the signal through my Mackie anyway. If the Mackie is really lower quality sound, then wouldn’t I lose anything the SPS-1 (or any other preamp) was giving me after I run the signal through it? I really would like an explanation, one that goes deeper than “it sounds better.” Why, from a technical standpoint, does it sound better? If it has higher quality components, in what way are they higher quality? In short, what does a preamp do better/differently to a signal than a mixer channel?

Again, I’m interested in sound quality reasons, not features (like number of EQ bands, notch filters, boost, mute or effects). Is there any reason I can’t I get Pendulum Audio SPS-1 quality sound by simply using 3 bands of my 4 band parametric EQ on the Mackie DL16s digital mixer?

I suppose there are the inherent differences in digital vs analog signal processing, but my understanding is that once digital sampling rates get high enough, not even the best ears can tell the difference. I’ve been known to be wrong, though. In any case, everything I want to amplify has to go through the digital mixer.

(A few notes: I play solo, and have my own PA, so I don’t need a rig that has to deal with who-knows-what from no-name-venue. Even if I did, I could run my blended signal out an aux send. If I want effects on my signal chain, I could run an aux send and then bring the signal back on another channel. As far as cable length, the mixer sits at my feet - no DI needed for long cable runs.)

[Doug Young]

Originally Posted by schinckley

For example, people rave about the Pendulum Audio SPS-1. What makes it so magical?

I gave you some answers on your other thread, and there are a number of SPS-1 owners (I no longer use one) that may answer, but think of it this way. The Pendulum cost around $2500, if I recall, for 2 channels. That's $1250 a channel. Your Mackie is $850 for 16 channels (correct?). That's around $50 per channel, even ignoring all the other features. Some people don't think cost matters, but I don't think Greg at Pendulum just said "hey, I could build 2 $50 channels and charge $2500 for them"! It's a quality preamp, studio quality. Built for the road, built to last, all analog, high quality components. You may or may not appreciate the difference, but they're there. Will you or your audience hear the difference? Hard to say.

But it's a bit like the question that comes up here all the time - you can get a guitar, brand X or $300, or brand Y for $5000, they're both just wood and strings, right? What makes one better than the other?

[jonfields45]

I think diminishing returns and observer bias make taking advice on this forum literally, a fool's errand :~).

Consider the AGF a source of vetted ideas from which to choose. Audiophile electronics marketing would make even Taylor's head of marketing blush (as an EE I am sometimes outright falling over laughing). I am a semi professional musician, not a semi professional roadie, so my prejudice would be to leave the pedals home, or better yet unbought in the online store's inventory. I even ditched our mixer a year ago and we use the back panel of a CP8 quite adequately. I think performance is about perfecting music, not about perfecting tone, which is another prejudice I bring to this besides being disinterested in multiple trips to my car.

With liberal online return policies try it for yourself, and given your prejudices and ability to hear, you will make a decision that works for you.

Not seen in this picture is a THR5 powered by a 12 volt rechargeable Lithium battery that I am using to buffer my passive guitars. My partner has a GE7 he uses as a boost pedal. Both his guitar and bass are active with EQ.

[lkingston]

I believe in good quality preamps, but they don’t have to be external. Both my Schertler Roy and my Elite Acoustics D6-8 have excellent class A preamps built in. I’ll use an external Tech21 preamp though if I am plugging into a cheap house PA.

[j3ffr0]

I believe in horses for courses. In the studio a great preamp or mic can make what seems to be a world of difference. Live we are always fighting feedback. We have to take extreme measures to reject the amplified sound in the space that are antithetical to capturing the best signal at the source. Hence the use of pickups of whatever type, internal mics, and modeling units. With a very few exceptions, it's all pretty low end stuff compared to what get's used in even a modest, semi-pro recording studio. Anyone ever check the specs on their pedals -- usually abysmal (which is why I don't use any).

So if you take an expensive preamp into a cheap live mixer preamp... the weakest link is still the weakest link. Is it the piezo, the mag, the battery, the pedal the cheap preamps in the live mixer, the PA speakers? It's a different answer for each of us, but the weak link is there for all of us. That said, the great preamp may have a really great sounding EQ not available on the typical mixer that makes all the difference for some players. We can be a finicky!! Also note that a great sounding EQ isn't necessarily about number of channels or parameters... It's about how it sounds, and sometimes it's worth paying for that.

I currently go directly into zoom livemix 12. I could likely eek out a better sound with a great preamp with a great eq, but it's just one more thing to deal with so I don't mess with it. I could change my mind and start running one at any time though!

[PANDAPANDELO]

I'm a newbie compared to the others great players of this forum, but I guess you should put two thing in the table to make a decision:

1. Is there something special about the preamp, that you really want/need?

For example, I like the LR Baggs Session DI because of the Comp Eq and the Saturation. I get a notch filter, high pass filter, ground loop, etc. All bonusses! I would be happy with just those two knobs. That's a nice pedal for me. Some people want some preamp or pedal to load IRs, etc.

2. Can your mixer handle by itself the mostly common live performances problems/challanges?

Mostly a good EQ to tame some bad frequencie, high pass filter... I have a QSC Touchmix 8 that can cover a lot on that. So, if I didn't need/want those Comp Eq or Saturation from the Session DI, I would probably be fine with only the mixer.

I guess that if you see that you have everything you need/want from the mixer only, you will probably be good with just that. I had my Session DI for repair for a loooooooong time (because I live in Brazil, and Caleb from LR Baggs worked on it in the US... great person and great services, by the way... thank you LR Baggs!), and I worked a lot with the Mixer only. Need to change a few things in the Mixer, but I made it work. Now, with the Session again, I'm even happier.

It might have some sonical differences between a direct signal and a signal that runs into a Preamp, but the audience will PROBABLY don't notice it.

I hope I have helped in something!

Rodrigo.

[varmonter]

I think you can only use your own ears.
I beleive for the most part in the "weakest link" theory. Sometimes when I play out as
A solo I plug directly into the high
Input if my zed 10. It sounds fine..quite good
actually.. if I plug my felix (on a pedalboard)
Into the equation it sounds better.
Is the difference in quality worth the extra
trip to the car..twice? I suppose it depends
On how far I have to walk. It's a decision only
you can make. When playing in my band
i need the pedalboard. I like
making incremental changes
during the gig. It's just easier
To make them at my feet rather
Than at the board which is a digital
Qsc and I'm not fond of it.
Sounds like your board is pretty feature
rich. But a good quality preamp will give
You a cleaner stronger signal to work with
At your mixer.

[MrErikJ]

Here’s my anecdotal insight:

I was once in the studio with my former label and producer and, I can’t recall which, but we were either recording a scratch track or a double part. For variety or simplicity, we were going direct to the mixer. My partner had a baritone guitar fitted with an active Baggs M80 and it sounded just fine going straight to the board. My particular guitar had a passive Baggs LB6 that I typically ran through a Baggs Para DI for direct tones. Out of laziness, I plugged directly and we proceeded to dial it in. My producer put on his headphones and fiddled with the controls, eventually he said “That’s peculiar. You have gain but no fidelity. It sounds terrible.” I replied “what does that mean?” he paused and said “you need a preamp.” Running it into the Para before the board resolved the lack of tone.

Now, as Doug said, using an active system or an endpin module (like pendulum or PUTW OR OTSS) eliminates the need for a floor preamp. An onboard system buffers the pickup elements as required and provides enough signal to give the board gas. The real “need” for a preamp prior to the board comes from passive elements, primarily piezo, that may need a hi-z input and additional gain to provide a quality signal to the board. In the case of higher output passive pups like the K&K and LB6, every board has different options and inputs but, per my experience, the tone may suffer if the board isn’t equipped to handle high impedance transducers. You could also bypass this issue by simply using an active DI with switchable impedance, like the Radial PZ DI. The circuit is active but it’s not a true preamp, per se, and it’s designed to accommodate magnetic pickups or piezos that react better to a 220k, and 1 or 10mohm input.

[Doug Young]

Originally Posted by MrErikJ

The real “need” for a preamp prior to the board comes from passive elements, primarily piezo, that may need a lo-z input and additional gain to provide a quality signal to the board.

The OP is trying to use a Ultra-tonic, which is passive, similar to the K&K, (along with an internal mic) which why I and many others keep telling him he should use a preamp. He also says tone is the most important criteria.

But I totally agree, it's all subjective. You don't need the world's best preamp to play music and have people enjoy it (and have your case filled with money). That's about other things. People make music with all kinds of gear.

I'm getting the sense that the OP is new to the world of amplification - so the best suggestion would be to try lots of gear and see what what works for you, sometimes you have to find your own path.

[phcorrigan]

Originally Posted by MrErikJ

The real “need” for a preamp prior to the board comes from passive elements, primarily piezo, that may need a lo-z input and additional gain to provide a quality signal to the board.

I think you mean Hi-Z (high impedance) input. Some mixers, such as my Behringer XR18 digital mixer, provide one or more Hi-Z inputs, while others, like my Behringer X1204USB analog mixer, do not. That covers the need, but external preamps can provide additional benefits, including better sound, more control for the player, etc.

[Doug Young]

Originally Posted by phcorrigan

I think you mean Hi-Z (high impedance) input. Some mixers, such as my Behringer XR18 digital mixer, provide one or more Hi-Z inputs, while others, like my Behringer X1204USB analog mixer, do not. That covers the need, but external preamps can provide additional benefits, including better sound, more control for the player, etc.

The OP is also trying to blend in an internal mic, which needs 9 volts bias power. I know his question here is about "quality", but his situation is really about functionality.

[MrErikJ]

Originally Posted by phcorrigan

I think you mean Hi-Z (high impedance) input. Some mixers, such as my Behringer XR18 digital mixer, provide one or more Hi-Z inputs, while others, like my Behringer X1204USB analog mixer, do not. That covers the need, but external preamps can provide additional benefits, including better sound, more control for the player, etc.

I sure did. Fixed!

[MrErikJ]

Originally Posted by Doug Young

The OP is also trying to blend in an internal mic, which needs 9 volts bias power. I know his question here is about "quality", but his situation is really about functionality.

For sure. In my view, you should use what works best for you and provides the most appropriate combination of sound and functionality for your performing needs. Per my point, plugging a K&K (or something comparable) straight into a mixer that isn’t able to accommodate a hi-z signal may produce unsatisfactory results. If it can handle the impedance and provide adequate gain, low noise, and satisfactory EQ control, all the better. Whatever works for you. There is no “best” solution besides what achieves your goals and needs.

To the point earlier about David Wilcox, I’m in agreement that I don’t find Dave’s tone (utilizing 4 or 5 pickups) and two stereo Pendulum modules, particularly worth the effort. However, Dave has the EQ hardwired in his modules and his settings are saved in the digital mixer he uses to combine the signals and feed the FOH. Why? Well, he says he has two cables and a sub-mixer that lets him always get the same sound he wants. It satisfies his needs, just as Doug’s use of passive pickups into an outboard preamp into a PA does, and someone else is happy with a K&K into a Tonedexter. Whatever works.

[phcorrigan]

Originally Posted by MrErikJ

Whatever works.

I think this is the correct answer!

[rockabilly69]

Originally Posted by jonfields45

I think diminishing returns and observer bias make taking advice on this forum literally, a fool's errand :~).

Maybe for some people, but in my case I totally disagree with this statement.

Why? If you add up all the gear I use on stage for 90% of my performing. It would take me about two weeks of gigs to pay for it all, of fifty two weeks a year.

Certain people here, are pros, in other words, pay all their bills and expenses from their musical endeavors, and then some are weekend warriors, and some people just play live once in awhile. I would say these groups might have different requirements, although some hobbyists like to have the best sound then can. I fit into the pro category.

In my case, the return was/is getting the gigs. Many years ago I focused on finding the best gigs in my area. I got tired of small street gigs, fairs, and most importantly, things like noisy sports bars or dive bars. So before I approached the higher end places to play, I went out and checked out the musicians that held these gigs. And the one consistent thing I saw, besides the fact they were all VERY talented singer/guitarists, was that these guys all had good sound. I checked out their equipment, and I talked to the sound man in some of the bigger places. I asked the soundman what equipment the best sounding guitarists and vocalists were using. I never checked out any internet forums, I didn't even know the AGF existed at this point! And after doing this, I started hearing about certain brands and types of equipment routinely. Names like AER, Schertler, B-Band (no longer made), Baggs, etc, started popping up so I checked them out. After a few misfires in buying some of this equipment, I dialed in in what would become the basis of my sound. The things I was focused on most were...

Vocal microphone: I ended up with a Shure Beta 87A because of it's polar pattern that rejects feedback very well, and a frequency curve that lines up with my voice best.

Pickup system: B-Band XOM. I have this system in five different guitars because it just plain works for what I do.

PA/Amplifier: I started with Allen and Heath Zed mixers, and powered speakers. I progressively went smaller and smaller until I found out what would work for what I do, and still be light and easy to move. I still use these systems in some places. And then I found the Schertler Acoustic amps, first the JAM400, and then the JAM250, as I once again was trying to scale back in size and weight, and frankly both of these amps sound like very good small PA systems. I eventually found, through a post here on this forum, that a music store was closing down and were selling a Schertler Sub and Extension cabinet at a ridiculously low closeout price, so I snapped them up too.

By this time I started sounding really good, but I would still fall short in one area. The the ability to quickly and effectively dial in EQ in problem venues! My first really good piece of gear that helped here was the Empress PARA EQ, and since I own a recording studio and have a very good working knowledge of parametric EQs, I found this piece of equipment to be a godsend!

After that, the next jump up was the Grace preamps, the Felix and Alix. These also had great EQ and notch filtering. But what really set them apart was their routing capability. Man I love that they have a 1/4" out with it's own volume control to route to an electric guitar amp for my blues gigs, and they also have a killer sounding transformer balanced XLR output for routing to house systems. Every time I played big gigs with the Grace preamps, which I did quite a bit of, until COVID that is, the sound-man would always compliment me on the signal that I fed to his/her rig. Other great features of Grace preamps, ground lift, multiple impedances, the ability to swap the notch filter for a HP filter, two ranges of mid-range frequencies for the parametric EQ and a Q filter,etc. The Alix even has an accessory 9V outlet to power FX. So the Grace stuff pretty much put an end to my search for a great EQ, and bonus, it turned out that the preamp in it just happened to make my guitars sound GREAT.

I should also mention that I found a good reverb/delay. Some of the places I play in are acoustically dead, so I need a little reverb to liven them up. I really didn't like the built in reverb on the amps or the mixers, so I checked out a few outboard pedals, and when I heard the Keeley Delay Workstation (combo reverb/delay) I thought it was perfect for me.

I am totally set now. I have used small variations of this setup for the last 4 years, and I only vary the setup with the size of the venue, not because something isn't sounding good.

None of my setups take more than 15 minutes to set up, and all of my equipment, minus the one of two guitars, can be brought in with one cart trip to and from the car.

There are more musicians like me, both pro and serious weekend warriors that frequent and post on this forum, and when somebody new is looking for equipment recommendations, I would think it would be nice for them to read about what has worked for other people so that they can save a few steps to get on the page quick, so to say. Do they need this equipment? Well, it depends how they want to sound. Sure you can get an acceptable sound, or maybe even a good sound with the right combo of pickup and powered speaker, but it's not going to sound like plugging into an ideal setup.