Pre-amps - What do they do?

[jorgemg1984]

historically guitar amps have not had perfect power amps I guess…

I guess not. I'm not an expert on the subject, but I think inefficient speakers that distort early plus distorted preamps and power amps ended up creating a sound that so many people revere these days. it was probably, at first, more of an accident or a consequence of poor technology than made on purpose.

If you lurk around TGP or YouTube it can be funny, for a jazzer, what is considered "clean" as a guitar sound. Even in a completely clean tube amp plenty of people seek the "colour" they bring, ie not neutral. The idea that an amp should be neutral and only amplify the guitar's sound is probably an exclusive of (some) jazz players and maybe steel players. Reggae and country people tend to play very clean too, but seek more colour from their amps.

[kwijibo]

I wonder why they fitted a legacy usb connector to a new device.

[John A.]

I could be wrong about this, but ...

Suppose you're running your amp well below its limits.

If you double the voltage of the input to the amp (say, by inserting a preamp in your signal chain), the amp will sound a little louder.

In my experience, inserting a pre—amp (or using a higher output pickup) can be a lot louder, with the caveat that I don’t know how much more voltage this is. Complicating the question, with some amps (especially Fenders), boosting has the effect of increasing midrange more than bass or treble, which is perceived as a loudness increase, even when it’s a relatively small measured SPL increase

But, if the amp is already running full bore and you double the input voltage, I think it gets more distorted.

It depends on the amp. For example, with my Princeton Reverb a clean boost pedal pushes the preamp section of the amp into some degree of distortion irrespective of where the volume knob is on the amp. On some other amps, clean boost is actually clean unless the amp is turned up pretty far.

I'm not sure of the math, but, I'm sure you can't get a 5 watt amp to be as loud as a 100 watt amp simply by amplifying the input signal by a factor of 20.

But, otoh, if the amp will tolerate more voltage at the input, there ought to be some benefit, but maybe not enough to notice.

Most of the guitar playing world is trying to get a clean 100 watt amp to sound like a distorted 5 watt amp.

[supersoul]

If you lurk around TGP or YouTube it can be funny, for a jazzer, what is considered "clean" as a guitar sound.

"ok, I'm going to start with a clean tone"
bzzzzzsssshhhhhhh
"and now here's the sound of the Hell Industries 2000 UltraMega Distortion pedal"
chggabhzzzzzhhhhhhh

[Christian Miller]

I guess not. I'm not an expert on the subject, but I think inefficient speakers that distort early plus distorted preamps and power amps ended up creating a sound that so many people revere these days. it was probably, at first, more of an accident or a consequence of poor technology than made on purpose.

If you lurk around TGP or YouTube it can be funny, for a jazzer, what is considered "clean" as a guitar sound. Even in a completely clean tube amp plenty of people seek the "colour" they bring, ie not neutral. The idea that an amp should be neutral and only amplify the guitar's sound is probably an exclusive of (some) jazz players and maybe steel players. Reggae and country people tend to play very clean too, but seek more colour from their amps.

Fender BF amps definitely have a bit of mush to them, esp when you get them warm

[jorgemg1984]

Fender BF amps definitely have a bit of mush to them, esp when you get them warm

Agreed. On the helix native I put all the settings related to that (bias, biasx, sag, hum, ripple) on ZERO and it makes any of the BF models a lot more natural for a jazz clean sound, although I understand why people who play other genres like to crank those settings.

[jorgemg1984]

Most of the guitar playing world is trying to get a clean 100 watt amp to sound like a distorted 5 watt amp.

This sums it up, basically. Maybe 40w, instead of 100w, but it's the general spirit. Jazzers do the opposite, but we don't count. On a modeler what I do is I get say, a Princeton at really low volume to sound exactly like that but loud. The exact opposite of why rockers use attenuators. Maybe we could call it a magnifier? If we mattered on the guitar market, someone would come up with that - make your Princeton on 2 sound as loud as a Twin.

[GuyBoden]

On a modeler what I do is I get say, a Princeton at really low volume to sound exactly like that but loud.

Yes, I think using a modeller with a power amp/speakers or powered speakers is easier to get a loud clean volume sound.

I played with a Fender Deluxe Reverb for over 20years, they broke up at louder volumes, which I didn't want.

[jorgemg1984]

Yes, I think using a modeller with a power amp/speakers or powered speakers is easier to get a loud clean volume sound.

I played with a Fender Deluxe Reverb for over 20years, they broke up at louder volumes, which I didn't want.

Ah, the DR paradox Rock and blues bedroom players want their gig sound at home volumes. We want the DR home sound at gig volumes.

A modeler is an excellent way of solving this equation, in both cases, in my experience.

[Spook410]

Some modeler setups are a lot more expensive than a combo amp. And there are cables running everywhere. I've got good powered speakers and I'm tempted to get one of the less expensive multi FX units just to simplify. I do still like my combo amp and use it daily but it is limiting compared to full on pedal board and powered speaker that provides a much greater variety at any volume I want.

[KirkP]

If you use two identical amps side by side, you get a 3 db level increase. You would need ten times the db power to perceive double the volume (meaning 500 watts sounds twice as loud as 50 watts).

It's a bit ambiguous. Volume doubles every 3db but loudness (meaning our perceived volume every 10db.

I often hear the rule of thumb about requiring a 10 dB increase to double the perceived volume. I don’t doubt it’s true, but that’s a subjective assessment of what people consider to be “twice as loud”.

What’s more important to a musician than perceived volume is signal to noise ratio. For example, you’ve got a gig in a noisy bar and you’d like to be heard over the background chatter. In those situations I think 3 dB would have a very significant effect. I used to bring two amps to noisier venues and it made quite a difference.

Of course a preamp (which is the topic of this thread) does nothing to increase available volume. That’s entirely determined by the power amp and speaker.

[KirkP]

The decibel scale is logarithmic, meaning you would need 10 combo amps of the same spec to double the sound pressure level.

That’s not correct. It may take 10 times the power to achieve a perceived doubling of volume (i.e., that an untrained listener would describe as “twice as loud”). But sound pressure level has changed by the same factor of 10 as the power.

Also, see my comment a few minutes ago about signal to noise ratio.

[Christian Miller]

I dunno really, I kind of find playing at live volume levels a different experience anyway. Maybe I’m warming to the tube thing after all.

[jorgemg1984]

Some modeler setups are a lot more expensive than a combo amp. And there are cables running everywhere. I've got good powered speakers and I'm tempted to get one of the less expensive multi FX units just to simplify. I do still like my combo amp and use it daily but it is limiting compared to full on pedal board and powered speaker that provides a much greater variety at any volume I want.

The HX Stomp costs around 500 euros, and if it's as good as the Helix Native, it's well worth the price. Very small, you only need two cables going to the two powered speakers and one from the guitar to the input, not that complicated.

Modelers have a big learning curve and each one has its own tricks, but, in my experience, they sound a lot better than any amp I tried and offer a lot mote flexibility, from equalizers to compressors to impulse responses etc.. (just for reference I played a Blackface Vibrolux fairly regularly in the past and I would still prefer a digital rig).

[rpjazzguitar]

I tried the Boss ME80 pedalboard into an Alto powered speaker. The Alto manual said you could plug in a mic, which I understood to mean that I could run a guitar level signal into the Alto. The problem was that to get any volume that way, I had to turn the Alto volume control to 3 o'clock or so, at which point the bass frequencies went crazy and the sound was useless. Not just bad. Useless.

The Alto wanted a preamp (the kind mixers contain) to pre-boost the guitar's signal.

The ME80 has settings that seem like you could do that, but I couldn't get a decent sound out of it. I don't recall if I tried the amp module on clean and then adjusted gain and level. I probably did try that, but I can't recall specifically.

What is going on is that a guitar signal isn't very many volts, or millivolts. You have to preamp it to "line level". "Line level" has both pro and consumer versions. The pro version is more volts. If your powered speaker expects a certain minimum voltage, that's that.

I think there are enough things that could go wrong that I'd strongly recommend trying it out at full volume before you buy.

EDIT: I then realized that I have an SRM350 powered speaker stored here that I had never tried this way. Unlike the Alto, it worked perfectly with the ME80. And, it sounded better than the LJ. It even sounded better direct from the ME80 than from the ME80 through the LJ (XLR out). I could hear the individual notes of chords more clearly in the SRM350.

One difference is that the Alto I tried did not have a switch for mic/line. Instead, part of the rotation of the volume pot was labeled mic.

I used the SRM350 on line-in. On mic it was too loud to even begin to use. I suppose I could have dialed down the ME80 output, but I didn't try that.

[Spook410]

The HX Stomp costs around 500 euros, and if it's as good as the Helix Native, it's well worth the price. Very small, you only need two cables going to the two powered speakers and one from the guitar to the input, not that complicated.

Modelers have a big learning curve and each one has its own tricks, but, in my experience, they sound a lot better than any amp I tried and offer a lot mote flexibility, from equalizers to compressors to impulse responses etc.. (just for reference I played a Blackface Vibrolux fairly regularly in the past and I would still prefer a digital rig).

The less expensive mutli FX are tempting for simplicity. Though I would like to play with one of the pricey high end models some rainy afternoon. I've been running a Strymon Iridium for a long time which starts quite simple and reasonably priced. But then there is the nice reverb, looper, and preamp/EQ (Grace Design Felix in this case). Works well. Sounds good. Not as plug and play as a combo amp. (yes.. I have too much gear.. I'm sure there's a 12 step program somewhere..)

[pingu]

these seem like a good pre amp
for going direct to a PA or
powered speaker

Phantom Block Quilter Labs

phantom powered off the XLR or
battery powered
anyone tried one ?

[JCat]

-Who wants to "go direct to the PA"?
A device without a speaker jack is limited to home recording and headphone practicing.

[pingu]

1273626[/URL]]-Who wants to "go direct to the PA"?
A device without a speaker jack is limited to home recording and headphone practicing.

nope , I’ve done a couple of gigs
‘direct to the PA’ and it worked fine

(going direct to PA through modlers and pre-amps etc is fairly common these days)

[st.bede]

This sums it up, basically. Maybe 40w, instead of 100w, but it's the general spirit. Jazzers do the opposite, but we don't count. On a modeler what I do is I get say, a Princeton at really low volume to sound exactly like that but loud. The exact opposite of why rockers use attenuators. Maybe we could call it a magnifier? If we mattered on the guitar market, someone would come up with that - make your Princeton on 2 sound as loud as a Twin.

There are attenuators out there that include a power amp. They are supposed to give you a clean volume level increase. Fryettte Power Station is one example. How well it works I do not know. It is on my list of potential future purchases.

[nevershouldhavesoldit]

-Who wants to "go direct to the PA"?
A device without a speaker jack is limited to home recording and headphone practicing.

To each his own. I’ve been running through the house system for a few months and love it - here’s the thread from the night I started doing this. You have to have good monitoring for it to feel right. We have 3 footers in front plus two stand mounts at the back of the stage, but I’ve used IEMs for a few years and love them. They block ambient sound like good earplugs, so I can control what I hear.

That Quilter DI is almost certainly either the front end of a Superblock or a similar circuit. My SBUS is an excellent DI, and the gain + volume controls let me dial in a nice, mild OD for blues. So I think the Phantom Block is probably a very good device.

[JCat]

nope , I’ve done a couple of gigs
‘direct to the PA’ and it worked fine

(going direct to PA through modlers and pre-amps etc is fairly common these days)

To each his own. I’ve been running through the house system for a few months and love it - here’s the thread from the night I started doing this. You have to have good monitoring for it to feel right. We have 3 footers in front plus two stand mounts at the back of the stage, but I’ve used IEMs for a few years and love them. They block ambient sound like good earplugs, so I can control what I hear.

That Quilter DI is almost certainly either the front end of a Superblock or a similar circuit. My SBUS is an excellent DI, and the gain + volume controls let me dial in a nice, mild OD for blues. So I think the Phantom Block is probably a very good device.

For the last 20 years (about the time for the first digital modelers to appear) the argument "Go direct to the PA" was an excuse for not having a speaker jack.
Lining out to the PA is an age old technique, and there are many different ways to do that, but traditionally there was always a guitar amp on stage for the player to control and monitor his tone.

Granted, there are situations when the player is not in control, when the guitar tone is in the hands of an audio engineer at the mixer table and when PA stage monitors and in ears would be dominating the guitar amp. But for a small club gig (typical jazz venue), especially when there's no vocalist, the main purpose of the inhouse PA-system is to introduce the songs. Of course, I could use it for lining out and mixing instruments, but this significantly increases complexity of sound check.

Yeah, to each his own, but let's be real; a home player that plays through PC-monitors and headphones all the time and thinks he could just "go direct to the PA" when time comes will run into problems. Mixing live sound and stage monitoring is a task that takes time to master and you've got to ask yourself; -who's in control of the mixer table?

[jorgemg1984]

For the last 20 years (about the time for the first digital modelers to appear) the argument "Go direct to the PA" was an excuse for not having a speaker jack.
Lining out to the PA is an age old technique, and there are many different ways to do that, but traditionally there was always a guitar amp on stage for the player to control and monitor his tone.

Granted, there are situations when the player is not in control, when the guitar tone is in the hands of an audio engineer at the mixer table and when PA stage monitors and in ears would be dominating the guitar amp. But for a small club gig (typical jazz venue), especially when there's no vocalist, the main purpose of the inhouse PA-system is to introduce the songs. Of course, I could use it for lining out and mixing instruments, but this significantly increases complexity of sound check.

Yeah, to each his own, but let's be real; a home player that plays through PC-monitors and headphones all the time and thinks he could just "go direct to the PA" when time comes will run into problems. Mixing live sound and stage monitoring is a task that takes time to master and you've got to ask yourself; -who's in control of the mixer table?

Even without a vocalist, I would say in a typical small jazz club you at least mic the piano... I don't think I remember the last time I went to a jazz club that the PA was off (anywhere in the world, really), so you're always dependent on the sound guy. Yes, that can be tricky, but is it better to carry an amp or to be reliant on the venue's amp, that are so rarely in decent conditions? If you know how to use a modeler, and feed the PA a good sound, most of the times the sound guy will only have to decide your level, and leave everything flat. Also, if you decide to monitor using an amp, you'll hear a different sound from the audience, because a miced amp sounds quite different from the actual amp (and the audience will hear a mix of both). With modelers, you'll hear what the audience hears.

Live sound in small and medium rooms is always tricky because the audience will hear sound from the PA and from the stage. In my opinion and experience, the more instruments you put trough the PA, the better, because you reduce stage sound - providing there's adequate monitors, of course (or that the PA sound is easy to listen on the stage, that happens a lot in a small club), If, say, in a guitar trio, the guitar and the bass go trough the PA, there's a lot less conflict between the stage sound (amps) and the PA sound.

I don't think it significantly increases the complexity of the check sound. With time, and experience, you can do a check sound very quickly with modelers.