Are practice amps flat?

[darwin-bass]

I realize full gig amps usually have a characteristic "sound" built into their preamps. SWR cuts mids at 250 hz, GK at about 800Hz, Ampeg at about 500Hz, Aguilar rolls off the treble and a bit of the bass.

But what about practice amps? Being simpler designs are they really just flat response with their sound being dictated by the speaker or do the manufactures build some shape into their preamp response?

- Keith -

 

[DigitalMan]

I would call practice amps anything but flat. Most of the name brand amps you mention have a character that IMO goes far beyond a frequency boost or cut. There are a number of high end DI and preamps that some people covet for their flatness.

I feel that practice amps all have a character of their own, some being outright amazing and others being downright abysmal. Having said that, there are a range of characteristics that are seldom heard in practice amps. Tubeyness and nice speaker breakup are two obvious categories that the practice amps don't often cover well if at all.

Bottom line is that there are lots of plain Jane practice amps, but there are also many others that sound fantastic. I would hesitate to make a generalization about the sonic qualities in the category.

For the record, I define practice amps as pretty much any combo. Your definition may be different.

 

[f.c.geil]

Nope. They are anti-flat, really. A good one to have would be a bright one, though, to emphasize technique errors, thus forcing you to get better.

 

[1958Bassman]

I realize full gig amps usually have a characteristic "sound" built into their preamps. SWR cuts mids at 250 hz, GK at about 800Hz, Ampeg at about 500Hz, Aguilar rolls off the treble and a bit of the bass.

But what about practice amps? Being simpler designs are they really just flat response with their sound being dictated by the speaker or do the manufactures build some shape into their preamp response?

- Keith -

You don't want flat. Flat-ish response is for audio reproduction systems, not when actually making the sound.

 

[darwin-bass]

Well, I don't plan to use it for bass practice! Silly people!

And I'm not asking about the frequency response coming through the speaker. No, I'm asking about the electronics; the preamp really.

Is the preamp in a practice amp flat?

Remember it takes extra effort to build in some sort of mid-cut curve. I'm guessing that effort is NOT taken with a practice amp.

Yes? No?

- Keith -

 

[JimmyM]

Not as a rule, no.

 

[Dave W]

It completely depends on the amp

 

[CnB77]

Remember it takes extra effort to build in some sort of mid-cut curve.

Not if you do it by accident, which is likely when you're just copying a reference design from the chip manufacturer and throwing on a tonestack.

There's a reason that truly flat gear costs a lot; it takes engineering and careful testing to get there.

 

[lpdeluxe]

Every amp designer builds in a response curve that they believe will help sell amplifiers. Generally, they don't design "practice" amps: they are given the assignment to produce a product that hits a certain price point, or demographic, or whatever, that will make money for the manufacturer.

In my experience, less expensive amps that qualify as practice amps are far from "flat," just as they are far from "good sounding."

And "pro" amps are no more nor less flat than the cheapos. Personally, I have always bought amplifiers based on how good they sound and "flat" be damned.

 

[JimmyM]

My practice amps sound pretty darn good, thank you. OK, so they're not SVT's, but I didn't expect that out of them.

 

[MegaSwing]

At lower volumes, at which you should be using said practice amp, I submit that flatness is irrelevant. You pretty much just want to be heard at all, even if it's just alone in your bedroom. I can see a whole product category arising from this—boutique practice amps: amps that sound great until you add other players, at which point you cannot be heard at all.

 

[bongomania]

Not if you do it by accident, which is likely when you're just copying a reference design from the chip manufacturer and throwing on a tonestack.

There's a reason that truly flat gear costs a lot; it takes engineering and careful testing to get there.

+1 it takes extra effort to REMOVE a curve that may be inherent to the basic design.

OP you seem to be mixing up the idea of "practice amp" with "purist design"; unfortunately minimal features and minimal cost do not equal any sort of purism.

 

[steve_rolfeca]

To the OP: your assumptions about circuit design are way off base.

The differences between a practice amp and a stage amp, are the extra hours invested in tweaking the tone profile, more expensive parts, some discreet components replacing IC's, and a more complex tone control layout. The stage amp might even have a tube or two in the preamp.

A practice amp is still a musical instrument amplifier. It wouldn't sell if it didn't sound like a bass amp, and sport at least a basic set of tone controls. They also need some extra pre-emphasis to compensate for the crappy stock speakers.

No effort required. Once you drop a standard tone control circuit into a design, it's just a matter of adjusting a couple of component values to voice the frequency response. This is very rudimentary stuff. If the designers didn't know how to do it, then they certainly wouldn't have the chops to design an entire practice amp.

If you want a practice rig with a flat-response preamp, don't buy a cheap bass amp. Buy a small mixer or a mic preamp, or even an audio interface and an app for your iPad/iPhone. Then pair it with a small powered PA speaker or a recording monitor.

 

[darwin-bass]

To the OP: your assumptions about circuit design are way off base.

OK, now we're getting somewhere!

No effort required. Once you drop a standard tone control circuit into a design, it's just a matter of adjusting a couple of component values to voice the frequency response. This is very rudimentary stuff.

So the pre-shape is due to some components in the tone control section? Makes sense.

If you want a practice rig with a flat-response preamp, don't buy a cheap bass amp. Buy a small mixer or a mic preamp, or even an audio interface and an app for your iPad/iPhone. Then pair it with a small powered PA speaker or a recording monitor.

FULL STORY - I have an Ampeg BA108. Very nice sounding practice amp for bass. I also play acoustic gtr. I'm thinking about upgrading the speakers on the BA108 to a better 8" and then adding a tweeter to turn it into a full range box. Then I can use it for bass practice and to amplify my acoustic guitar. But before I go to the trouble of adding the crossover and tweeter I wanted to know if I was starting with an amp that would work OK for guitar.

I suppose I could find the answer by playing a CD through the CD Input and then through the instrument input (with tone controls flat) to see if there is any difference between the signal paths.

- Keith -

 

[remainthesame]

It's funny cause I was just talking about this with my singer: I have a little peavey 15 watt combo and I love the tone. Even more-so than my stage rig. But its simply not loud enough due to the fact that its a little combo amp.

I know I could mic the little combo amp at any show with a decent PA however I am compensating for my insignificant genitalia and therefore need at least two 410 cabinets.

 

[Pimmsley]

It completely depends on the amp

+1

 

[Downunderwonder]

The cab they are put with is small and has no bottom end. No biggie.

 

[RickenBoogie]

There are inexpensive acoustic guitar amplifiers that would work much better, cost less than modifying a bass combo, and make more sense overall.

 

[1958Bassman]

Well, I don't plan to use it for bass practice! Silly people!

And I'm not asking about the frequency response coming through the speaker. No, I'm asking about the electronics; the preamp really.

Is the preamp in a practice amp flat?

Remember it takes extra effort to build in some sort of mid-cut curve. I'm guessing that effort is NOT taken with a practice amp.

Yes? No?

- Keith -

You didn't specify how you want to use it, posted on TalkBass about a practice amp and WE'RE the silly ones?

If you want to find out, contact the company. Filters are cheap and easy but it's a practice amp- it's not meant to be able to sound great, unless by accident. If you want to use it for a gig, you'll get what you paid for.

 

[gavinspoon]

OK, now we're getting somewhere!



So the pre-shape is due to some components in the tone control section? Makes sense.



FULL STORY - I have an Ampeg BA108. Very nice sounding practice amp for bass. I also play acoustic gtr. I'm thinking about upgrading the speakers on the BA108 to a better 8" and then adding a tweeter to turn it into a full range box. Then I can use it for bass practice and to amplify my acoustic guitar. But before I go to the trouble of adding the crossover and tweeter I wanted to know if I was starting with an amp that would work OK for guitar.

I suppose I could find the answer by playing a CD through the CD Input and then through the instrument input (with tone controls flat) to see if there is any difference between the signal paths.

- Keith -

Have you tried playing acoustic through it as is, to see how it sounds?

That'd be my starting point. If I didn't like that i'd try a preamp into the cd input (or fx loop if it's got one).