E drum amp kit or design like roland pm-100

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#2
Functionally it's just a mixer, amp, and a speaker in a nice cabinet.
If you don't need a mixer, it's easy to mount a small amp inside a speaker cabinet,
especially a class D amp. You can build a cabinet and choose a driver yourself,
for a lot less than the $500. Roland. Haven't seen an actual kit, though.
 
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#3
rayma said:
Functionally it's just a mixer, amp, and a speaker in a nice cabinet.
If you don't need a mixer, it's easy to mount a small amp inside a speaker cabinet,
especially a class D amp. You can build a cabinet and choose a driver yourself,
for a lot less than the $500. Roland. Haven't seen an actual kit, though.
Click to expand...
@rayma, Thanks for your reply, that makes sense! its pretty much a speaker with a 10inch sub and a 2 inch tweeter with like you said amp and mixer

Now i just need to learn how that all works lol
 
#4
You can buy the both amp, power supply, and mixer ready built. Then you just mount everything
together in the box and wire it. For a personal monitor you might not want a tweeter anyway.
If it's for home use, it doesn't need to be loud.
 
#5
I have no idea about the sound quality, but Amazon has this Donner, relatively cheap, and you can always return it if the sound quality is not up to your requirements: https://www.amazon.com/Donner-Elect...85-4209-b4f2-0de601c65cd6&pd_rd_wg=QdABI&th=1

A year or two ago, I wanted something very similar, but for vocals and guitar, not drums. I ended up doing almost exactly what Rayma suggested in post #4: I bought a cheap class-D amplifier board, a suitable switching power supply, a small cheap mixer, and mounted all of them on the back of a pair of small Sony loudspeaker enclosures I found for four bucks (!) in a local thrift store. (I glued the two speakers together into a single unit.)

Depending on the speaker, you may not need a separate tweeter. I have an Acoustic AG30, a commercial product very similar to the Roland you mentioned. The AG30 has an 8" woofer, with a little Mylar dome tweeter built right into the center of it, like many car speakers. Sound quality is excellent for its intended applications - I've used the AG30 for vocals, acoustic guitar, and keyboards.

Depending on your ability (tools / knowledge / space) to do carpentry, building an enclosure may be a big challenge, or an easy project. If carpentry is not your thing, look around for something you can re-purpose. Boom-box and Hi-Fi speakers have been thrown out by the thousands during the last decade or two, and you might get lucky and find something you can use in a thrift or surplus store. If you do, it will save you a lot of money too, and will work, as long as you don't intend to get loud.

Do you plan to play drums through it, or something else? Drums do require a beefy woofer, especially if you expect to play them at anything other than very quiet volume. So if it's drums you're after, you probably do really need a 10" or bigger woofer.

-Gnobuddy
 
#6
Gnobuddy said:
I have no idea about the sound quality, but Amazon has this Donner, relatively cheap, and you can always return it if the sound quality is not up to your requirements: https://www.amazon.com/Donner-Elect...85-4209-b4f2-0de601c65cd6&pd_rd_wg=QdABI&th=1

A year or two ago, I wanted something very similar, but for vocals and guitar, not drums. I ended up doing almost exactly what Rayma suggested in post #4: I bought a cheap class-D amplifier board, a suitable switching power supply, a small cheap mixer, and mounted all of them on the back of a pair of small Sony loudspeaker enclosures I found for four bucks (!) in a local thrift store. (I glued the two speakers together into a single unit.)

Depending on the speaker, you may not need a separate tweeter. I have an Acoustic AG30, a commercial product very similar to the Roland you mentioned. The AG30 has an 8" woofer, with a little Mylar dome tweeter built right into the center of it, like many car speakers. Sound quality is excellent for its intended applications - I've used the AG30 for vocals, acoustic guitar, and keyboards.

Depending on your ability (tools / knowledge / space) to do carpentry, building an enclosure may be a big challenge, or an easy project. If carpentry is not your thing, look around for something you can re-purpose. Boom-box and Hi-Fi speakers have been thrown out by the thousands during the last decade or two, and you might get lucky and find something you can use in a thrift or surplus store. If you do, it will save you a lot of money too, and will work, as long as you don't intend to get loud.

Do you plan to play drums through it, or something else? Drums do require a beefy woofer, especially if you expect to play them at anything other than very quiet volume. So if it's drums you're after, you probably do really need a 10" or bigger woofer.

-Gnobuddy
Click to expand...
THanks for the Great advice 🙂

Not in the USA so returning things etc is a hassle, but could be an option, it would just be a practice amp for my son, so doesn't need to be loud but needs to have decent sounds, Drum is a lot about feeling rather than hearing 🙂

I might have to do some learning, making a two channel mixer should be easy (would be great for him to be able to play along with music)
Just need to learn more about AMPs and speakers 🙂

thanks again!
 
#7
Just adding you will need tweeters,of course, unless you want your Zildjian or Paiste Cymbal samplings sound like aluminum pot covers ... or worse.

As of woofers, no need to go ultra deep either , so no 20-30Hz subwoofers; a kick drum gets its chest thump from a reasonable peak (a couple dB, 5-6 dB tops) between 60 and 90Hz or so.
 
#8
Easier to buy
After cost of speaker, enclosure, amplifier, mixer

More expensive

The Roland design is similar to " wedge monitor"
you could use 10" or 12" coaxial speaker designed for wedge monitor.
then cabinet with proper airspace.
Or just buy a wedge monitor and power with amplifier and mixer
or find used " Powered Mixer"

You still need amp and mixer.

Another cheaper option is " Keyboard amplifier Combo Amp"
or Behringer powered monitor with 12" speaker and horn.
 
#10
KifaruNZ said:
...making a two channel mixer should be easy (would be great for him to be able to play along with music)
Click to expand...
Here's the thing: it's very easy to grab a dual op-amp and make yourself a two-channel summing amplifier. Now you can mix drums and music.

But then you need a way to control the level of each signal in the mix. Not too bad, two volume pots will do the trick.

You also need a master volume. Okay, one more pot, 3 in total.

How about tone controls? You'll most likely want them. Now you need at least two more pots per channel (treble and bass). We're up to 5 pots now, plus the caps and resistors around the tone control, plus an extra couple of op-amps. Plus knobs for everything.

Signal level indication? You may not need sophisticated level meters, but you probably want at least a clip indicator. So you need another op-amp or two, along with suitable rectifier circuitry, and maybe a trimpot or two to set the sensitivity.

Let's not forget input and output jacks. At a minimum, two input jacks, one output jack.

And a suitable enclosure in which to mount everything.

And a power supply for all the op-amps in the mixer.

Of course you also need schematics for all this circuitry, which you have to hunt down, if you can find them. You need to translate the schematics into layouts, and either build awkwardly on protoboard / veroboard, or design, etch, and drill your own PCB.

At about this point, you may find that the simple two-channel mixer is actually not that simple, and the cost of all its parts might add up to considerably more than you'd pay for a cheap no-name mixer off Amazon!

For example, here a little mixer for $42 Canadian (roughly $32 American): https://www.amazon.ca/ALPOWL-Profes...ix=audio+mixer,aps,113&sr=8-5#customerReviews

From the reviews, the analogue features of the "Alpowl" (!!) mixer work fine, but the usb interface capabilities are worthless. If you don't care about the USB-to-PC aspect, it might work for you.

Here's a better-reviewed little mixer for $62 CAD (roughly $47 USD): https://www.amazon.ca/A4-4Channels-.../dp/B07MLGS622/ref=sr_1_13?crid=2KXRBEW1615Z6

I couldn't buy all the bits and pieces necessary to DIY my own mixer, for the purchase cost of either of these little gizmos.

I DIY a lot of little electronic bits and pieces I need, but mixers are not among them. Too complex, too expensive.
KifaruNZ said:
Just need to learn more about AMPs and speakers 🙂
Click to expand...
Now that we know you actually intend to use this with drums, we know you are going to need a fairly beefy speaker. This is actually a fairly challenging application, as drums will tear apart an inadequate speaker.

The speaker needs to be in a proper enclosure, of a size matched to the speaker. Enclosure design is another whole story by itself.

If you can find a suitable cast-off speaker+enclosure in a thrift store or through local classified ads, that will make the rest of the project relatively easy.

-Gnobuddy
 
#13
WhiteDragon said:
Easier to buy
After cost of speaker, enclosure, amplifier, mixer

More expensive
Click to expand...
You sure?
This Roland Drum Monitor is $343 at Sweetwater
https://www.sweetwater.com/store/detail/PM100--roland-pm-100-80-watt-1x10-inch-personal-drum-monitorAdd shipping + Import Duty + Tax and the NZ price becomes scary.

Using US prices as a comparison and building exact same product, not "improving" which was not asked for:

* 10" speaker , similar to the one Roland fitted in their amp: https://www.parts-express.com/Dayton-Audio-DC250-8-10-Classic-Woofer-295-315

* you can use a Piezo Tweeter. Cheap and STRONG, much used in Keyboard amps, affordable stage monitors, Acoustic Guitar amps, etc. but more important: you won´t burn it with those cymbals.

* you can find lots of 80-100W amps on EBay for very reasonable price, get one which includes power supply (or get one which can feed it)

* just checked V Drum specs: they have multiple outputs, and at least one which provides all signals combined into Mono and at Line level, which can straight drive a power amp.

If still needed for convenience, there are a couple mixer-preamp boards available, you should mount everything in some kind of cabinet, of course.

You are free to build your own cabinet to house everything, or if all thumbs , get one of those cheap as dirt grey carpet covered cabinets intended for Car speaker mounting.

Or an unfinished one (raw MDF) and paint it black.

Your total bill will hover around 100-120 bucks , maybe 150 if you splurge, and you´ll have a ton of Builder´s Pride, believe me 😉
 
#14
NZ?
Expensive.
Find car sub woofers, amps and speakers at a car breaker yard.
Build a 12V linear supply with beefy caps.
Done.

Or buy an old amp at a thrift store / flea market, and go ahead.
Boom box and hi fi speakers may also be available cheaply.
Ask at a local electronics repair shop, if there are any left, they might find you some bits.
 
#15
NareshBrd said:
Find car sub woofers, amps and speakers at a car breaker yard.
Click to expand...
Good idea! Some of those woofers can take a lot of abuse, and that will help them survive in a drum monitor.

A lot of car "subwoofers" don't really go down very low in frequency, either. Fs is often in the range of 50 Hz, and will move up if you plonk the woofer into a sealed box (instead of the entire trunk volume of a car.) They also tend to have high Qts (more "boom").

These are bad qualities for Hi-Fi audio, but might not be a bad thing for a drum monitor.
NareshBrd said:
Build a 12V linear supply...
Click to expand...
12 volts gives you only about 10 watts RMS into 4 ohm speakers - and even that, only if you use a bridge-mode amplifier. If not bridge-mode, you only get a miserable 2.5 watts RMS or so into a 4-ohm speaker.

For a drum monitor, I think you need more power than that to avoid constantly clipping the amp.

Don't most of us have an old 18V or 19V laptop power supply lying around the house? That's enough voltage to give you 30+ watts (RMS) with a bridge-mode class D amplifier and a 4-ohm woofer. And laptop power supplies are sufficiently beefy to be able to provide enough current to comfortably support a 30 watt class-D amp, too.

-Gnobuddy
 
#18
Enzo said:
modern car stereo gear runs on 12vDC but has SMPS power supply inside to provide any rail voltages you desire.
Click to expand...
Certainly. I remember that this was already a popular solution (at least for aftermarket car audio) about twenty years ago. High power audio amplifiers for cars were early adopters of SMPS, long before they became ubiquitous in every consumer electronic product. If you want 500 watts to drive your "thumpa-thumpa" subwoofer from a car battery, there aren't that many other options.

(The other option was a special 48-volt lead acid battery in the trunk - and you still got "only" 250 watts RMS into a 4-ohm subwoofer!)

I lived in Los Angeles County at the time. For a lot of young men in tough urban neighbourhoods, their perceived route to success with the ladies was to buy an old Honda Civic, have a 4" diameter chrome exhaust tip welded to the exhaust, then add a couple of 12" woofers and several hundred watts worth of power amplifier. Turn up the bass until the entire car rattles, then go cruising.

But those old circuits tend to be really power-hungry. The audio amplifier was still a class B monster, around 70% efficient at its best, with huge heat sinks and maybe forced-air cooling. Those old SMPS were not all that efficient either. Nothing like current-generation ones.

Combined, SMPS plus class B power amp might only be 50% - 60% efficient. Current draws of 30 - 60 amps from the 12V car battery were not unusual (not surprising if you're trying to make 500 watts RMS from a nominally 13.4V battery).

Back then, at least, there were lots of "40W" audio amplifiers that were really four 10-watt bridged, class-B channels (for speakers at all four corners of the car.) No SMPS in those.

And then, there were high-powered aftermarket amps with SMPS. Usually the amplifier by itself was the size (and weight) of a hard-cover volume of the Encyclopædia Britannica.

I don't remember seeing a lot of in-between power ratings, audio power amps that would make, say, 30 watts RMS into a single 4-ohm speaker, while powered from 12 volts. I got the feeling that the teenage boys who ponied up for aftermarket audio power amps were not impressed with anything that didn't make at least a couple of hundred watts. So manufacturers didn't bother making them.

Has that changed since then? Are there now auto power amps with SMPS that use small, light, class D audio amps, and make 30 - 50W rather than 300 - 500 W?

I agree entirely with Naresh that junkyard car audio components are a fantastic way to lower the cost of the project. I just wonder about sufficient power output for a drum monitor.

I use a couple of little Lepai class-D amplifiers around the house, attached to desktop PCs and the TV in the spare bedroom. They run on 12V DC, and contain two bridge-mode class D power amps, delivering about ten watts RMS per stereo channel, into a 4 ohm speaker. This is more than enough power to satisfy me or my wife in those applications.

But for an e-drum monitor?

To me, a refugee laptop power brick looking for a home, and a pack-of-cards sized class D board, able to spit out about 30 watts RMS per channel into 4-ohm speakers, is a very appealing solution.Small, light, inexpensive, a sweet spot in a lot of ways. Just my opinion.

-Gnobuddy
 
#19
Original amp is 80W RMS and speaker is high sensitivity MI type, I would NOT replace it with a lesser power amp and no way I would us a horrible Car type woofer, those who stand 1kW .... because they NEED 1 kW to sound at all.
Plus they are muddy as hell.
Just use something similar to what Roland used, they should know.

As shown, 10" speaker is used almost as a full range, bet it reaches 3500 to 4500Hz easily (similar to Guitar/keyboard/many PA speakers) , "augmented/extended" by a tweeter which might very well be a Piezo or a small cone type.

Bass will NOT be chest thumping and Roland knows that very well, the compromise here was to get a small compact monitor, period, to be used by drummer at arm´s length, say 3 feet or so, and pointing at his ears.

Audience instead will get the full wide range signal, powered by all the kW the PA system can offer.

Drums are LOUD, even if played in a bedroom or bathroom.
 
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#20
Two things...the car amp still will have issues with 19 V from a SMPS supply, better feed it 12V, that is its diet.
The internal workings are not relevant here.

And car speakers of different sizes may be available, my impression was that a monitor was needed for practice sessions.
There comfortable, compared to loud, levels are needed.
Of course, used speakers for home or office use may be available for those on a small budget.

Object was that in mind, and also they are a bit easier to haul around from site to site.
 
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