Heyyas,
i'm looking into building me a pair of nice *small* FAST speakers that can stand on the desktop and still won't let you miss the feeling of system with subwoofer ... but that aside, wrong forum - i'd like to activate them. What i want to drive are two Speakers, one 4Ohms Subwoofer (which should need around 60-80watts, add dynamics, ~100watts) and one small 8ohms broadband speaker (which doesn't need that much, i'd say adding dynamics 30-40watts is *plenty*) with a active crossover (L-R 24db/oct). I was looking for a solution with minimal "external" components - i'd like to put them *in* the box, or at least in a really small cabinet integrated with the box. I was starting to look around, there are plenty of chipamps that would fullfill my needs (setting heat problems aside for the moment). Only problem: almost all of them (excluding maybe the tda1562q which needs 14.4v) need lunatic supply voltages of +-20 to +-35 volts (so 40 resp 70 volts) - which are hard to generate given a limited amount of space. Big trafos with big caps would be a no-go here. I was really hoping that somewhere i'd find something decent that needs < 20volts so i could use a readymade SMPS, old laptopcharger with a little more wattage, whatever and i'd be in. Unfortuneatly it really seems like there is no such thing - except for the 40watts internally bridged(?) TDA1562Q which seems to have problems with lower frequencies unless you throw tons of large caps at it...
I'm a little lost here - how do commercial producers of active speakers (almost all studio monitors out there, yamaha, genelec, you name it) solve that? Class-D with a SMPS? Or are there other solutions (than a huuuge trafo) that could supply me with a high enough voltage for - say - a lm3886?
Thanks in advance
And sorry for my bad english!
Regards
- NebuK
i'm looking into building me a pair of nice *small* FAST speakers that can stand on the desktop and still won't let you miss the feeling of system with subwoofer ... but that aside, wrong forum - i'd like to activate them. What i want to drive are two Speakers, one 4Ohms Subwoofer (which should need around 60-80watts, add dynamics, ~100watts) and one small 8ohms broadband speaker (which doesn't need that much, i'd say adding dynamics 30-40watts is *plenty*) with a active crossover (L-R 24db/oct). I was looking for a solution with minimal "external" components - i'd like to put them *in* the box, or at least in a really small cabinet integrated with the box. I was starting to look around, there are plenty of chipamps that would fullfill my needs (setting heat problems aside for the moment). Only problem: almost all of them (excluding maybe the tda1562q which needs 14.4v) need lunatic supply voltages of +-20 to +-35 volts (so 40 resp 70 volts) - which are hard to generate given a limited amount of space. Big trafos with big caps would be a no-go here. I was really hoping that somewhere i'd find something decent that needs < 20volts so i could use a readymade SMPS, old laptopcharger with a little more wattage, whatever and i'd be in. Unfortuneatly it really seems like there is no such thing - except for the 40watts internally bridged(?) TDA1562Q which seems to have problems with lower frequencies unless you throw tons of large caps at it...
I'm a little lost here - how do commercial producers of active speakers (almost all studio monitors out there, yamaha, genelec, you name it) solve that? Class-D with a SMPS? Or are there other solutions (than a huuuge trafo) that could supply me with a high enough voltage for - say - a lm3886?
Thanks in advance
And sorry for my bad english!Regards
- NebuK
FAST speakers......................>>>>
Look at racing wheels and high temperature lubricants if you want them to go FAST!
;-) Sorry!
Look at racing wheels and high temperature lubricants if you want them to go FAST!
;-) Sorry!
Hi the voltage is important . Also the current you will need is important.
From your post i feel this is the first amplifier you will build??.
A mistake is to put problems aside as they for sure return and bite ya ***.
All of this must be calculated into the design . if you want small size and low heat.
then class d will fit your needs . im guessing you will be needing stereo so two channels needed for the desktop speakers and 1 for the sub. you will also need a Active crossover. your calculations or guesses about power are not true. a good point to crossover from the subs to your full rangers 300hz or lower depending on the frequency response of the full rangers. At such a low crossover frequency i would say as a ball park your power split will be more 50/50.
This also depends on the sensitivity of the respective speakers.
ps are you going to build the speakers yourself??.
There is lots more to consider . have a look at the elliott sound products web page
Aka E.S.P the owner is part of the furniture onthis forum and his site is gold mine of very usefull audio circuits . and recomendations .
From your post i feel this is the first amplifier you will build??.
A mistake is to put problems aside as they for sure return and bite ya ***.
All of this must be calculated into the design . if you want small size and low heat.
then class d will fit your needs . im guessing you will be needing stereo so two channels needed for the desktop speakers and 1 for the sub. you will also need a Active crossover. your calculations or guesses about power are not true. a good point to crossover from the subs to your full rangers 300hz or lower depending on the frequency response of the full rangers. At such a low crossover frequency i would say as a ball park your power split will be more 50/50.
This also depends on the sensitivity of the respective speakers.
ps are you going to build the speakers yourself??.
There is lots more to consider . have a look at the elliott sound products web page
Aka E.S.P the owner is part of the furniture onthis forum and his site is gold mine of very usefull audio circuits . and recomendations .
Last edited:
Easy Frank
"Fast" dynamic maybe?. not too much of a problem with smaller drivers.
Add a very dynamic sounding amplifier. and i would say the sound is fast.
Friendly Regards Mad mark.
This is a very very good and technical forum.
If you cant be helpfull please stop wasting post's.
Mad Mark
@ Frank
"Fast" dynamic maybe?. not too much of a problem with smaller drivers.
Add a very dynamic sounding amplifier. and i would say the sound is fast.
Friendly Regards Mad mark.
This is a very very good and technical forum.
If you cant be helpfull please stop wasting post's.
Mad Mark
Not so fast
Yes i am aware of F.A.S.T.
I typed Fast.
also im aware of using a broad range speaker with a sub that is why i did not agree with the proposed power split as you well know the power is distributed in a diffrent ratio compared to a more conventional 2 way speaker system..
Im not really sure i get your point.
Mad Mark
Yes i am aware of F.A.S.T.
I typed Fast.
also im aware of using a broad range speaker with a sub that is why i did not agree with the proposed power split as you well know the power is distributed in a diffrent ratio compared to a more conventional 2 way speaker system..
Im not really sure i get your point.
Mad Mark
That means you want 120-160 W of output power and you will need a transformer that can at least supply that amount of power.
The size of a transformer depends on the power, not on the voltage. A 160 VA transformer will have the same dimensions (~120x40 mm), whether it has 1x12 V or 2x30 V output.
Most studio monitors are not so small that you couldn't fit a decent power supply in them. And the small ones usually have less power than one would think.
In nearfield, like you want to use them, they don't need much power, either. You will be sitting less than a meter away from them, so you already have a 10 dB higher SPL than you would have at a normal listening position around 3 m away. That means your 100 W stereo amp in the living room can shrink to a 10 W amp for nearfield listening.
I am using a 2x3,5 W amp for my desktop speakers and I haven't felt the need for more power there. They actually become botheringly loud before the amp starts to clip.
Hey,
sorry, i seem to have misunderstood some of those posts.
Ooookay, so first: After i spent another one or two days of reading into Class-D (or rather Class-T?) Amps i'm pretty sure that's probably what i want. Only problem is that while i'm good at soldering and okay at etching (PCBs) i'm really really bad when it comes to lowlevel electronics. So if i'm not using readymade designs and layouts, be it the application notes from datasheets or whatever i'm pretty lost. And if i've got it right Class-[D,T] need *good* layouts due to the fact that high energy signals PWMd with very high frequency are used... So i'm a bit scared off by the complexity. That's why i thought to start with ChipAmps/GainClones ... maybe?
As for the power distribution in my FAST system: I thought of using a OmnesAudio BB 3.AL and a TangBand W4-1658 (or a W5-876SA, not sure yet, but probably the 1658). I did a little Simulation and looked at the {uh, missing english technical terms} and i thought that would do, but, please, i'm here to learn, what would you propose?
I know that for the extreme near-field little power is okay, but in this case i'd like to also use them for something else than near-field mixing, namely somehow-higher-volume listening while sitting on the couch which is in the other corner of the room, so i figured as little power as you proposed wouldn't suffice. Again, please(!) do correct me if i'm wrong here!
As for the transformers: I was hoping that maybe one could use something more "common" and smaller than a full-fledged copper-beast with +-28V output. I though of either Switchmode Powersupplies or simply a design that needs a smaller voltage to run on (as the tda1562q (just without the lower-frequency-problems?!) or most class-d chips i've looked at so far).
Anyways, thanks for you great help so far!
Greetings from (the rainy, yes, we're worse than london) Germany
- NebuK
sorry, i seem to have misunderstood some of those posts
.Ooookay, so first: After i spent another one or two days of reading into Class-D (or rather Class-T?) Amps i'm pretty sure that's probably what i want. Only problem is that while i'm good at soldering and okay at etching (PCBs) i'm really really bad when it comes to lowlevel electronics. So if i'm not using readymade designs and layouts, be it the application notes from datasheets or whatever i'm pretty lost. And if i've got it right Class-[D,T] need *good* layouts due to the fact that high energy signals PWMd with very high frequency are used... So i'm a bit scared off by the complexity. That's why i thought to start with ChipAmps/GainClones ... maybe?
As for the power distribution in my FAST system: I thought of using a OmnesAudio BB 3.AL and a TangBand W4-1658 (or a W5-876SA, not sure yet, but probably the 1658). I did a little Simulation and looked at the {uh, missing english technical terms} and i thought that would do, but, please, i'm here to learn, what would you propose?
I know that for the extreme near-field little power is okay, but in this case i'd like to also use them for something else than near-field mixing, namely somehow-higher-volume listening while sitting on the couch which is in the other corner of the room, so i figured as little power as you proposed wouldn't suffice. Again, please(!) do correct me if i'm wrong here!
As for the transformers: I was hoping that maybe one could use something more "common" and smaller than a full-fledged copper-beast with +-28V output. I though of either Switchmode Powersupplies or simply a design that needs a smaller voltage to run on (as the tda1562q (just without the lower-frequency-problems?!) or most class-d chips i've looked at so far).
Anyways, thanks for you great help so far!
Greetings from (the rainy, yes, we're worse than london
) Germany- NebuK
you will find the smallest and maybe cheapest parts on
Digital amplifier modules from CAD AUDIO DK
> PWM + SMPS amplifier modules <
You need many know-how, if you like to build such tings as DIY
Digital amplifier modules from CAD AUDIO DK
> PWM + SMPS amplifier modules <
You need many know-how, if you like to build such tings as DIY
That is difficult to predict, because the perception of high volume is a very personal thing. Fact is that few people ever use as much as 1 W at home, even when they perceive the music to be loud already. That is why tube amp owners with single digit output powers rarely complain about missing power.
Again, the size of a transformer depends on its rated power, not on its output voltage. For a certain output power you need a certain voltage, there is no way around that. And that is the case for class B (chipamp) as well as for class D. You can increase the output voltage swing through BTL design, but you will still need the same transformer size, because then it takes higher current to achieve the same output power.
For a split power supply you need two SMPS and each of them must be able to supply the peak current so that its built-in current limiter does not limit the music signal, while the transformer for a conventional unregulated supply can be chosen for the average output power. E. g. an amplifier feeds a real load of 4 Ohm and you want it to supply 100 W into that load. The output voltage is then 20 V and the output current 5 A. If you leave the losses aside, you need a 100 VA transformer for this with 2x20 V 2x2,5 A. Or you need two SMPS with 20 V 7,07 A (5 A x 1,41) each. That means two 140 W SMPS vs a 100 VA transformer plus rectifier plus smoothing capacitors.
@ pacific
"because then it takes higher current to achieve the same output power''
Volts multiplied by amps equals watts (output power). Quick do an edit before Andrew T reads this.
Just a word of caution when using two smps to provide dual rail power.
If the smpsu over current protection trips it will most likley be only one that trips leaving you with a large dc voltage on the output of amplifier.
I have tried a couple of laptop psu's. it was only a quick experiment because i didnt like the sound. Also they produced lots more heat than my usual 160va toroid.
Regards Mad Mark
"because then it takes higher current to achieve the same output power''
Volts multiplied by amps equals watts (output power). Quick do an edit before Andrew T reads this.
Just a word of caution when using two smps to provide dual rail power.
If the smpsu over current protection trips it will most likley be only one that trips leaving you with a large dc voltage on the output of amplifier.
I have tried a couple of laptop psu's. it was only a quick experiment because i didnt like the sound. Also they produced lots more heat than my usual 160va toroid.
Regards Mad Mark
Output power is quite meaningless
Of course we may swing between the 86 and 91 dB/W/m or towards 95 dB/W/m of sensibility ,which may be too 'revealing' for the electronics ...but still dynamic range is the word.
I'm using some kind of FAST well lubricated ( dual wf isobaric + 3" FR )and now I'm powering it with a TDA 7394 ( 30 +30 W BTL ) which performs quite well .
Of course we may swing between the 86 and 91 dB/W/m or towards 95 dB/W/m of sensibility ,which may be too 'revealing' for the electronics ...but still dynamic range is the word.
I'm using some kind of FAST well lubricated ( dual wf isobaric + 3" FR )and now I'm powering it with a TDA 7394 ( 30 +30 W BTL ) which performs quite well .
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