looking for someone to build high frequency amp
HI Guys
New here so hope this is ok?
Im looking for someone to build me an amp to drive 4-8 piezos up to around 200w. frequency range 10-38khz.
Tryed doing it myself as im a computer enginner and thought it would be simple enougth but this is a whole different ball game.
Im in the UK so anyone over here would be better but shipping from anywhere is,nt the end of the world.
Any takers please email or PM me.
cheers for your time.
HI Guys
New here so hope this is ok?
Im looking for someone to build me an amp to drive 4-8 piezos up to around 200w. frequency range 10-38khz.
Tryed doing it myself as im a computer enginner and thought it would be simple enougth but this is a whole different ball game.
Im in the UK so anyone over here would be better but shipping from anywhere is,nt the end of the world.
Any takers please email or PM me.
cheers for your time.
High frequency amp
Whats the application, piezo element frequency impeadance and load requirements?
Chips are possible and probably the cost will be about the some as ST.
Whats the application, piezo element frequency impeadance and load requirements?
Chips are possible and probably the cost will be about the some as ST.
Told i should post here, origionaly posted in chip thread
HI Guys
New here so hope this is ok?
Im looking for someone to build me an amp to drive 4-8 piezos up to around 200w. frequency range 10-38khz.
Tryed doing it myself as im a computer enginner and thought it would be simple enougth but this is a whole different ball game.
Im in the UK so anyone over here would be better but shipping from anywhere is,nt the end of the world.
Any takers please email or PM me.
cheers for your time.
HI Guys
New here so hope this is ok?
Im looking for someone to build me an amp to drive 4-8 piezos up to around 200w. frequency range 10-38khz.
Tryed doing it myself as im a computer enginner and thought it would be simple enougth but this is a whole different ball game.
Im in the UK so anyone over here would be better but shipping from anywhere is,nt the end of the world.
Any takers please email or PM me.
cheers for your time.
Thanks for the reply,
Its to be used on a farm for an anti pest and possible security system, Will have IR sensors set up to detect Foxs. I have a deal with the farmer that if i can stop the foxs he'll stop having them shot.
The piezos im looking to use are
Specifications:
Frequency range: 4kHz - 40kHz
Power: 150Wmax / 75Wrms
Impedance: 250 - 50Ù over operating range*
Pretty standard, also looking if nessersary to place the piezos into tubes and directing along the paths, won't know untill tested.
Loading will be ten mins on activation.
I have soursed a frequency generator that im looking to use and am hoping to drive an amp with this. If this is not possible having the Frequency Generator built at the same time on to the same board would be even better?
freq-gen
http://www.kemo-electronic.com/en/module/m071n/index.htm
Any input advice greatfully recived.
Cheers
Its to be used on a farm for an anti pest and possible security system, Will have IR sensors set up to detect Foxs. I have a deal with the farmer that if i can stop the foxs he'll stop having them shot.
The piezos im looking to use are
Specifications:
Frequency range: 4kHz - 40kHz
Power: 150Wmax / 75Wrms
Impedance: 250 - 50Ù over operating range*
Pretty standard, also looking if nessersary to place the piezos into tubes and directing along the paths, won't know untill tested.
Loading will be ten mins on activation.
I have soursed a frequency generator that im looking to use and am hoping to drive an amp with this. If this is not possible having the Frequency Generator built at the same time on to the same board would be even better?
freq-gen
http://www.kemo-electronic.com/en/module/m071n/index.htm
Any input advice greatfully recived.
Cheers
hmm, interesting request. The last large power amplifier I built for myself has a power bandwidth extending to 444KHz at 500W per channel on 4 ohms....
"Specifications
500 Watts RMS into 4 Ohms RMS Min Continuos
300 Watts RMS into 8 Ohms RMS Min Continuos
Frequency Response: 5hz to 200khz
SIgnal to Noise Ratio -125db ..." from: http://aussieamplifiers.com/nx500ln.htm
"Specifications
+-56vdc Voltage Rails (Idle, No Signal)
146 Watts RMS into 8 Ohms
230 Watts RMS into 4 Ohms
+-63vdc Voltage Rails (Idle, No Signal)
185 Watts RMS into 8 Ohms
275 Watts RMS into 4 Ohms
Frequency Response: 2hz to 160khz (Input Filter Limited)
Power Bandwidth 2Hz - 500khz -3dB Filter Limited
THD Typically 0.005% @ 8 Ohms 1khz
Damping Factor 400
Input Impedance 34k Ohms
Input sensitivity for full power out into 8 Ohm load 900mv ..." From: http://aussieamplifiers.com/nx150.htm
500 Watts RMS into 4 Ohms RMS Min Continuos
300 Watts RMS into 8 Ohms RMS Min Continuos
Frequency Response: 5hz to 200khz
SIgnal to Noise Ratio -125db ..." from: http://aussieamplifiers.com/nx500ln.htm
"Specifications
+-56vdc Voltage Rails (Idle, No Signal)
146 Watts RMS into 8 Ohms
230 Watts RMS into 4 Ohms
+-63vdc Voltage Rails (Idle, No Signal)
185 Watts RMS into 8 Ohms
275 Watts RMS into 4 Ohms
Frequency Response: 2hz to 160khz (Input Filter Limited)
Power Bandwidth 2Hz - 500khz -3dB Filter Limited
THD Typically 0.005% @ 8 Ohms 1khz
Damping Factor 400
Input Impedance 34k Ohms
Input sensitivity for full power out into 8 Ohm load 900mv ..." From: http://aussieamplifiers.com/nx150.htm
Duo said:
😱 444khz, why such a crazy high frequency, surley you can't get antthing to drive past 50khz and probably can't hear past 22khz anyway? Is this just over spec of components or is there a reason for building it to those specs?
Sorry if its a dumb question, im a comp eng by trade just a novice with audio.🙂
Piezo transducers are typically capacitive, so amplifier design is problematic. Almost all the power is dissipated in the amp, not the transducer. Best bet is to resonate the transducer with a suitable inductor (suitable=troublesome-to-design) so the reactance mostly disappears and the amp just has to drive the remaining more-or-less non-reactive load. This only works at one frequency, so if you need to cover a range, a much more complicated and expensive solution will be needed. You can also do a power oscillator like an ultrasonic cleaner, in fact stealing the board out of one might be a good place to start.
Duo said:
Thanks , just taken alook at them, one looks rather like this one: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190086540878&sspagename=ADME:B:AAQ:UK:1
Must reitterate, im not an electrical enginneer like you guys, i just build and fix computers so im a bit wary of building from a kit or connecting moduals. Must admit even the power supply side confuses me eg:This is regarding the modual linked above.
Use a 600VA transformer, with 2 secondary outputs each one with a voltage of 60V
Use a power supply with the following specifications: 10A min.(25A recommended), filtering capacitors of 4700uF / 80V (10000uF /80V recommended)
Whats the difference between transformer and a power supply?
The other thing im not sure about is running just piezos of an amp with regards to the ohmage of the piezos as apposed to normal speakers. Is this a problem? Im thinking wireing several in parallel will help, is my thinking correct?
Sorry for all the questions but im a newbie hungry for info 🙂 and yes i have been googling but thats left me more confused so i thought get it from those who know.
cheers
Hello fasterstill: The amplifier I speak of was more of a push to the limits of parts and design than a need for such ridiculous bandwidth.
The amplifier is not used just for audio however. I use it as a scientific power supply either for a regulated DC output or for power function generation. More for things not DC though... (The amplifier is useful for driving things like small induction heater tank circuits (output stage capable of more than 80A).
I wouldn't use such a nice thing for deterring pests though.
As Conrad Hoffman states, something like an old ultrasonic cleaner is a nearer choice to what you want. Since distortion is not really an important characteristic, one could use a class C output stage of all things if one wished.
The amplifier is not used just for audio however. I use it as a scientific power supply either for a regulated DC output or for power function generation. More for things not DC though... (The amplifier is useful for driving things like small induction heater tank circuits (output stage capable of more than 80A).
I wouldn't use such a nice thing for deterring pests though.
As Conrad Hoffman states, something like an old ultrasonic cleaner is a nearer choice to what you want. Since distortion is not really an important characteristic, one could use a class C output stage of all things if one wished.
hi,
don't get confused with all the power specs. You need a stable amplifier capable of driving large voltage swings into capacitive loads at ultrasonic frequencys.
These power ratings of the piezo speakers are purely theoretical.
They take the voltage swing and a nominal impedance of 4-8 ohm.
This is done for comparison purposes and has nothing to do with transfered power.
regards
Jürgen
don't get confused with all the power specs. You need a stable amplifier capable of driving large voltage swings into capacitive loads at ultrasonic frequencys.
These power ratings of the piezo speakers are purely theoretical.
They take the voltage swing and a nominal impedance of 4-8 ohm.
This is done for comparison purposes and has nothing to do with transfered power.
regards
Jürgen
A PSU is an acronym for Power Supply Unit, which would include the transformer, if one is used, as well as things like rectifiers (diodes turning AC to DC), filters (the capacitor banks you normaly see), and regulation (parts that keep voltage at the same level)
Re: Some info ...
Thanks for that, had seen most of that doc but only in smaller parts on different websites. Makes more sence when read as a whole.
DRC said:
Thanks for that, had seen most of that doc but only in smaller parts on different websites. Makes more sence when read as a whole.
Thats about what i thought but the amp i linked to said they can supply the power supply but not the transformer,
The 75W rating was full spectrum input assuming 8 ohms impedance.
The real Mororola piezos can handle 14V RMS (about 1W at 20Khz) at frequencies above 5Khz, the cheap copies you find today cannot handle that much.
If you used about 200 of the piezos it might give the fox a headache, but if he is hungry he is going to suffer it to raid the hen house.
The real Mororola piezos can handle 14V RMS (about 1W at 20Khz) at frequencies above 5Khz, the cheap copies you find today cannot handle that much.
If you used about 200 of the piezos it might give the fox a headache, but if he is hungry he is going to suffer it to raid the hen house.
Instead of using a freq. generator,and an amp,which could be tricky...
What about a simple power oscillator? Run the piezo's full-out,at resonance?
A friend and I once did a similar experiment,on a smaller scale.We used a 555 timer chip (adjustable from ~20-30khz),and a HOT from an old TV set wired to a Motorola piezo horn,all powered from a 9V battery.
It was enough to give you a serious headache after a bit,and make you quite cranky. 😡
Maybe feed your freq. genny into a Horiz. output transistor,or something similar (fast,and beefy) run it from a +24V supply,and feed that to a few piezo horns?
Similar to our experiment,but with more power!
What about a simple power oscillator? Run the piezo's full-out,at resonance?
A friend and I once did a similar experiment,on a smaller scale.We used a 555 timer chip (adjustable from ~20-30khz),and a HOT from an old TV set wired to a Motorola piezo horn,all powered from a 9V battery.
It was enough to give you a serious headache after a bit,and make you quite cranky. 😡
Maybe feed your freq. genny into a Horiz. output transistor,or something similar (fast,and beefy) run it from a +24V supply,and feed that to a few piezo horns?
Similar to our experiment,but with more power!
missed the obvious
some of our friends here missed the obvious except djk i think
the speakers you want to drive when the say that they are rated 150 w rms mean exactly what i say that they are parts of a 3 or 4 way speaker that totally can absorve 150w
from these 150 w almost 120 are going to be given to bass some 20 will given to low mid and the rest will be given to high and super tweeter ...... may be my calculation is wrong and its even more less ....
so power for starts is not your issue
see at domestic pest repeler inside there is a small chip batery operated that probably can produce a few milliwatts and this is enough ...look at your fysics ....high frequency sounds can travel through the air much faster and go also longer distance
so since we solved power issue and finally 5-10 watts may be enough any transistor amplifier can do that as long as you play a litle with input filtering just in case there is limits to 20khz .......
after that you have to remove a filter network that exists in the outs of the amp to prevent sounds of that high frequency to reach in to the speaker but also amplifier it shelf ....
and then the final issue ...audio amps are not designed to drive capacitive loads ( this tweeters of yours are capacitors ) so the only thing you have to do is to fool the amp adding resistors both in serious and in parallel with your speakers and the amp will thing that driving resistive load !!!!!😀 😀 😀
this of course consume some power on the resistors but if you just use a home transistor amplifier of 50-60 watts with all these may be you finally manage to send to your speakers totally 5-10 w which it sould be more than enough
of course expect the amp to boil hot depending in the power you ask from it but with a litle calculation and carefully steps you will get it
another thing is that you cannot use one frequency as a audio source only !!!!!!it would be clever to remove this 555 circuit from a domestic pest repeler that actually sweep through a range of frequencies so that animals dont get used to it . also moving to a range of frequencies instead of one frequency will make the amp work more safe and better
if that circuit also produces armonics in lower frequencies may be aditional filtering either in the input or the out of the amplifier is required cause in these speakers of yours if you manage to send them low frequencies also and especialy at that power they are going to meet the creator for shure .......
also keep in mind that you are about to produce a headake genarator for both people and animals .....cind of dangerous i think
from this point of view you are done in couple of hours my friend
enjoy ............
some of our friends here missed the obvious except djk i think
the speakers you want to drive when the say that they are rated 150 w rms mean exactly what i say that they are parts of a 3 or 4 way speaker that totally can absorve 150w
from these 150 w almost 120 are going to be given to bass some 20 will given to low mid and the rest will be given to high and super tweeter ...... may be my calculation is wrong and its even more less ....
so power for starts is not your issue
see at domestic pest repeler inside there is a small chip batery operated that probably can produce a few milliwatts and this is enough ...look at your fysics ....high frequency sounds can travel through the air much faster and go also longer distance
so since we solved power issue and finally 5-10 watts may be enough any transistor amplifier can do that as long as you play a litle with input filtering just in case there is limits to 20khz .......
after that you have to remove a filter network that exists in the outs of the amp to prevent sounds of that high frequency to reach in to the speaker but also amplifier it shelf ....
and then the final issue ...audio amps are not designed to drive capacitive loads ( this tweeters of yours are capacitors ) so the only thing you have to do is to fool the amp adding resistors both in serious and in parallel with your speakers and the amp will thing that driving resistive load !!!!!😀 😀 😀
this of course consume some power on the resistors but if you just use a home transistor amplifier of 50-60 watts with all these may be you finally manage to send to your speakers totally 5-10 w which it sould be more than enough
of course expect the amp to boil hot depending in the power you ask from it but with a litle calculation and carefully steps you will get it
another thing is that you cannot use one frequency as a audio source only !!!!!!it would be clever to remove this 555 circuit from a domestic pest repeler that actually sweep through a range of frequencies so that animals dont get used to it . also moving to a range of frequencies instead of one frequency will make the amp work more safe and better
if that circuit also produces armonics in lower frequencies may be aditional filtering either in the input or the out of the amplifier is required cause in these speakers of yours if you manage to send them low frequencies also and especialy at that power they are going to meet the creator for shure .......
also keep in mind that you are about to produce a headake genarator for both people and animals .....cind of dangerous i think
from this point of view you are done in couple of hours my friend
enjoy ............
😱 fewwww! thats what i like loads of contrasting views, brilliant.
First on the power handeling. From DRC's Info link above i got this info:
"The power rating of CTS piezoelectric speakers is determined using the EIA RS426 test method. This is a continuous 8 hour noise test with peak voltage spikes twice (4 times higher in terms of power) the average applied signal. Thus, for a speaker to be rated at 75 watts (25 volts), it must not degrade after 8 hours of continuous operation at 75 watts with 300 watt spikes. As a result of using the EIA test method, CTS power ratings for its piezoelectric speakers tend to be conservative compared to conventional industry claims for speaker systems. In addition, the extremely dense, high-quality ceramic manufactured by CTS withstands cracking and other high power failure mechanisms much better than the piezoelectric ceramic used by many other manufacturers."
This makes it sound as if they test them on there own at the quoted power?
DigitalJunkie:
I like the way you "think outside of the box" sorry for the lame terminology
Do you have any more info on this methord or some links i can recearch? or was it just an idea of the top of your head.
Did wonder if there was another way to creat the sound level required, as quality and frequency range was not as important as in a proper amp.
sakis:
The small pest signal generators you mention are what im using at the moment to experiment with, and belive me when i say the output is tiny.
I have tryed to connect the output to a 40w amp modual.http://www.maplin.co.uk/Module.aspx?ModuleNo=37737&doy=17m4 the results were disapointing.
Output connected the the piezo and i could not tell any difference in volume, although i must add the piezo output was audiable even when the input was set to 38khz, not right at all.
Connected output to 8ohm speaker at lower frequency and it did seem a little bit louder but not much.
Thought it might be low input signal so tryed small radio as input and same results? So i take it this is were adding resistors both in serious and in parallel will come into effect.
You also mention not trying to drive the amp with a single frequency, the frequency generator im using sweeps 3khz twice a second so that should be ok, yes?
djk:
If as you say general high frequency sound over a general area wont work im also looking at placing the piesos into tubes and directing them along the bounderys, having them set off as they cross a beam hopefully using a short sharp shock approch. I understand this has been used with wild boars but can only find a small refference to this, no tech info.
There is plenty of natural food , rabbits etc available, they just prefer to take the easy route. Hopefully i'll make it a less easy route.
The more i read up on this ultrasonic pest control the more interesting it gets, evidently you can get rid of mosquitos with it as well, brilliant, if it works.
Thanks again guys for all your input, keep it comeing, much apreciated.
First on the power handeling. From DRC's Info link above i got this info:
"The power rating of CTS piezoelectric speakers is determined using the EIA RS426 test method. This is a continuous 8 hour noise test with peak voltage spikes twice (4 times higher in terms of power) the average applied signal. Thus, for a speaker to be rated at 75 watts (25 volts), it must not degrade after 8 hours of continuous operation at 75 watts with 300 watt spikes. As a result of using the EIA test method, CTS power ratings for its piezoelectric speakers tend to be conservative compared to conventional industry claims for speaker systems. In addition, the extremely dense, high-quality ceramic manufactured by CTS withstands cracking and other high power failure mechanisms much better than the piezoelectric ceramic used by many other manufacturers."
This makes it sound as if they test them on there own at the quoted power?
DigitalJunkie:
I like the way you "think outside of the box" sorry for the lame terminology
Do you have any more info on this methord or some links i can recearch? or was it just an idea of the top of your head. Did wonder if there was another way to creat the sound level required, as quality and frequency range was not as important as in a proper amp.
sakis:
The small pest signal generators you mention are what im using at the moment to experiment with, and belive me when i say the output is tiny.
I have tryed to connect the output to a 40w amp modual.http://www.maplin.co.uk/Module.aspx?ModuleNo=37737&doy=17m4 the results were disapointing.
Output connected the the piezo and i could not tell any difference in volume, although i must add the piezo output was audiable even when the input was set to 38khz, not right at all.
Connected output to 8ohm speaker at lower frequency and it did seem a little bit louder but not much.
Thought it might be low input signal so tryed small radio as input and same results? So i take it this is were adding resistors both in serious and in parallel will come into effect.
You also mention not trying to drive the amp with a single frequency, the frequency generator im using sweeps 3khz twice a second so that should be ok, yes?
djk:
If as you say general high frequency sound over a general area wont work im also looking at placing the piesos into tubes and directing them along the bounderys, having them set off as they cross a beam hopefully using a short sharp shock approch. I understand this has been used with wild boars but can only find a small refference to this, no tech info.
There is plenty of natural food , rabbits etc available, they just prefer to take the easy route. Hopefully i'll make it a less easy route.
The more i read up on this ultrasonic pest control the more interesting it gets, evidently you can get rid of mosquitos with it as well, brilliant, if it works.
Thanks again guys for all your input, keep it comeing, much apreciated.
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