hi guys,
I hope somebody has some experience with this component...I'd like to build an amplifier with the stk4241, but I have a +/-30V power supply and a 4ohms load...Is it possible?does it work?an how much power can it deliver?
thanx a lot...
max
I hope somebody has some experience with this component...I'd like to build an amplifier with the stk4241, but I have a +/-30V power supply and a 4ohms load...Is it possible?does it work?an how much power can it deliver?
thanx a lot...
max
I'm afraid its made for higher supply voltage and 8 ohm load.
Can we help you with the datasheet ?
Homepage: http://katalog.elektroda.net/
/Hugo 🙂
Can we help you with the datasheet ?
Homepage: http://katalog.elektroda.net/
/Hugo 🙂
i've built stk 4046XI on 27VOLT dual supply and it worked well...
see my other thread of resistor burn at 4ohm load
see my other thread of resistor burn at 4ohm load
output power...
Approximate power from a +-30v supply into resistive 4 ohms is easy...
Assuming 3 volts dropped in the PSU, across the output devices, emitter resistors etc the peak voltage swing is +-27, since power = v^2/resistance, peak power is approx. 180w, rms power is half peak power, ie 90w.
If you plan to really use this power, say for a gig, party, etc you will need a PSU capable of 5 amps per channel average for that output level, or the voltage will 'droop' further and less output will be available...thats 300va per channel...not a trivial amount...
Stuart
Approximate power from a +-30v supply into resistive 4 ohms is easy...
Assuming 3 volts dropped in the PSU, across the output devices, emitter resistors etc the peak voltage swing is +-27, since power = v^2/resistance, peak power is approx. 180w, rms power is half peak power, ie 90w.
If you plan to really use this power, say for a gig, party, etc you will need a PSU capable of 5 amps per channel average for that output level, or the voltage will 'droop' further and less output will be available...thats 300va per channel...not a trivial amount...
Stuart
more comments
The datasheet shows output power with rails down to +-25 volts, so you are getting close to the lower end of the scale, going too low will eventually screw up the bias and increase distortion etc...
At a minimum, (based on 120wRMS/8ohms) the device has a current capability of approx. +-5.5 amps, so at your supply voltage you shouldn't run into issues, but again you are close to the limit, probably shouldn't push your luck too far, ie +-35v rails with 4 ohm load might kill the thing...
Good luck
Stuart
The datasheet shows output power with rails down to +-25 volts, so you are getting close to the lower end of the scale, going too low will eventually screw up the bias and increase distortion etc...
At a minimum, (based on 120wRMS/8ohms) the device has a current capability of approx. +-5.5 amps, so at your supply voltage you shouldn't run into issues, but again you are close to the limit, probably shouldn't push your luck too far, ie +-35v rails with 4 ohm load might kill the thing...
Good luck
Stuart
hmm...
morbid, u say that it works with +-27V...but with a 4ohms load or a 8ohms load?so, if it's with 4, it must work with30...I know that the datasheet doesn't say anything about the 4 ohms, but I think it won't be a problem(I hope..)
Better Ideas for an amplifier 100wrms with a single layer pcb?
thanx...
morbid, u say that it works with +-27V...but with a 4ohms load or a 8ohms load?so, if it's with 4, it must work with30...I know that the datasheet doesn't say anything about the 4 ohms, but I think it won't be a problem(I hope..)
Better Ideas for an amplifier 100wrms with a single layer pcb?
thanx...
i forget...
and what about a pari of stk4044v?+-30V are ok for this, always at 4 ohms?
(If somebody has something better than the sanyo datasheet, I'll be very pleased to know where to find it!!)
and what about a pari of stk4044v?+-30V are ok for this, always at 4 ohms?
(If somebody has something better than the sanyo datasheet, I'll be very pleased to know where to find it!!)
stk modules for 100w/4 ohms
I'd recommend checking out the 4040 series, I know of 2 examples yielding 100w/4 per module...I recently dismantled an old pyramid car amp, rated at 2x100w into 4 ohms per channel. Before cannabalizing it I checked it's max output and it *just* met it's specs with a hard 14.5v into the SMPS. The modules it used were 4040xi (fully complementary) with approx. +-36v rails. For years Velodyne used the 4040iv (quasi complementary) in their servo subs, and rated the output >100w, though I havent verified this number yet...
I have recently purchased more of the 4040xi, not sure if the other version is still available.
Good luck
Stuart
I'd recommend checking out the 4040 series, I know of 2 examples yielding 100w/4 per module...I recently dismantled an old pyramid car amp, rated at 2x100w into 4 ohms per channel. Before cannabalizing it I checked it's max output and it *just* met it's specs with a hard 14.5v into the SMPS. The modules it used were 4040xi (fully complementary) with approx. +-36v rails. For years Velodyne used the 4040iv (quasi complementary) in their servo subs, and rated the output >100w, though I havent verified this number yet...
I have recently purchased more of the 4040xi, not sure if the other version is still available.
Good luck
Stuart
+/- 30 volt rails
hi morpheus82,
To answer your email to me earlier..
From what I know both the 4241 and 4048XI should work OK with +/- 30 volts. In both cases the distortion may be slightly higher than if you used a higher voltage.
At +-30 volts heat dissipation and output current won't be a massive issue so besides a few extra watts you won't get much more out of a beefier single channel like an stk4048.
The 4241 has 2 channels capable of ~72 watts each into 4 ohm loads with +-30 Volts if regulated. The 4048xi has 1 channel capable of ~77W at the same voltage. This less than expected performance is due to STK's having ghastly clipping voltages at the high current outputs required of 4 ohm loads.
Remember also that these figures would be worse if the Power supply is not a feedback regulated Switched Mode Power Supply and far worse if you're not using a SMPS at all!
PS. STK's seem to have a reputation for being hazardous when it comes to oscillations so watch your gain, layout and grounding.
hi morpheus82,
To answer your email to me earlier..
From what I know both the 4241 and 4048XI should work OK with +/- 30 volts. In both cases the distortion may be slightly higher than if you used a higher voltage.
At +-30 volts heat dissipation and output current won't be a massive issue so besides a few extra watts you won't get much more out of a beefier single channel like an stk4048.
The 4241 has 2 channels capable of ~72 watts each into 4 ohm loads with +-30 Volts if regulated. The 4048xi has 1 channel capable of ~77W at the same voltage. This less than expected performance is due to STK's having ghastly clipping voltages at the high current outputs required of 4 ohm loads.
Remember also that these figures would be worse if the Power supply is not a feedback regulated Switched Mode Power Supply and far worse if you're not using a SMPS at all!
PS. STK's seem to have a reputation for being hazardous when it comes to oscillations so watch your gain, layout and grounding.
why smps??
hey, I have 2 toroids rated 800VA double output 25V...secondary rated for 32A...custom made...It's a great unregulated power supply!!with 33000uF at the out...Why it won't work fine?
hey, I have 2 toroids rated 800VA double output 25V...secondary rated for 32A...custom made...It's a great unregulated power supply!!with 33000uF at the out...Why it won't work fine?
Hi,
The SMPS references I think come from my comments regarding pyramids use of the modules in a car amp. Your toroidal PSU will work very well.
Rectified and smoothed your transformers are going to give +-35v, and are massive enough that the voltage won't droop much under load. How many channels do you need, those toroids could power 5 or 6, probably more for normal domestic work, where continuous output is not maxed out.
Stuart
The SMPS references I think come from my comments regarding pyramids use of the modules in a car amp. Your toroidal PSU will work very well.
Rectified and smoothed your transformers are going to give +-35v, and are massive enough that the voltage won't droop much under load. How many channels do you need, those toroids could power 5 or 6, probably more for normal domestic work, where continuous output is not maxed out.
Stuart
ive built and modded a couple of amps with stk 4xxx chips, and while they are great at high powers ive never got them quiet, ive always had problems with input noise, all quiet with no input conected, but hook up phono leads and hummmmmmmm, maybe ive needed buffers or just rewire inputs V.carefully, or rearange the grounding, but ive never goten rid of that hum at low volume.
look else where on site coz there was a thread a couple of days ago about this problem. and most of the stk 4xxx series should be pin and supply compatable, so +-30v is fine. hope this helps coz i think they are great chips, nice and easy pin layout, and boy can they pack some punch. see you soon, steve.. ..
look else where on site coz there was a thread a couple of days ago about this problem. and most of the stk 4xxx series should be pin and supply compatable, so +-30v is fine. hope this helps coz i think they are great chips, nice and easy pin layout, and boy can they pack some punch. see you soon, steve.. ..
8 channels...
it's for a 2 way system, but each box has 2 woofers, 1 mid and 1 tweeter, 100wrms eache one...i used an electronic xover. just need the ampli now...but I.m thinking to use an stk 4044v now...do you have any experience?and...sorry but che power rating indicated is rms or peak?i hope rms...but it's not written on the datasheet...
it's for a 2 way system, but each box has 2 woofers, 1 mid and 1 tweeter, 100wrms eache one...i used an electronic xover. just need the ampli now...but I.m thinking to use an stk 4044v now...do you have any experience?and...sorry but che power rating indicated is rms or peak?i hope rms...but it's not written on the datasheet...
noise...
Hi,
Just hooked up one channel of 4040xi module, doesn't have noise or hum, at least not with a 2ft interconnect from a battery powered walkman CD player I use for a test input.. Layout is pretty close to that shown in the datasheet, perhaps different ground arrangements are harder to get silent...
Anyway it works perfectly using +-30, in fact works down to +-23v, though the clipping is asymmetric and the output power is not worth the effort...I doubt the low voltage performance is something to rely on...
Think I'm gonna make me a subwoofer...I have a couple of empty velodyne boxes, some very cheap 12" woofers and now some 100w amps to fill the void...
Stuart
Hi,
Just hooked up one channel of 4040xi module, doesn't have noise or hum, at least not with a 2ft interconnect from a battery powered walkman CD player I use for a test input.. Layout is pretty close to that shown in the datasheet, perhaps different ground arrangements are harder to get silent...
Anyway it works perfectly using +-30, in fact works down to +-23v, though the clipping is asymmetric and the output power is not worth the effort...I doubt the low voltage performance is something to rely on...
Think I'm gonna make me a subwoofer...I have a couple of empty velodyne boxes, some very cheap 12" woofers and now some 100w amps to fill the void...
Stuart
hey stuart, any chance of some pic's? and where did you get your boards? ill try and get my camera working so i can finaly post some pics.
i was thinking of taking my latest stk to pieces and building it on strip board, if i put chip in middle of board, and a T mount to the computer style heat sink, i can put components both front and back of chip under the sink, making the foot print of board, chip and sink almost square. meaning i can fit 4 amps, into the same space as 2. with 8x90 watts thats a loud party. see you soon, steve.. ..
i was thinking of taking my latest stk to pieces and building it on strip board, if i put chip in middle of board, and a T mount to the computer style heat sink, i can put components both front and back of chip under the sink, making the foot print of board, chip and sink almost square. meaning i can fit 4 amps, into the same space as 2. with 8x90 watts thats a loud party. see you soon, steve.. ..
pictures...
The sad part about the boards is I just hacked up the main board from the car amp, literally...Used a dremel to get each of the 2x2 section that the module was mounted on, I just finished screwing the stuff together on a piece of perspex, or plexiglass as they call it here.
I could easily have proto'ed the board but in the end my lazyness and coolness of re-using the existing board won out...
I've taken a couple of pics, of the hacked board and the final assembly...
Stuart
The sad part about the boards is I just hacked up the main board from the car amp, literally...Used a dremel to get each of the 2x2 section that the module was mounted on, I just finished screwing the stuff together on a piece of perspex, or plexiglass as they call it here.
I could easily have proto'ed the board but in the end my lazyness and coolness of re-using the existing board won out...
I've taken a couple of pics, of the hacked board and the final assembly...
Stuart
Attachments
more info
heatsinks are a pair of athlon CPU coolers on a scrap of aluminium, used thermal epoxy to attach the scrap to the sinks, seems to work very well.
So far total investment is approx $35 per channel...single most expensive component is the xformer, 120va, just adequate for one channel...
Best part is that as a full range amp it actually sounds pretty good....
Stuart
heatsinks are a pair of athlon CPU coolers on a scrap of aluminium, used thermal epoxy to attach the scrap to the sinks, seems to work very well.
So far total investment is approx $35 per channel...single most expensive component is the xformer, 120va, just adequate for one channel...
Best part is that as a full range amp it actually sounds pretty good....
Stuart
Attachments
power ratings
Morpheus,
The voltages that are specified for the output powers listed in the datasheets pretty much guarantee that they are RMS ratings. My own playing has shown me the ratings for the 4040xi are definitely RMS and very conservative.
Stuart
Morpheus,
The voltages that are specified for the output powers listed in the datasheets pretty much guarantee that they are RMS ratings. My own playing has shown me the ratings for the 4040xi are definitely RMS and very conservative.
Stuart
Re: why smps??
Cool! Nothing beats a good 50/60Hz mains power supply with a huge toroid and heaps of bypassing capacitance. It sounds like you have a pretty damn good power supply that will work well.
If the +-30V you quoted for your power supply is measured at full load then you will get the power outputs I stated for a regulated supply if not more.
I thought it was possible you might be using a SMPS because STK's are commonly used in car amps.
To be honest I'm not a big fan of SMPS's. They are not as rugged as linear supplies and are potentially noisy but for all their problems they are easy to regulate.
The reason I quoted regulated power was that a linear power supply with a "nominal" +- 30V might drop much lower at full output reducing the amplifiers output capabilities.
For example I had a very decent 500VA 2x 25VAC toroid rated at 6.8% transformer regulation. Rectified and bypassed through 40 000uF per rail It produced +-36.5V at no load and drooped to +-31V at full load (500VA). This amounts to a disappointing 18% DC regulation, which is not atypical for a power supply of this size. I always find this really annoying because the supply voltage is still high when the amplifiers are producing the most internal heat dissipation and then the voltage drops off when you really want it to stay high!
It is likely that your power supply will have a similar droop. You really have to measure the DC output voltage at full load to know what your power supply can feed your amps. Calculating the ripple voltage based on the capacitance and a nominal load current yields an optimistic and quite inaccurate result.
Having said all this, your toroids are so big(2x800VA) that your not likely to get anywhere near their full load unless you run many amplifiers at maximum power.
You probably already know most of this but I wanted to clarify why I quote the performance under a regulated power supply.
morpheus82 said:
Cool! Nothing beats a good 50/60Hz mains power supply with a huge toroid and heaps of bypassing capacitance. It sounds like you have a pretty damn good power supply that will work well.
If the +-30V you quoted for your power supply is measured at full load then you will get the power outputs I stated for a regulated supply if not more.
I thought it was possible you might be using a SMPS because STK's are commonly used in car amps.
To be honest I'm not a big fan of SMPS's. They are not as rugged as linear supplies and are potentially noisy but for all their problems they are easy to regulate.
The reason I quoted regulated power was that a linear power supply with a "nominal" +- 30V might drop much lower at full output reducing the amplifiers output capabilities.
For example I had a very decent 500VA 2x 25VAC toroid rated at 6.8% transformer regulation. Rectified and bypassed through 40 000uF per rail It produced +-36.5V at no load and drooped to +-31V at full load (500VA). This amounts to a disappointing 18% DC regulation, which is not atypical for a power supply of this size. I always find this really annoying because the supply voltage is still high when the amplifiers are producing the most internal heat dissipation and then the voltage drops off when you really want it to stay high!
It is likely that your power supply will have a similar droop. You really have to measure the DC output voltage at full load to know what your power supply can feed your amps. Calculating the ripple voltage based on the capacitance and a nominal load current yields an optimistic and quite inaccurate result.
Having said all this, your toroids are so big(2x800VA) that your not likely to get anywhere near their full load unless you run many amplifiers at maximum power.
You probably already know most of this but I wanted to clarify why I quote the performance under a regulated power supply.
i had problems running this amp on 4ohms the output resistor got burned couple of times
( i use 2 speakers).
i've changed the configuration to 16ohm (2x8ohm in serial) and now it works good...
dont know if it will get burn again...the chip doesnt get anymore than room temp. and also the wires/output resistors.
maybe there is a volt burst from the PS causes high load on the output...
also the Humm thing....im using a metal shielded box connected to the ground and still i have a little humming...
( i use 2 speakers).
i've changed the configuration to 16ohm (2x8ohm in serial) and now it works good...
dont know if it will get burn again...the chip doesnt get anymore than room temp. and also the wires/output resistors.
maybe there is a volt burst from the PS causes high load on the output...
also the Humm thing....im using a metal shielded box connected to the ground and still i have a little humming...