Cristi, I would just like to add that for this specific project I only need an amp module that can take the +-80V from the linear supply without damage or reliability issues. The ultimate power handling is secondary. I'm looking for four channels, either four kits or two stereo.
Actually that leads me to another question I hadn't thought of. Can a pair irs2092s kits be bridged? I'd like the ability to bridge from four to two channels.
Actually that leads me to another question I hadn't thought of. Can a pair irs2092s kits be bridged? I'd like the ability to bridge from four to two channels.
I will prepare the 750W version of the IRS2092 kit. will use the same board but heatslug instead of heatsink and some componets upgrade.
Till will be available, you can consider this board Connexelectronic for stereo 700W or two of these boards for 4x700W. This amplifier can be easily bridged by just connecting the balanced inputs out of phase. for more details please read the manual. (some ppls never read, and complain about the lack of information - see one of the reviews)
Two of the IRS2092 kit boards cannot be bridged so easily, since there is no balanced input and will require a phase shifter such as BIPS to be used.
Till will be available, you can consider this board Connexelectronic for stereo 700W or two of these boards for 4x700W. This amplifier can be easily bridged by just connecting the balanced inputs out of phase. for more details please read the manual. (some ppls never read, and complain about the lack of information - see one of the reviews)
Two of the IRS2092 kit boards cannot be bridged so easily, since there is no balanced input and will require a phase shifter such as BIPS to be used.
IRS500SMPS
Recently got one of Cristi's newest amp/smps modules. Connexelectronic
It's the 500 watt @ 4 ohm version. Smallest and lightest amp available anywhere with this much POWER.
Check it out. It will definitely knock your socks off!
~ Jay
Recently got one of Cristi's newest amp/smps modules. Connexelectronic
It's the 500 watt @ 4 ohm version. Smallest and lightest amp available anywhere with this much POWER.
Check it out. It will definitely knock your socks off!
~ Jay
Soviken: I ordered already one batch of heatslugs which are required for the higher power version, I made some tests already with a modified heatsink and the results are promissing. at +-88V I got nearly 800W with less than 1% THD. thus the target of 750W would stand up. Output inductor will be bigger as well as few other components changed. Also, I recommend to use separate supply for drive stage, unregulated, 16-25V applied just before the regulator. details will follow once the kit is ready.
Strah: depending on the output voltage. 19.2mF at 36V or up to 40V SMPS800RS is not an issue but same capacitance at higher output voltage will require much more current to charge and the soft start time must be increased otherwise the overcurrent protection might trip and SMPS will not start.
Below I quote my answer from another thread about the same topic:
Some ppls keep asking me by mail why the OC protection can trip if larger capacitors are used, especially if connected to a power hungry amplifier (high quiescent current) as this does not happen with their previous configuration, mains transformer, rectifier bridge, capacitors. The answer is: if the capacitance is much larger than the maximum capacitance allowed for safe and reliable start, the following phenomenon will happen: the soft-start period allows the power supply to start with limited output power capability, thus slowly rising the output voltage to nominal value. This soft start period is finite and last around 100-200ms. Just enough to fully charge the stock capacitors. If larger capacitors are used, the soft-start will ramp-up the output power with the same pace but the capacitors will demand a higher current than the power supply is able to provide to follow the output voltage while charging. then the power supply will enter in OC protection, SMPS will shut-down for a small amount of time, typically one two seconds, and the cycle will repeat with the power supply being reset to minimum output power capability and again slowly ramp-up towards maximum power. BUT.... there's always a butt... if the amplifier or any load connected to SMPS quiescent current is high enough, this will discharge the fatty capacitor which was just about to be charged and at the next soft-start cycle the power supply will have to start-over, because the capacitor was discharged in during the interval when the SMPS was shut-down due to OC condition.
If I would have to make a comparision, is like we try to fill a large bottle with water (capacitor) with a spoon (soft-start) while the bottle has a tiny hole at the botom through the water leak-out (amplifier quiescent current). we can't fill-it as fast as it leaks. Moreover, the power supply trying to start with a killing charge hanged at the output might eventually fail because the very first moment of the start-up the transistors are working in hard-switched mode (with all the related issues of the regarding the body diode and cross-conduction) for few cycles till the converter starts up to steady state. This opperation mode is normal, is described in many papers, and is better to be avoided, thus many conventiona LLC converters would have latched OC protection just to avoid this scenario.
I would like to add that this behaviour was considered during design and it was intended to be this way to prevent damage in case that something was connected wrong. being a product for DIY use, sometimes the user might connect something wrong or the amplifier connected to SMPS might fail and if there won't be some kind of over-load detection, the smps would supply a huge current which can be dangerous.
Strah: depending on the output voltage. 19.2mF at 36V or up to 40V SMPS800RS is not an issue but same capacitance at higher output voltage will require much more current to charge and the soft start time must be increased otherwise the overcurrent protection might trip and SMPS will not start.
Below I quote my answer from another thread about the same topic:
Some ppls keep asking me by mail why the OC protection can trip if larger capacitors are used, especially if connected to a power hungry amplifier (high quiescent current) as this does not happen with their previous configuration, mains transformer, rectifier bridge, capacitors. The answer is: if the capacitance is much larger than the maximum capacitance allowed for safe and reliable start, the following phenomenon will happen: the soft-start period allows the power supply to start with limited output power capability, thus slowly rising the output voltage to nominal value. This soft start period is finite and last around 100-200ms. Just enough to fully charge the stock capacitors. If larger capacitors are used, the soft-start will ramp-up the output power with the same pace but the capacitors will demand a higher current than the power supply is able to provide to follow the output voltage while charging. then the power supply will enter in OC protection, SMPS will shut-down for a small amount of time, typically one two seconds, and the cycle will repeat with the power supply being reset to minimum output power capability and again slowly ramp-up towards maximum power. BUT.... there's always a butt... if the amplifier or any load connected to SMPS quiescent current is high enough, this will discharge the fatty capacitor which was just about to be charged and at the next soft-start cycle the power supply will have to start-over, because the capacitor was discharged in during the interval when the SMPS was shut-down due to OC condition.
If I would have to make a comparision, is like we try to fill a large bottle with water (capacitor) with a spoon (soft-start) while the bottle has a tiny hole at the botom through the water leak-out (amplifier quiescent current). we can't fill-it as fast as it leaks. Moreover, the power supply trying to start with a killing charge hanged at the output might eventually fail because the very first moment of the start-up the transistors are working in hard-switched mode (with all the related issues of the regarding the body diode and cross-conduction) for few cycles till the converter starts up to steady state. This opperation mode is normal, is described in many papers, and is better to be avoided, thus many conventiona LLC converters would have latched OC protection just to avoid this scenario.
I would like to add that this behaviour was considered during design and it was intended to be this way to prevent damage in case that something was connected wrong. being a product for DIY use, sometimes the user might connect something wrong or the amplifier connected to SMPS might fail and if there won't be some kind of over-load detection, the smps would supply a huge current which can be dangerous.
Hi Cristi, just bought a couple of your SMPS500R modules, (from Hifimediy), you didn't have the voltage I needed in stock ), and am very impressed. I'm currently driving a Shure IRS2092, (yes, I know! 
) and was wondering, looking at your new 2092 kit that you have separated the aux driver voltage, if you will be supplying a SMPS module with that aux voltage built in as an extra tap?
And another thing, it would really be handy if there was a separate fan supply, so we can sort out fan cooling if required without putting noise on the normal aux supplies, so they can be used for crossover/ preamp duties.
Once again, thanks for an excellent product.
) and was wondering, looking at your new 2092 kit that you have separated the aux driver voltage, if you will be supplying a SMPS module with that aux voltage built in as an extra tap?And another thing, it would really be handy if there was a separate fan supply, so we can sort out fan cooling if required without putting noise on the normal aux supplies, so they can be used for crossover/ preamp duties.
Once again, thanks for an excellent product.
So if we could adjust the soft-start time period (or have a 'smart-start' that monitors current) then this issue would be avoided?
Is there any useable advantage or need for these larger capacitors?
Pinkmouse:
thank you for your appreciation. I'm designing now some new SMPS's which will have multiple aux. outputs to supply all the voltages required to class D amplifiers as well as control functions, mute during power on and power off, speaker DC protection with latched shut-down. Two of these power supplies are ready, SMPS2000RxE and the tiny SMPS400RxE, the smallest SMPS on the market within this power range, just 50x100x35mm.
SMPS2000R(xE) and SMPS800R(E,S) have on-board supply for cooling fan.
MartinQ:
soft-start time is fixed and optimized during design. I chose the most suitable time for each SMPS. it can be changed by replacing one small capacitor but is not recommended unless there is no other way to charge a huge amount of capacitance.
In most cases there is no point to use anything more than 20-50% of the existing capacitance of the SMPS board on the amplifier boards. each SMPS version has different amount of capacitance. is not a surprise to see that 5 versions have 5 different caps. they are all optimized for best performance. Most amplifiers can work with few hundreds uF per rail when supplied from SMPS, there are many examples on the market of SMPS+amps. I think the misconception of using extremely large capacitors is a legacy from class A amplifiers which require a smooth DC voltage, even if unregulated because some of them are NFB and the PSRR is very poor, having ripple on supply lines will be heard on speakers.
thank you for your appreciation. I'm designing now some new SMPS's which will have multiple aux. outputs to supply all the voltages required to class D amplifiers as well as control functions, mute during power on and power off, speaker DC protection with latched shut-down. Two of these power supplies are ready, SMPS2000RxE and the tiny SMPS400RxE, the smallest SMPS on the market within this power range, just 50x100x35mm.
SMPS2000R(xE) and SMPS800R(E,S) have on-board supply for cooling fan.
MartinQ:
soft-start time is fixed and optimized during design. I chose the most suitable time for each SMPS. it can be changed by replacing one small capacitor but is not recommended unless there is no other way to charge a huge amount of capacitance.
In most cases there is no point to use anything more than 20-50% of the existing capacitance of the SMPS board on the amplifier boards. each SMPS version has different amount of capacitance. is not a surprise to see that 5 versions have 5 different caps. they are all optimized for best performance. Most amplifiers can work with few hundreds uF per rail when supplied from SMPS, there are many examples on the market of SMPS+amps. I think the misconception of using extremely large capacitors is a legacy from class A amplifiers which require a smooth DC voltage, even if unregulated because some of them are NFB and the PSRR is very poor, having ripple on supply lines will be heard on speakers.
Hi colleague,
The ripple at 100Hz, or as ripple "voltage drop under transient", does not create any problem on a amp power stage, obvious changes the dynamics, spl product, and fidelity in reproducing some musical instruments with fast attack,as well unlinearity,(as compression) also.
The big problem is another with smps used in audio amps. that you're a designer smps, you know I think.
But I never hear you talk about on this aspect.
regards
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Cristi said:
I do not question the validity of this statement, but sometimes(in our case, the Fetzilla class AB) it is also a question of supplying current for bass notes to the speakers, something which small caps just cannot do. Some people have built this combo(SMPS300RE + Fetzilla) already, and report diminished bass compared to regular supplies.
The tweaking of the startup time(maybe just to 500-1000ms) could indeed be the answer we seek, as the alternative is to either live with worse bass, or implement a series charging resistor bypassed after a time delay(not very elegant).
If we understand fully that we are on our own if we do this, how would we go about tweaking the soft-start time constant?
I believe the SMPS300RE and the Fetzilla are a match made in heaven, we just need to iron out the details.
Thank you for your consideration.
Cheers,
Kris
For the Fetzilla, we need about 7400uF(9400-2000) additional capacitance per rail to reach design specifications and optimum bass response. Maybe we can get away with 6800 uF additional. How long do you reckon the soft-start phase of the SMPS should be to safely accomodate this?
After studying the PDF for the SMPS300RE as well as the datasheet for the L6599A, it seems to me this cap(C6? on the SMPS300RE) is a small smd cap(105 in picofarad code=1.0uF?) close to a diode, and as such seems pretty tricky to desolder and change. Parallelling another cap on top could potentially be possible, with an extremely steady hand. Any recommendation?
Thanks!
Kris
After studying the PDF for the SMPS300RE as well as the datasheet for the L6599A, it seems to me this cap(C6? on the SMPS300RE) is a small smd cap(105 in picofarad code=1.0uF?) close to a diode, and as such seems pretty tricky to desolder and change. Parallelling another cap on top could potentially be possible, with an extremely steady hand. Any recommendation?
Thanks!
Kris
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Regulation
Hi Christi
I don't see any specifications for the SMPS300RE regarding regulation. People are talking about bass response, so here is a question-
If this module is running at full rated current, powering an amplifier producing 50Hz into a load, what is the 50Hz ripple voltage on the main output of the SMPS300RE?
Jeremy
Hi Christi
I don't see any specifications for the SMPS300RE regarding regulation. People are talking about bass response, so here is a question-
If this module is running at full rated current, powering an amplifier producing 50Hz into a load, what is the 50Hz ripple voltage on the main output of the SMPS300RE?
Jeremy
Hi Cristi
I appreciate your explanation concerning "hiccup-mode" when soft-start is to short to charge output caps. Personally I do not like the idea power down/restart on overcurrent - better is a cycle-by-cycle current limit that enables permanent constant current output in case of short circuit, so the function is not broken by temporary overload like oversized caps.
So I designed a short-circuit-proof LLC-offline converter delivering some 400w without any softstart involved.
It takes two clamping diodes at the primary resonant tank to establish a cycle-by-cycle current limit - no shunts - no shutdown.
My credo is, if a smps needs a softstart, there is something wrong with it.
I appreciate your explanation concerning "hiccup-mode" when soft-start is to short to charge output caps. Personally I do not like the idea power down/restart on overcurrent - better is a cycle-by-cycle current limit that enables permanent constant current output in case of short circuit, so the function is not broken by temporary overload like oversized caps.
So I designed a short-circuit-proof LLC-offline converter delivering some 400w without any softstart involved.
It takes two clamping diodes at the primary resonant tank to establish a cycle-by-cycle current limit - no shunts - no shutdown.
My credo is, if a smps needs a softstart, there is something wrong with it.
Interesting! I guess this sort of solution is impossible/very difficult to retro-fit to the SMPS300RE? If it uses double resonant caps per rail it seems possible.
It's a bit annoying that i must design and implement an external soft-start mechanism when the board already has a soft-start present, the solution you used does seem more elegant.
All the best,
Kris
Dear friends and cothread members, I am a little profane in the major mathematics laws that justify the electronics in SMPS and many other electronic fields, anyway I am an learner with many questions and doubts.
Recently I discover the VSSA amplifiers in this forum. They're using SMPS (Hypex and Connexelectronics) I got one connex. for this circuit (SMPS500R) and I became happy because its kinds of devices can solve many problem to anyone: space, efficiency, soft start, price.
After that I start to follow the group for Vfet part 1 from the venerable Nelson Pass. They don't recommend that kind of PS for class A amps for the 120Hz ripple and counsel in add filters (big capacitance) and add a formerly in rush starter for protect the initial high current. What you can counsel to us about the mentioned.
I attach the link.
http://www.diyaudio.com/forums/pass-labs/253411-article-sony-vfets-part-1-a-6.html#post3893847
Best Regards and Happy Easter
Recently I discover the VSSA amplifiers in this forum. They're using SMPS (Hypex and Connexelectronics) I got one connex. for this circuit (SMPS500R) and I became happy because its kinds of devices can solve many problem to anyone: space, efficiency, soft start, price.
After that I start to follow the group for Vfet part 1 from the venerable Nelson Pass. They don't recommend that kind of PS for class A amps for the 120Hz ripple and counsel in add filters (big capacitance) and add a formerly in rush starter for protect the initial high current. What you can counsel to us about the mentioned.
I attach the link.
http://www.diyaudio.com/forums/pass-labs/253411-article-sony-vfets-part-1-a-6.html#post3893847
Best Regards and Happy Easter
While i think the statement that *any* SMPS is a bad match for any amp, including the VFET may be a bit broad, i would like to quote here a smart person from another thread:
It seems to me that unless the SMPS is specifically designed for it(using clamper diodes across a pair of resonant capacitors it seems), it's not a good match for Class AB amps in general, and those designed by people on diyaudio.com in particular.
This is due to two reasons: high transient current demands which cannot be met by the reservoir caps on-board the SMPS, and medium-high quiescent current demands leading to problems during startup and possibly ripple(although to be fair i still think the ripple data of the SMPS300RE is absolutely fine even at max output). It's borderline false advertising from Connexelectronic to claim it is "suitable for Class AB" and that large reservoir caps only help reduce ripple/smooth the DC is also not entirely accurate(see quote above).
It would be better to flesh out that line in the marketing materials to include specifics, such as the approximate maximum reservoir capacitance following the supply that can be accomodated.
It seems to me that unless the SMPS is specifically designed for it(using clamper diodes across a pair of resonant capacitors it seems), it's not a good match for Class AB amps in general, and those designed by people on diyaudio.com in particular.
This is due to two reasons: high transient current demands which cannot be met by the reservoir caps on-board the SMPS, and medium-high quiescent current demands leading to problems during startup and possibly ripple(although to be fair i still think the ripple data of the SMPS300RE is absolutely fine even at max output). It's borderline false advertising from Connexelectronic to claim it is "suitable for Class AB" and that large reservoir caps only help reduce ripple/smooth the DC is also not entirely accurate(see quote above).
It would be better to flesh out that line in the marketing materials to include specifics, such as the approximate maximum reservoir capacitance following the supply that can be accomodated.
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