Yes, I am going to mention those when I get around to finishing the list of mods. I'm using 2200uF/6.3V across the zeners and also at the output of the EFs. They happen to be about the physically largest which will fit in the space available. I have tried adding more uF (in parallel on the bottom side) but can't hear any improvement, even with ~7000uF or so. So I reckon 2200uF is about as good as it gets.
Mods list, continued
Input circuitry mods (powered through pins 1 & 6) :
i) Reduce the zener diodes to 5.6V (Z103,Z104). This reduces the quiescent current, no downside that I've found so far.
j) Increase the rail and zener decouplers to 2200uF/6.3V. I used NCC KZJ (8mm dia) but I doubt the particular model is highly critical.
k) Decrease the zener biassing resistors to 6k8 (use 1206)
l) Add an X7R cap between pin1 and pin6 as recommended in the appnote. These pins power some CMOS logic as well as the OTA so need a close-in HF current path (AN-1138, p17)
m) Adjust R11 to give an idle switching frequency of ~400kHz. I found I need something between 300-330R (249R is fitted) due to the changes in low side drive voltage, dead time and gate resistors.
n) Remove C2 (input RF filter) as I already have an output filter on my DAC.
o) Remove CP1 if your DAC/pre output is already AC coupled. Its an unbiassed polar electrolytic so you're better off without that, SQ-wise.
p) Re-use the CP1 pads for a series resistor to give the appropriate gain for your system - in many cases having 31dB gain is too much, feel free to reduce it by ~6dB by adding a 3k3 in place of CP1.
Input circuitry mods (powered through pins 1 & 6) :
i) Reduce the zener diodes to 5.6V (Z103,Z104). This reduces the quiescent current, no downside that I've found so far.
j) Increase the rail and zener decouplers to 2200uF/6.3V. I used NCC KZJ (8mm dia) but I doubt the particular model is highly critical.
k) Decrease the zener biassing resistors to 6k8 (use 1206)
l) Add an X7R cap between pin1 and pin6 as recommended in the appnote. These pins power some CMOS logic as well as the OTA so need a close-in HF current path (AN-1138, p17)
m) Adjust R11 to give an idle switching frequency of ~400kHz. I found I need something between 300-330R (249R is fitted) due to the changes in low side drive voltage, dead time and gate resistors.
n) Remove C2 (input RF filter) as I already have an output filter on my DAC.
o) Remove CP1 if your DAC/pre output is already AC coupled. Its an unbiassed polar electrolytic so you're better off without that, SQ-wise.
p) Re-use the CP1 pads for a series resistor to give the appropriate gain for your system - in many cases having 31dB gain is too much, feel free to reduce it by ~6dB by adding a 3k3 in place of CP1.
It seems these little guys are fun to mess with, but really not ready for prime-time some of the time. Especially when 'real' speakers are involved. I vote for a more costly solution using an ICEPower module like this. Since the PSU is onboard, you only need to add an enclosure and I/O connectors. Sounds equally as good(if not better) than the IRS modules (I have those too). All protection aspects are built-in as well. Great little module from a reliable company(B & O).
I recently built a small amp using this module and it sounds great and works as expected and reliably. A few years back I also built another class D amp using a higher wattage output ICEPower module. I've been very happy with their sound and performance.
I know it's more money, but for the peace of mind......
I agree, given the price disparity between the amp and speakers, some kind of fail-safe protection is mandatory.
I have one of those supplied in a box from Taobao, price was 880RMB. Sounds better than a typical IRS2092 module stock to my ears (more dynamic). However with the power supply tweaks, the IRS2092 climbs ahead, (the dynamics become about the same) primarily on HF cleanliness. To my ears the HF of the IcePower sounds a bit 'op-amp-y'. And since pretty much all the active circuitry is on their custom IC there isn't any option to tweak.
I'd argue that speaker protection is a must with any amplifier, regardless the price or manufacturer.
I need a tad bit more power then those. Was considering the 125x2ASP(?) I need at least 50x4 into 8 Ohms for the mids and ribbons. The woofers will have ~200x2 into 8Ohms.
But I think I will give my 4x Twisted Pear Mauro My_Ref a go and see if they can cut it. The mid section is a mild 6 Ohms so roughly about 40-50 watts.
View attachment 779363
I have an amplifier test rig.
It has flying leads with croc clips on the end for connections to the pcb.
On the output is a simple relay speaker DC protect module.
Must have saved me a fortune in speakers over the years.
I must admit though when first powering an amp I monitor speaker out with a scope to make sure I don't get DC.
It has flying leads with croc clips on the end for connections to the pcb.
On the output is a simple relay speaker DC protect module.
Must have saved me a fortune in speakers over the years.
I must admit though when first powering an amp I monitor speaker out with a scope to make sure I don't get DC.
Rather than scrapping your almost completed amp
For what it's worth, you've already laid it out nicely, drilled your holes. There's space in the chassis to squeeze two stereo speaker protect boards. Perhaps you can swap out the damaged module with a new one and run it as planned, but this time with the speaker protection in place.
I ran a similar set up for a few years without fail. The same 4 amp modules, in bridged pairs to an 8 ohm load, only I ran all 4 off a single Abletec SMPS with 15,000μF per rail... I'd originally planned to use one Abletec per bridged pair but after testing all 4 boards with just one SMPS, it was already more power than my dual 6.5" woofers could handle.
Anyway just a thought.
For what it's worth, you've already laid it out nicely, drilled your holes. There's space in the chassis to squeeze two stereo speaker protect boards. Perhaps you can swap out the damaged module with a new one and run it as planned, but this time with the speaker protection in place.
I ran a similar set up for a few years without fail. The same 4 amp modules, in bridged pairs to an 8 ohm load, only I ran all 4 off a single Abletec SMPS with 15,000μF per rail... I'd originally planned to use one Abletec per bridged pair but after testing all 4 boards with just one SMPS, it was already more power than my dual 6.5" woofers could handle.
Anyway just a thought.
Nope, garbage can.
I will start with 4x My_Ref ver.C and and my Crown amp for the servo sub, if I need more will go to ICE modules or Hypex NCores. I have UcD180's x 4 on my old speakers but 6 channels of NCores are pricey.
There are other ICE modules that output more power. Some with onboard PSU, some not.
I understand that and I was looking at the 500 w/PS and the 200 wo/PS.
The 8x ribbons and 8x 6.5" mids per side really don't need more than 50 watts each. Anything more will never be used but less may mean more work to redo again later.
I understand speaker protection is a must, but these class d devices do like to blow themselves up, reworking them is no joy, so I guess it depends on the design.
I have just completed 2 x 2012 silicon chip classic class D amp modules will see if these last long enough to enjoy at least I have the schematics and setup instructions on how to test and set them.
I have just completed 2 x 2012 silicon chip classic class D amp modules will see if these last long enough to enjoy at least I have the schematics and setup instructions on how to test and set them.
We can never beat this. the t.amp E-400 – Thomann Danmark
If we need to buy both amp modules, speaker protection, case, connectors, leds etc then we are above the 100 $ price range. But, we like to give the amp a personal touch and the fun is also looking for something cheap that is better than the previous one we bought
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@Kjeldsen
You are perfectly right, but have to go the whole way: Get such an amp, throw out the amp section and re-use transformer, caps and whatever you like. Put in the D-amp you like. You get a well build metal case which contains any (illegal) high frequency radiation.
The Behringer KM750 is really nice and you will not get such a solid case for €125 anywhere. The parts used are inexpensive but good quality.
To bad more people have realised this, so defective eBay offers are often overpriced.
You are perfectly right, but have to go the whole way: Get such an amp, throw out the amp section and re-use transformer, caps and whatever you like. Put in the D-amp you like. You get a well build metal case which contains any (illegal) high frequency radiation.
The Behringer KM750 is really nice and you will not get such a solid case for €125 anywhere. The parts used are inexpensive but good quality.
To bad more people have realised this, so defective eBay offers are often overpriced.
hello guys
How can I look if the IRS2092 chip is broken?
I solderd some new caps and change VCC regulator for Step-Down. I plug the amp in and some cracy noise came out. Extremly loud. I change VCC back to linear but no funktionc. No PWM led. Amp consumes only 5W at 230V socket.
Some ideas?
How can I look if the IRS2092 chip is broken?
I solderd some new caps and change VCC regulator for Step-Down. I plug the amp in and some cracy noise came out. Extremly loud. I change VCC back to linear but no funktionc. No PWM led. Amp consumes only 5W at 230V socket.
Some ideas?
