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Hypex UcD180HG HxR amplifier module analysis and review

opel

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I hope you have the basic understanding of electronic circuits. With output LC filter (2nd order LPF) tuned at about 50kHz/-3dB it is physically impossible to get flat FR up to 20kHz without having unstable response and low stability margin. You would need to go to much higher switching frequency and this would bring new issues. And this topology keeps FR invariant of load, so getting 20kHz flat means underdamped filter and wild overshoots in step response. Take or leave, I ask for professional discussion.
Take it easy. I understand what you are writing

Thanks for the explanation
Some claim that you get better sound by removing the input capacitor. what is your opinion here?
I know that everything you have in the series of signal does something with the sound in one way or another

If you are interested then I have compare Naim NAP 250 clone (ljm) with hypex usd180st. hypex is much better in higher bright frequencies, frequencies where naim struggles a lot.

NAIM NAP250 amp.

(2 x 4 ohm 50hz)
Volt. 22.6V
Amp. 5.66A
= 129.916w
 
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EJ3

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A correction. NAD 2200 Power output: 100 watts per channel into 8Ω (stereo), 400 watts into 8Ω (mono)
You almost NEVER get double watts in 4 ohms.
As per Amirm's measurements:

NAD 2200 Vintage Amplifier Review

index.php




Wow, we have one kilowatt of power coming out of this amp in short duration!
Lab Input Measurements
I was surprised that the frequency response was not flat but was relieved to see later in the thread that this is due to insertion of low and high pass filters. So here is the frequency response with Lab input that doesn't have such a filter:

index.php




Response now (in green) as it should be, ruler flat to below 10 Hz, and well extending past the 40 kHz limit of this measurement.
Zoomed:

index.php




And signal to noise ratio:


index.php




Conclusions
Nice to see innovation like this from equipment that is over 30 years old! Shame on manufacturers that produce amplifiers for much less power, more distortion and higher prices these days. No, you don't get a fancy case here and sheet metal is strictly budget category. But you are not going to sit on the amp. The guts are where it matters and NAD 2200 delivers.
 

opel

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As per Amirm's measurements:

NAD 2200 Vintage Amplifier Review

index.php




Wow, we have one kilowatt of power coming out of this amp in short duration!
Lab Input Measurements
I was surprised that the frequency response was not flat but was relieved to see later in the thread that this is due to insertion of low and high pass filters. So here is the frequency response with Lab input that doesn't have such a filter:

index.php




Response now (in green) as it should be, ruler flat to below 10 Hz, and well extending past the 40 kHz limit of this measurement.
Zoomed:

index.php




And signal to noise ratio:


index.php




Conclusions
Nice to see innovation like this from equipment that is over 30 years old! Shame on manufacturers that produce amplifiers for much less power, more distortion and higher prices these days. No, you don't get a fancy case here and sheet metal is strictly budget category. But you are not going to sit on the amp. The guts are where it matters and NAD 2200 delivers.
NAD 2200 is a good amplifier. It's RMS. watts which is correct. I measure with ocilocope all the way to signal clips and then I turn down a little so it no longer clips.

max. does not counts! It is watts you can run all the time (rms) and not max
 

EJ3

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OK. I'll play your game:
It is power measurements where the magic of this amplifier comes to life so let's look at that with 4 ohm load first:

index.php




We can see a kink in distortion when we hit 200 watts as the unit sails past that to produce whopping 337 watts per channel, both driven!
 

EJ3

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NAD 2200 is a good amplifier. It's RMS. watts which is correct. I measure with ocilocope all the way to signal clips and then I turn down a little so it no longer clips.

max. does not counts! It is watts you can run all the time (rms) and not max
and here is a video of an un-refurbished NAD 2200 loaded onto a SMD AMPLIFIER DYNO AD-1 (particularly look at the page of certified results at 10:22 of the video for 8 Ohms, 4 Ohms, 4 Ohm bridged mono & the 4 Ohm bridged mono burst test resulting in 1799 watts):
 

TimW

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This thread inspired me to buy a couple UcD180HG HxR modules for my desk setup subwoofers. Right now I have them powered from by a 500VA 24V transformer, which should yield 34V unloaded. They sound great and haven't shut down or seemingly run out of steam at high (nearfield) volumes. Is there any way to calculate or estimate the maximum output power from these modules at this lower supply voltage?
 

restorer-john

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He is trying to say the 2200 cannot deliver its dynamic power output continuously. Fair enough. After 500mS or so, the high voltage rails collapse and they are switched out. It is designed that way.

The 2200 can deliver around 140-150 watts continuous per channel into 8R and a little over 200 watts continuous into 4R per channel. It is a champion in the dynamic stakes due to the +/-95V rails and commutating design.
 
OP
pma

pma

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This thread inspired me to buy a couple UcD180HG HxR modules for my desk setup subwoofers. Right now I have them powered from by a 500VA 24V transformer, which should yield 34V unloaded. They sound great and haven't shut down or seemingly run out of steam at high (nearfield) volumes. Is there any way to calculate or estimate the maximum output power from these modules at this lower supply voltage?

Glad to hear it works well for you. Yes there is a simple way to predict output power depending on power supply voltage, quite reliably. You need to know PSU DC voltage when it is loaded (red trace, +Vs = 39V). Then the peak amplifier output voltage would be about 3V below the PSU DC output. Here it is about Vp = 36V. RMS output is Vrms = Vp/1.414. Power is Vrms^2/Rload. However, as always, you need to do your homework yourself ;).
This estimation is valid for SE output amplifier with dual (+Vs/-Vs) power supply. It cannot be used for BTL configuration.


100VA_supply.png
 

EJ3

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Glad to hear it works well for you. Yes there is a simple way to predict output power depending on power supply voltage, quite reliably. You need to know PSU DC voltage when it is loaded (red trace, +Vs = 39V). Then the peak amplifier output voltage would be about 3V below the PSU DC output. Here it is about Vp = 36V. RMS output is Vrms = Vp/1.414. Power is Vrms^2/Rload. However, as always, you need to do your homework yourself ;).
This estimation is valid for SE output amplifier with dual (+Vs/-Vs) power supply. It cannot be used for BTL configuration.


View attachment 176359
Thank you, I was wondering the same thing.
 
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viperflyer-us

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Hypex UcD180HG HxR module analysis and review

After buying and testing AIYIMA A07 amplifier (based on TPA3255 class D chip) in January 2021 I was quite disappointed with the frequency response modulated by speaker complex impedance and its audible consequences. This is, unfortunately, inevitable for the class D design with output LC filter outside the feedback loop, because the LC filter response damping not only depends on load resistance, but also LC filter impedance interacts with connected speaker complex load impedance, which may modify the frequency response even more. This was confirmed by measurements of A07 frequency response into various speakers and into speaker dummy load.

So I was seeking for a different class D topology (and not only hysteresis switching with PFFB) that would have affordable price and would be free of the mentioned frequency response modulation by the complex load. Yes there are Ncore and Purifi modules that are close to amplifier perfection, but they are quite expensive, NC400 module would cost 349.00 EUR (incl. Tax), without a power supply. So I started to review another options and turned my attention to the older UcD design, namely UcD180HG HxR, the latest datasheet [1] link is here:

https://www.diyclassd.com/img/upload/doc/ucd/ucd180hg/Documentation/UcD180HG_datasheet_R5.pdf

I ordered the module from Audiophonics France at the following price:
UcD180HG HxR module at 115.96 EUR, 4-pin Hypex signal cable at 8.97 EUR, shipping 13.71 EUR, total price 138.64 EUR incl. tax.

Hypex UcD180HG HxR description and analysis

Block diagram of the UcD180HG is shown in Fig.1 (from [1])

View attachment 163425
Fig.1. UcD 180HG block diagram

We can try to make a circuit analysis in MicroCap circuit simulator, starting with a circuit diagram as shown in Fig.2 which is based on information published in paper [2]
View attachment 163426
Fig.2. MicroCap UcD simulation

It is a self-oscillating circuit with phase-shift control using the reconstruction filter L1,C1 and phase lead network R3,C2. The frequency of the self oscillations would be at the point where loop gain phase shift is 180°, see plots in Fig.3.

View attachment 163427
Fig.3. Simulation of UcD oscillating frequency by loop gain analysis

The feedback is taken from the load, behind the output LC filter. This results, in simulation, in low output impedance and frequency response almost independent of load impedance. The manufacturer states in [1]:
  • Flat, fully load-independent frequency response
  • Low output impedance
  • Very low, frequency-independent THD
  • Very low noise
  • Fully passive loop control
and
  • Runs on unregulated +/- rail
  • Pop-free start and stop control
  • Differential audio input
  • No compromise components
  • LM4562 buffer OpAmp
  • HxR12 ready
  • Improved on-board buffer supply
  • Overcurrent and overvoltage protection
  • Weight: 90gms (3.1oz.)
HxR stands for high-performance voltage regulators developed by Hypex. They are based on transconductance amplifiers and have very low noise and very good ripple rejection, far much better compared to usual voltage regulator ICs. This should contribute to excellent CMR and power supply ripple rejection of UcD180HG HxR module.

Parameters as declared by the manufacturer

View attachment 163428
Now it will be my goal to measure what I get from the module in my amplifier setup.

Amplifier setup

The amplifier was built in one of my prototype cases (Fig.4).
View attachment 163429
Fig.4. Test case for the UcD180HG module

It has side heatsinks and pre-drilled holes for speaker binding posts, XLR input connector and 230Vac input plug with switch and fuse. Case dimensions are 376 x 216 x 70 mm. Wiring can be seen in Fig.5.
View attachment 163430
Fig.5. Wiring diagram of the amplifier

Transformer Tr is 230V~/2x32V~/100VA and it will, unfortunately, restrict the maximum power of the amplifier. DRC is a bridge diode rectifier with capacitor bank 2 x 11500uF. 230Vac input plug is 3-pin with PE pin connected directly to the metal case. XLR input connector has pin 1 connected via 47nF/1kV foil capacitor connected to the metal case. I know it would be optimal if it was directly connected to the case, however only if all audio components in the chain were properly built this way. This is unfortunately not the case and the DACs and soundcards used have pin 1 connected to PCB analog ground and in case of 2 class I components interconnected the balancing ground current flows between 2 different PE plug pins and in my case it makes as much as 30mA between 2 rooms. Then, CMR of the audio components plays a considerable game. As the amp has only one signal connector, no further PCB ground current is created except for that through the transformer stray capacitance and this current is low enough to create any issues. The photo below (Fig.6) shows the real amplifier layout and wiring. The detailed photo of the UcD module is in Fig.7.

View attachment 163431
Fig.6. The amplifier assembled

View attachment 163432
Fig.7. UcD180HG module

Measurements

Switching frequency


was measured as 422kHz with 372mV amplitude, see Fig.8

View attachment 163433
Fig.8. Switching frequency output residuals

Frequency response (Fig.9)

View attachment 163434
Fig.9. Frequency response into 4ohm and 8ohm

Frequency response was measured from 20Hz to 40kHz and is almost independent of load impedance, as stated correctly by the manufacturer. And there is no peaking.

THD and THD+N

Distortion plots vs. power are shown below, measured at 20Hz, 1kHz and 6kHz. Please note they are almost independent of signal frequency. Maximum power is limited by the 100VA transformer in the linear power supply. The amplifier gave 130W/4ohm/1kHz with THD+N = 1%.

View attachment 163435
Fig.10. THD and THD+N at 20Hz

View attachment 163436
Fig.11. THD and THD+N at 1kHz

View attachment 163437
Fig.12. THD and THD+N at 6kHz

SINAD at 5W

SINAD at 5W/4ohm is 76dB and at 5W/8ohm 82dB.

View attachment 163438
Fig.13. 5W/4ohm

View attachment 163439
Fig.14. 5W/8ohm

@Matias you can use the values for your SINAD chart.

CCIF intermodulation distortion 19+20kHz
was measured 0.024% at 20W/4ohm

View attachment 163440
Fig.15. CCIF IMD 19+20kHz

Thermal management

In a long term continuous sine test 45W/4ohm the side heatsink remained almost cold to touch and the module heatsink was mildly warm to touch. No thermal issues with the case and heatsink used.

Conclusion

Hypex UcD180HG HxR module is an older class D circuit solution which cannot compete in distortion parameters with Ncore or Purifi, however it has several very interesting features. It is a simple circuit, price is about 1/3 of NC400, it has frequency response independent of load impedance and nonlinearity almost independent of frequency. These are features I appreciate much and I have to say I like this module.

Literature:
[1] Hypex UcD180HG_datasheet_R5

[2] Putzeys, B.: Simple self-oscillating class D amplifier with full output filter control. AES 118th convention, 2005
Has anyone here tried this amp for a subwoofer application? I have JBL PB10 that was gifted to me 20 years ago. Sadly I shorted the module out from accidently slipped out test leads after repairing one of the caps....side effects of getting old and not getting used to bifocals in insufficient lighting. Shame on me.

I'd like to use the same power supply circuit and woofer from PB10.

On paper, it seems like I should be able to do this but I am not sure of the sound quality if unbalanced input is used. Has anyone tried it out in a sub with unbalanced inputs? Would hate to a slightest hum....

Thanks.
 

viperflyer-us

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This thread inspired me to buy a couple UcD180HG HxR modules for my desk setup subwoofers. Right now I have them powered from by a 500VA 24V transformer, which should yield 34V unloaded. They sound great and haven't shut down or seemingly run out of steam at high (nearfield) volumes. Is there any way to calculate or estimate the maximum output power from these modules at this lower supply voltage?
Hello Tim. Are your inputs signals unbalanced or XLR?
Thanks.
 

opel

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Hypex UcD180HG HxR module analysis and review

After buying and testing AIYIMA A07 amplifier (based on TPA3255 class D chip) in January 2021 I was quite disappointed with the frequency response modulated by speaker complex impedance and its audible consequences. This is, unfortunately, inevitable for the class D design with output LC filter outside the feedback loop, because the LC filter response damping not only depends on load resistance, but also LC filter impedance interacts with connected speaker complex load impedance, which may modify the frequency response even more. This was confirmed by measurements of A07 frequency response into various speakers and into speaker dummy load.

So I was seeking for a different class D topology (and not only hysteresis switching with PFFB) that would have affordable price and would be free of the mentioned frequency response modulation by the complex load. Yes there are Ncore and Purifi modules that are close to amplifier perfection, but they are quite expensive, NC400 module would cost 349.00 EUR (incl. Tax), without a power supply. So I started to review another options and turned my attention to the older UcD design, namely UcD180HG HxR, the latest datasheet [1] link is here:

https://www.diyclassd.com/img/upload/doc/ucd/ucd180hg/Documentation/UcD180HG_datasheet_R5.pdf

I ordered the module from Audiophonics France at the following price:
UcD180HG HxR module at 115.96 EUR, 4-pin Hypex signal cable at 8.97 EUR, shipping 13.71 EUR, total price 138.64 EUR incl. tax.

Hypex UcD180HG HxR description and analysis

Block diagram of the UcD180HG is shown in Fig.1 (from [1])

View attachment 163425
Fig.1. UcD 180HG block diagram

We can try to make a circuit analysis in MicroCap circuit simulator, starting with a circuit diagram as shown in Fig.2 which is based on information published in paper [2]
View attachment 163426
Fig.2. MicroCap UcD simulation

It is a self-oscillating circuit with phase-shift control using the reconstruction filter L1,C1 and phase lead network R3,C2. The frequency of the self oscillations would be at the point where loop gain phase shift is 180°, see plots in Fig.3.

View attachment 163427
Fig.3. Simulation of UcD oscillating frequency by loop gain analysis

The feedback is taken from the load, behind the output LC filter. This results, in simulation, in low output impedance and frequency response almost independent of load impedance. The manufacturer states in [1]:
  • Flat, fully load-independent frequency response
  • Low output impedance
  • Very low, frequency-independent THD
  • Very low noise
  • Fully passive loop control
and
  • Runs on unregulated +/- rail
  • Pop-free start and stop control
  • Differential audio input
  • No compromise components
  • LM4562 buffer OpAmp
  • HxR12 ready
  • Improved on-board buffer supply
  • Overcurrent and overvoltage protection
  • Weight: 90gms (3.1oz.)
HxR stands for high-performance voltage regulators developed by Hypex. They are based on transconductance amplifiers and have very low noise and very good ripple rejection, far much better compared to usual voltage regulator ICs. This should contribute to excellent CMR and power supply ripple rejection of UcD180HG HxR module.

Parameters as declared by the manufacturer

View attachment 163428
Now it will be my goal to measure what I get from the module in my amplifier setup.

Amplifier setup

The amplifier was built in one of my prototype cases (Fig.4).
View attachment 163429
Fig.4. Test case for the UcD180HG module

It has side heatsinks and pre-drilled holes for speaker binding posts, XLR input connector and 230Vac input plug with switch and fuse. Case dimensions are 376 x 216 x 70 mm. Wiring can be seen in Fig.5.
View attachment 163430
Fig.5. Wiring diagram of the amplifier

Transformer Tr is 230V~/2x32V~/100VA and it will, unfortunately, restrict the maximum power of the amplifier. DRC is a bridge diode rectifier with capacitor bank 2 x 11500uF. 230Vac input plug is 3-pin with PE pin connected directly to the metal case. XLR input connector has pin 1 connected via 47nF/1kV foil capacitor connected to the metal case. I know it would be optimal if it was directly connected to the case, however only if all audio components in the chain were properly built this way. This is unfortunately not the case and the DACs and soundcards used have pin 1 connected to PCB analog ground and in case of 2 class I components interconnected the balancing ground current flows between 2 different PE plug pins and in my case it makes as much as 30mA between 2 rooms. Then, CMR of the audio components plays a considerable game. As the amp has only one signal connector, no further PCB ground current is created except for that through the transformer stray capacitance and this current is low enough to create any issues. The photo below (Fig.6) shows the real amplifier layout and wiring. The detailed photo of the UcD module is in Fig.7.

View attachment 163431
Fig.6. The amplifier assembled

View attachment 163432
Fig.7. UcD180HG module

Measurements

Switching frequency


was measured as 422kHz with 372mV amplitude, see Fig.8

View attachment 163433
Fig.8. Switching frequency output residuals

Frequency response (Fig.9)

View attachment 163434
Fig.9. Frequency response into 4ohm and 8ohm

Frequency response was measured from 20Hz to 40kHz and is almost independent of load impedance, as stated correctly by the manufacturer. And there is no peaking.

THD and THD+N

Distortion plots vs. power are shown below, measured at 20Hz, 1kHz and 6kHz. Please note they are almost independent of signal frequency. Maximum power is limited by the 100VA transformer in the linear power supply. The amplifier gave 130W/4ohm/1kHz with THD+N = 1%.

View attachment 163435
Fig.10. THD and THD+N at 20Hz

View attachment 163436
Fig.11. THD and THD+N at 1kHz

View attachment 163437
Fig.12. THD and THD+N at 6kHz

SINAD at 5W

SINAD at 5W/4ohm is 76dB and at 5W/8ohm 82dB.

View attachment 163438
Fig.13. 5W/4ohm

View attachment 163439
Fig.14. 5W/8ohm

@Matias you can use the values for your SINAD chart.

CCIF intermodulation distortion 19+20kHz
was measured 0.024% at 20W/4ohm

View attachment 163440
Fig.15. CCIF IMD 19+20kHz

Thermal management

In a long term continuous sine test 45W/4ohm the side heatsink remained almost cold to touch and the module heatsink was mildly warm to touch. No thermal issues with the case and heatsink used.

Conclusion

Hypex UcD180HG HxR module is an older class D circuit solution which cannot compete in distortion parameters with Ncore or Purifi, however it has several very interesting features. It is a simple circuit, price is about 1/3 of NC400, it has frequency response independent of load impedance and nonlinearity almost independent of frequency. These are features I appreciate much and I have to say I like this module.

Literature:
[1] Hypex UcD180HG_datasheet_R5

[2] Putzeys, B.: Simple self-oscillating class D amplifier with full output filter control. AES 118th convention, 2005
Hello. Wish someone could measure Hypex ucd180 with optimal power supply 45v-0v-45 and enough amps to see if it measures those that the factory writes? Have searched the internet but no one has measured watts.

No one writes how big a transformer you have to have to get the max out of the hypex ucd180 !?
 

opel

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Hello. Wish someone could measure Hypex ucd180 1% THD 4ohm with optimal power supply 45v-0v-45 and enough amps to see if it measures those that the factory writes? Have searched the internet but no one has measured watts.

No one writes how big a transformer you have to have to get the max out of the hypex ucd180 !?
 

voodooless

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Hello. Wish someone could measure Hypex ucd180 1% THD 4ohm with optimal power supply 45v-0v-45 and enough amps to see if it measures those that the factory writes? Have searched the internet but no one has measured watts.
I’m pretty sure the specs in the datasheet are correct. Hypex is quite precise with this.
No one writes how big a transformer you have to have to get the max out of the hypex ucd180 !?
Something like 200VA should be fine (per channel)
 

opel

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I’m pretty sure the specs in the datasheet are correct. Hypex is quite precise with this.

Something like 200VA should be fine (per channel)
Ok. Thank you for the answer.

I have now ordered DC 46v-0v-36v DC 500w switch mode power supply.
Ebay.163574609001
Ebay.163780392129

Almost all amplifiers I have bought measure less than what is written on the paper from the factory / seller.
Therefore I do not trust 100% on datasheet.
 

pjug

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@pma
I discovered that one of my speakers (carmody overnight sensations) really causes problems with Class D with no PFFB. Here it is (red curve) being driven by an old Lepai Tripath amp. The amp s OK driving a JBL A130 (green curve). I suspect this is because the Carmody speaker has a large negative phase between 10-20KHz. The Carmody details can be found here: https://sites.google.com/site/undefinition/bookshelf-speakers/diy-overnightsensations

I wonder if you have seen similar, or would want to experiment with this kind of load. And it would be interesting to verify that Class D with PFFB have no problem with this (unfortunately I don't have a hypex or purifi amp to try).
1647647579827.png
 
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