I have for sale a few more PoPs, R1 this time with better layout and performance.
These can be tuned to have more or less flavor so it can suit all tastes by changing a few key components in the front end. Depending on your taste you can mention what exactly you want, less flavor meaning less thd.
From the strongest flavored to the light flavored at some power levels the thd is half.
Please see the new thd graphs at the bottom of the post where I compare the same module setup in 2 different ways.
Since some time I go ahead with the Xa252 PoP being the reference amp in my system.
It can work from +/-16v to +/-24.5v. Bias is preset at 1.4a.
The schematic looks like this
Stable as before when handling square waves
The new pcb has same drill hole pattern as R0
And here some thd measurements
All modules are tested and working. If no preference for the thd the modules will ship with the stronger flavor.
Later edit:
I am adding a crc psu pcb together with the modules for the same price.
Price for 2 channels and the crc psu pcb 160€
Later edit:
Someone said he uses a 5U400 enclosure for his builds (which is quite big) and is able to take 1.8A bias at +/-24V. So the user wanted to use the modules at a higher bias(1.8A) than the 1.4A as I set them.
With a higher bias for the output stage you will get more power output in class a(which you have plenty already with 1.4a bias) but also a bit more thd at high output power. So I think this time it`s better to keep it at 1.4A.
The maximum bias that can be set for the PoP modules is 1.6A so I took the measurements here, didn`t bother to modify the tested module to go to 1.8A. It isn`t really needed for the PoP.
These can be tuned to have more or less flavor so it can suit all tastes by changing a few key components in the front end. Depending on your taste you can mention what exactly you want, less flavor meaning less thd.
From the strongest flavored to the light flavored at some power levels the thd is half.
Please see the new thd graphs at the bottom of the post where I compare the same module setup in 2 different ways.
Since some time I go ahead with the Xa252 PoP being the reference amp in my system.
It can work from +/-16v to +/-24.5v. Bias is preset at 1.4a.
The schematic looks like this
Stable as before when handling square waves
The new pcb has same drill hole pattern as R0
And here some thd measurements
All modules are tested and working. If no preference for the thd the modules will ship with the stronger flavor.
Later edit:
I am adding a crc psu pcb together with the modules for the same price.
Price for 2 channels and the crc psu pcb 160€
Later edit:
Someone said he uses a 5U400 enclosure for his builds (which is quite big) and is able to take 1.8A bias at +/-24V. So the user wanted to use the modules at a higher bias(1.8A) than the 1.4A as I set them.
With a higher bias for the output stage you will get more power output in class a(which you have plenty already with 1.4a bias) but also a bit more thd at high output power. So I think this time it`s better to keep it at 1.4A.
The maximum bias that can be set for the PoP modules is 1.6A so I took the measurements here, didn`t bother to modify the tested module to go to 1.8A. It isn`t really needed for the PoP.
Last edited:
Nice job Schultzsch!
Lots of soldering time in the pile of Goodness👍🏻
Lots of soldering time in the pile of Goodness👍🏻
The thd plot at 1w/4r for the low thd version had a mistake which is now corrected so it has half the thd of the flavored one as expected.
Doing some testing these days I noticed that I hit the limit of what my soundcard can measure. Had to increase fft length from 128k to 512k to make my soundcard behave better. At this point I think that the thd of the amp is even lower than what I measured at 512k fft length.
