Stellar P3 DC blocking capability

I have just acquired the 230 VAC version of the Stellar P3 and I now have a nice sine instead of clipped sine. But I think I have still problems with DC as my toriods in my two mono block amps hums a bit and it comes in “waves”. Sometimes they are silent. I read about the DC blocking ability in P15 which can block 2VDC but what about the P3? …it has less DC blocking capability?
I will install a heavy DC-blocker in front when it arrives. It is a 4 didoes in series blocker and with some very large caps. When I look inside the P3 (images from web) there seems not be be installed a standard DC blocker?
By the way…the two larger caps in P3 are those for the DC-rails when converting the mains to DC?

It seems I solved my problem so now my transformers are quite silent and my DC-offset at amp output stable. It is easier to measure amp when AC mains is regulated. Have uploaded how my AC input to the P3 looks like. Think I will install the DC-blocker in front of P3 when it arrives to give P3 best possible working condition. If image shows up…does this AC mains looks particular bad or does is look “normal”?

1 Like

And this is how it looks out of the P3:


Hi Meper,
Could you please compare the sound quality before and after adding a DC blocker? Your views matter.

Yes, I will do that. DC-blocker has been shipped (it is a DIY based but I purchased it assembled as I was lazy) but it has to be mounted in a chassis with connectors etc. so it will take some time. This one:

But sound has improved after I got P3 to power my system. I would say a bit “darker” background and maybe a bit more crisp bas response but I have to listen more to be sure what I hear :slight_smile:
What is nice is that I can adjust DC-offset on my power amps to without 1 mV and it stays there.

From the various posts on this forum, it seems users of regenerators gain more spatial info by adding one. They have been reporting better sound stage depth and height, spot light effect on musical instruments, better detail and lifelike presentation etc. I have ordered the P15, and it should ship within a few days. I will compare the sound before and after. I am hopeful I won’t have those hum and DC issues some users had. I consider myself unlucky with cars, but so far, lucky with hi-fi :grin:

1 Like

that sine from wall seems quite bad. i have also capped peaks, but i don’t recall i’d be seeing it this much capped. But you have used regular oscilloscope while i am viewing the waveform only on my P10 display. My input THD is usually between 1,8 and 2,8 , depending on day hour and week day.

EDIT - just made screenshot from P10 - ok mine looks quite similar to your yours actuallly… :smiley:

1 Like

Ok, so that is probably the normal picture. Then there can also be a bit of DC on the mains. It seems the Stellar P3 has not very heavy DC-blocking features like the bigger power plants. What I notice is that DC on mains seems to be able to change rail voltage a bit like 0.2 - 0.3V lower DC even with P3 connected. Will see if this change when I get the DC-blocker installed.

DC would definitely come in waves depending on when other devices on the network / grid run & stop. Do the toroidals in the amps produce a loud hum when you connect them to the regenerator, but go silent when plugged into the mains outlet?

They are not louder when connected to P3. I would say more silent than louder but I can still hear something going on the the toriods when I notice my DC-offset goes from very stable at few mV to suddenly fluctuate between 50 - 100 mV. Then I found the reason was that one rail was dropping 0.2 - 0.3V. My conclusion so far is that it is mains DC that is hunting me and not a bad connection or uneven current draw from one rail. I will continue making measurements and try to be more clever…
It is good to have a stabilized AC when doing these measurements.

My view is that this is a global phenomenon, though it varies depending on the local network and the people sharing your power substation and / or building. I am no techie, but I hear most amplifiers benefit from accurate regulation first and foremost, especially tube amps.

Why shouldn’t it block DC when you rectify the power to DC and then generates a new AC? For me sounds like the components them selves creates the DC.

1 Like

Yes components convert AC received from the mains, conditioner, or regenerator into DC for use with electronic circuits.

I may have found the reason for unstable rails. It is probably not DC but the NTC (10 ohm) I use as in-rush limiter. The current is not large enough to get the resistance below 1 ohm. It is only about 50 C so resistance is probably about 5 ohm or more and I guess it modulates my rails. When I heat it up using a hair dryer rails comes back to stable leve. So I remove the NTC’s and will start the 2 x 400VA toriods directly on P3. Total wattage is only about 175 watts. I guess P3 will limit the inrush even that in spec says surge current = 60,000 A ? …is that 60000 A? …or how should I interpret this?

The Stellar P3 continuous loading capacity is 300VA. I think your amps are a handful for this power regenerator. 60,000 amperes sounds huge to me. I am not qualified to interpret this.

The 400 VA toroid’s in each mono block are “over dimensioned”. Each class A mono block draws about 80 watts. So should be fine. I removed the NTC’s and started them on P3 (one at a time) and it was ok. The blue led turns red for at short time and then back to blue again.
Yes, 60,000 A and not 60.000 A …there is a difference…unless it is an error in the spec. You use comma just as an indicator. It is different in Europe.

1 Like

Everything seems fine now after removing the NTC’s. Stable and symmetrical rails and DC offset and toroid’s dead silent. Think the “cool” NTC’s has caused some distortion. Also P3 is silent so I don’t think DC is entering the toroid in P3. Music sounds very good.


I checked the P15 and the peak current surge is 84,000 A for the 230 version. These numbers are astronomical! (Amps=Watts/Volts)

I am glad you have the right loading, and that you have resolved your problem. Sounds like you could enjoy the system even more over the weekend. Have a good one!

Yes, now I solved my problems and I can enjoy music and fully evaluate the P3. The 60000 A surge current must be because of the very low impedance of the P3 (and the other power plants). It will be fun to perform distortion/noise measurements with P3 in the loop. What is good it that toroid’s in my amps are silent. Also the P3 itself is silent. But it will not “hurt” to install a heavy DC-blocker in front of it…just in case.

1 Like

This 60,000A rating is the amount of current the MOV protection can absorb. But, only for 20uS, which is 1/50,000 of a second. So an insanely high current for an insanely short period of time.