DC Blocker

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Here's the latest on my P20 issue... those that have followed this will remember that the last recommendation from PS Audio support was to block the IR port with some electrical tape. Well, it's now been four months and I have not had my P20 lockup once. Of course, I also haven't had remote control use either. I checked back with them to see what I should do next (unit is still under warranty), and was told that I could either remove the tape and just deal with climbing behind my rack and doing a hard reset every time it locks up, OR I could leave the tape in place and just not use my remote. Neither option is a very good option, especially on this class of equipment. Not happy...
 
PS Audio finally came up with a solution that I would have never expected...

I received a message from the man himself, Paul McGowan! He was apologetic about the situation we are both stuck in, and fully agreed that I shouldn't have to disable the remote (or reset the unit) to be able to use the P20 in my environment. He also explained the challenges they had in trying to duplicate my problem and resolve it. One of my big questions was how I could also have a P12 located near my P20, and the P12 has worked flawlessly. He explained that the coding is significantly different between the two units so they could not 'just suss out' the differences.

His solution... he offered me a FULL REFUND!!! o_O What company does that??? :unsure:

So now the ball is back in my court. The way I see it, I can either ship my P20 back to them, and come up with another solution for my power conditioning/management, OR... I guess I can just live with the frustration of either no remote, or using my remote and having to go behind my rack to reset it.

For those of you that are now wondering why I would even consider holding on to my P20... two reasons. First, when I installed it and brought my system back up, I really can't think of any other single hardware change we've made that has had as dramatic an impact on our sound. Second, in starting to look at my options, I'm kind of limited as I need a device to hang off a 20A service, and deliver power to a dozen outlets. Also, while I could move to a couple of eight outlet boxes, I want to try to avoid having to re-wire my power cables.

I thought this was a very generous offer out of PS Audio, and I'm going to just have to work thru my options. Thx Paul... it's good to be a part of your 'Hi-Fi Family'... (y)
 
That P20 has an ethernet port on the back. Is it able to respond to an aftermarket remote that sends commands via ethernet?

Edit: I'm guessing no, but thought it might stoke some creative thoughts...
 
Last edited:
Since the power going to your P20 doesn't matter. Could you put in a heavy duty 20 amp power strip or something with a switch on it? You could put the switch somewhere hidden but easy to get to? Flipping a switch to fix the problem is MUCH better than back breaking work. I'm just thinking of giving you an EASY fix that you can be happy with long term. Those power supplies are very nice and do what they are supposed to do. Think about something like what I'm suggesting. That way you get to use the remote and switch power on and off to the unit very easily.
 
My LG TV needs a hard reboot every now and then and it’s a real PITA to reach since it’s a wall mounted TV in our bedroom. I installed a Kasa smart outlet and now can do it from my phone.

There are stronger devices available controlled by SmartThings or Lutron that might fit your needs.
 
So they still think it’s a rogue IR command that’s causing the crash? I know you’ve had a good few months run with the IR blocked but I am not convinced yet. You could uncover it now and see if it happens again, but pay close attention every time you use another remote and check if the P20 locks up. You might eventually be able to reproduce the problem on demand and send them the exact remote code.

You could also ship it back for a replacement unit (maybe with the culprit remote control) now that they’ve admitted the problem and won’t say “no fault found”.

By the way how many watts are you actually pulling from it? Maybe a P15 is good enough.
 
That P20 has an ethernet port on the back. Is it able to respond to an aftermarket remote that sends commands via ethernet?

Edit: I'm guessing no, but thought it might stoke some creative thoughts...
I can shut it completely down, or power off individual zones thru their PowerPlay web app. Although, one thing I never looked at was whether once it is locked up, if it responds to their app. If that does work, I could just log in with my iPad and take care of it. (y)

Since the power going to your P20 doesn't matter. Could you put in a heavy duty 20 amp power strip or something with a switch on it? You could put the switch somewhere hidden but easy to get to? Flipping a switch to fix the problem is MUCH better than back breaking work. I'm just thinking of giving you an EASY fix that you can be happy with long term. Those power supplies are very nice and do what they are supposed to do. Think about something like what I'm suggesting. That way you get to use the remote and switch power on and off to the unit very easily.
That's an interesting suggestion. Since my P20 is sitting on a mostly dedicated 20A circuit (there is a power strip with wall warts for things like the remote, the cable box, etc), so I guess I could just flip the breaker off/on. I don't see why this wouldn't work, but I guess I'll need to let it lock up again, then give it a try...

So they still think it’s a rogue IR command that’s causing the crash? I know you’ve had a good few months run with the IR blocked but I am not convinced yet. You could uncover it now and see if it happens again, but pay close attention every time you use another remote and check if the P20 locks up. You might eventually be able to reproduce the problem on demand and send them the exact remote code.

You could also ship it back for a replacement unit (maybe with the culprit remote control) now that they’ve admitted the problem and won’t say “no fault found”.

By the way how many watts are you actually pulling from it? Maybe a P15 is good enough.
I think I will go ahead and uncover the IR port as I need to try resetting thru PowerPlay, or flipping the breaker next time it locks up to see if either resets the unit the way I would expect it to. Trying to find an offending remote will be more of a challenge as usually things are working fine, I turn things off for the night, and the next time I go to use the system, either it is working fine or it is locked up. IOW, I think every time it has locked up, it has been at night when no one is touching any remotes...

If I ship my P20 back to Boulder, I don't see it coming back to me. Either I'll have them refund my cash, or send me either a pair of P12's, or a P15 (but it doesn't have enough outlets). I haven't looked at power draw on my P20 for some time but I have no doubt a P15 would easily handle it as most of the components running off it are sources, with the exception of my surround amps, and one of my REL 212/SE subs.

I still hate having to use work arounds on this class of equipment, but at least they give me another option to climbing behind my rack... OR, to having to ship my P20 half way across the Country, and depending on what I would put in to replace it, doing a bunch of rewiring...
 
I can shut it completely down, or power off individual zones thru their PowerPlay web app. Although, one thing I never looked at was whether once it is locked up, if it responds to their app. If that does work, I could just log in with my iPad and take care of it. (y)


That's an interesting suggestion. Since my P20 is sitting on a mostly dedicated 20A circuit (there is a power strip with wall warts for things like the remote, the cable box, etc), so I guess I could just flip the breaker off/on. I don't see why this wouldn't work, but I guess I'll need to let it lock up again, then give it a try...


I think I will go ahead and uncover the IR port as I need to try resetting thru PowerPlay, or flipping the breaker next time it locks up to see if either resets the unit the way I would expect it to. Trying to find an offending remote will be more of a challenge as usually things are working fine, I turn things off for the night, and the next time I go to use the system, either it is working fine or it is locked up. IOW, I think every time it has locked up, it has been at night when no one is touching any remotes...

If I ship my P20 back to Boulder, I don't see it coming back to me. Either I'll have them refund my cash, or send me either a pair of P12's, or a P15 (but it doesn't have enough outlets). I haven't looked at power draw on my P20 for some time but I have no doubt a P15 would easily handle it as most of the components running off it are sources, with the exception of my surround amps, and one of my REL 212/SE subs.

I still hate having to use work arounds on this class of equipment, but at least they give me another option to climbing behind my rack... OR, to having to ship my P20 half way across the Country, and depending on what I would put in to replace it, doing a bunch of rewiring...

Well, it IS a very difficult problem. Intermittent issues are very hard to fix as they will not stay broken long enough for PS Audio to remote the problem. You now have a couple of fantastic quick work arounds and as a last resort you can always get another one. The piece of equipment itself is a very nice power plant. You didn't skimp on what you bought. Also, it is delivering very clean power to your system. :) I hope you find happy ground with it.
 
Just wanted to post an update on the problems I've had with my P20...

The front panel lockups have continued as before... intermittent and sporadic (sometimes as often as three times per week, and sometimes not for a couple months). One thing that is really interesting is during one of my lockups I didn't bother going behind my rack to reset the P20 since it was still powering all my gear just fine (I just couldn't use the remote or front panel)... and then a few days later, and with no input from from me... the P20 returned to normal operating condition!!! This has actually happened twice now, and by their reaction, I think has PS Audio completely confused.

Unfortunately, recently I had a new error that actually shut the whole P20 down. Since I have been dealing with these various issues for approximately two years, and was still under warranty, I tagged Paul (who had been read in on my P20 issues), and just asked him to swap my unit for a new one. He immediately agreed! I installed my new P20 on Saturday, and FedEx is picking up my old P20 tomorrow! So far, so good...

While I wish we could have gotten to this point a little sooner, it's really nice working with a company like PS Audio that stands behind their products and supports their customers. Now I just need to hope that all my P20 issues are on their way back to Boulder, never to be seen again!
 
Glad you (finally) came to a (hopefully) successful resolution with the P20.
I essentially have the PS Audio power treatment product line in my audio system including one of the original P300 AC regenerators. Knock wood, have not had any issues with any of the units. Back in the day, I considered the P300 to be one of the best system upgrades that I made.
Paul and his staff have always been responsive to questions and product use guidance.
I am guessing Paul & Co will be doing an autopsy on your P20.
 
Glad you (finally) came to a (hopefully) successful resolution with the P20.
I essentially have the PS Audio power treatment product line in my audio system including one of the original P300 AC regenerators. Knock wood, have not had any issues with any of the units. Back in the day, I considered the P300 to be one of the best system upgrades that I made.
Paul and his staff have always been responsive to questions and product use guidance.
I am guessing Paul & Co will be doing an autopsy on your P20.
Paul did offer to buy my original P20 back awhile ago. I seriously considered his offer, and I looked at most of the similar products as potential replacements, but in every case there was always something missing so I decided to just keep it even if I occasionally had to reset it. Like you, my P20 has been one of the best upgrades I've made over the 'decades'. While I don't think I could actually explain it... not only did I immediately hear it, but my wife (who is not very involved with our system) immediately asked me what I had changed... :unsure: Of course, some of this is likely dependent on the quality of the local power.

I'm glad I stuck it out, and as I said before... just hope that all the problems I had with it are on their way back to Boulder (although, I sure hope they don't infect any of the other PS Audio products)! :ROFLMAO:
 
I thought I should actually close this issue out for anyone that has been following it or interested in a PS Audio Powerplant...

As stated above, I installed my new, replacement P20 at the end of February. It has now been running for more than three months without a hiccup! (y) The only thing that is different between my two P20 installations, is Paul asked me not to plug in the ethernet cable. I left it unplugged for the entire three months, but with the new P20 running fine, I finally went ahead and connected it to my network a few days ago. So far, no issues...

I returned my old P20 to PS Audio for their investigation... and their analysis showed that it runs perfectly. Go figure... :unsure:

Anyway, thanks for everyones help and suggestions on this issue, and a big thanks to PS Audio for working the issue and actually making it right!!!
 
While I've been paying attention to this thread, I didn't think it really applied to me. That was until today!

PS Audio has been trying to chase down a very intermittent problem with the P20 that feeds most of my system. While it has always delivered power to my system, the front panel turns on by itself, and then locks up not responding to any user input requiring a trip behind my rack to do a power down reset. They've been looking at my P20 remotely and today I was told... "I looked over the data and on 2-12-21 around 2am, your P20 shows a large DC spike, which seems to fit the timeline and could explain the issue."

While we plan to just watch the issue for now... I guess I may be looking for a DC blocker of some type as well...
"DC spike" is kind of an oxymoron.
 
After the success with the front end he is, probably today, finishing 2 more DC blockers for my mono amps.

Due to the current draw and the transformer size in the amps the parts are substantially larger. On these I chose to make my own power cords from single crystal OCC copper wire with Furutech ends of both.

I don't know the total parts cost yet but I think it will be near $900 for both.
I will again sell of un-needed power cords and put money back in my pocket.

View attachment 21334View attachment 21335
So he's just using capacitors in series with the load? For a large load, unless those caps are HUGE, on the order of 1F or so, you'll be blocking AC as well. That is, there will be a load dependent voltage drop, which in my opinion is far worse than any DC offset coming through the line.
 
Audiophiles often use 'DC blockers' as a solution in search of a problem. There as to be a DC offset on the AC power line for them to do anything. Something big has to be creating the offset and many big AC power users don't run 24/7.
For others: So does the transformer hum change from time to time? Does it change in another building?
If there's asymmetrical distortion of the sine wave, there will be a DC component to the Fourier series. But if you're transformers are buzzing, the problem is the distortion itself, not whether it's symmetrical or asymmetrical. The best solution then would be complete reconstruction of the incoming sine wave. Such things exist, but are expensive. I think that's what PS Audio is doing.

Of course, a high current sine wave reconstructor must start with a hefty transformer. A high quality one is a DC blocker. But by itself it will just pass the distorted waveform faithfully, perhaps slightly shifted if there was a DC component to start with.

If you think you have a DC offset on your line, just measure it with a multimeter on a DC scale. I'd be amazed to see even a volt there.
 
Hi

Thanks for the replies however I understand about the results on amplifiers but wondered what effect they when connected ML’s electrostics via the mains plug.

Has anybody tried this?

Regards
William
One experiment you can try, if you're worried about the possible effects of power line noise on your ESL panels, is to pull the plug. Most of them will play for several minutes that way. Have someone cut the power, in a blind test, and see if you hear any difference.
 
So he's just using capacitors in series with the load? For a large load, unless those caps are HUGE, on the order of 1F or so, you'll be blocking AC as well. That is, there will be a load dependent voltage drop, which in my opinion is far worse than any DC offset coming through the line.

The parts you see are inside of either
a 12 in.² or 14 in.² PVC junction box.
They were pretty good size. Don’t know exactly the designation.
They plugged directly into the wall and then directly into the back of the mono blocks.

0E45AA5E-0D7F-45C4-9068-9681FF88D472.jpeg
DD935304-AA49-4289-BCF7-6C30F143AC1A.jpeg
 

Latest posts

Back
Top