Duelund/Mundorf Ultra Loudspeaker Purifiers

I have been eying the Duelund/Mundorf Ultra Loudspeaker Purifiers that Audioman58 have been advertising and knew based upon the forums I have been following for years that he was quite knowledgeable on capacitor typologies.

So, I took the plunge and ordered these and they arrived in 3 days to my SW state! I knew from experience that they will need over 200+ hours just to hear a glimpse of what these Duelunds are capable of but they didn’t disappoint right out of a cold box. I immediately heard more clarity, a deeper soundstage with better separation and a much lower floor noise…

These purifiers have been burning in 24/7 in my secondary system for nearly 2 weeks now and are really starting to open up. I listened to these purifiers last night in my primary system with just over 200 hours and the change was quite remarkable; musicality, tighter image focus, much better decay and note sustainment, unbelievable airy and spacious 3D sound, more vibrant and engaging sound with clarity being the standout.

These purifiers work as Audioman58 described and I’m still shaking my head on the beauty I’m hearing in my system and would Highly recommend this amazing product….



I have been tempted, but my speakers have built in amplification for the bass and wonder if it would damage the built in amp?

Post removed 

Reach out to the builder to see if they would be compatible with your built-in amp.


I was a skeptic especially afterhav8ng the synergistic purifiers ,but I far totally wrong these are night and day better, the clean up the signal through the mundoff ultra resistors then to the top of class Duelund capacitors which are much better 

then in most speakers for sure, unless you have tried these new Products don’t 

give a opinion it’s just  speaking out of ignorance ,myself and 2 friends tried these That have the same  4 ohm speaker as myself they are. Built per speaker. 
after 150 hours burnin it’s very apparent.

This is a well known zobel network, been around for many years and most x-over builders have probably tried a version or 2 when load is of and you need to even out impedance over the frequency band . How much it influences the sound have probably more to do with the amplifier not having a hard time driving the speakers.  A well built speaker with a well built network and good drivers have no need for this " purification " 

All the best 


I would like to share my experience with the purifiers that I purchased from Audioman58. I have been in this hobby for some time and over the years have auditioned many speakers, amplifiers, tweaks etc. This experience has helped me sort out the many of the snake oil tweaks from the real deal. That said, my experience with the purifiers is that they performed exactly as described by Audioman58. In regard to the post by iseland, while I agree that high quality crossover components will provide many of the benefits that the purifiers provide, let me say that I have a Hegel H390 amplifier with a 4000 damping factor providing 2x250w into 8 Ohm and 400w into 4 Ohm. I say that because this amp is cable of driving and more importantly controlling drivers on the most difficult speakers. When I added the purifiers, they provided their value in short order; exactly as described. They will improve SQ even if you have high quality crossover components in your speakers. BTW many high priced speakers on the market use many sub par components in their crossovers. Happy user! 

I am the builder , I will answer several question, yes these will work even if amplified ,for the amplified section is fed the audio signal then goes  to the preamplifier -internal Xover ,these Filter which = cleans the audio band of noise ,not the same as a RC filtering in a Xover ,for one there is much times spent using various size capacitors for the the filtering ,and your speakers ohms, impedance determine which resistors I use ,which BTW these parts are night and day better then then 95% of the Xover parts in most speakers including anything at $25 k for example.once these are runin at least 100 hours they then start to open up. And get better to 300 hours.
Tony gee of humblehomemade Hifi capacitor helped me over 4 years  ago ,today these are a very well thought out design ,to Ass ume  the answer is self defined. 1st try them ,then make a call.  Magico A5 is the 1st  company to use these superb Mundorf Ultra resistors ,Yes even more defined then the path audio resistors I have directly compared them, and the Duelund copper foil oiled paper need no introduction  .and head shaking  is a good thing when the music sounds good !!


I checked with Golden Ear yesterday and they do not recommend using on my Triton Refs, saying it could possibly damage the internal amp and DSP. With that being said, although I would love to try it, I don’t gamble so I very reluctantly will pass. Unless of course someone with my speakers is using them successfully. 

BTW many high priced speakers on the market use many sub par components in their crossovers. Happy user! 


Just watch any of Danny's videos at GR Research.


I have Walker HDL links, I love them, they are no joke and mandatory around here. I wonder if they are similar. 

Just ordered a set for my son in Texas will let you know what he thinks. BTW he is an audio engineer in Austin his wife is an EE.

"Just ordered a set for my son in Texas will let you know what he thinks. BTW he is an audio engineer in Austin his wife is an EE".

Awesome! They should be able to hear the change immediately but will get much better after crossing that 150 hour mark and continue to improve past 300 hours.

I was considering a Loki Mini+ EQ but the positive change in clarity, smoothness and musicality these purifiers brought to my system and I have no desire for an EQ now.


@ abd1

I have been burning in my purifiers on my crossover less full range speakers and the difference is very noticeable.

These will ultimately go into my main system that utilizes a crossover.


Using MAGICO Q3s they have the best crossover, cabinet and drivers ill pass.

I have a psaudio p12 regenerator and a preamp with its own regen power supply. My speakers are single driver full range. Curious if these will make an audible difference. Wig says there is in his system. Is there a trial period?

Get with @ audioman58 for compatibility concerns with crossover less full range speakers.


Are purifiers beneficial on Magneplanar speakers, and has anyone tried this on MG20's? I have rebuilt/replaced the stock internal crossover components with Janzen silver and Audine copperfoil capacitors with Dueland 14 Ga air core copper foil inductors. There are Mundorf 0.01 MFD Silver foil bypass caps in parallel with the Janzen Caps. After a lengthy break in the speakers sound much improved. Will these purifiers help more?


Right out of the box using a 1970’s Akai receiver for breakin, holography plus what wig said. Head shaking not mandatory but unavoidable. They will not be going back. Thank you Audioman58.  

I received my purifiers from Audioman58 last week.  I thought I would try them out since my amps plug directly into the wall.  I have dedicated circuits for my amps and the front end but the front end components are supplied power through a Niagara 5000 conditioner.  My thinking was that some filtering on the amp/speaker side might be beneficial.  I have 100 hours now on these purifiers that Audioman58 designed for my 4 Ohm Thiel CS6 speakers that I am using with Pass Labs mono amps.  

After doing a 72 hour break in on my old HT receiver I put them into my stereo system and let them play for another 15 hours or so.  They are still changing but I have made some conclusions.  I hear a smoother sound.  I don't necessarily hear a bigger soundstage but there is a bit more air to instruments.  Af first the smoother sound seemed almost blah.  But the next day the sound was better.  Whatever these purifiers do, I found that I had to reposition my speakers.  After two 1/4" speaker position adjustments the soundstage came back into focus and the clarity was back.  The other notable difference is no more ear fatigue when listening at high volumes.  All gone.  I don't hear a change in the highs but I wonder if these filter out some high frequency energy that I don't necessarily here but still has an impact.

I wasn't sure at first but now these purifiers are growing on me.


So, if I understand correctly, these have to be built specifically for your given amp/speaker combo to have the appropriate values for the resistor and capacitor?

With that said, has anyone tried them on Green Mountain Audio speakers?



I got mine from Audioman for use on my Spatial X5s.   They do everything promised.  This tweak for sure works in my system.  

I'm curious about these.  Would these work with a bi-wire cable setup?  I'm all bananas, so not sure if these would even fit.

You might have to get 2 sets for bi wire. You can get them in spades or banana's. I actually elected to get bare wire ends.

Does any else who has has these have any more comments? Not much interest on this thread since March. 


I just priced out the parts used in Duelund/Mundorf Ultra Loudspeaker Purifiers from the Parts Connection website, and just the parts would actually cost more than entire assembled unit costs! Audioman58 must be sourcing the parts at a discount in order to make a profit.

Jury is still out on its effectiveness. I probably have about 40 hours on them and it has been recommended to give them several hundred hours of break in.



@ ozzy

Yes, you will start to hear improvements at the 200 hour mark and by 350+, you will be right in their sweet spot...😁


350 hours is a heck of a long time running tube amps. I think I have about 75 hours on them thus far.



I'm all tubes as well but I ran mines on my secondary system 24/7 for a month.😁