02-21-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1901 Post ID: 27066 Reply to: 27065 AC shared between 200 apartments If I am working on AC quality because the AC quality in the big building is very very bad.My apartment is in a big complex shared between 200 apartments + 7 big elevator and ...This Building has three phase AC power , in most homes the AC is better between 2AM to 5AM but in my home the dc offset increase after 2AM. It is very awful . I do not disagree with you but I had many amplifiers in my room , more than 10 different amplifiers (kondo 300b, Audiopax ...)Even Pure Power can not help when AC quality is bad. You know Audiopax designer was very smart designer . About grounding:Yes, Earth wire will decrease RF but I think RF is not the main problem. I hope you let me know which amplifier is less sensitive to AC ? There are different aspect of bad AC quality :- sometimes the sound is very forward and compress , rough and aggressive , reminds me bad/noisy computer playback- sometimes the sound change less than 10min , it is quality is variable - sometimes the sound lost liveness/accuracy and get creamy/soft. This softness is un-natural and it reminds me high jitter dac playback- sometimes the sound lost transparency and is opaque- sometimes the sound loose weight and bass- sometimes the sound loose midrange emotion/tone/harmonics- sometimes the sound is pure harshness www.amiraudio.com, www.hifi.ir

02-22-2023 Post does not mapped to Knowledge Tree Paul S San Diego, California, USA Posts 2,656 Joined on 10-12-2006 Post #: 1902 Post ID: 27067 Reply to: 27066 Noisey Ground Of course apartments are among worst cases in terms of noise on the ground. I understand and sympathize that there are situations where it is either impossible or extremely difficult to install bleeder ground rods and wires. In any case, there is always a delicate balance between main/neutral and safety/bleeder grounds, because impedance to ground is typically variable, and at any given time there might might be anything from RFI to EMF on any given wire in any given installation. Basically, the problem itself is dynamic rather than static, whch means any fixed "solution" might even add to problems at a given time. While specific electrical situations require specific electrical solutions, a hi-fi system is a moving target. Again the apparent efficacy of the PP got me thnking long ago that it ameliroates a wider-than-usual range of sonic problems rather than "correcting" electrical problems. Best regards, Paul S

02-22-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1903 Post ID: 27068 Reply to: 27067 AC is like big giant Paul I have listened to some friends systems in their home from morning to night and the AC quality was also variable accross the time but overally my AC quality was worse in comparison by my friends home. In Iran the new year holiday is 21 March - 2 April and believe it or not I only have good sound in New year holidays (12 days) . I have tested many solutions but this Market is full of useless expensive solutions like AC cables, Ground controls , AC filter , Regenerators , RF eliminator and ... I have paid for many of them but non of those products worked for me.Between all of them only the pure power is good and I love it. I feel fighting with Electricity is like fighting with big giant, it is impossible to win. www.amiraudio.com, www.hifi.ir

02-25-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1904 Post ID: 27069 Reply to: 27068 DPOLS vs Good AC Power After more than 20 years of playing audio game I think only two things are real game changers.   DPOLS and Good AC quality I do not claim I listened to Wilson Speaker in DPOLS but I am sure it was near DPOLS 14 years ago.  I remember for the first time I found this forum GSC for DPOLS experience in 2009. After that night I never had DPOLS experience in my life. It was a shocking experience. I think good AC quality could lower the noise and improve harmonics/tone in all frequencies. believe or not super good AC quality can change a low feedback low stage high power solidstate tone more close to a low power low feedback SET. please do not blame me for the BS comment , I had an experience only one time in my life for less than 15minutes when the AC Quality was very very good. that night the sound (especially tone/harmonics) of my high power solidstate amplifier was 1000% better than normal AC quality. I had a feeling of god tone (like red glow of molten iron), It fills the room with emotion of music and I will never forget this experience and if DPOLS unlock all dynamic/Image/tone then Good AC quality could unlock tone/harmonics. I know most solidstate amplifiers are dead sounding machines but few of them are good and AC quality can change their sound by wide margin.God is in the AC quality :-))) www.amiraudio.com, www.hifi.ir

03-03-2023 Post does not mapped to Knowledge Tree DHT4ME Las Vegas NV Posts 18 Joined on 08-27-2008 Post #: 1905 Post ID: 27070 Reply to: 27069 DC issues with early AM power Amir, Taking note that the DC condition is present when you say the power is cleanest yet Pure Power does not help leads one to want to investigate a high current DC blocker BEFORE the PP. Its possible that heavy DC could effect the PP in some way. Most DC blockers only work to block a few millivolts up to just under 1V of DC . How high is the DC on your line in the early AM? Robert www.Robert-Park.com

03-04-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1906 Post ID: 27071 Reply to: 27070 I can not measure DC When I use Pure Power then I hear no noise/buzz from Big transformers of Power amplifier.It seemd Pure Power 3000 blocks DC .I have no device for measuring DC voltage of AC line.I did not use any DC blocker before Pure Power and I have no idea about it but I doubt DC blocker could help without adding negative effect on the sound.I have used Isolasion transformer before Pure Power and You know Isolation transformer can block DC but isolation transformer does not help and degrades the sound.All AC power devices I have tried were not good for sound. This is my conclusion :If you have low power system go for : AC panel -> Good AC Cable -> Pure Power 3000 -> Audio SystemIf you have high power system go for : AC panel -> Good AC Cable -> Audio System No AC filter No isolation device EMI filter No thing . Even many expensive audiophile AC cables degrade the sound.  www.amiraudio.com, www.hifi.ir

03-05-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1907 Post ID: 27072 Reply to: 27071 One step forward, two steps back The problem of most solutions in high end audio is "one step forward, two steps back".  Personally I prefer to hear all information/dynamics of  sound even if the sound is out of control.when I use Isolation Transformer, AC filters (both parallel and series), Acoustic Panels, Bass Traps, Hifi Racks,Vibration control devices ,most expensive AC Cables, Ground Control devices and ... all of them only change the sound in a wrong direction and when we use these devices we lost some information in the sound (like compressing dynamics) and when you lost those information in the sound then your system transparency will decrease and you can not properly judge a new device in your system. I can order a DC blocker and check it in my system but I doubt if it can help.  www.amiraudio.com, www.hifi.ir

05-03-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1908 Post ID: 27082 Reply to: 27072 Ayre AC filter - Lessloss X640 I have listened to six different AC filters recently in two different audio systems , four of six ac filters were awful but two of them (lessloss and Ayre) were better:- Ayre L5XE - Lessloss x640 I do not judge these two AC filters because I did not put enough time to carefully listen to those filters.you may find those filters useful in your system and I think Ayre L5xe is ok in some systems.What I say is these filters can not solve the AC quality problem when your AC quality is awful. I removed both filters from my system and now I connect the system directly to home wall AC. I think the only way is going for high power AC regeneration from purepower . www.amiraudio.com, www.hifi.ir

11-18-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1909 Post ID: 27293 Reply to: 27082 Bad Electricity I had some experience with bad electricity so i would like to share it here. My audio system does not have ground loop.  1- digital sources (I have CD Player) is more sensitive to Bad Electricity than Pre/Powers.  2- if your audio system Continuously play music for many hours when electricity is awful then the sound quality will degrade even if your ac quality back to good level so the system should be shutdown for awhile if you want to have normal sound. It seems like "magnetization phenomena" the bad electricity change/degrade the sound of audio system , I do not know what happen but I guess the bad electricity may affect on transformer core or capacitor or diodes of power supply, actually I do not know what happen there. www.amiraudio.com, www.hifi.ir

11-25-2023 Post does not mapped to Knowledge Tree Bill Kensington, NH Posts 117 Joined on 03-15-2010 Post #: 1910 Post ID: 27299 Reply to: 27293 Quality after shutdown i shut down my system every night. After 16-18 hours disconnected from the lectricity that it sounds somewhat quieter and more musical. But I Have also noticed that if I shut down the system for several days, on tunen the sound is greatly improved, quieter, smoother with removal of most digital grunge and more lifelike. So something must take several days to occur to remove the damage caused to the music by whatever the electricity is doing to the equipment. I had one such session last week where he sound was close to the best I’ve heard in my system.

11-26-2023 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1911 Post ID: 27300 Reply to: 27299 System Warm up when I play over 10 hours per day my audio system in good electricity days (like 13 days of Iranian new year in spring) the sound get better and better every day (fully warm up) but in normal days the best way is shutting down the system when AC quality is bad. when I play less than 2 hours per day in normal days there is no improvement in sound after some days because the system does not fully warm up . in normal days of spring and summer I had only two mid-quality days (friday and saturday) and now in autumn the friday is not good, I do not know why and I do not know what happened to friday.  My friend recently bought the Victron Inverter / battery (Living Voice use these Inverters) and listened to it and convinced this is not a perfect solution. it seems there is no solution for AC problem. www.amiraudio.com, www.hifi.ir

11-18-2024 Post does not mapped to Knowledge Tree Romy the Cat Boston, MA Posts 10,155 Joined on 05-28-2004 Post #: 1912 Post ID: 27699 Reply to: 2931 The Puritan Audio Lab There is some noise among audio people that the Puritan PSM156 Studio Master Mains filter works well.   http://www.puritanaudiolabs.com/products/master-purifiers/psm156/   I did not try it and have no intention to but I would point it out to the people who are interested in the subject "I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-18-2024 Post does not mapped to Knowledge Tree Paul S San Diego, California, USA Posts 2,656 Joined on 10-12-2006 Post #: 1913 Post ID: 27700 Reply to: 27699 AWG A quick look at the unit shows wire sizes and small parts that are guaranteed to induce current limiting. Can't bring myself to read the "reviews". Paul S

11-18-2024 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1914 Post ID: 27701 Reply to: 27700 7000 I have checked the market and find Audioquest Niagara 7000. Two isolation transformer (total 8 outlet) in the box: one for digital cd/dac and one transformer for phono/pre.Four direct connections for high power amplifiers with PFC to deliver higher current at short duration.it seems There is no current limiting series filter and there is no dc blocker in high power amp path.There is also a powerful ground noise filtering . https://hifiplus.com/articles/audioquest-niagara-7000-power-conditioner/ I have no experience with Niagara 7000 www.amiraudio.com, www.hifi.ir

11-18-2024 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1915 Post ID: 27702 Reply to: 27701 Before Purepower 3000 I would like to use PS Audio P20 or Accuphase PS-1250 before my Purepower 3000+ for my low power tube system. PS audio P20 is class AB double conversion ups but accuphase use different way to generate waveform. Accuphase use isolation transformer and correct the output waveform by some transistors. I think when electricity is awful I needs one step ac regeneration before purepower 3000. I have used 10k isolation transformer before pp3000 but it was not good. I do not know why but isolation transformer was not helpful. I also used isolation transformer (without purepower) for my high power system but it changed the bass and also pace. My guess was Isolation transformers are not bad but my experience shows isolation transformer change the bass in wrong way. www.amiraudio.com, www.hifi.ir

11-18-2024 Post does not mapped to Knowledge Tree Romy the Cat Boston, MA Posts 10,155 Joined on 05-28-2004 Post #: 1916 Post ID: 27703 Reply to: 27702 No one knows anything.... Amir, I would like you to know that I personally do not pay too much attention to whatever you talk about electricity. It is centrally not out disrespect, but I feel that the nature of power grid, power problem and power in US and Iran are not compatible. For instance, I know that in US we suffer from all kinds of power problem but it looks like Japanese folks do not. I hear that there are different problems in US between the guys who live in the industrialized costs vs the guys who live in very rural mid country.  We all might suffer from power problems but it is not necessary from the same. Who knows, no one knows anything about the electricity.... "I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-18-2024 Post does not mapped to Knowledge Tree Amir Iran Tehran Posts 347 Joined on 02-11-2009 Post #: 1917 Post ID: 27704 Reply to: 27703 Tehran 230v Romy, I live in a big complex and 3 phase shared between 200 apartments. The AC quality in my apartment is awful most of the time. In past on friday and saturday (weekend in Iran) ac quality was better and first 13 days of spring (Iranian new year holiday, norouz) is very good but now friday is not good, I never understand why friday ac quality changed.My friends have also AC problem in Tehran but my problem is bigger. I remember one night I invited my friend to listen to my setup , that night the AC quality was awful, you can not believe how crap was the sound.  www.amiraudio.com, www.hifi.ir