Kharma Matrix MP 150 issues???

Thanks everyone for your support! The issue has been resolve. Their was a DC leaking out from the kharma class D monoblock. I am so lucky nothing serious as damge my gears. Thank god!! In a review by: POSITIVE FEEDBACK ONLINE - ISSUE 25, reviewed by Marshall Nack; The MP150 is a purist design with minimal parts in the signal path. (Which was a surprise. Not so sure why, maybe it's because their appearance is so unassuming.) Like other purist designs, the MP150 eschews the usual DC protection. Most amps have a capacitor buffer stage up front to cancel any stray DC from the preamp. Especially when there are tubes upstream, there's the potential for DC leakage. If your pre-amp causes the MP150s to cycle on and off repeatedly, two minutes on your dealer's workbench is all it takes to engage the protection. The amps are shipped with the buffer stage in place but disengaged, because Kharma feels the extra capacitors degrade the signal. My class D now has a DC filter switched on. Everything should be fine now. In the long run, i might consider getting a soild state pre amp to go with my Class D. I really think the Class D matchs the best with my 3.2 speakers. I would give up my ART for the kharma class D and the 3.2. I hope i wont regret selling my Cj ART pre-amp later.

Hi Clark_h,
If you say there is a switchable DC buffer inside. How come Bill at GTT Group said; He can ad $50 service fee + shipping to engage the dc protection circuit in my amp?? Is there something i should know, but didn't know of? I call Cj and left them a message today. I hope i will hear from them soon. I wonder what the problem is on my ART? The lower chassis right channel tubes does not light up? I check the tubes with my tester. They work fine. I just hope is just is not a big problem or i can just go and hang myself. J/K

Thanks for the input. BTW, where is the switch located? Inside? I will look in to the 808 CDP. I want to thank you for letting me know something that i should have know of. I apprecitated! Jim

Hello from Canada. The Kharma Matrix MP 150 amps have a switchable DC buffer that is installed but not switched on. The amp sounds better with it switched off but some tube preamps will leak DC and stress the amp. If You fix the CJ preamp and the problem still occurs try turning on the DC buffer. I have the Nola Viper Reference speakers and am considering buying the Kharma amps to tighten up the bottom end a little. My Bel Canto EVO2i needs better grip. Looking for a good CD Player? Try the Meridian 808
or if Your CJ pre is dead then kill two birds with one stone and consider the Aurum CD/Preamp. All the best, Clark.

Hi Mikelavigne,
I only have two years of experience on audio. My first high end gear was the older Cj classic gears. I was never willing to try others at the time when i thought Cj was one of the best out there IMO. I am very happy with the way the ART sounds. It just sounds right! It looks like i have to narrow down to either Emm labs or Reimyo?

Jimbox; you are welcome. sorry you have a problem.

do you like the tonal character of the CJ Premier phono stage? particularly compared to the Marantz SA11? the CJ has a warmth that is very nice if not strictly neutral.....and it comes at the expense of micro-dynamics, transparency and ultimate clarity.

my taste runs toward the vivid clarity of the EMM Labs gear. which, while very natural, does not add warmth at all. the Reimyo (which i've had in my system) is a bit warm but not too much. the EMM 'SE' DAC6 is the very best digital i have heard when combined with the CDSD with the USB port (which is the same as SE whether or not badged that way). i don't know the April music.

there are lots of very good digital systems.....and i have not heard all of them. it comes down to your reference. i use the vdH Colibri cartridge on my Rockport tt as my reference of how reproduced music should sound; the EMM Labs gear comes closest to that to my ears.

there is a new 'one-box' EMM Labs digital player that i think is very very good at under $10k list price. you might consider that.

i hope this is of some help.

Hi Mikelavigne,
The left channel is working fine. The right channel did have a little sound before i swap the tubes up and down. However, after swaping them, no sound is coming out from the right channel. I assume the ART right channel has a problem? I will try and hook up with my suround speakers and give it a one more try. If still no luck, i will take your advice and conrad johnson monday and expain the whole story to them. I just hope is a simple issue like you said. I am so glad you came on board and help out. Many Thanks!

May i ask you another quesiton regarding a CD player opinion? I am planning on getting a used CDP or Transport and DAC combo. I understand everyone have different preference and taste. You seem to use alot of TOP gear in the past and it would be great to ask you for advice. My budget is around 7 grand. I have a few brand and model listed down below. I'm also open on opinion as well if you recommended.

1. Reimyo CDP-777
2. April music Eximus T1/DP1
3. Emm labs DAC6e/CDSD non-se
4. ??

hi Jimbox; thanks. your father's system and room is really on another level beyond anything i have ever seen.

i assume from your description that you have determined that the 'pop' originated from the right channel of the ART? is that correct? since the ART is a true dual mono design; the left channel should be working fine....is that correct?

are the tubes in the lower chassis of the ART for the right channel? that is not clear from your comments?

if so; and you have then switched those bottom tubes into the top and they all work.....you likely have some sort of failed part in the right channel. i am afraid i have no further thoughts about what to do to for an easy fix. you really need to contact Conrad Johnson or your dealer.

the preamp is not 'leaking' DC; but the 'Pop' might contain DC which can occur when there is a 'short' someplace which can be the result of a failing part. one guess about why might be that once this failing part reaches operating temperature it shorts out.....this 'pop' resulting triggers the protection circut in the MP150. the POP may just be a very loud sound and not contain 'DC'....but non-the-less it triggers the protection circut.

you can likely thank the design of your amps for preventing damage to your speakers. in essence; the amp is acting as the 'filter' you mention.

you must fix the ART before it can be used.....at least as i am reading your repsonse to my initial post. hopefully the 'fix' will be something simple.

in your efforts to isolate the 'pop' did it occur again? if so; how long after you turned on the ART did it happen again?

also...are you sure there is only one fuse on the bottom of the ART? maybe consult the owner's manual.

Hi Mike,
I really apprecitate your support. I am always on Agon and happen to see your system. What a wonderful dream you got there!!! It reminds me of my fathers system in Asia. Here is what i find below this morning.
I find out my Cj ART pre-amp lower chassis tubes are not lighing up. Here is what i did. I change all tubes from the bottom chassis to the Top chassis to test if the tubes were ok? Yes, there fine, thank god! I also check the fuse inside the art and its ok. Does this sign means, my lower right side channel is done? The light still stays on, but not the tubes, and no sounds.

However, if the preamp is leaking DC? Does this mean i need a module for DC filtering before the input? Does kharma make that? Or, maybe i have change my preamp better to work with my Mp-150?

hi Jimbox; first...very nice system; i'll bet it sounds excellent.

i would strongly recommend that you disconnect your speakers from your amps temporarily. the reason is that the ceramic mid-range of your wonderful CRM 3.2's is relatively fragile and those 'pops' could easily shatter them. i use to own Kharma Exquisite Reference speakers with the same drivers and i shattered three of them over the three years i owned them.

next find another speaker (it could be just about anything) and connect it to the right hand Matrix MP150. play the music again and see if you get another 'pop'. if you do then connect this speaker to the other MP150 to see if that side pops. if it does not then switch interconnects with the right and left output of the ART preamp and then see if the right MP150 'pops'with the left input of the ART. you simply need to isolate the problem to the one amp before you go any further (but without blowing up your ceramic driver).

obviously; if you don't get a 'pop' with the left input from the ART your problem is not the amp. you then need to isolate the right channel of your preamp; followed by the right channel of your source.....until you determine the source of the 'pop'. i do agree that the amp is the likely source but not for certain until proven. a 'pop' from your ART could trigger the protection circut of the MP150 and shut it down. the ART has those nasty tube thingys.....which when going bad can 'flare' or 'sputter' and could be your problem. this would be the 'DC' (direct current) your friend speaks of.

don't assume anything.

once you isolate the problem to the right hand MP150 e-mail your dealer or Kharma directly; Kharma was always very helpful to me. a class 'D' amp is pretty simple but you may have some sort of 'part failure'.