Martin Logan Ascent-i and Pathos Logos

[ilidra]

ML Ascent-i and Pathos Logos

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Just after 2 days of enjoying ML Ascents-i and music, bad suprise. One chanall on my Amp (Pathos Logos) develop popping and cracking noise. I fliped speaker wires and noise follow to another speaker. Just wondering is anything on ML Ascent-i that couse that. Also checked tubes,fliped tubes,source and everything is OK.

 

[miljac]

ML Ascent-i and Pathos Logos

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Just after 2 days of enjoying ML Ascents-i and music, bad suprise. One chanall on my Amp (Pathos Logos) develop popping and cracking noise. I fliped speaker wires and noise follow to another speaker. Just wondering is anything on ML Ascent-i that couse that. Also checked tubes,fliped tubes,source and everything is OK.

IIRC you are not the first member reporting MLs causing Pathos to fail.

Seems that Pathos are not built for driving such a difficult (and capacitive!) load. Less than 1 Ohm impedance of capacitive nature is the probable cause, maybe causing Pathos to oscillate and damage the output devices.

Years ago I was attracted by the Logos looks and asked the dealer if I could trade my McIntosh for a Logos, but was (wisely as I know today) discouraged to do it, "Logos not having enough current capability to drive Ascent".

Your amp may be needing repair as it looks, good opportunity to exchange it with something more appropriate for driving electrostatics.

 

[ilidra]

Thank you!

 

[miljac]

Good luck!

 

[ilidra]

Just reading tread of another member who actually have same settings.
In his case no problems at all between Pathos Logos and Ascents-i. He is talking all good about Pathos Logos and ML Ascents-i.
Also I contacted both ML and Pathos tech. support and both state that Pathos Logos can esaly drive ML Ascents-i. Pathos tech support also state that they tested Pathos Logos with ML Ascent-i in factory.
Not sure how to procide after I fix Pathos Logos wich I realy like much.
Also thinking about bi-amping ML Ascents-i. Pathos Logos on panels and Parasound A21 on wofers.
Any opinions appriciated.

 

[Gordon Gray]

First determine the source of the problem and then decide what your next steps should be.

GG

 

[ilidra]

First determine the source of the problem and then decide what your next steps should be.

GG

According to Pathos Logos tech.support problem with Pathos Logos is accidently same time as I hocked up MLs. Even Pathos tech.team from hq in Italy state that Pathos Logos can easly drive ML Ascents-i.
Right now I'm powering ML Ascents-i with Parasound A21 without any problems.

 

[Gordon Gray]

Hi ilidra,

Seems a bit odd that the Pathos would malfunction two days after you hooked it up to the Ascent. How many hours was the system in use? How loud for how long?

Whenever I have a problem, which fortunately has been extremely rare, I ask myself what has changed. Seems too much of a coincidence to be taken lightly.

Given the fact that the Parasound is working fine with the Ascents, this would further suggest that the problem is with the Pathos.

Gordon

 

[ilidra]

I listened Pathos Logos and ML Ascents-i all together less then 10 hours. I didn't play loud at all. Not even at 1/3 of Pathos Logos power. Also Pathos Logos didn't overheat at all. I powered down my system without any issues or problems or noise. Next day when I fresh startup my system I experianced problem(popping noise from rt.chanal) and discovered that Pathos Logos have some problem.

 

[ilidra]

Just want to update info. My Pathos Logos is "fixed". Resistor in pre-driver pre output stage on Rt.chanal is bad and replaced.
I hocked-up ML Ascents-i to Pathos Logos hopping for good sound. In 45 seconds from start-up Lt. chanal develop same problem as Rt chanal before-pooping noise. Now rt.chanal sound good but now Lt. chanal on Pathos Logos is demaged.

 

[miljac]

It surely oscillates, whatever Pathos may say about driving capability.

You can tell them to load the amp with 1 Ohm and 0.2uF in parallel, feed the amp with 10 kHz square wave and have a look on the 'scope how the circuitry behaves.

It's a pity, Pathos looking so good and Ascent sounding so nice.

You can also try to hook a tube amp to the panels and feed the bass drivers through Pathos, this will surely work. Not sure though if pre out exists on the Pathos.

 

[ilidra]

Miljac, thank you! I forwarded your idea to Pathos team.
Also today I picked up Amp from repair shop. Pathos Logos is fixed. Also per Pathos advise faulty resistors 4k7 5w are replaced with 5k6 5w in both chanals. I still didn't try Logos Amp and ML Ascents-i again.

 

[miljac]

Good luck! Hope it solves your problem once for good. Happy listening.

 

[ilidra]

Just to update. Pathos Logos is fixed. Resistors in both chanals pre-driver preoutput stage are replaced from 4k7 ohm 5w to 5k6 ohm 5w (per Pathos tech. request). I connected Pathos Logos to ML Ascents_i and sound is amazing. Listening for last 14 days and so far no problems at all. Just amazing how good they sound together. Lets hope will stay that way.
Thanks all of you for help and suggestions.
Ilija