2. amps-preamps
  3. 132283-5323

Changed amplifiers and need some feedback...

First the details. My current 3 year old system is system is entry level as I am in the audiophile world.
Speakers: I built the Jim Holtz Mini-Statements
Pre-amplifier: Transcendent Sound; Grounded Grid, Mullard 12AU7 tubes
Amp: NAD 326BEE (using pre inputs)
Music source mostly Spotify through Sonos Connect
DAC: Rega Dac R (a recent addition with nice improvement)
CD Player: Onkyo C-7030
Listening room is 16'x16', 9' ceiling with more open space to the rear.

So I decided it's time to upgrade my NAD integrated and look for a pure amplifier.  Purchased a used Odyssey Khartago Extreme stereo amp.  I am the 4th owner as far as I can tell.  Talked with Klaus before I bought and he verified its upgrades via the serial number.  The Khartago arrives and I remove the NAD form the system.  My sample music was Melody Gardot, Sarah Jaroz, Dire Straits, Patricia Barber and the Cars.  My first impression of the Khartago was "what's wrong!"  Something didn't sound right.  It sounded really really airy.  Bass was subdued.  Details were there but it all sounded so different.  Checked polarity of all connections.  All good.

With my original system, vocals were smack dab in the middle of the speakers, as if the singer was standing there.  Instruments were spread between the speakers and I could point to each instrument.  Now, I understand I've listened to the current system for 3 years, of course it's going to sound different.  But the Khartago seems to sound like it has an enhanced spatial effect turned on.  The bass sounds like it's almost in my ears, the vocals are not square in the middle, they're floating in a wide space.  When listening to Drive, by the Cars the bass was very present and powerful with the NAD.  It got lost with the Khartago, it was quiet and seemed to be coming from all directions.  At times I looked at my rear surround speaker as if sound was coming from them!  Just really strange.  If I had to chose this moment I'd stay with my NAD.

So, I'm hoping someone can shed some light on what's happening.  Perhaps there's a problem with the Khartago.  Maybe that's why I'm the 4th owner in 3 years or so.  I did talk to Klaus briefly and he felt it was presenting the music as it was intended.  Maybe?   Is the Khartago a very airy amp by design?

Any thoughts would be appreciated!

jeff
jfmerk
noromance's avatar
noromance
1,780 posts
 
Awesome!
Well done @lowrider57 
lowrider57's avatar
lowrider57
3,018 posts
 
Thanks nononsense. But the issue  may be caused by the preamp.

That's a good catch.

mulveling's avatar
mulveling
502 posts
 
@jfmerk
Lol! That definitely explains the 3 prior owners. I think this sort of thing -- gear sounding bad because of a significant wiring/circuit mistake, etc -- happens far more often than we’d like to admit. I once had a headphone amp serviced, and the guy said the new caps would "take a while to break in". But even so, it sounded so anemic in bass (as in NO bass), I had to crack it open for a look. Instead or wiring a tiny 0.47uF bypass cap in parallel to the big output cap, I saw that he wired it in series! I did the capacitor ESR calculation, and determined the bass was rolling of (-6dB an octave) starting at 1kHz! It would have been down by more than 20 dB at 100 Hz. A million years of burn-in couldn’t fix that! I also notice L/R channels occasionally being mis-wired in gear, etc.

Glad you got it sorted. Your excellent description of the issue is what lead to the solution!

ALWAYS questions things. Don't assume it was built correctly; people make mistakes (some more than others).
kosst_amojan
2,095 posts
 
I'll be honest. My first impulse reading the post title was to reply "wwwrrrrrreeeeeeeEEEEEEEEEEEEEE". 
That's my best try at feedback. 
jfmerk OP
14 posts
 
Inspected the inside of the amp tonight.  The left channel speaker terminal had the polarity reversed.  A simple 5 minute job with the soldering iron and it’s back in phase😊.  Simple mistake, simple fix.  I’m going to replace the blue power led too.  It barely illuminates.  Thanks again to all for the assistance!

@kalali, my preamp is phase correct.  That was good to know, even though I’d never guess a preamp would be nothing but phase correct. 

@mulveling I agree, ask questions.  I’m surprised the original owner didn’t send it back under warranty.  Yes, these little errors can easily happen amongst thousands of units custom built.
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