Topic: Inside the Odyssey Stratos amp

[Nick's Picks]

this is actually one of my monoblocks.  they came to me from eBay...for a song and dance price that I could not refuse.  Barely more than what I had paid for my beloved Cyclops (khartargo based integrated).

any way..
when I got my Apogee miniDAC, I wanted to use its balanced outputs.  No prob...the Stratos is balanced.  But my right channel wasn't working.  Only the RCA input was active.  The Apogee does have a single ended line out, but its via a 3.5mm stereo jack.  not that it would be inferior (IMO) to any other single ended output...but all the same, I wanted to use the balanced outputs.

so...I pop opened the stratos today and quickly diagnosed my problem.  Old crappy wiring in there.  I can see green oxidation on the exposed parts of copper (AR wire used throughout most of the critical applications in there).
a quick solder...all finished.
but I was looking...and this is strange...., the input from the RCA jack is the main input.  its receiving piece of wire runs directly into the PCB.  Jumped off of it (which was the broken piece) is another short run of the same wire...which is a single conductor, shielded wire which makes up the contacts of the *balanced* input.
but there ain't nothing balanced about it.  In fact, it doesn't even represent a "purist" approach in design at all.  (see last image)
I"m a bit disappointed and have an email in to Klaus to see if he can shed some light on this.
I opened the left channel amp to see if it was the same, which it was.

so basically its just an unbalanced XLR input.  not even made to be unbalanced, its just that there is only a single hot input on these amps (and then ground).
am I missing something here?  or is this sort of ...well...., bullshit ?

either way..., I do love the sound of these amps and have been running Odyssey equipment now for about a year (a lifetime for me) w/o any intention of replacing them.  i do want to send them to Klaus for the EXTREME version upgrade.  New caps and such.  New wiring...for SURE.

[Frank in JC]

this is actually one of my monoblocks.  they came to me from eBay...for a song and dance price that I could not refuse.  Barely more than what I had paid for my beloved Cyclops (khartargo based integrated).

any way..
when I got my Apogee miniDAC, I wanted to use its balanced outputs.  No prob...the Stratos is balanced.  But my right channel wasn't working.  Only the RCA input was active.  The Apogee does have a single ended line out, but its via a 3.5mm stereo jack.  not that it would be inferior (IMO) to any other single ended output...but all the same, I wanted to use the balanced outputs.

so...I pop opened the stratos today and quickly diagnosed my problem.  Old crappy wiring in there.  I can see green oxidation on the exposed parts of copper (AR wire used throughout most of the critical applications in there).
a quick solder...all finished.
but I was looking...and this is strange...., the input from the RCA jack is the main input.  its receiving piece of wire runs directly into the PCB.  Jumped off of it (which was the broken piece) is another short run of the same wire...which is a single conductor, shielded wire which makes up the contacts of the *balanced* input.
but there ain't nothing balanced about it.  In fact, it doesn't even represent a "purist" approach in design at all.  (see last image)
I"m a bit disappointed and have an email in to Klaus to see if he can shed some light on this.
I opened the left channel amp to see if it was the same, which it was.

so basically its just an unbalanced XLR input.  not even made to be unbalanced, its just that there is only a single hot input on these amps (and then ground).
am I missing something here?  or is this sort of ...well...., bullshit ?

either way..., I do love the sound of these amps and have been running Odyssey equipment now for about a year (a lifetime for me) w/o any intention of replacing them.  i do want to send them to Klaus for the EXTREME version upgrade.  New caps and such.  New wiring...for SURE.

Unless it says something in the documentation that the XLR is simply a "convenience" input (i.e. suppose you don't have any spare RCA interconnects, but do have XLRs), it's pretty silly. 

I believe that most amp manufacturers who provide balanced inputs on their unbalanced amps do the summing with an op-amp before the signal enters the amplifier circuit proper.  At least you'll get the benefit of common-mode rejection if you're picking up garbage on your interconnects.  However, a short run of RCA is usually better than a long run of XLR whose signal then has to pass through a $1 chip.

Same deal with most "balanced outputs," they're not all they appear to be.

[scervin]

In my search for amps, there are not many balanced amps that are actually balanced throughout the circuit.