Hey man,

Indeed the 33 Ohm was original and intended to be the lowest possible while all still decently working. This was for RCA and XLR the same. However, since BNC is a 75 Ohm official path, those resistors where replaced with 75 Ohm.
Leave that be when changing to XLR ? this is harmless, but the relation with the device at the other end will be slightly worse. Officially, when the other end bears 600 Ohm (a typical pre-amp I think ?) then the 75 is just a tad too high (and the 33 is fine).

Where to put which wire is somewhat harder for me to explain because I don't know how the DAC in question was set up or changed and how "obvious" the wires are visible on their function. However, I suppose that first changing the hot from XLR to "a" pin on XLR is fine always, as long as you apply it the same for both channels. And the other wire (per channel) goes to the other pin. All you could imply is a reverse absolute phase but if you use XXHighEnd, that's settable in there.

Best regards !
Peter

Hi Peter,

My NOS1a has 2x BNC stereo sockets.

Q: What is required for reversing 1x BNC stereo sockets back to former XLR sockets (with the intention using solely just the XLR sockets)

Is it simply a matter of replacing 1 pair of the BNC sockets with XLR sockets - pin 2 hot....
Or should the 4x 75ohm resistors also be replaced back to original 33ohm(?) resistors for proper XLR SQ/operation.

Thank you Peter !
Pete

(maybe) Try to interpret that Refresh button as it is intended (LOL). The ToolTip on it could help.
I don't know better than hat this robustly works. But maybe it can conflict with your own setting (which is not persistent) ? Thus, reboot so that your own setting is out of the way, and then next work with the XXHE setting. And of course do that in non-RAM mode. When that works, you can boot from RAM and it will work from there too.

Thank you Peter. I tried modifying through XXHE and rebooting a couple of times without success.  Could be a problem on my side. 

Hi Ramesh,

XXHighEnd takes care of that adequately. See below.

Regards,
Peter

All,

I just went through the process of installing the driver for the NOS1 on a new machine, and thought I'd share this just in case anyone else is doing this and has any problems.

- When you run the setup file, you will get an error if you do not configure Windows to allow installation of unsigned drivers;
- There is an option in XXHE to "Change" driver signing to not require signing.  However this option does not seem to work;
- You can temporarily disable signing of drivers in Windows by following instructions to restart with the shift key pressed, and then following the configuration setting options on the screen.  These instructions are readily available online.

Hi Ramesh,

I think it is best to continue this by email; later today I will respond there.

Regards,
Peter

Thank you for this Peter.  I never replaced the DSP boards, and they have not given me a problem yet.  My first task is to see if I have the Hypex DSP file or software somewhere.  I'm sure you mentioned this, but I did not pay attention at the time.  Is the software the Hypex Filter Designer that is available from Hypex?  Or something else.  If I do not have the DSP file, is there a default setting that the Orelos are shipped with that I can begin with?  I never made any changes to the default settings.

Hi Ramesh,

Unfortunately the DSP settings can not be read out. I know, not much user friendly, but that is how Hypex made it ...
So it is expected that you know what the settings are, register that (after changes) and maintain that documentation. Notice that you (everybody) received that documention from me, together with the speakers.
Knowing this now, you will find (implied) references to it in the topics I referred to in my first post.

Documentation : This is merely the DSP settings file which is used by the Hypex software to load its settings from, and which are meant to be equal to what you uploaded to the speaker (which is called "downloading" by the software). Indeed via USB (from your PC running the Hypex software to the speaker).

This should get you started ?
But please take note of the very first thing to do : find your DSP settings file, given by you together with the Hypex software. If you don't have that / don't use that, you will be over-writing what's in the speaker with "nothing".
BTW, you will have done the procedure at replacing Hypex boards ?

Best regards,
Peter

All,

Wanted to share this.  I have the Mach III in a cabinet with an open back, along with the original XXHE PC, which I use to store music. While the XXHE PC core temp at idle is around 35 C, the Mach III runs quite a bit hotter at 59-60 C.  I have the rear switch on the side down (faster fan speed).  To cool the Mach III, I bought an external fan (the Aircom T10 exhausting to the back). With the T10 on top of the Mach III, and at the lowest fan speed (and very quiet), the idle core temp drops almost 10 C.  It seems a workable solution if others have to keep the Mach III inside a cabinet.  Since the fan is external it does not draw power from the Mach III that could compromise SQ.