CD Direct To Ref 9 Inputs

gostan · « **on:** 22 Nov 2005, 12:45 pm »

My Cary CD303-300 has an internal volume control and I want to go direct from balanced ouputs of cd player to balanced inputs of my Ref 9's. I can toggle between the balanced and rca's to bypass my pre-pro completely and utilize the internal volume control of the cd player.

Is there any reason relating to NuForce design to not undertake this type of direct connection? A few Cary owners that I have conversed with are doing so with other amplifiers with great sounding results. Pristine sound with no outside manipulation of the sound at all.

Stan

nuforce-casey · « **Reply #1 on:** 22 Nov 2005, 11:45 pm »

Hi,
The switch is not a selector switch, but only configures the ground so the amp could work with RCA/XLR. Both signal wires are connected to the amp PCB in parallel, while the switch connects/disconnects the -ve phase to ground.

While it's OK to run CD directly to NuForce, using the switch as a selector is not adviced.

gostan · « **Reply #2 on:** 23 Nov 2005, 02:21 am »

Quote from: Casey

Hi,
The switch is not a selector switch, but only configures the ground so the amp could work with RCA/XLR. Both signal wires are connected to the amp PCB in parallel, while the switch connects/disconnects the -ve phase to ground.

While it's OK to run CD directly to NuForce, using the switch as a selector is not adviced.

Casey:
Thanks for your response. I interpret this to mean that I should only have connections to one or the other: RCA or XLR. And not both.

By the way, the Cary player does sound spectacular when connected direct to the Ref 9's with a pair of Nordost TYR XLR cables. More brilliant and cleaner than running through my Arcam AVP-700 (which also sounds pretty damn good)!

Stan

gostan · « **Reply #3 on:** 29 Nov 2005, 11:42 am »

Well, I decided that the Cary player sounds better when connected through my Arcam AVP700 pre-pro. A little smoother with a fuller midrange.

What was interesting and a little disturbing is that when I connected the cd player and/or the preamp to the Ref 9's with Nordost Try XLR's the hiss through the tweeters was much louder. When connected with Nordost Helmdur RCA's there was almost not such hiss.

Stan

KJ · « **Reply #4 on:** 29 Nov 2005, 03:20 pm »

Stan,

Just to clarify, you're speaking of the hiss when music is not playing correct?

-KJ

gostan · « **Reply #5 on:** 30 Nov 2005, 02:22 pm »

Quote from: KJ

Stan,

Just to clarify, you're speaking of the hiss when music is not playing correct?

-KJ

Yes I am. I tried another manufacturer's xlr cables and an uncomfortably loud hiss sound eminated from the tweeters of my N803's. No such hiss when using RCA's. As this hiss was audibly visible when direct connected from my Cary player and from the L&R fronts of my Arcam AVP-700, it has to be an issue with the amps. Is there a problem with the balanced connections of my Ref 9's? Has anybody else had a similar issue?

Stan

KJ · « **Reply #6 on:** 30 Nov 2005, 02:51 pm »

Stan,

I'm confused as to which method you feel promotes more "hiss." You posted these remarks earlier:

Quote from: gostan

I did connect the Cary direct to the XLR inputs of the Ref 9's tonight with a pair of Nordost TYR balanced cables. The results are even better than I had hoped for. The XLR connections are definitely quieter than the use of RCA's as those promoted a slight hiss from my tweeters. None at all with the XLR's. The soundstage is much deeper yet centered. Less is definitely better.

This appears the opposite of:

Quote from: gostan

I tried another manufacturer's xlr cables and an uncomfortably loud hiss sound eminated from the tweeters of my N803's. No such hiss when using RCA's. As this hiss was audibly visible when direct connected from my Cary player and from the L&R fronts of my Arcam AVP-700

The ICs I use are not balanced and any hiss during idle operation is minimal. Per Nuforce:

Quote

NuForce's feedback and control system runs at 1MHz and actively performs noise cancellation in real time (comparing noise with music signal) at every switching cycle. But when there is no input signal, it merely amplifies noise in the system and therefore you can hear hissing noise from up to 1 ft away from the speaker. When the source device (Preamp or CD player) is turned off, it acts as a noise receiver/transmitter and could generate even more noise for NuForce amplifier during idling time.

Sounds like your amps are functioning normally.

-KJ

gostan · « **Reply #7 on:** 30 Nov 2005, 10:10 pm »

KJ:

Out of context, out of time-maybe I have confused the hiss issue at hand.

Let's limit the discussion to use of XLR connections from pre-pro to amps. Simply stated, there is a louder hiss from the XLR connections than from the RCA connections whether the music is on or off. The preamp is on because if I turn it off, as NuForce states, the hiss noise is amplified even louder.

I have eliminated any discussion about direct connect between source cd player and amps as music simply sounds better when played through the pre-pro, regardless of the cable type.

Stan

rustydoglim · « **Reply #8 on:** 1 Dec 2005, 03:20 am »

Stan,
Give us a call!

It is easier to talk on the phone and our support line is very lonely.
You can post the result after we sort it out.
Jason

nuforce-casey · « **Reply #9 on:** 1 Dec 2005, 03:23 am »

Try using the XLR cable between the Pre/Pro and flipping the switch to 'RCA', if there is less/no noise by doing this, then the signal is truly single ended, with the -ve phase of the XLR signal flipped from the RCA signal (therefore, you will have 2x the noise).

rustydoglim · « **Reply #10 on:** 1 Dec 2005, 07:21 am »

I think what Casey is saying is that you want to check if the pre-pro is simply actively convert the RCA to XLR (by flipping the +ve signal to get +ve and -ve signal for XLR). If that's the case, there isn't much advantage going with XLR.