Denon 4700H - Denon RCA outs to External AMP w/ XLR ins -- is this a problem?

[MidwestDude8q5]

Setting up a 5.1.4 system with 4700H running KEF R3/R2C For LCR.

I am thinking about getting on waitlist for a 2 channel purify amp from Buckeye.

Dylan @ buckeye is saying that amp will have XLR ins only. The 4700 has RCA outs.

1.). My understanding is I am able to assign the Front Left and Front Right channels to pre amp and have them disconnect from internal Denon amp while still running the L/R Surrounds and 4 Atmos speakers from 4700. Is this correct?

2.). What is best way to hook Denon RCA pre outs to Buckeye Amp XLR ins? Does this create a voltage issue re: Denon RCA outs max voltage (1.4v?) before clipping or degradation of signal occurs?

3.). My understanding is I am unable to disconnect center channel from internal Denon amp. That being the case, is there any benefit to buying a 4 channel amp to run my KEF R2C center through external amp as well as Left and Right?


Thank you, I'm loving this forum!

 

[HarmonicTHD]

Setting up a 5.1.4 system with 4700H running KEF R3/R2C For LCR.

I am thinking about getting on waitlist for a 2 channel purify amp from Buckeye.

Dylan @ buckeye is saying that amp will have XLR ins only. The 4700 has RCA outs.

1.). My understanding is I am able to assign the Front Left and Front Right channels to pre amp and have them disconnect from internal Denon amp while still running the L/R Surrounds and 4 Atmos speakers from 4700. Is this correct?

2.). What is best way to hook Denon RCA pre outs to Buckeye Amp XLR ins? Does this create a voltage issue re: Denon RCA outs max voltage (1.4v?) before clipping or degradation of signal occurs?

3.). My understanding is I am unable to disconnect center channel from internal Denon amp. That being the case, is there any benefit to buying a 4 channel amp to run my KEF R2C center through external amp as well as Left and Right?


Thank you, I'm loving this forum!

Hi I am also new to this forum, but let´s see if I can answer some of your questions:

To 1) Yes. The Pre-Outs are always on, when you use the internal amps, in your case for your Surrounds etc.

To 2) Built or buy a cable which is configured like this (most commercially available cables are configured like this. I usually built mine with Neutrik connectors and vanDamme Starquad cable. No it does not create a voltage issue (at least not at reasonable lengths which you find in a domestic application).

To 3) Your understanding is correct. Let me elaborate: The X4700/X3700 etc. can be configured to run in pre-amp only, where they measure (THD+N) best and all internal power amps are switched off (also leads to cooler temps). What I personally would do, but this is ultimately a matter of your personal preference and taste is: Maybe get the low distortion (Purifi) for the main L&R and for HiFi/Stereo listening program one of the two configuration settings in the dennon to pre-amp only for 2.0 or 2.1 in case you have a subwoofer. For movie / surround listening program the second configuration for 5.1 or higher so the internal amps run your surrounds and center. I personnally cant recognize a difference, if the internal amps or my low THD+N amps run the surrounds, especially when immersed in a nice movie plot. Make sure the Purifi have the gain setting which more or less matches the 1.4V pre-out (a gain setting of 26dB (factor 20) would get you (20x1.4V)squared/8ohms equals ca. 100WRMS, 29dB gain will get you almost 200W).

My System: X3700H in pure pre-amp mode with L&R, Center into three mono-blocks Neurochrome Mod686 via the XLR/RCA cables (see above). Surrounds into a two-channel Neurochrome Mod268. Whether I run the surrounds or center through the very low THD+N Neurochromes or not is not audible for me.

Hope this helps...

To the experts in this forum: Please add or correct me if I am mistaken.

Cheers.

 

[MidwestDude8q5]

Hi I am also new to this forum, but let´s see if I can answer some of your questions:

To 1) Yes. The Pre-Outs are always on, when you use the internal amps, in your case for your Surrounds etc.

To 2) Built or buy a cable which is configured like this (most commercially available cables are configured like this. I usually built mine with Neutrik connectors and vanDamme Starquad cable. No it does not create a voltage issue (at least not at reasonable lengths which you find in a domestic application).

View attachment 193248

To 3) Your understanding is correct. Let me elaborate: The X4700/X3700 etc. can be configured to run in pre-amp only, where they measure (THD+N) best and all internal power amps are switched off (also leads to cooler temps). What I personally would do, but this is ultimately a matter of your personal preference and taste is: Maybe get the low distortion (Purifi) for the main L&R and for HiFi/Stereo listening program one of the two configuration settings in the dennon to pre-amp only for 2.0 or 2.1 in case you have a subwoofer. For movie / surround listening program the second configuration for 5.1 or higher so the internal amps run your surrounds and center. I personnally cant recognize a difference, if the internal amps or my low THD+N amps run the surrounds, especially when immersed in a nice movie plot. Make sure the Purifi have the gain setting which more or less matches the 1.4V pre-out (a gain setting of 26dB (factor 20) would get you (20x1.4V)squared/8ohms equals ca. 100WRMS, 29dB gain will get you almost 200W).

My System: X3700H in pure pre-amp mode with L&R, Center into three mono-blocks Neurochrome Mod686 via the XLR/RCA cables (see above). Surrounds into a two-channel Neurochrome Mod268. Whether I run the surrounds or center through the very low THD+N Neurochromes or not is not audible for me.

Hope this helps...

To the experts in this forum: Please add or correct me if I am mistaken.

Cheers.

Out of curiosity, did you ever compare your Front L/R speakers running off the Denon internal amps vs your Neurochrome Mono-blocks? Was the difference audible?

 

[HarmonicTHD]

Out of curiosity, did you ever compare your Front L/R speakers running off the Denon internal amps vs your Neurochrome Mono-blocks? Was the difference audible?

No I never did. It would have to be a double blind test before I would trust myself with the results. Also I had the Neurochromes before I had the Denon, so the question never arose of not putting them to use.

But let me try some rough back of the envelope estimate so you might be able to judge for yourself. If memory serves me correctly the X3700H measurements show that you loose about 10dB in THD+N when using the internal amps (ca. -90dB) vs pre-amp only mode with a THD+N of ca -100dB. Let’s also, for the sake of simplicity, regard the Purifi and the Mod686 at over -110dB THD+N as transparent, meaning not contributing any audible deterioration into the audio chain.

Then your question from above boils down to whether you personally can hear the difference between -90dB vs -100dB THD+N.

I think I, at 50 plus, would be hard pressed to to do so in a double blind test. But maybe some of the experts here can quote a statistically significant DBT study about what differences in THD+N at this level people can usually recognize.