Question about using amp with xlr connections only with receiver with RCA preamp outs only

[petek]

I am confused about knowing whether a 3 channel Buckeye Class D amp would be a worthwhile addition for my Emotiva MR1 recever.
The MR1 has RCA preamp outs only.

The Buckeye of course is XLR input only. But RCA to XLR cable acceptable.

But I read that the sound will be cut 6 dB or more when using RCA out to the XLR.

Now that would seem to negate using such a configuration.....???

The Buckeye is 425w peak into 4 ohm.
The Emotiva is 100 watt peak with all 11 channels driven.

But if the Buckeye will be reduced 6 dB then wouldnt the effective be around 100 watts anyway...? Knowing that every decline of 3 dB causes a halving of perceived volume.
Or maybe I am misunderstanding.

And I saw one you tube video where the dude said yeah the sound seems stellar when using the Buckeye BUT he was disappointed the volume was not louder than when set to the same level as when he had just the receiver amps going.

I think perhaps looking for a good deal I bought the MR1 in haste, but instead should have sprung for their best processor that had XLR outs...? But 6k outlay of cash lot harder sell to wife than 1700 the MR1 cost.

Anyway thanks, and sorry if my ignorance shows I am not understanding something properly. Just again wondering if using an external amp with the MR1 will even be worthwhile....

 

[TLS Guy]

I am confused about knowing whether a 3 channel Buckeye Class D amp would be a worthwhile addition for my Emotiva MR1 recever.
The MR1 has RCA preamp outs only.

The Buckeye of course is XLR input only. But RCA to XLR cable acceptable.

But I read that the sound will be cut 6 dB or more when using RCA out to the XLR.

Now that would seem to negate using such a configuration.....???

The Buckeye is 425w peak into 4 ohm.
The Emotiva is 100 watt peak with all 11 channels driven.

But if the Buckeye will be reduced 6 dB then wouldnt the effective be around 100 watts anyway...? Knowing that every decline of 3 dB causes a halving of perceived volume.
Or maybe I am misunderstanding.

And I saw one you tube video where the dude said yeah the sound seems stellar when using the Buckeye BUT he was disappointed the volume was not louder than when set to the same level as when he had just the receiver amps going.

I think perhaps looking for a good deal I bought the MR1 in haste, but instead should have sprung for their best processor that had XLR outs...? But 6k outlay of cash lot harder sell to wife than 1700 the MR1 cost.

Anyway thanks, and sorry if my ignorance shows I am not understanding something properly. Just again wondering if using an external amp with the MR1 will even be worthwhile....

You are correct if you use an RCA to XLR cable, which is called a floating line, then the amp may not be loaded correctly as RCA line voltage is lower than balanced line voltage. The bigger issue is that those connections can result in noise.

The optimal solution is to use an active line to XLR converter, like this one.

 

[Speedskater]

Does the Buckeye have volume controls? Most modern amps have enough gain to deal with the (often) 6 dB difference.
An XLR balanced input is always good, even with a RCA output.

 

[petek]

The Buckeye has gain switch:
Gain settings:
4ohm - 25.5dB/2.17Vrms (High), 20.5dB/3.89Vrms (Medium), 15.5dB/6.93Vrms (Low)
8ohm - 25.5dB/2.24Vrms (High), 20.5dB/4.02Vrms (Medium), 15.5dB/7.16Vrms (Low)

Does the Buckeye have volume controls? Most modern amps have enough gain to deal with the (often) 6 dB difference.
An XLR balanced input is always good, even with a RCA output.

 

[petek]

I am thinking the
Whirlwind LM2B 2
looks nice. But for 3 channels I guess I'd need 2 of them.

No hurry---I'll dwell on this and research further. Continue using the built in amps until at least summer.

And Emotiva is currently replacing my MR1 anyway due to some sounds that should be muted upon turn off, but they are not.

You are correct if you use an RCA to XLR cable, which is called a floating line, then the amp may not be loaded correctly as RCA line voltage is lower than balanced line voltage. The bigger issue is that those connections can result in noise.

The optimal solution is to use an active line to XLR converter, like this one.

 

[highfigh]

Manufacturers who are targeting the consumer market need to stop including XLR to their products. The confusion leads to problems and I haven't seen anything about the output circuitry that makes me think it's really balanced.

 

[WaynePflughaupt]

And I saw one you tube video where the dude said yeah the sound seems stellar when using the Buckeye BUT he was disappointed the volume was not louder than when set to the same level as when he had just the receiver amps going.

The YouTuber is confused. All that means is that the Buckeye’s input stage matched that of the amplifier section in his receiver. You’ll only be able to tell the difference with the more powerful amp at the top end (read high volume), when the lesser one runs out of steam.

But I read that the sound will be cut 6 dB or more when using RCA out to the XLR.
But if the Buckeye will be reduced 6 dB then wouldnt the effective be around 100 watts anyway...? Knowing that every decline of 3 dB causes a halving of perceived volume.
Or maybe I am misunderstanding.

Misunderstanding. The 6 dB only relates to a loss of input signal strength to the amp. That’s easily compensated for by the amp’s gain switch.

I’ve been using pro equalizers with XLR connections in my otherwise all RCA system for years, with no issues, and no noise penalty. In my experience, "noise penalty" begins and ends with the equipment chosen.

There’s probably no need to worry about a signal converter. Emotiva specs the RCA pre-amp outputs at 2 Vrms. Hypex specs the NCx 500 inputs under 2 Vrms when using the “Hypex onboard buffer stage,” whatever that is. A line booster is going to introduce noise; the ART Cleanbox is rated for only 90 dB S/N, which is less than the Emotiva. Thus, I would only use one as a last resort.

BTW, did you look up the specs for that YouTuber’s front-end, to see what it’s output voltage is, to compare with your Emotiva?

Regards,
Wayne A. Pflughaupt

 

[petek]

Great! Thankyou! And I am right now in the middle of a you tube with Dylan (Dr Buckeye) being interviewed and half way in he talks about the topic. He confirms what you say----with the MR1 at its voltage, his 3 channel amp "loses" nothing as long as the gain is set to high. He also mentioned about the convertors having higher noise.
Guess when I decide to upgrade and add his amp next summer all I will be needing are some good cables---

.......
Misunderstanding. The 6 dB only relates to a loss of input signal strength to the amp. That’s easily compensated for by the amp’s gain switch.
.......... There’s probably no need to worry about a signal converter. Emotiva specs the RCA pre-amp outputs at 2 Vrms. Hypex specs the NCx 500 inputs under 2 Vrms when using the “Hypex onboard buffer stage,” whatever that is. A line booster is going to introduce noise; the ART Cleanbox is rated for only 90 dB S/N, which is less than the Emotiva. Thus, I would only use one as a last resort.........

Regards,
Wayne A. Pflughaupt

 

[Verdinut]

Everything depends on the voltage gain of the power amp being used and the clean voltage output of the AVR preouts. Most popular pro audio power amps have voltage gains of 30-32 dB and Denon/ Marantz AVRs having clean preout output voltages up to at least 2 volts are amply adequate, so there's no need for a line to XLR converter or transformer isolation.

 

[Speedskater]

Manufacturers who are targeting the consumer market need to stop including XLR to their products. The confusion leads to problems and I haven't seen anything about the output circuitry that makes me think it's really balanced.

A balanced XLR interconnect system is one thing.
A totally balanced internal circuit is another very different thing.
* * * * * * * *
A balanced XLR interconnect system is always a good thing.
A totally balanced internal circuit is a challenging, expensive engineering decision.

 

[highfigh]

A balanced XLR interconnect system is one thing.
A totally balanced internal circuit is another very different thing.
* * * * * * * *
A balanced XLR interconnect system is always a good thing.
A totally balanced internal circuit is a challenging, expensive engineering decision.

Don't care if it's expensive (it really isn't), using cables meant for LowZ/balanced equipment on consumer equipment that's unbalanced won't do anything that LowZ/balanced provides. Challenging? It requires inverted signal to be sent to Pin3 with the proper circuit impedance on both ends, often using an OpAmp. Lots of inexpensive equipment has this.

 

[Speedskater]

What is 'LowZ/balanced equipment' ?
It isn't about the cable, it's about the interconnect system.
1] RCA to XLR is always as good as RCA to RCA, and sometimes better.
2] XLR to RCA can be tricky and often is.

 

[TLS Guy]

What is 'LowZ/balanced equipment' ?
It isn't about the cable, it's about the interconnect system.
1] RCA to XLR is always as good as RCA to RCA, and sometimes better.
2] XLR to RCA can be tricky and often is.

It is pretty simple actually.

In an unbalanced circuit, the signal swings +ve and -ve above ground.

This would be a typical circuit.

You can see that the input is connected to pin 3 of the op amp. The impedance is set by R1 L which is 47 K, and this is a PU front end.

In a balanced circuit the signal swings +ve and -ve around ground.

So if a sine wave were presented the +ve part of the wave is connected to pin 2 of the op-amp. The negative parts of the wave is connected to pin 3 of the Op-amp.

So they swing negative and positive above ground and so are balanced. If pins 2 and three connections are reversed there is a phase reversal just like reversing the connections to a speaker.

The input impedance of these circuits is generally around 600 ohms.

The main advantage of these circuits is noise cancellation which is really important in microphone connections, or other long runs.

Since the wires connected to pin 3 and 4 are identical except for their color, they pick up any noise and interference equally. Since these voltages oscillate equally above ground connected to pin 1, the noise is cancelled out at pins 2 and 3, as the interference in the wires connected to lins 2 and 3 are 180 degrees out of phase and therefore cancel.

 

[PENG]

I am confused about knowing whether a 3 channel Buckeye Class D amp would be a worthwhile addition for my Emotiva MR1 recever.
The MR1 has RCA preamp outs only.

The Buckeye of course is XLR input only. But RCA to XLR cable acceptable.

But I read that the sound will be cut 6 dB or more when using RCA out to the XLR.

Now that would seem to negate using such a configuration.....???

The Buckeye is 425w peak into 4 ohm.
The Emotiva is 100 watt peak with all 11 channels driven.

But if the Buckeye will be reduced 6 dB then wouldnt the effective be around 100 watts anyway...? Knowing that every decline of 3 dB causes a halving of perceived volume.
Or maybe I am misunderstanding.

And I saw one you tube video where the dude said yeah the sound seems stellar when using the Buckeye BUT he was disappointed the volume was not louder than when set to the same level as when he had just the receiver amps going.

I think perhaps looking for a good deal I bought the MR1 in haste, but instead should have sprung for their best processor that had XLR outs...? But 6k outlay of cash lot harder sell to wife than 1700 the MR1 cost.

Anyway thanks, and sorry if my ignorance shows I am not understanding something properly. Just again wondering if using an external amp with the MR1 will even be worthwhile....

The signal voltage from the unbalanced output of your preamp will be halved, or 6 dB. As long as the preamp can output high enough voltage, you can still get the full rated output of the buckeye amp.

So the question is, what is the rated maximum output voltage of the preamp? As an example, the popular Denon and Marantz avrs can output 4 V before clipping, so they can drive the buckeye amps to their rated output level easily.

The rated output of the MR1 is 2 V, that's a little low, but typically if they say rated 2 V, it is not the maximum. You need to ask Emotiva what the maximum pre out voltage is, I suspect it will be much higher than 2 V.

 

[Speedskater]

From post #13
In the first schematic, R1 L is more likely to be 10k to 20k than 47k.
In the second schematic, the input impedance is 20k not 600 Ohms.
The 'ground' label should be 'shield'

 

[highfigh]

What is 'LowZ/balanced equipment' ?
It isn't about the cable, it's about the interconnect system.
1] RCA to XLR is always as good as RCA to RCA, and sometimes better.
2] XLR to RCA can be tricky and often is.

A cable IS an interconnect. Anything else is equipment.

XLR to RCA is easy- connect Pin 1 & 3 to shield/sleeve, connect Pin 2 to tip. Done.

 

[Speedskater]

The cable is only one third of an interconnect system.
output stage >> cable >> input stage
The cable is the easy design part of the system.
* * * * * * * * * * *
on XLR to RCA
there are three & a half types of XLR output stages.
No single type to XLR to RCA adapter will work with all outputs.