Musical Fidelity M1CDT through a Arcam IRDAC using RCA cables into AVR Clipping

[Dean Kurtz]

I had an old AVR, a Yamaha RXA1300. The Musical Fidelity M1CDT through a Arcam IRDAC worked fine. I got another Marantz SR5500 and it clipped using the RCA ins. Do newer Denons have this same problem? My Musical Fidelity shows .07 V peak to peak using RCA outs. It worked using the coaxial cable going in, but that's using the internal DAC of the AVR. I want to get a new Denon, but I will get a Yamaha if that's problem. Thanks.

 

[lovinthehd]

Without a dac in the Musical Fidelity cd transport how is it outputting an analog signal? Does it work fine with your external dac? All you have are digital outputs on the transport....

 

[Dean Kurtz]

Without a dac in the Musical Fidelity cd transport how is it outputting an analog signal? Does it work fine with your external dac? All you have are digital outputs on the transport....

It's going through the Arcam IRDAC to the AVR.

 

[Dean Kurtz]

It's going through the Arcam IRDAC to the AVR.

And it did work fine with the old Yamaha AVR. Both AVR's are dead now. I liked how the transport through the DAC sounded. I'm just not sure if the newer Marantz and Denon's have better internal processing so the analogue rca inputs don't clip using the M1CDT though the Arcam IRDAC.

 

[Verdinut]

Are you connecting the Arcam output to the Marantz analog inputs? On the SR5550 there are RCA jacks which are optical digital inputs. Have you been using the right inputs?

 

[lovinthehd]

So you measured the output from the Arcam dac at .07V (70 mV) rather than the cd transport? Can't imagine why it would be a clipped signal at that level in any case...is the Arcam dac level output adjustable? What inputs on the receivers are you using? How is the clipping manifesting itself?

 

[TLS Guy]

I had an old AVR, a Yamaha RXA1300. The Musical Fidelity M1CDT through a Arcam IRDAC worked fine. I got another Marantz SR5500 and it clipped using the RCA ins. Do newer Denons have this same problem? My Musical Fidelity shows .07 V peak to peak using RCA outs. It worked using the coaxial cable going in, but that's using the internal DAC of the AVR. I want to get a new Denon, but I will get a Yamaha if that's problem. Thanks.

So you must be playing to the analog inputs via the Arcam DAC. It is the Arcam that is rogue and your problem. Consumer line level is 0.5V to 1.4V rounding the numbers off. That is - 10 dBV to 0 dBU. Pro line level is 1 volt to 1.7 volts, again rounding the numbers off. That is 0 dBU to + 4dBU

Now your Arcam is specked at 2.2 volts. That is way above consumer line and above pro unbalanced line voltage. 2.2 is balanced pro line voltage.

So you will not find many consumer devices that would not clip with that input. Most would not have the headroom. So you need line attenuators.

 

[Dean Kurtz]

Are you connecting the Arcam output to the Marantz analog inputs? On the SR5550 there are RCA jacks which are optical digital inputs. Have you been using the right inputs?

Yes. They were the correct inputs. I read that AVR could not handle some of the cd players outputs through their analogue inputs. I'm just wondering if the newer ones took care of that. I know CD players are becoming a thing of the past, but i have that and two Denon Universal players. Lots of cd's, dvd audio and sacd's.

 

[Dean Kurtz]

So you must be playing to the analog inputs via the Arcam DAC. It is the Arcam that is rogue and your problem. Consumer line level is 0.5 mv to 1.4 mv rounding the number off. That is - 10 dBV to 0 dBU. Pro line level is 1 volt to 1.7 volts, again rounding the numbers off. That is 0 dBU to + 4dBU

Now your Arcam is specked at 2.2 volts. That is way above consumer line and above pro unbalanced line voltage. 2.2 is balanced pro line voltage.

So you will not find many consumer devices that would not clip with that input. Most would not have the headroom. So you need line attenuators.

Won't that degrade the sound?

 

[Dean Kurtz]

So you must be playing to the analog inputs via the Arcam DAC. It is the Arcam that is rogue and your problem. Consumer line level is 0.5 mv to 1.4 mv rounding the number off. That is - 10 dBV to 0 dBU. Pro line level is 1 volt to 1.7 volts, again rounding the numbers off. That is 0 dBU to + 4dBU

Now your Arcam is specked at 2.2 volts. That is way above consumer line and above pro unbalanced line voltage. 2.2 is balanced pro line voltage.

So you will not find many consumer devices that would not clip with that input. Most would not have the headroom. So you need line attenuators.

I wonder why it worked so well on the old Yamaha. But you solved my problem. I was looking at the Transport and not the DAC. Thanks.

 

[TLS Guy]

Won't that degrade the sound?

Well if your sound is clipping now, it is really degraded. It does not come in a more degraded form than voltage clipping. So if you prevent clipping with those two resistors in each of those line attenuators, then you will upgrade your sound.

I have a strong feeling you have been sniffing audiophool glue almost to the point of unconsciousness, and are in urgent need of detoxification before it is terminal!

 

[lovinthehd]

So you must be playing to the analog inputs via the Arcam DAC. It is the Arcam that is rogue and your problem. Consumer line level is 0.5 mv to 1.4 mv rounding the number off. That is - 10 dBV to 0 dBU. Pro line level is 1 volt to 1.7 volts, again rounding the numbers off. That is 0 dBU to + 4dBU

Now your Arcam is specked at 2.2 volts. That is way above consumer line and above pro unbalanced line voltage. 2.2 is balanced pro line voltage.

So you will not find many consumer devices that would not clip with that input. Most would not have the headroom. So you need line attenuators.

The line level inputs on his Yamaha have a sensitivity rating of 150mV, the Marantz 168mV.... .5mV to 1.4mV sounds like a weak cartridge output. If the output is 2.2V instead of .07V, tho....

 

[Dean Kurtz]

Too many concerts and drumming all those years for these ears. I'll have to go into the AVR direct with the transport and use that DAC. Thanks guys. Now the Yamaha or Denon debacle.

 

[TLS Guy]

The line level inputs on his Yamaha have a sensitivity rating of 150mV, the Marantz 168mV.... .5mV to 1.4mV sounds like a weak cartridge output. If the output is 2.2V instead of .07V, tho....

Good catch lovin! I made a typo. It should read 0.5V to 1.4V. I have edited it to correct the mistake.

On looking into this further, it seems analog input specs are not usually stated in the spec. sheet. They should be in the range of 0.5 to 1.4 volts, but it seems many are out of spec. being 0.4 V or a bit less. However 0.4 is close to the 0.5 spec. But they should be able to handle 1.4 volts before clipping and preferably more. Most consumer devices output in the 0.7 to 1 volt range.

 

[lovinthehd]

You might check the avr for an input level adjustment, too....might help. Overall I'd just use the dacs in the receivers and be done with it.

 

[Dean Kurtz]

Don't most cd players have about 2 V outputs too. Just sayin'.

 

[Dean Kurtz]

Here's what the Yamaha RXA 2080 says:

Maximum Input Sensitivity (Line)

2.4 V (1 kHz, 0.5% THD)

 

[TLS Guy]

Don't most cd players have about 2 V outputs too. Just sayin'.

I think around 1 volt is usual. 2 Volts would be above spec. for a high Z balanced output, but not for a balanced one.

 

[Pogre]

I... I don't understand what's going on here? Why not remove the DAC from the equation and be done with it?

 

[TLS Guy]

Here's what the Yamaha RXA 2080 says:

Maximum Input Sensitivity (Line)

2.4 V (1 kHz, 0.5% THD)

That would be unusual that is top end for a balanced output or input. It is certainly out of spec. for an unbalanced input. By spec. it is also clipping at that point. 0.5% THD is not good. So in fact it is in reality at the 1.4 volt spec. I would expect.