Audiolabyrinth: An amp that is 3.58v to get it to give full output, is very unusual. Most amps are around 1.5v-2v in to get full output. In this case it could be likely you may need an active preamp.
I would still do the "Bolero Test" as it still comes down to if your source can give the amp enough volts to get to a decent loud level on whatever speaker you have, and if they are efficient enough you still may not need an active preamp.
Cheers George |
Atmasphere:
"The rule of thumb here is:
If you can hear differences between interconnect cables then the source is not controlling the cable."
Sorry, wrong again Atmasphere, the only time all cables will be made to sound the same/equal.
Is when the input of the poweramp is made extremely low input impedance as well, like 500ohm or less. And what's driving it (pre or source) has an output impedance extremely low like 1ohm or less so it can drive that very low input impedance of the amp.
This then will negate any differences in interconnect sound and they should then all sound the same.
The only down side is with that lower input impedance poweramp hardly any sources or preamps can drive it.
Cheers George |
You you didn't even bother to look before making ridiculous statements of this system quote:
"this is not really true, unless that source also has the ability to control the cable."
You put a White Paper out on this Atmasphere and you'll be shot down in flames. Mathematically how is the Nuforce not going to control the interconnects to the Belles?? You flat earthers are just too much!!!
Phusis sytstem:
Nuforce dac 9 has RCA Output impedance: 0.01 Ohm. It also has Output Voltage: RCA 2.0/4.0Vrms adjustable.
Belles SA30 30w Class A:Input impedance 100kohm. Input sensitivity .74v for full rated output.
hORNS Mummy MkII speakers: 94db sensitivity
Cheers George
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Swampwalker:
I have to set the record straight for you, not once have I trashed the sound of dc coupled output tube preamp. In fact as active tube preamps go it would sound the most transparent way of doing it, no coupling caps in the signal path on it's output.
Unlike 99% of most tube preamps that have coupling caps or transformers on their outputs to stop any dc from getting to the poweramps.
It's fact that if Audiolabyrinth uses it with a dc coupled poweramp like his Krell, should any fault cause dc on this preamps output, it will take out the Krell and most probably the speakers as well. As the Krell's engineer's have also had the same concerns.
As if a dc coupled tube preamp going faulty the dc offset on it's output is far more deadly than a solid state preamp going dc on it's output.
Audiolabyrinth just wants assurance that this will not happen to his prize Krell and speakers.
Cheers George |
Audiolabyrinth go with your gut on this, as the Krell engineers have voiced their concerns about direct coupled tube output and recommended an input cap on the Krell.
I not the one trying to sell you anything, and I agree I would not like to put a cap on my dc coupled poweramp either to protect it, the best cap is no cap.
Second is why not give assurance if it's not an issue in writing, that it will not blow your Krell and probably your speakers as well, if it goes dc on it's output.
Cheers George |
You have rights to be cautious Audiolabyrinth about protecting your expensive poweramps, I agree get it in writing.
A tube pre if it's output is capacitor or transformer coupled gives some safeguard to precious large power dc coupled poweramps.
But if a tube pre is direct coupled and you get a bad tube or something goes haywire then your dc coupled power amps are in grave danger, even if the pre has output relays which can switch too late.
If something goes wrong, the dc offset in a direct coupled tube preamp premap can be up to 100 x larger that a transistor pre. Your poweramp may survive a dc coupled transitor pre going bad, but not a dc coupled tube pre.
Cheers George |
Audiolabyrinth:
You don't have to match the source output volts to the amps max input volts. As you reduce the source volts with the volume control anyway.
So long as you can reach the desired max level you want from your speakers, it does not matter if the source is lower than the amp.
Cheers George |
In short do the "Bolero Test" with your source directly connected to the poweramp.
And go with Arthur Salvatore's 2 closing statements:
1/ "In short, if you need an active line stage because your source is not up to the task of driving the amplifier(s), then...
Any good active line stage, from any era, will improve the sonics in some obvious and clear manner"
2/ "Alternatively, if your source is up to the task of driving your amp(s), then...
No active line stage, no matter how good it is, will ever equal the sonics of your direct connection (or an equivalent passive)"
Cheers George |
Yes Brownsfan:
Arthur Salvator's "Bolero Test" (linked) is most enlightening to the need of active preamps.
If you like the sound of your system without the colourations of a active preamp involved using this test, then don't use it use a passive preamp. As this test gives exactly what the source is giving to your poweramp/s nothing added nothing removed.
BTW you can do it with other cd's that start of low in volume.
http://www.high-endaudio.com/RC-Linestages.html#BOLERO
Cheers George
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Don't worry Phusis and others you have it right don't listen to them. When ever there is a thread that threatens the existence of preamps these three to four flat earthers always rear their heads. It's almost like they have shares the slowly decaying dinosaur the preamp.
You are correct the source (if it has volume) direct into the poweramp will give the highest transparency, highest dynamics and least colouration there is, anything added to the signal path is going to colour the sound and be less transparent.
Cheers George |
Here we go again, the flat earthers rebuke.
I didn't even mention the Lightspeed Attenuator or passives. "I said if his source has volume control" it will be the most transparent, dynamic, and least coloured way of getting the sound of the CDP/DAC to the poweramps. You guys make it up as you go.
Cheers George |
