Mauro's "Myreference Rev.C" building queries and guide.

No need to spend $150. See this & this

The Valabs looks good. Will save the trouble of matching a few dozen resistors with closest readings to pair them for L+R channels when doing custom assembly. However SMD resistors are carbon based which I believe are more "noisy" than metal film resistors.

Enough to aggravate audiophile neuroses and cause recurring attacks of psycho-acoustic paranoia induced suspicious delusions about how volume pot is adversely affecting SQ :eek:hyeah:

:)
Cheers
 
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I think it will be safe to use just preamps volume. you can test it by keeping it to minimum and slowly turn up the volume. If volume is too loud two options would be (1) increase the preamp's pot value or (2) add pot to mauro's amp. I think then 10 k would be enough. I am just guessing though. may be linuxguru would help.
 
I think I am using 50k on my preAmp , now considering I need to tame excess loudness pairing the pre power, will 25k be enough? It's already a wee too loud for late night listening at minimum+1...

The value of the volume potentiometer doesn't have any significant impact on the input signal level. If it's too high even at the minimum setting, then you probably need an attenuator or some other way to reduce the gain in the pre-amp.

On a related note, the sound quality through the passive LightSpeed attenuator will easily trump anything that can be obtained with stepped attenuators, high-quality wirewound pots, etc. - the LightSpeed is entirely contact-free and purely resistive in the signal path.
 
the sound quality through the passive LightSpeed attenuator will easily trump anything that can be obtained with stepped attenuators, high-quality wirewound pots, etc. - the LightSpeed is entirely contact-free and purely resistive in the signal path.

Yes, I heard about it. Can we have a group buy for this also?:licklips:
 
The value of the volume potentiometer doesn't have any significant impact on the input signal level. If it's too high even at the minimum setting, then you probably need an attenuator or some other way to reduce the gain in the pre-amp.

On a related note, the sound quality through the passive LightSpeed attenuator will easily trump anything that can be obtained with stepped attenuators, high-quality wirewound pots, etc. - the LightSpeed is entirely contact-free and purely resistive in the signal path.

More steps in the volume pot means more refined control. But yep you are right, the higher value pot needs to be in the input side in order to be effective. Right now it appears to be too loud only on some recordings...

The LS needs a source with very low output impedance like 100 and amp with really high input impedance to really "shine" according to the original doc. I doubt if any of our budget CDPs go below 300... But I am in for a group buy if there is going to be one ... :licklips:

Cheers
 
Yes, I heard about it. Can we have a group buy for this also?

I think Uriah still sells them on his website - you'll need PayPal to transact and shipping to India might be a trifle expensive.

If I were to do it, I'd probably redesign the circuit with a high-impedance op-amp/buffer on both sides of the LightSpeed to take care of the impedance issues - this is likely to be a longer time-frame project.
 
What about digital ic volume control ? Schematics look simple. Can we replace regular vol. pot with this ? Are there any advantages over regular vol. pot. ? Just needs DS1669 IC and .1uf capacitor and 5 V battery. Can we replace the 5v battery and take it from the transformer itself.
volume.gif
 
What about digital ic volume control ? Schematics look simple. Can we replace regular vol. pot with this ? Are there any advantages over regular vol. pot. ? [/IMG]

The question is - how linear is the analog signal path in these digital volume controls? I'm guessing that it will be ok, but not linear enough compared to the rest of the signal path of the MyRef.
 
Yes, I heard about it. Can we have a group buy for this also?:licklips:

One of us can use his paypal and ship to the rest within country ... :eek:hyeah:

But impedance matching is the thing ... 100 for output and 100K for input impedance of power amp is the stated ideal scenario. Not sure how SQ is affected when otherwise. Most of us will not have gear that matches the ideal.

Cheers
 
If I were to do it, I'd probably redesign the circuit with a high-impedance op-amp/buffer on both sides of the LightSpeed to take care of the impedance issues - this is likely to be a longer time-frame project.
Hi Shiva,

We are definitely willing to wait.:licklips: Wot say guys?

One of us can use his paypal and ship to the rest within country ... :eek:hyeah:
That is also a very good suggestion Rahul.:clapping:
 
I think Uriah still sells them on his website - you'll need PayPal to transact and shipping to India might be a trifle expensive.

If I were to do it, I'd probably redesign the circuit with a high-impedance op-amp/buffer on both sides of the LightSpeed to take care of the impedance issues - this is likely to be a longer time-frame project.

OpAmps!! :eek: :sos: <typical reaction of ignorant audiophool> :rolleyes: :eek:hyeah:

how long is long term? :)
 
OpAmps!! :eek: :sos: <typical reaction of ignorant audiophool>

how long is long term?

There are very low distortion op-amps available these days at reasonable prices, e.g. LME49720/1/2 etc. For line-level signals, these exhibit negligible distortion, that is not even measurable with test equipment - say around -150 dB, well below the noise floor of some of the passive components in common use, like resistors.

Long term is something like 3 months, plus the lead time to get PCBs built and delivered. It won't be before December-January, at the earliest.
 
I think I am using 50k on my preAmp , now considering I need to tame excess loudness pairing the pre power, will 25k be enough? It's already a wee too loud for late night listening at minimum+1...
For excess loudness other option would be... when you assemble the amp you can put(solder) a proper value resistor to input in the myref amplifier and test it. And if you will be using this combination permanently there would be no need for volume control.
 
For excess loudness other option would be... when you assemble the amp you can put(solder) a proper value resistor to input in the myref amplifier and test it. And if you will be using this combination permanently there would be no need for volume control.

Resistor will color the sound will it not? and also mess with impedance matching?

Lets build it then face the troubleshooting challenges if any. :) Anyways my nad 325 is there for late night listening. :eek:hyeah:

Cheers
 
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