John Curl's Blowtorch preamplifier part II

[Kindhornman]

Christophe,
You have to remember that I am from California the car capital of the world. If it existed and it wasn't from behind the Iron Curtain we had them. There are few cars that I haven't seen here at some time, we are car crazy here even if we have the highest pollution standards of anywhere in the world. I've been driving European cars since I was 16, Mercedes, my sister had BMW and many American hot rods. We do know our cars. I can still remember early Alfa's and many other Italian cars and most anything British or German. French cars have been more rare but we have them also. I remember the early Citroen"s well, they just were so different they stood out. We of course had all the early Volvo's and many other cars also. This is car paradise, we have just about any collectable car in the world here somewhere in somebodies garage.

[wayne]

I have a friend with a business of exporting European autos back home. A very large portion of 911's came to southern California about 20% if he is correct.

[SY]

Can we get back to discussing Pepsi?

[wayne]

Well I have discovered Coke Zero instead of Pepsi. Renewing my Pilot medical has me looking at my weight.

Back on topic for analog volume chips the Maxim DS1882 is OK as is the very nice NJR Muses 72320. No op amps built in use what you want. I measured and listened to more than a few types and like these. They are small, accurate and repeatable with good matching. Hard finding quad pots that can do this these days.

[Chris Hornbeck]

Should a truly all-out effort at gain control include attenuation at more than one signal path location? Or variable closed loop gain of some stage(s)? To optimize "gainstaging".

Thanks,
Chris

[john curl]

I got 95,000 mi from my Renault Dauphine before I sold it in good condition. However, I learned that extra care could only go so far. Nobody told us that the Renault Dauphine had a limited lifetime. The VW Beetle cost just as much at the time, which would have been a wiser purchase.

[Esperado]

Originally Posted by wayne

Back on topic for analog volume chips the Maxim DS1882 is OK as is the very nice NJR Muses 72320. No op amps built in use what you want. I measured and listened to more than a few types and like these. They are small, accurate and repeatable with good matching. Hard finding quad pots that can do this these days.

It seems the NRJ muse need caps in the signal path ?
I would be interested to know what devices you had tested, and your results. Including your version, of course :-)

[Nelson Pass]

Originally Posted by Kindhornman

Vacuphile,I think I would rather be in the Dauphine than an Isetta any time.

I grew up in a household with an Isetta, a Dauphine, a Corvair, a Fiat, a
Kaiser and a pink '59 Cadillac.

MuuuuHahahahahaaaa...

[qusp]

Originally Posted by BV

Yes,analog chain S/N, but not the ratio Signal to (D/A conversion artifacts+I/V + LP filter noise), which is the case with digital domain attenuation, and is subjectively much worse..
qusp
I am using preamp with gain 6dB, power amp with gain about 30dB. Do You mean, that it is too much? And normal listening level is somewhere between -30 to -20dB at preamp.

My dac is 132dB SNR to start with, its internal DSP (the ES9018/12/16) uses 48 bit calculation for the digital filter and volume control. and then there are the methods in software with 64bit floating point calculation, leaves me quite a bit to play with wouldnt you say?

the actual gain needed will vary on room, speakers etc.
what i'm saying is, that if your normal listening level is more than -30-40db less than what you have, you have to much gain and it will affect your sound quality whether using digital attenuation or not. if using digital attenuation with a sensible amount of gain, you shouldnt/wouldnt be able to hear any artifacts.

so basically if you build your system using correct principles there should not be any situation where it effects the output and if you create a situation where it does, its user error, rather than the fault of the digital volume control.

remember we are talking about digital source here, or at least I am. +30dB of gain puts me into kV territory; can your poweramps handle +30dB of gain on a standard line level source without clipping?

No.

Apple to apples.

[john curl]

Today's power amps have a gain of 28.2 or or 29dB. This is the THX standard.