John Curl's Blowtorch preamplifier part III

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Bill,
If I had the minidsp I would want to connect an ADC, maybe some people wouldn't care. If digitizing phono, some people might use a SPDIF ADC for that.
Different use case to the one I was proposing. For ripping vinyl the noise floor is laughably high compared so any SRC grot so I personally wouldn't worry.


Regarding SRC4392 vs SRC4382, I have a fair amount of experience with SRC4392, and I hear some distortion that I don't know the exact cause of. After I noticed that I heard from someone else the same basic observation. In both cases it was using the part for SPDIF in and out, which is not the only way to use it. I am also aware that DAC-3 uses an SRC4392 and I am not aware of the same distortion in it, but I also don't know how they are using it. Given the distortion I have experienced, I would be reluctant to commit to SRC4382.

Also, distortion in SRC4382 is given as down at -125dB, down around where if I play around with distortion compensation with ES9038Q2M I hear some slight change in brightness of music. As I said before, I suspect what is audible with music is possibly IMD from a lot of mixed signals. Don't know about SRC chips with IMD and music, but my inclination would be to play it safe and opt to spend $3 per chip for lower rated distortion.

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I can't hear the brownian motion of air molecules in my room so it really doesn't bother me except for a bit of specmanship. As you haven't heard the part in question claiming its midfi seems jumping to a conclusion?
 
Bill when the standard sound level meter reads 65 dBa an instantaneous peak hold meter could show 95 dBa. Or to produce 1 watt average energy would require 1000 watt amplifiers.
Commercial recording I can buy that has that?


So when the band plays louder that peak power requirement might go to 100,000 watts. However your actually don't require that because as the average level goes up your hearing perception shifts to a lower sensitivity.

So with a reasonable efficiency loudspeaker at what I would consider reasonable listening levels 100 watts or so is fine.

Even if you want to listen at 90 dBa average level then one's preference would be for more efficient loudspeakers and require about the same amplifier power.
Mark listens very quietly with speakers that can't take much power. That was my point. 90dBA (you told me off for a lower case 'a' in the past) is waay to loud for me as a ref level. I did get -20dBFS as the ref point for the 65dBA which I hoped would prevent handwavingly inapplicable comparisons with the second violins at the Boston symphony 😛.
 
It would depend on what you want to do with the ADC and what software and drivers are on the computer, etc. I still find it can get complicated sometimes, depending.

Just use it in place of the miniDSP's ADC. On more consideration, I will use its' USB. I will use the Sony HAP-Z1 as primary source (Not TT nor CD) which has wave files stored from HD (uncompressed) files downloaded direct from Masters.

-Richard
 
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Mark listens very quietly with speakers that can't take much power. .

Beside your point is that Mark listens in near field (close to speakers). The cone displacement is very much lower this way and lower listening level also aids in reduced listening fatigue. This minimizes the spkr distortion and also suppresses the room influence . All together, it is much easier to detect any differences.

Under those conditions, the only down side is detecting differences in the bass. Higher spl is needed here for the obvious reason.


THx-RNMarsh
 
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Where is THAT? Magic silver BT hook up wire. Why read and get upset about that stuff. Its like Fox entertainment news. Too much is fake info. In Asia all real info is allowed. Chinese, Russian, Japanese, Arab etc but not Fox "news".

Not that silver isnt different from copper plated steel wire. But directionality could only come from crystal structure is in one direction/asymmetrical.

IMO

THx-RNMarsh
 
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Scott,

CABLES are not wires. Most of the effect comes from the connectors. If you do not use a cleaner like Deoxit on them there is a very clear difference in my measurement gizmo when you turn them around. Even when treated there can still be a bit of effect particularly on thicker gauge center conductor cables.

As to measurement levels dBa spl has a reasonably well defined meaning down to meter ballistics. There is a bit more difference among the meters on peak level.
 
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