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Old 10th April 2003, 08:08 AM   #11
EC8010 is offline EC8010  United Kingdom
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Default If you include the 3.18us, the replay numbers are...

DC 19.909
20 19.272
50 16.944
100 13.087
200 8.218
500 2.646
1k 0
2k -2.583
5k -8.168
10k -13.566
20k -18.979
50k -24.536
infinity -27.543

This does not include the IEC 7950us time constant, which is a naff replay-only recommendation aimed at reducing turntable rumble.
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Old 10th April 2003, 01:42 PM   #12
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Default Here's the table.....

Right from the horse's butt, er, ah, I mean mouth. [joke]
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File Type: zip riaadb.zip (39.8 KB, 62 views)
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Old 10th April 2003, 04:02 PM   #13
stigla is offline stigla  Norway
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Thanks guys!! This is very appreciated!

So, I've been comparing the different suggestions from the different pepole, and there seem to be some disparity between them,

For example for the 50Hz there's -16,96 from Jocko Homo, -16,944 from EC8010, and -17,03 from the excel at Bonavolt's site...

Ive got a -2,50 at 2000Hz, and -2,61 (Jocko Homo) and -2,583 (EC8010)

But than again, theres probably a roughly 0,1dB difference max between the three, Where Jocko Homo's seems to be the "brighter" one, Bona's the "darkest" one and EC8010 in the middle. (but closer to Bona's)

I guess it would be quite meaningless to start making calculations for a filter and then worrying about a 0,1dB difference, but I really want to be shure that I'm using THE one riaa cure as a reference. (despite the fact that in real life my actual curve will NOT be so close to the calculations)

Anyway it is interesting to observe that Jocko Homo's and Bona's equations are almost identical. Why are they not?

Come to think of it, it really IS meaningless to compare the different curves, it really is more important that the final amp plays music that pleases the ear. If I get there by intense calculation of values or lenghty tweaking it makes no differense.

So thanks for the numbers guys! (the 50kHz in particular)
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Old 10th April 2003, 11:49 PM   #14
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Default Mine came from the RIAA.....

So, I assume that it is accurate.

I have trimmed RIAA networks to +/- 0.05 dB, relative to the curve using an FFT with fancy interface. A bit of a pain, even with a passive network. (Feedback one would be harder.)

Most RIAA networks have a hump of about 0.25 - 0.5 dB in the 250 - 500 Hz range, which is hard to take out. Most of our customers prefered the one with the hump.

Jocko
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Old 10th April 2003, 11:52 PM   #15
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Default Riaa.

Hi,

Quote:
which is hard to take out. Most of our customers prefered the one with the hump.
Which would be like having an ever so slight presence effect?

Funny how people don't like it when it's really accurate...

Cheers,
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Old 11th April 2003, 02:04 AM   #16
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It made the bass sound fuller. One dealer was especially upset, until I pointed out that the CD of the LP he loved so much didin't have that flabby bass sound.

After I cured him of that bad habit, I built 2 identical RIAA preamps: except that one had his favourite mystery wire du jour, and the other with wire that was neutral.

"You can keep that one, it sounds all nasty and rolled off in the top end. What is the difference between them?"

Opened the lid, and showed him. It was weeks before he talked to me again.

Little weasel that he is.............

Jocko
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Old 11th April 2003, 02:09 AM   #17
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Default LOL.

Hi,

Quote:
Little weasel that he is.............
Must have been a frog, must have....
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Old 11th April 2003, 06:42 AM   #18
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Quote:
Originally posted by stigla
For example for the 50Hz there's -16,96 from Jocko Homo, -16,944 from EC8010, and -17,03 from the excel at Bonavolt's site...

Ive got a -2,50 at 2000Hz, and -2,61 (Jocko Homo) and -2,583 (EC8010)
Notice that the frequency is not the same in all examples!

If you want convince yourself how it really is, start with one LP-link and then add the dB figures!
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Old 11th April 2003, 07:30 AM   #19
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Default Re: Texas Here I Come.

Quote:
Originally posted by fdegrove
and than...Canada???
Come on up ... my end of Canada is closer to California thou.

And to add something on subject... i like having that top-end additional EQ point.

dave
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Old 11th April 2003, 09:21 AM   #20
stigla is offline stigla  Norway
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Quote:
Notice that the frequency is not the same in all examples!

If you want convince yourself how it really is, start with one LP-link and then add the dB figures!

Hmmm, I'm not really sure I know what you mean? for the first example I used 50Hz for ALL the three numbers, and 2000Hz for all the next numbers...

I DID notice that at 50Hz, I wrote -xdB, it should of course be +.


Very interesting about the "hump" in the 250-500Hz area, though I can't say that I've spotted it...

The phonoamp that I have buildt is quite sharp in the high, so much that my ears get tired. It needs serious trimming, so I've been doing some hefty simulating (yeah yeah) to see what components I should be trimming. (aint got any fancy measuring stuff )

Mine does not invorporate the 3.18us time constant for the moment.

Simulations showed that it had a -18,48dB at 20kHz an -1,97dB at 2000Hz so that'll explain it. (if one would trust the software )
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