Flat phono amp

[Walter]

Are Mike Inputs on a Makie sound board the same as a Flat Phono AMP?
I have the CT1000 Balanced preamps and donot hear any difference in sound.

[Craig Maier]

Mic inputs on soundboards such as your Mackie have the correct gain characteristic, but I am not sure if they have the correct terminating resistance which should be 47 KOhms for most phono cartridges. I believe that you will find that mic inputs often have a lower value of terminating resistance, but it does vary a bit from board to board.

You can check the specifications for the input resistance (or impedance) on your Mackie mic inputs and see if they call it out. If the termination resistance (and to a lesser extent, the termination capacitance) is not correct in value, it will have an impact on the frequency response of your magnetic phono cartridge, most noticeably on the top end of the spectrum. If the R value is too low, the top end will be somewhat muted and the sound will be dull and if the R value is too high, the top end will be more sibilant than expected.

Craig

Note: The bottom end of the spectrum will also be slightly effected by improper cartridge termination but to a less noticeable degree.

[Jan Myren]

"Flat" recording

HI!

Have a little question here:

I now feed the sound from the turnable thought the new flat pre-amp CTP 1000 and into the PC.

BUT; may there be any advantages to do any of the sound restoration processes (like de-click or de-hiss) BEFORE adding the "new" RIIA curve or should "new" RIIA always be the first stage before sound restoration?
What is best to use and where or when to use; the "Virtual phono pre-amp" (pre-amp hardware: FLAT, (record type: EUROPEAN 78's) OR the paragraphic EQ and the pre-set: "RIIA phono EQ curve - improved pr."

In the user manual there is also shown an example which increases both the bass and high end, using two Virtual Valve Amps in a multifilter chain (page 6) Unfortunately the pictures are so small that I can not see them clearly. Can you please explain the settings, please?

Hope to hear from somebody!
Have a really nice summer as well!

Regards
Jan
NORWAY

[Craig Maier]

The impulse noise reduction system was designed to operate with a properly EQed signal. So, the system design is based on decoded EQ curves.

On the other hand, I have not experimented with the system on a flat signal comming directly off of the phono cartridge in terms of impulse noise reduction. It does no harm to experiment and see what happens. If the results using a flat signal are not satisfactory, you can always go back and apply the VPA and proceed again.

Let us know what you discover.

Craig

[Jan Myren]

HI!

NICE; but can you please answer those questions also?

What is best to use and where or when to use; the "Virtual phono pre-amp" (pre-amp hardware: FLAT, (record type: EUROPEAN 78's) OR the paragraphic EQ and the pre-set: "RIIA phono EQ curve - improved pr."

In the user manual there is also shown an example which increases both the bass and high end, using two Virtual Valve Amps in a multifilter chain (page 6) Unfortunately the pictures are so small that I can not see them clearly. Can you explain the settings, please?

Regards
Jan

[Craig Maier]

Jan asked:

"What is best to use and where or when to use; the "Virtual phono pre-amp" (pre-amp hardware: FLAT, (record type: EUROPEAN 78's) OR the paragraphic EQ and the pre-set: "RIIA phono EQ curve - improved pr.""

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Answer: The most accurate curves are generated by the Virtual Phono Pre-Amplifier based on a flat input signal. Choose the curve that is appropriate for the material that you are working with. If you have an RIAA LP, use that setting; if you have an early Columbia LP, then choose that one. If you are working with 78s, you can choose between European or American.

Craig

[Craig Maier]

Jan states:

"In the user manual there is also shown an example which increases both the bass and high end, using two Virtual Valve Amps in a multifilter chain (page 6) Unfortunately the pictures are so small that I can not see them clearly. Can you explain the settings, please?"

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I do not see that in my copy of the users guide(s). I checked the DC7 and the DC7.5 version. What version of the users guide to you have? Maybe I am looking at the wrong one.

Anyway, I always use the Virtual Valve Amplifier after I have completed the noise reduction process. Sometimes, I will put two in a multifilter. One example of this would be where I desire to improve both the top-end and also add a "Fat Bass" bottom end. Multiple VVAs can also be used to simulate different types of Valve based amplifiers by using the multifilter. As a matter of fact, there are a bunch of presets in the presets sharing portion of this forum that simulate a wide array of valve (tube) based amplifiers. You can find one of these at the following link:

http://www.diamondcut.com/vforum/showthread.php?t=1851

If you look around the presets sharing section, you will find some more too.

I just found another one which is at this link:

http://www.diamondcut.com/vforum/showthread.php?t=1853


Craig

[Jan Myren]

HI again!

I do experimenting with the Virtual phono preamp right now. What I can hear when using "from" flat preamp "to" European 78's is that very little bass sound is added. See there also are 3 tone controls that makes it possible to "boost" the bass sound. Is it reccomended to use this one, or is it better to boost the bass sound at very last stage, after the basic sound restoration process, I mean when doing VVA and EQ (enhancing the sound).

By the way I have made myself a "enhance multifilter" that I use after the last restoration stage, the CNF. That consisting of 3 enhancers; a 10 bands graphic eq (pre-set "high definition", a paragraphic eq (where the bass are lifted - 100 hz band up to 12.00) and a VVA.
Any suggestions for further improvements?

Since last time I have also experimented with the CNF and found that FFT 4096/overlap 50%, Attac: 125 and Release: 250 and Atten.: 20 is a good starting point. After the sound sample is taken, I just "shift" the treshold line up with about 5 "clicks". After doing some further adjustments with the "blue dots", and put in some more of them, I adjust the attenuation further up until the most of the "white noise" is gone. This use to work very well.
Any suggestions for further improvements?

Hope to hear from you, since I am working on a new CD transfer project and is very close to success!!

Regards
jan

[Craig Maier]

Hi,

The European 78 Turnover (if memory serves me correctly) has a 250 Hz break frequency. The American 78 Turnover is 500 Hz. Thus, the American 78 Turnover will provide more bass than the European one.

But, if you are playing a record that used a turnover of 250 Hz, that is the correct setting to decode it. Now, it may not have enough bass for your taste, so use the tone controls. Since the bass and treble controls are of the shelving type, they are quite compabatle with the concept of Turnover.

As for your CNF settings, they seem a little aggressive to my taste, unless you are using artifact suppression mode. I also up-click the threshold around 5 to 6 clicks. I usually find that the best attenuator setting lands around 10 in non artifact suppression mode, but it is strictly a matter of personal taste. When using Artifact Suppression mode, I often set the control as high as 50 and obtain good results.

As for your lineup of enhancing devices (EQ's, VVA, etc) that is strictly a matter of taste. Some folks like to bring in the Punch and Crunch effect and many use it with low values of "ratio" in either expander or compression mode depending on the material. Low values of ratio means around 1.5.

And, do not forget to sum to mono when cleaning up 78s. I sum to mono with the file conversion filter (filter menu) right after de-noising the record but before enhancing the recording. This step (sum to mono L+R) provides a few more dB of noise reduction.

Craig

[Craig Maier]

An often overlooked filter/enhancer

Hi Jan,

Here is another suggestion. Few people realize the existance of the Dynamic Noise Filter (under the Filter Menu). When placed in "Enhancer" mode with a frequency setting between 3000 to 5000 Hz and the HF gain set for around 5 or 6 dB, you will find some impressive expansion of the top end of your signal without introducing more noise. Adjust the threshold control for the best enhancement while minimizing noise. Read more about it in your users manual.

Craig

[Jan Myren]

HI again!

Thanks for very valuable answers!

Just a few "clear-outs":

You wrote:
As for your CNF settings, they seem a little aggressive to my taste, unless you are using artifact suppression mode. I also up-click the threshold around 5 to 6 clicks. I usually find that the best attenuator setting lands around 10 in non artifact suppression mode, but it is strictly a matter of personal taste. When using Artifact Suppression mode, I often set the control as high as 50 and obtain good results.
-> I don't use the artifact suppression mode, but I maybe filter a bit "heavy", since some noise use to come back during the enhancement process.

As for your lineup of enhancing devices (EQ's, VVA, etc) that is strictly a matter of taste. Some folks like to bring in the Punch and Crunch effect and many use it with low values of "ratio" in either expander or compression mode depending on the material. Low values of ratio means around 1.5.
-> I have done some experimenting with the punch&crunch but without success. I just ends up with a sort of "pumping" sound. Can you please give me a few hints on how to begin?

And, do not forget to sum to mono when cleaning up 78s. I sum to mono with the file conversion filter (filter menu) right after de-noising the record but before enhancing the recording. This step (sum to mono L+R) provides a few more dB of noise reduction.
-> I use to record the music and do de-click (using EZ imp.n.) in stereo, thereafter convert to mono before I do further processing, using median, bandpass and CNF filters. I was adviced to do that earlier, is that a mistake?

Dynamic Noise Filter and enhancer; see there is 3 different pre-sets. Which one do you reccomend to start up with?

By the way, yesterdays experiments for restoring a 78 rpm records was done using those steps:
Step 1: Recording the 78 rpm disc in stereo using flat pre-amp
Step 2: Virtual preamp: flat pre amp / European 78's
Step 3: EZ Imp. filter
Step 4: File conversion; stereo to mono
Step 5: Median filter
Step 6: Band pass filter; 50/10.000 / 24 db Butterworth
Step 7: CNF; as described in previous post
Step 8: Enhance multifilter; Graphic eq / Parapraphic eq and VVA
Step 9: Analogue reverb (live ambiance) using a reverb box that also give a kind of "stereo feel", much like the Parker-sound
(hope that last stage can be performed on the new DC8, that will make the process even easier for me!!)

That's so far; hope to hear from you again with some comments, since I will continue on the project this evnening. Maybe you'll got the CD for free when it's released.....

Regards
jan

[Craig Maier]

Hi Jan,

Here are some attempts to answer your questions:

-------------------------------------------------------------

You wrote:
As for your CNF settings, they seem a little aggressive to my taste, unless you are using artifact suppression mode. I also up-click the threshold around 5 to 6 clicks. I usually find that the best attenuator setting lands around 10 in non artifact suppression mode, but it is strictly a matter of personal taste. When using Artifact Suppression mode, I often set the control as high as 50 and obtain good results.
-> I don't use the artifact suppression mode, but I maybe filter a bit "heavy", since some noise use to come back during the enhancement process.

Answer: Again, it is greately a matter of personal preference. What may sound the best to you may not sound the best to me or others. So, you have to go with your own taste and judgement. Keep in mind all of the variables such as your sound system, your own hearing acquity, and your personal taste. They are all variables which will drive your settings. I would suggest that you try the artifact suppression mode; it not only reduces artifacts but reduces intermodulation distortion commonly found on worn old records.




As for your lineup of enhancing devices (EQ's, VVA, etc) that is strictly a matter of taste. Some folks like to bring in the Punch and Crunch effect and many use it with low values of "ratio" in either expander or compression mode depending on the material. Low values of ratio means around 1.5.
-> I have done some experimenting with the punch&crunch but without success. I just ends up with a sort of "pumping" sound. Can you please give me a few hints on how to begin?

If you are getting a pumping sound, that is indicative that the attack and/or release times are not adjusted properly and that the ratio is set too high. Start with a ratio of 1.5 (in either compression or expansion mode) and start with an attack time of 50 mSec and a release time of around 400 mSec. Fast music (like pop) will require smaller values of attack and release and slower music (like classical) will require larger values. You need to adjust these parameters until you achieve a good correlation between the time constants and the envelope of the music that you are working with.



And, do not forget to sum to mono when cleaning up 78s. I sum to mono with the file conversion filter (filter menu) right after de-noising the record but before enhancing the recording. This step (sum to mono L+R) provides a few more dB of noise reduction.
-> I use to record the music and do de-click (using EZ imp.n.) in stereo, thereafter convert to mono before I do further processing, using median, bandpass and CNF filters. I was adviced to do that earlier, is that a mistake?


No, that is not a mistake. Some folks will perform the CNF function before converting to mono (and so do I sometimes), but it results vary a bit depending on the source material. But, generally, your procedure is fine.


Dynamic Noise Filter and enhancer; see there is 3 different pre-sets. Which one do you reccomend to start up with?

I do not recall which presets to use, but if you use the actual parametric settings that I called out earlier in this thread, you should obtain a very good result.


By the way, yesterdays experiments for restoring a 78 rpm records was done using those steps:
Step 1: Recording the 78 rpm disc in stereo using flat pre-amp
Step 2: Virtual preamp: flat pre amp / European 78's
Step 3: EZ Imp. filter
Step 4: File conversion; stereo to mono
Step 5: Median filter
Step 6: Band pass filter; 50/10.000 / 24 db Butterworth
Step 7: CNF; as described in previous post
Step 8: Enhance multifilter; Graphic eq / Parapraphic eq and VVA
Step 9: Analogue reverb (live ambiance) using a reverb box that also give a kind of "stereo feel", much like the Parker-sound
(hope that last stage can be performed on the new DC8, that will make the process even easier for me!!)

I see nothing wrong with your procedure. It should work just fine.


That's so far; hope to hear from you again with some comments, since I will continue on the project this evnening. Maybe you'll got the CD for free when it's released.....

I would love to hear one of your restorations. Let me know when one is available!

Craig

[Jan Myren]

HI again!

CNF; have tested out the artifact suppresion mode once again. Maybe I do something very wrong, but very little surface noise is removed and the sound is more like a "tin-can" sound on high values (50 ++) on the att.- control. I am doing testing using a relative nice disc without too much noise. I use it the same way as with the normal mode, with a noise sample and some 5 or 6 "up-clicks" with the treshold line.
I also use attac: 125, rel.: 250, att.: 50 (++), FFT: 4096, overlap: 50.
any suggestion about what I may do wrong? I am very eage to succed using the cnf filter in this "new" mode....

Punch & Crunch; I am now testing it in expander mode, since that's useful for dynamics on 78's, according to the user manual. Ratio: 1,5, att.time: 50, BUT Rel.time om 400 seems impossible since it starts with 0,05 and stops at 2,99. Maybe you meant something else???
Anyway; is it ideal to add this punch&crunch tool into my "enhancer" multi-filter chain, as described in my previous mail?

Regards
Jan

[Craig Maier]

Hi Jan,

Not sure why the CNF in AS Mode is causing problems. I usually set the Artifacts control for around 350 to 500. I set the Attenuation for around 50 to 60 after clicking up the threshold around 6 clicks. Somtimes, I manually move the blue inflection points above 5,000 Hz even more to further reduce the hiss, but it works quite well.

Maybe somebody else can provide some more insight based on their experience.

The Punch and Crunch release time units are in Seconds. Thus, 0.05 = 50 mSec and 2.99 = 2900 mSec. As for whether or not it is ideal to add the Punch and Crunch effect to the multifilter string, that is a matter of personal preference and your ability to obtain satisfactory results with it.

Craig

[quartet87]

Jan, you mentioned that you get artifacts after using CNF. I assume you're referring to "birdies". If that's the type of artifacts you're getting, you might try a method I've discovered which results in no birdies. Bear in mind, I haven't delved into 78's yet...I work only with LP's...but I do use a flat pre-amp in transfer.

I record at a sample rate of 96 and bit rate of 24, then I raise the FFT in CNF to its highest value...16324 if I recall correctly. The combination of a high resolution file with the highest FFT lets CNF be more discriminate...EZ Impulse performs better also on a 96/24 file at more aggressive settings.

In fact CNF is the last filter I use on a file...after impulse and any eq, EZ Enhancer, VVA, high/low/band pass filters. I'll run CNF in normal mode after taking my noise sample and drop the filter threshold line well below the noise floor up to 2 or 3 kHz range, clicking the threshold up as desired on the upper frequencies. Then I run CNF in Artifact Suppression (also at its highest FFT) after taking my noise sample at the same location as the first run, again dropping the threshold up to the point where the noise floor drops down which is a reflection of the first CNF run result. I use Artifact Suppression to smooth out any leftover fuzziness.

Hope this helps.