What is the RIAA curve from your Phono Preamp? Best PreAmp you never heard of

[@fredflintstone8048]

Hey Eddie. Great presentation. One thing I think you didn't mention was the main reason for RIAA and that was to be able to get more music (play time) on a record. The low frequencies required more groove width to properly represent the low frequency amplitudes, so to be able to narrow the grooves in order to get longer playing records, as the frequency goes down, the amplitude (groove width) would narrow. The RIAA curve would restore the frequencies to their 'normal' amplitudes. Basically a sort of decoder to restored the narrowed, 'encoded' vibration patterns represented by the narrowed groove. Hope I made sense there.

[@KissAnalog]

Thanks for your great feedback!

[@MichaelBeeny]

Plus the HF is boosted on record and cut on playback in an effort to increase the signal to noise ratio, as most hiss and noise from a disc tends to be in the HF band. Lower frequency noise is less noticeable. The S to N ratio is still quite poor at around -40/45dB. On a good day! The 2-step curve is made like that for ease of circuit design, one circuit for bass lift and another for HF cut. An interesting point is if the cartridge is a crystal or ceramic type, it does NOT need RIAA EQ providing it is feed into a high impedance of 1-2 meg ohms. Perfect for old cheap valve amplifiers. Because rumble and very low frequency noise can give excessive cone movement on the bass loudspeaker drive unit, The RIAA should have a very high roll off at about 30Hz and below. Nothing is recorded on the disc at that frequency anyway. Without this the amplifier can run quite hot producing high powers into the loudspeaker at sub sonic frequency's, very common in Jap amplifiers of the day that gave the frequency response of the phono input as 7hz- 20Khz. Looks good but a bad design.

[@KissAnalog]

@@MichaelBeeny Thanks Michael for the great feedback!

[@andymouse]

That's a great looking curve and looking unit...cheers.

[@KissAnalog]

Thank you!

[@waltercheatle1794]

Hi Eddie, Great topic. The RIAA curve (Recording Industry Association of America) was developed because of the mechanical limitations of recording music tracks on vinyl. At low frequencies, a needle would be required to make fairly high excursions and would exceed mechanical capabilities of recording and playback equipment of the time. Vinyl records were thus made with the low frequencies de-emphasized and the higher frequencies accentuated. This high frequency emphasis followed by attenuation during playback pushed the noise floor (hiss) lower. The low frequency boost during playback meant that the turntables needed to be fairly rumble free.

[@KissAnalog]

Great feedback! Thanks for the info! You guys are helping a lot;)

[@versace885]

Hi Eddie, Thank you for the articulated discussion on this Issue. Great video.

[@KissAnalog]

Thanks so much!

[@jstro-hobbytech]

Very cool video. I love that scope man. Use it more haha

[@KissAnalog]

It is a nice scope - but my favorite is the Picoscope:)

[@sparkyskinner4729]

Thanks Eddie for another great Vid. Looking forward to you doing the Analysis of the pre amp to compliment the Frequency response that you've completed here. Looking at the Distortion etc, will be interesting. Looking forward to that one. Ya, the RIAA curve is a bit of a brain wrap for sure. And then there are the different "curves" used through out the years. Wasn't there a British Curve too ? The RIAA was the American record company curve !

[@uni-byte]

The RIAA equalization on playback is there to account for (remove) the equalization applied during recording. The idea behind it is to reduce the hiss and click noise caused by the stylus in the record groove. This noise is much more prominent in the higher frequencies. So what is done is that the higher frequencies are recorded hot (at a higher level) then the playback at those frequencies is reduced. By doing this you get back the right amount of the high frequencies in the original signal and at the same time reduce the audible noise. It had nothing to do with play time. Playtime was parameter associated with the media. Play time, disk size and RPM defined the groove spacing. Long before the RIAA standardization pressing masters were cut with the bass end de-emphasized in order to prevent overcutting into adjacent grooves. However, there was no standardization of this. Every record manufacturer had their own way of doing this and even altered it based on the nature of the recording they were trying to press into disks. Reproduction equipment (record players and amplifiers) were not initially built to compensate for this. The result was that you didn't expect much in terms of ground shaking bass back in the early days of record playback. As the reproduction equipment (electronics, moving coil speaker) got better the hiss, pops and clicks became more and more apparent. This was the impetus for the RIAA to standardize on a way to compensate. The resulting recording and playback curves took into account the need for de-emphasis of the bass that had been an industry wide "practice" from the advent of magnetic disc cutters and emphasize the treble to reduce the noise floor and put this into a standard that could be followed by both the manufacturers of teh records and of the playback equipment. That's my story and I'm sticking to it because it is what happened. I'll say again, the RIAA standard had/has nothing to do with fitting more music on a record. To do that you change the size and RPM of the media to suit your needs then record at levels that will allow to take best advantage of the parameters defining groove spacing for that media.

[@KissAnalog]

Thanks for the great feedback! Great info!

[@pa3eka]

The riaa curve was done to store more music files on a record low freq gives more swing to overcome that problem they antenuate lower freq while cutting the record and when you want to hear it correct you amplify the lowerfreq the same as attenuated it as in the beginning

[@KissAnalog]

Thanks Bert for the great feedback!

[@pa3eka]

@@KissAnalog Done With pleasure Eddy, its cheaper toen a cup coffee 😄

[@KissAnalog]

@@pa3eka LOL

[@KissAnalog]

It is true that this was a way to increase noise to signal ratio. I’m sorry I didn’t explain all the reasons and benefits.

[@gerryroberts662]

My used disk cutter was created befire RIAA.. It supposed to run on a crystal. but cannot get the parts,, it is an RC 36 bell record-o-fone..

[@johnshaw359]

It worked like Dolby NR boost highs then cut to improve SNR and mechanically to cut down on excessive LF excursion, a win, win situation.

[@Hellhound604]

😂😂😂 Apologies… I commented earlier on another video you posted about this pre-amp, and I commented on why the phono-preamp was different to the line-in. Never saw you had another video on axactly that. In my defense, I just discovered your channel, and I am brain-damaged….

[@KissAnalog]

Thanks - no worries. I'm happy to have you here ;)

[@RCook-iy4xk]

When are you going to tell us how you think it sounds?

[@KissAnalog]

Thanks for asking! I did tell a story in a video where I presented this preamp and talked about how good I thought it sounded. I might need to use it with my amplifier projects so I can see how it sounds to me now after all these years. Here’s the link to the other video: Best PreAmp you never heard of - A FET PreAmplifier - the QMI GC20 Reference Standard kzbin.info/www/bejne/q4KthWV6obmqmpo

[@FileFixer007]

RIAA curve in almost any relatively good phono preamplifier have good precision and it follow RIAA standard but best phono pramplifier in the world can't fix it unmatched right input impedance and capacitance for flat frequency respons thru all audio spectre. Sadly that many people with expensive turntables, phono preamplifiers and other audio gears don`t know how much only little wrong input matching can degrade sound on output. Also many, to be precise, almost all phono premplifier don`t have any ability for adjusting impedance and capacitance on preamplifier input side. When I buy AT-440MLb cartride I decide to experiment with input because that almost all reviewers said that this cartridge have tiny bass and very loud high tones. At the end in my experiment with more then fifty audio tests with different adjustments I realise because that sometimes I fix and adjust many turntables I need to DIY one phono preamplifier which is flexible for different phono cartridges. Result is phono preampifier which have DIP switch with more than 96 combination on input impedance. For aligning tonearm I made custom protractor for any tonearm and turntable. Also making custom XLS cartridge resonance In specific tonearm calculator. I have many conversations and posts about tests on VE and Audiokarma forums on that thematics. Euipment what I use for all test are osciloscope, multimeter, ARTA software, SB Audigy 4 Pro sound card (need calibration before measuring), computer and few more little handy tools for adjusting cartridge and tonearm.

[@KissAnalog]

WOW - thanks for the very interesting feedback!

[@niftybass]

Eddie, what's your last name? When you introduce yourself at the beginning of videos, I can't figure out what you're saying your last name is.

[@KissAnalog]

LOL I can see that;) It is Aho (like Ahh - ho) (it came from my Grand parents who came here from Finland).

[@niftybass]

@@KissAnalog That's actually really cool. Close-ish: I have family from Holland (immigrated here in the 1800's. And (you probably already know): Linus Torvalds began writing Linux at the University at Helsinki.

[@Kris_M]

You might want to lock the focus on the camera when you're gonna move your hands in front of it all the time.

[@KissAnalog]

Thanks I’ll have to do that.

[@peteb2]

Great seeing the GW-Instek earning its keep Eddie. As others have said...your camera needs a manual set & lock button for focus however....

[@KissAnalog]

Thanks for your feedback! I'll have to work this out;)