Ed: I said designed since 1975. You've so far come up with nothing. You seem to have lost your mojo this week!
Thats OK. Not many here have either.
"You will find here techniques and circuits that are available nowhere else."
-Richard
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Why would you use anything else? Having said that, I’ve just done s discrete reg. it that’s not my preferred route.
You were extolling the virtues of the 7805 a few days ago.
Chill Bill,
Just count your fingers!
BTY 1977 was the year of introduction to the market for the TDA1034 which is the basis for the NE55233 and NE55234. This is different than the SBF3a chip also intended as an audio opamp.
Current offerings include what started as National's products; LM4562, LME49710, LME49720, LME49860, LME49600 (actually a buffer). Then what I think started as Burr Browns line; OPA1637, OPA1656, OPA1671, OPA1692, OPA1641, OPA1622, OPA1612, OPA1688, OPA1602, OPA1604. Of course the golden oldies, also post 1975, I think; LM381, LM382, LM387, LM1303, NEC4570, NJM4580...
If you need more I can get into the Japanese SIL opamps used in much of the audio inputs stages of gear that passes through here for repair, or I could go to more websites of folks who market audio products.
Not sure what Scott's idea of marketing might be, but I have been told to expect visits from the manufacturer's sales engineers when I buy more than 1,000 pieces of a new product in the first year.
(These days I am beginning to sometimes buy full reels!)
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Yes of course sighted listening is best then you can apply all the prejudice you want.😉 For the record I do almost none of the listening. Target shooting and my airplane haven’t been the best for my ears over the years despite protection.
No. Please don't exaggerate. I said it sounded better in one particular application verses an LT1963. It was AKM that made the choice to use NJM7805 in that instance, not me.
However, it is true that high performance LDOs (super regs, if you like) when used to power audio circuits with very low PSRR tend to result in audio that does not sound as good to ear/brain as some other types of regulators do. Its a trend multiple people have noticed independently. I did some experimenting with ADM7150 to try to minimize the audible effects and was able to get quite a bit of improvement, but still not as good as some other regulators known to be good for the particular application (e.g. AD797 buffer). Some people may not like the foregoing claim. They may even get very upset about it. I suggest for people to listen and form their own opinions. A lot of bs shouting is neither helpful nor productive, although the shouter may find some emotional relief.
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Quite a few members of diyAudio appear to believe that the DIFET opamps made by Burr Brown (DIFET == Dielectric Isolation Field Effect Transistor) are specifically designed for audio use. After all, it DOES say "Burr Brown Audio" in the selection guide on DigiKey's website. And the prices! OPA627 ($28.37) and OPA2107 ($22.98) have that certain nosebleed appeal: if it costs so much it therefore must be superior.
But a little searching on TI's website uncovers the actual motivation for DIFET processing: electrometer-grade leakage. Not audio, not phonostages: very expensive scientific instruments.
_
Pants on fire: https://www.diyaudio.com/forums/dig...8-ak4499eq-adc-dac-boards-20.html#post5857662
You eventually tried to "fix it" by comparing with the LT1963 (which, FWIW, happens to be yet another crappy linear regulator). Of course, when it comes from you, "comparing" means nothing more than a blank statement.
Noooooooooo!
For a musical instrument, life is good: a piano needs to sound a bit like a piano, and that is that. An amp needs to deal with everybody else in the band, and so does its owner.
Everything for checking L-loaded telephone lines, for eons.
In audio, if at all, just because the instruments were available.
You need some kind of award for being the king of misunderstanding and mischaracterization.
I was not trying to fix anything. I reported a brief experiment I had tried earlier. At the time of the post you linked we were in the midst of an argument about whether to keep or replace the NJM7805 AKM used in the eval board, for use in a new AK4499 dac board design. I argued against arbitrarily using a super reg for the particular application without listening to the regulators under consideration first (as the eval board was designed to support doing). The other side argued there is no need to listen because a super reg measures better. Of course, the other side never bothered to listen.
I don't care if people want to design their equipment however they like. I didn't like them trying to force their personal beliefs on other people though, so we argued. Let the others decide what sound they like for themselves.
Some on your list are not op-amps and "superior sound" is not a verifiable specification, actually meaningless out of context. There is invariably some reuse and/or re-branding there too. Please show some actual evidence rather than marketing copy that for instance a part was compromised for other applications for the sake of audio performance or designed for audio with no other applications. If you actually take a look there are many general purpose op-amps i.e. not micro power these days that drive 600 Ohms in fact many drive 100 Ohms (power permitting).
1000 pieces might get a visit from a local disti rep or field service person looking for what else they can sell. As I said there are little or no margins for simple op-amps in high volume audio. The last sales trip I did was for 10M piece quantities for reuse of ADSL drivers in cell phones.
@Mark Johnson which to me seems to imply that audio is really not a critical application . . . As long as distortion is low enough and the power BW up to standard you’re good to go.
LDO’s have a nasty set of poles (c.f. the common emitter pass transistor configuration) so they do need to be decoupled properly ie with the correct ESR’s and it may be that in some of the DAC implementations this was not considered in enough detail ( seen circuits with XR7’s all over the place on the 3V3 rail), hence the 7805 solution Mark noted which uses a common collector pass configuration and is much more forgiving of the decoupling devices.
Reading the app notes, I always get the feeling LDO’s are troublesome. My preferred weapon is the 7815 with split supplies that I then combine. They are about 1/3rd the noise of a 317.
For low power, low voltage and low noise regs, an LM4562 makes a fantastic linear reg. If you divide down and decouple the 15 V rail, you theoretically can get c. 40 pV/rt Hz at 1kHz, and the PSRR at LF is up at 120 dB.
Reading the app notes, I always get the feeling LDO’s are troublesome. My preferred weapon is the 7815 with split supplies that I then combine. They are about 1/3rd the noise of a 317.
For low power, low voltage and low noise regs, an LM4562 makes a fantastic linear reg. If you divide down and decouple the 15 V rail, you theoretically can get c. 40 pV/rt Hz at 1kHz, and the PSRR at LF is up at 120 dB.
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Gerhard,
The first audio systems around here used telephone system parts and standards. That is why 600 ohms is so common. A bit still around is that many audio amplifiers still have gain setting where 0 VU units or 1.4 volts will produce maximum output voltage. A hangover from the days when radio broadcast stations used telephone lines to connect the studio to the transmitter site. Higher levels would cause unacceptable cross talk to other users.
Scott,
Just because Analog Devices doesn't send out sales engineers, has no influence on others. I have had factory contacts on as little as 25 pieces of a new and not very low cost part.
Yes often it is salesmen who follow up on most products. But I do get to see real degreed engineers. Recently one even had those letters "PHD" on his card.
I was recently surprised to have a visit from the local Digikey salesman. Seems they are getting into local sales offices. So far Digikey swag has been a dry erase calendar, notebooks and a pair of slippers.
Also if it does loads lower than 600 ohms that is fine, but 600 ohms is almost always a reference it can handle profesional audio levels. Just like the aforementioned calibration noise source used with gear that accepts telephone/audio standards.
BTY which items were not opamps? That way we can figure out how many fingers Bill needs.
The first audio systems around here used telephone system parts and standards. That is why 600 ohms is so common. A bit still around is that many audio amplifiers still have gain setting where 0 VU units or 1.4 volts will produce maximum output voltage. A hangover from the days when radio broadcast stations used telephone lines to connect the studio to the transmitter site. Higher levels would cause unacceptable cross talk to other users.
Scott,
Just because Analog Devices doesn't send out sales engineers, has no influence on others. I have had factory contacts on as little as 25 pieces of a new and not very low cost part.
Yes often it is salesmen who follow up on most products. But I do get to see real degreed engineers. Recently one even had those letters "PHD" on his card.
I was recently surprised to have a visit from the local Digikey salesman. Seems they are getting into local sales offices. So far Digikey swag has been a dry erase calendar, notebooks and a pair of slippers.
Also if it does loads lower than 600 ohms that is fine, but 600 ohms is almost always a reference it can handle profesional audio levels. Just like the aforementioned calibration noise source used with gear that accepts telephone/audio standards.
BTY which items were not opamps? That way we can figure out how many fingers Bill needs.
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