Does anyone know of any 15 Band Graphic Equalizer that does not use Op Amps ? Though I disagree, my good friend does not like Op Amps, so we need to find him an Equalizer that uses discreet transistors instead of Op Amps.
People get such rediculous ideas in thier heads, The little piece of silicon used in a descrete transistor is the same as that used in an opamp in many cases, as with anything the level of quality produced is more about the actual circuit design than the components used.
To get something that doesn't use any opamps will mean it's rather old now and that brings with it a bunch of other potential problems like dried out electrolytic caps and dirty or corroded control switches/sliders which would require a rebuild by an experienced service tech. Of course the other way to avoid opamps is to use EQ in the digital domain, and if doing that it's far more effective to use parametric filters. I think I have an old ADC graphic eq from the '80's that is all descrete but it is a perfect example of the above with some glitchy controls on the front panel
To get something that doesn't use any opamps will mean it's rather old now and that brings with it a bunch of other potential problems like dried out electrolytic caps and dirty or corroded control switches/sliders which would require a rebuild by an experienced service tech. Of course the other way to avoid opamps is to use EQ in the digital domain, and if doing that it's far more effective to use parametric filters. I think I have an old ADC graphic eq from the '80's that is all descrete but it is a perfect example of the above with some glitchy controls on the front panel
What conanski says is actually pretty fair: people get the darned-est ideas in their heads regarding the audio 'purity' of opamps versus discrete component solutions.
Thing is, you (he, the friend wanting a 15 band equalizer) need to understand something about how equalizers work, to begin with. The signals (L + R) are first fed to a unity-gain amplifier to transform a possibly high input impedance source to a low one, which can then drive ... 15 filter channels. That is some load, but no problem for any of 10 different unity amp design choices. OK, now the 15-split signal heads to each filter, which turns out not just to be 'a filter', but kind of a dual filter. Half of which is a band-pass boost filter, and half is a band-pass cut filter. (one can make a zillion arguments why it properly is a single filter, but my experience has been otherwise).
What's a filter then, a bandpass-or-bandcut type? Well by the gods-of-filters ethics, it is something which minimally mangles the signal within the band frequency 'rails' it is designed to be active within. Sounds like I'm spoon feeding a baby? Nope. This bit is actually the hard bit.
For instance, will your bandpass filter attempt to result in minimally distorted impulse response, or the flattest pass band response with hard ... or soft ... skirt fall-off response? Will it be a Butterworth optimal filter, an elliptic filter, a Chebychev filter, a Bessel filter, or one of the fancy-schmancy Rimsky-Flannigan (made up) filters with emerald soldering posts and single crystal cryogenic copper wiring?
Yes, I'm making the usual sport of taunting the thousand-dollar power cord bunch. But this too goes into the thinking, "I don't want an op-amp multiband graphic equalizer" position. Humbug specs. I'm willing to bet the good fellow also wouldn't countenance Korean transistors, Chinese capacitors, carbon film generic resistors, or reverse osmosis tap-water filters. No, no, no, no! Must be refined stuff, since of course, the signal knows that it is being diced-and-minced by Japanese transistors, French capacitors and Russian resistors.
That's the point.
Anyway -- good luck. It is perfectly fine to have / find / deploy an old-school, and definitely long-of-tooth antique graphic equalizer with scratch pots and suspect power supply if he likes. Full to the brim with secret-sauce transistors, capacitors, resistors and inductors maybe.
The secret in the end though is this: his graphic equalizer is an EFX box, designed hopefully to least impact the signal at 'all-zero' position, and creatively relevel the signal when not. His mileage will vary.
Thing is, you (he, the friend wanting a 15 band equalizer) need to understand something about how equalizers work, to begin with. The signals (L + R) are first fed to a unity-gain amplifier to transform a possibly high input impedance source to a low one, which can then drive ... 15 filter channels. That is some load, but no problem for any of 10 different unity amp design choices. OK, now the 15-split signal heads to each filter, which turns out not just to be 'a filter', but kind of a dual filter. Half of which is a band-pass boost filter, and half is a band-pass cut filter. (one can make a zillion arguments why it properly is a single filter, but my experience has been otherwise).
What's a filter then, a bandpass-or-bandcut type? Well by the gods-of-filters ethics, it is something which minimally mangles the signal within the band frequency 'rails' it is designed to be active within. Sounds like I'm spoon feeding a baby? Nope. This bit is actually the hard bit.
For instance, will your bandpass filter attempt to result in minimally distorted impulse response, or the flattest pass band response with hard ... or soft ... skirt fall-off response? Will it be a Butterworth optimal filter, an elliptic filter, a Chebychev filter, a Bessel filter, or one of the fancy-schmancy Rimsky-Flannigan (made up) filters with emerald soldering posts and single crystal cryogenic copper wiring?
Yes, I'm making the usual sport of taunting the thousand-dollar power cord bunch. But this too goes into the thinking, "I don't want an op-amp multiband graphic equalizer" position. Humbug specs. I'm willing to bet the good fellow also wouldn't countenance Korean transistors, Chinese capacitors, carbon film generic resistors, or reverse osmosis tap-water filters. No, no, no, no! Must be refined stuff, since of course, the signal knows that it is being diced-and-minced by Japanese transistors, French capacitors and Russian resistors.
That's the point.
Anyway -- good luck. It is perfectly fine to have / find / deploy an old-school, and definitely long-of-tooth antique graphic equalizer with scratch pots and suspect power supply if he likes. Full to the brim with secret-sauce transistors, capacitors, resistors and inductors maybe.
The secret in the end though is this: his graphic equalizer is an EFX box, designed hopefully to least impact the signal at 'all-zero' position, and creatively relevel the signal when not. His mileage will vary.
I have a Radio Shack GE that - at least - uses inductors in the op-amp circuitry for the upper frequencies. Radio Shack / Realistic. Even they didnt want those nasty 'ol capacitors effecting the high frequency sound. A design that I'd bet trumps discrete with capacitors.
It's for sale, I'd want $50 for it, but its only 10 bands / channel...
It's for sale, I'd want $50 for it, but its only 10 bands / channel...
Maybe DIY yourself into warm tube frequency splitting nirvana? Might have to add bands....
https://www.diyaudio.com/community/threads/vaccum-tube-equalizer-schematic.317272/
https://www.diyaudio.com/community/threads/vaccum-tube-equalizer-schematic.317272/
Use a computer software based equalizer, the music is likely stored as a digital file anyway...
Your friend has no clue, why follow him into his madness?
Not good fo sane people.
If anything let HIM waste HIS time, not yours.
By the way, the music he listens to has already gone through DOZENS of Op Amps, unless he only listens to 50´s Frank Sinatra albums or early Beatles and similar.
The fun and obsessive behavior will start when the op amp type, and brand are discussed.
And capacitor matching.
Resistor tolerance, and brand.
PCB design.
Power supply.
Case.
Front panel design and fabrication.
Sliding pots or rotating?
And so on.
🤣
Buy an old one, less hassle.
Your friend can always find other things to be OCD about.
And capacitor matching.
Resistor tolerance, and brand.
PCB design.
Power supply.
Case.
Front panel design and fabrication.
Sliding pots or rotating?
And so on.
🤣
Buy an old one, less hassle.
Your friend can always find other things to be OCD about.
If your friend is such a purist he should not be contemplating a graphical EQ either.
The speakers he is using the Graphic Equalizer on are a pair of Roger Russell Prototypes. They are a line array made up of 16 small 3 inch drivers per side, and were designed to be equalized. The drivers have no crossovers. I have been trying to get him to go to at least a digital equalizer, hopefully a parametric. But so far he has resisted my efforts to help him.
After I posted this thread, he informed me that he does not want my help! He came out and told me he is not going to buy another equalizer, even though one pair of the speakers he has require equalization. LOL, I know, because he got them from me! I bought them from Roger Russell, who lives over in Orlando. Roger Russell is the ex McIntosh Engineer. They are very tall speakers, and flat would not fit under my listening room ceiling, so I sold them to my friend.
Here is a link to the newer version of them, but his speakers are very similar, but don't use drivers as good as these. http://www.roger-russell.com/ids/ids.htm
They require equalization of course, and were designed that way.
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Bass would probably be flabby because you would have to wire them in a series/paralell configuration, killing dampingn factor.
Unless they were custom made drivers that you could run in parallel and still get 4 to 8 Ohm. Current drive might work better for these.
No wonder that they need an equilizer.
Unless they were custom made drivers that you could run in parallel and still get 4 to 8 Ohm. Current drive might work better for these.
No wonder that they need an equilizer.
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Well, they fit in my very small front room of my house, and they would literally shake the room! Bass was fast and tight, believe it or not. My friend has a big Parasound Amp that has fairly high current to drive these with. If I had not sold them, I would have crossed them over at 80 to 100hz, problem solved, except for the highs
I could (somewhat) understand your friend wanting to use a discrete design, but the reputation for hard, cold, maybe even annoying treble sound from op amps was largely the result of poor designs from years ago. Many of those IC-based EQs were part of lower-tier component lines, and yeah, they made everything sound compressed or just downright gross.
There are many examples of great sound from devices using op amps, and the first to hit the keyboard here are good CD players and well regarded DACs’ analogue outputs. They’re quite simple compared what your friend was after.
A 15-band discrete equalizer that summed flat would be very complex and troublesome to diagnose, if a problem occurred. I’ll echo that a digital-based solution would probably suit the needs of the speakers better than 15 fixed frequency bands.
There are many examples of great sound from devices using op amps, and the first to hit the keyboard here are good CD players and well regarded DACs’ analogue outputs. They’re quite simple compared what your friend was after.
A 15-band discrete equalizer that summed flat would be very complex and troublesome to diagnose, if a problem occurred. I’ll echo that a digital-based solution would probably suit the needs of the speakers better than 15 fixed frequency bands.
My friend is a great guy. However, compared to me, he is a new audiophile. I TRY to help him, but it seems to strain our friendship. For instance, he has a top of the line Parasound 2200 Amp. I have several amplifiers, including several really good Pro Sound ones. LOL, he think his Parasound is better, because it is "High Current" and my Pro Sound amps are not "High Current" When I explain to him that my Pro Sound amps will drive 2 ohms all day long, and his Parasound 2200 will not, he does not seem to grasp the idea that you can not drive 2 ohms w/o very high current. My friend watches YouTube video's, and that Paul McGowan guy is his guru, LOL
Paul McGowan does not like Non Discreet Op Amps, nor does he use them, probably so he can justify the high prices he charges for his mediocre crap.
I find most all SS power amps sound identical, save for a very small few. Generational testing and recording or measuring the amp under load while driving the speaker is an effective way to truly tell the difference and share it with others. Essentially any well made power amp is good enough for my tastes, and I consider myself picky. I never understood the audiophile obsession around them.
If there was an appreciable change in the presentation it most always originated at line level. This is where I focus my attention in the amplification chain.
If there was an appreciable change in the presentation it most always originated at line level. This is where I focus my attention in the amplification chain.
SAE 2700 and MK 27b equalizers - all discrete with inductor LC filters
will drive 600 ohm load with low distortion. 21 band EQ .
i have 2 that will go up for sales soon, with spare faders etc…
will drive 600 ohm load with low distortion. 21 band EQ .
i have 2 that will go up for sales soon, with spare faders etc…