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Old 24th August 2010, 08:36 PM   #931
tmblack is offline tmblack  United Kingdom
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I change out speakers all the time so I need something that works without me redoing every crossover, although that would be ideal.
Also small speakers loose bass from wrap around.
I use tone controls rather gently, if at all but a 3 to 6dB might be all thats needed.

Maybe a passive Baxandall-type can be added to the front end.
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Old 24th August 2010, 08:42 PM   #932
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I bet if you go to Rod Elliot's site there would be something interesting.

Expandable Graphic Equaliser

http://sound.westhost.com/project97.htm
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Old 24th August 2010, 10:37 PM   #933
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EQ? Professional grade? Now there's a contradiction. Tons of op-amps in them.
There's nothing wrong with op amps. All the music you listen to was recorded or processed at some point with op amps, including inside the instrument!
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Old 24th August 2010, 10:45 PM   #934
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Quote:
Originally Posted by DavidSchwab View Post
There's nothing wrong with op amps. All the music you listen to was recorded or processed at some point with op amps, including inside the instrument!
there was short period of time when I thought exactly the same ........

anyway - feel free to keep your opinion as long it suits you

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Old 24th August 2010, 11:19 PM   #935
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Originally Posted by Zen Mod View Post
there was short period of time when I thought exactly the same ........

anyway - feel free to keep your opinion as long it suits you

It's not an opinion that all the music you listen to was recorded through op amps. Even op amps used to master and "press" the CDs. That's a fact. So you are hearing the tone of op amps all the time.

Discrete is fine, but it often colors the signal. I make pro musical instruments and electronics like pickups. I use a buffer amp very similar to this JFET circuit, which is a common circuit you will find in the app notes for JFETs. JFETs have a pleasing tone. Tubes have a pleasing tone too, but neither is very accurate a lot of the time, and tubes never are.

But then accurate isn't always musical.

So my "short period of time" doing this is since about 1972. So it's not based on some fad. It's based on real world circuits.

A luthier did a double blind test to see if people could discern or preferred an op amp preamp compared to a JFET. The JFET circuit used is very similar to the JFET BOZ.

Lutherie Myth/Science: A Listening Evaluation
of Discrete vs Integrated Circuit Audio Preamplifiers in Stringed Musical Instruments


Quote:
Abstract
Audio preamplifier circuitry is increasingly used in electric guitars and electric bass guitars. A general preference for circuits built using discrete solid state components vs integrated circuit operational amplifiers appears to be building within the user community for these instruments. A double blind experiment was conducted to determine if users showed a preference between a JFET discrete component preamp and an opamp preamp following a listening evaluation. Results indicate no clear preference for either type.
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Results
The experiment was unblinded and the questionnaires tabulated with the following results. Two (2) subjects found the tone of the discrete FET preamp preferable. Two (2) subjects found the tone of the opamp preamp preferable. Five (5) subjects found the sound identical in both preamps. Five (5) subjects found the two preamps sounded different but that neither one was superior in tone. As the data are so obviously distributed normally about the mean no additional statistical evaluations were performed. Subjects that indicated a preference also indicated that perceived differences were very subtle.
So most of the pro recording equipment uses op amps. So we want the clearest playback equipment.. to hear the tone of the op amps used in recording it. The rest is cork sniffing.
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Old 25th August 2010, 12:26 AM   #936
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I didn't tell that you said anything wrong or untrue , regarding myriads of opamps in signal chain , during music production ;

that issue is beaten to death , and anyone is entitled to have own opinion ;

on the other side - I can't agree with you that either tubes or jfets are music coloring devices ; good stage is good stage , whatever gain device you are using .

maybe you had misfortune to hear only mediocre jfet and tube stages .....

that page you linked to - it's just semi informative , that's why false in objectivity ; there is no any information about power supplies used in evaluation ; anyway - knowing a little about guitar circuits and technology , one can presume that batteries were used ; they're hardly any etalon PSU , at least for me .

besides that - judging any type of gain stage - used for amplifying guitar signal - can be just matter of personal preference for this or that kind of tone - same issue as preference for Trainor or Marschall or Vox or Ampeg or Orange amps ......

apples and oranges , in fact .

I'm doing these things for living little shorter (time) than you , but I'm certainly much shorter in my willingness to proclaim any expertise , as universal truth .

enjoy in your choices
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Old 25th August 2010, 12:40 AM   #937
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that page you linked to - it's just semi informative , that's why false in objectivity ; there is no any information about power supplies used in evaluation
Sure it did... a 9 volt battery. These are internal preamps in the electric bass pictured. They even show the schematic from each preamp.

Also unlike some audiophile tests, this was a real double blind test. All anyone involved new was the switch on the bass said A and B.

I like tubes and I like transistors. I play through a solid state bass amp, but with a tube preamp. The tube is for coloration. It fattens up the tone.

I also have an all tube Mesa Boogie 400+ bass amp. Very hi-fi, but also very different from a solid state amp. Tube amps have output transformers, and transformers color the tone. Not a bad thing, just a fact.

But there is nothing intrinsically wrong with a high quality op amp. You can make some very low distortion circuits very easily. I think they got a bad name back in the day when people used LM741s.
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Old 25th August 2010, 03:38 PM   #938
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Originally Posted by DavidSchwab View Post
There's nothing wrong with op amps. All the music you listen to was recorded or processed at some point with op amps, including inside the instrument!
I listen primarily to vinyl recordings made in the 60', 70's which used real instruments and tube or transistor equipment. The electric guitars and basses did not include built in amps either. Those recordings sound better to me that the 80's recordings which sound thinner and less natural.

My power amp is a giant op amp using discrete transistors!
However I am pleasantly surprised at how good 1 or 2 gain stages in single ended mode can make music sound more natural.
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Old 25th August 2010, 04:37 PM   #939
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Quote:
Originally Posted by tmblack View Post
EQ? Professional grade?
Maybe opamps gave EQ's the bad rap.

Last EQamikaze work out i did was a 3-band balanced 6dB up/down one with discrete JFET input opamps, loosely based on Cello's design and the tone control of the '83 Elektor Prelude.
I'd love to do a stretch limo version with minimum 4-layer (main) boards, preferably 8.
Just not worth a one-off, about as life sucking as constructing a Spyker in the back yard garage.
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Old 25th August 2010, 08:31 PM   #940
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Quote:
Cello's design
Cello's is the first and only EQ I think of whenever someone brings up tone controls in high end. Never heard it myself, but it received a great review.
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