simpler choice is to improve the power supply...
C505/506 in the emitter of the regulators Q503/504
can be increased from the current value of 47uF to 470uf...
C520 and his symetrical (C521?) can be increased from current
22uF to 100uF.....
i dont know if it will work, but it seems from the spectral analysis i saw
that there s power supply noises..
C505/506 in the emitter of the regulators Q503/504
can be increased from the current value of 47uF to 470uf...
C520 and his symetrical (C521?) can be increased from current
22uF to 100uF.....
i dont know if it will work, but it seems from the spectral analysis i saw
that there s power supply noises..
I use Adobe Audition but It was not free...
I'm not arguing that 5532 is not a better opamp, I'm saying that it would be wasted here - look at the schematic and keep in mind what this unit is designed to do.
Also, don't take this the wrong way but you are one of the "magical component" types who puts exaggerated importance on each part. Sure, it's nice to have the very best in each position but is it necessary? Not really.
Absolutely important and theres nothing magical about it, its pure semiconductor theory, exaggerated no, maybe you just used to hifi , sorry Im into high end, its a completly different ball game when it comes to its design ing and knowing which parts and in which way to use the parts is what seperates high end from hifi.
I havent had a look at the scematic yet, will do so.
And in your high end system will we find a unit such as the one being discussed here?
Indulge us, what type of graphic equalizer do you use?
Indulge us, what type of graphic equalizer do you use?
No way Jose, not even a opamp in sight, all discrete, Ive used it as servos but I do so prefer discrete servo but the parts needed are all being discontinued.
Btw, bypass the NE5532 input stage LTP and use a jfet LTP in its place, youll be surprised how good that opamp can be, for a opamp that is.
So here's how I see it:
Rick wants to get this thing working properly - he wants to reduce that awful hum he recorded (over-the-air and my program had no problem picking out the HUGE spikes at mains frequency and its harmonics - see post #32).
Changing the opamps will not do it.
I have a similar unit and I've done some testing on it. It is dead quiet and it has 4 of these terrible opamps in it.
Help him with his problem, don't fill his head with nonsense.
Rick wants to get this thing working properly - he wants to reduce that awful hum he recorded (over-the-air and my program had no problem picking out the HUGE spikes at mains frequency and its harmonics - see post #32).
Changing the opamps will not do it.
I have a similar unit and I've done some testing on it. It is dead quiet and it has 4 of these terrible opamps in it.
Help him with his problem, don't fill his head with nonsense.
If filling your head with nonsense is saying that a 4558 is as good or will make no difference you have much to learn, dont forget you said this even before knowing what the opamps did in the circuit.
As for what to do it has already been said, change the 20 year old caps, replace power supply circuit, it has most probably a simple zener circuit, something better and simple would better the original circuit, like voltage regulator or build simple shunt regulator which is another step up, depends on how much trouble the owner wants to go through.
I still havent had a chance to look at the schematics tough.
It's true I have much to learn but I want to focus my learning in a sensible way. For example: Understanding the limitations of the equipment you are attempting to improve. It's like putting a dress on a pig, changing opamps in this unit - everyone seems to miss my point here (except jleaman back in post#13 oddly enough).
You see an opamp and the immediate urge is to change it out with a better speced one? That isn't smart. The smart thing to do is assess the benefits of any action before you take it.
Look at the PS, it's regulated - it should be very quiet. Changing the caps is the first, easiest step but it still may not solve his problem.
Fix the hum first, then "improve" the design.
Exactly. The hum is not being caused by poor opamps - it's being caused by a bad supply. Dropping in OPA2134's is only going to make it worse, because they will oscillate.
OK all thanks for your input. Tommorow i will begin with recapping the whole equalizer and give the ne5532p a try.
For the powersupply, Do you think it`s beter to build a new one, and to disconnect the old one. First i will give it a try with new caps, if that not works fine, i will build a new one i think. Some suggestions for a really good power supply wit any schematics?
For the powersupply, Do you think it`s beter to build a new one, and to disconnect the old one. First i will give it a try with new caps, if that not works fine, i will build a new one i think. Some suggestions for a really good power supply wit any schematics?
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Use either 7815/7915 regulators or if you want to be a little more posh, use LM317/337. I wouldn't bother with anything more complex than this.
You could simply remove Q503/Q504 and connect the regulator inputs to where the collector pins were, and the outputs to where the emitter pins were.
You could simply remove Q503/Q504 and connect the regulator inputs to where the collector pins were, and the outputs to where the emitter pins were.
Hi Guys.. I know it is an old topic. Just got mine out of the storage and after cleaning all sliders and pots it is working fine although might need to change the bypass.
The spectrum lights are always on lit in full even if there is no input on. Any idea what needs to be changed. Thank you
The spectrum lights are always on lit in full even if there is no input on. Any idea what needs to be changed. Thank you
