op amps for a preamp

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#21
Thanh,
2134 is dual 134
Click to expand...
Yes! I know this. Ryssen didn't mention OPA134. If he ever used OPA134 and he said that he prefer AD847, LT1468---> I will try to use LT1468

@Lineup: I have just finished building PSU with LM337/LM137. Regulated voltage is 10V, protecting diode, 0.1uF tantalium capacitor.
I disconnect my amp to my sound card, set volume to maximum level, --> I can still hear noise. Because I use TL084 ?
I wish I couldn't hear any noise.
 
#23
thanh said:

@Lineup: I have just finished building PSU with LM337/LM137. Regulated voltage is 10V, protecting diode, 0.1uF tantalium capacitor.
I disconnect my amp to my sound card, set volume to maximum level, --> I can still hear noise. Because I use TL084 ?
I wish I couldn't hear any noise.
Click to expand...


I don't think this noise you can hear comes from Op-Amp TL084.

some questions:

1. What amp did you build?
Circuit?

2. How did did you arrange the input components?
Any high frequency filter at input?

3. How are your ground rails drawn?
Ground wires and such.

4. Exactly what 'noise' is it?
Is it hum at lower frequency, like from transformer
or is it 'white noise' with higher frequency.
Like when somebody says: Schhhsssss
 
#26
I'm integrating a preamp/mixer with a 41hz amp6 kit. Therefore, I've got 12V from the amplifier's voltage reg.

What I'm looking for is a single-supply opamp suitable for unity gain application similar to
http://sound.westhost.com/project94.htm
I try to source from Mouser because they're quick and they've treated me well so far. I've found lots of single-source amps, but I lack the knowledge to select the best one.
 
#27
You don"t really need a single supply opamp as most opamps can be configured to use a single supply....

To make an opamp work off of a single supply you have to bias the Input to Vref, which is half supply with can be made useing a simple Voltage divider, You will also have to cap couple the output to prevent the Bias voltage DC offset from the output....


read this...it will help you will useing opamps with a single supply....

http://www.eng.yale.edu/ee-labs/morse/compo/sloa058.pdf



Cheers
 
#29
Opamps do sound very different, and most of them are annoying in one way or the other. Over at Head-fi.org there are always discussions about them, and there are many reviews. Many of us love to hate them😀. My personal favourite at the moment is AD797. It's very "unfatiguing" and pleasant and fairly neutral. It's said to be hard to implement, and I don't think I have it optimal implemented but it still sounds good.
 
#30
Thanks so much for the quick reply and the great link, Minion. I saw an article mention using a dual supply opamp with single supply and a voltage divider, but this is enough to design from. I was concerned about its usability for audio, but it looks like this will work nicely. Time for me to fire up Spice.
 
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