ruby/gem/cricket ?? opamp

[LightSoundGeometry]

http://www.ti.com/product/OPA2134

http://www.ti.com/lit/ds/symlink/lm386.pdf

if I wanted to use a nicer opamp shouldnt they work the same? I cant use the inverter on the 2134 like the 386 ..does it need something else I cant see or am missing ? 

the gem/ruby I have on bb is quiet and nasty decay no matter what I do to it ..so i wanted to use a higher dollar opamp but looking at common pinouts I cant get any sound out of anything else but the 386 ..

im confused

[bloxstompboxes]

The LM386 is not an opamp but a Low Voltage Audio Power Amplifier as described in this datasheet.

http://www.ti.com/lit/ds/symlink/lm386.pdf

When used in pedals it is being used very much outside of its normal design parameters or design intentions.

[LightSoundGeometry]

The LM386 is not an opamp but a Low Voltage Audio Power Amplifier as described in this datasheet.

http://www.ti.com/lit/ds/symlink/lm386.pdf

When used in pedals it is being used very much outside of its normal design parameters or design intentions.

im trying to build a basic amp with an IC

and isint the 2134 a "High Performance Audio Operational Amplifiers" with a +/- inverter on one side just like the 386 ?

http://www.ti.com.cn/cn/lit/ds/symlink/opa2134.pdf

i thought I could build a circuit around the two inputs and output similar to what the lil gem does..I am not good with data sheets and cannot get any sound so I guess I just dont understand how to build up an opamp properly ..nothing really on google or youtube for the 2134 i found useful to me

thanks anyway for responding

[karbomusic]

What I did was grab the LM386 datasheet and the 2134 datasheet. I then created the amplifier from the LM386 and the input buffer from the 2134 and it worked out great (if I remember the LM386 could use a buffer in front). I knew of the cricket, ruby etc. but somewhere along the way I had downloaded a bad schematic from the net. I got so frustrated that I went to the original datasheets and rolled my own and even added an fx loop between the buffer/amp. It is now my bedroom practice amp.

i thought I could build a circuit around the two inputs and output similar to what the lil gem does..I am not good with data sheets and cannot get any sound so I guess I just dont understand how to build up an opamp properly ..nothing really on google or youtube for the 2134 i found useful to me

If I remember, both datasheets have an example schematic that you can almost build as-is for a buffer (2134) and amp with gain (386). I will tell you up front that with the 386 you'll likely need a electro cap across the power rails to keep it from going bananas oscillation wise or similar. I forget the particulars since it has been two years but I know something similar is needed.

[induction]

Your confusion seems to be mainly one of technical vocabulary.

isint the 2134 a "High Performance Audio Operational Amplifiers" with a +/- inverter on one side...

Yes.

just like the 386 ?

No, because:

The LM386 is not an opamp but a Low Voltage Audio Power Amplifier

The symbol in the schematic looks similar, but they aren't the same thing. You can't replace a power amp with an op-amp and expect to run a guitar amplifier from it.

If you don't need much volume, you can build any pedal that gives you the sound you like, and use it as a preamp for the Ruby. If you don't push it too hard, volume-wise, the Ruby won't distort too badly, which should solve your problem. If you want more volume than the 386 can deliver cleanly, there are many other audio amplifier chips to choose from, though the builds quickly become far more difficult.

[LightSoundGeometry]

right on, thats what i figured. I had the two functions mixed up .I tried buffering the 386 using the ruby input stage with the FET and had a power filter on it


will try to mess around with it again

I thought opamps had near ideal conditions and didnt need a buffer in front for example? I dont know ..I guess if there were an upgrade and better parts to use for this, someone else would already have a schematic floating around the webs ..I ordered 4 386's from small bear yesterday so maybe my bad sound was coming from the IC itself ..rog artcile goes on and on about how good this thing sounds ..could be my speakers I am trying to use as well ..not sure

[bluebunny]

The 386 isn't really a hi-fi part, and you're playing geetar into it and connecting it to (presumably) a geetar speaker (also not hi-fi).  So putting a £2 op-amp in front is of questionable value (to your wallet).  Personally, I'd stick with a cheap-but-good part (e.g. TL072) if you want to front-end with some kind of preamp.  Or a simple JFET or similar.

Keep the 2134 for your Clay Jones overdrive.  (Personally, also a waste of money, but that's just me.)

[exztinct01]

just a quick off topic question. I commonly see TL072 for applications that uses dual op amp. 2134's are recommended for lowest noise, like for the P27 preamp by Rod Elliott. Can I use 4558's for these applications since I do have a bunch of them?

[bluebunny]

Yep.  You're playing guitars through this stuff.  Low noise is overrated (or irrelevant!).   

[induction]

I thought opamps had near ideal conditions and didnt need a buffer in front for example?

Correct. That's one of the big differences between the 386 and an op-amp. From the datasheet linked above, the input impedance of the 386 is about 50k, which is 200 million times lower than the value quoted in your 2134 datasheet, and 20 million times lower than a simple TL071.

The 386 also has 1000 times higher quoted THD than the 2134.

On the other hand, the 386 has much higher output power and can drive much heavier loads (like guitar speakers).

I guess if there were an upgrade and better parts to use for this, someone else would already have a schematic floating around the webs

There are plenty of other schematics with different chipamps floating around the webs (even floating around this forum). Look for Punch and Tiny Giant. Look for LM3886, TDA7240, TDA2030. Whether they're better for your purposes or not depends on what your purposes are, which you haven't said. Do you want lots of distortion or lots of clean headroom. Do you high volume capability or low volume? How much work and money are you willing to put into the power supply and heat sink? You need to specify your goals before you specify your parts.

..rog artcile goes on and on about how good this thing sounds

My 386 amp sounds fantastic for low volume with an open-back 1x12 cabinet. I use other methods for generating distortion, and avoid clipping the 386.

..could be my speakers I am trying to use as well ..not sure

Yes, speakers will have a huge impact on the sound. What speakers are you using? Run it through a 4x12 cab and you'll get massively different results than if you run it through some cheap, passive, 2" computer speakers.