Noob Question About TL072 Replacement

[Agung Kurniawan]

Hi everyone
I am a TL072 user, all of my diy stompboxes use 072 on it. either use for booster, buffer, mixer, and filter. even my diy 50W amp use 3 of TL072

I always use 4 stompbox for my gigs. Gaang Preamp, Cyclon Delay, ChoChorus, and Boss MT-2.
the first three pedals is my own signature one when the MT-2 have been moded with 4-band EQ. i love that Boss MT-2 its sounds best if you using Send Return jack on amp head. and im planing to built my own signature 3gain distortion pedal with MT-2 like tone control. and of course, with 072 inside it...
why im using 072? cause it was the only one that i can easly get from the lokal market

I am a Progressive Metal player, for me low noise is the 2nd goal on my tone. im using distortion for my base sound. can you guys recomend me some good op amp to work with less noise but doesnt decrease the sound quality in the same time?

Thanks...

[PRR]

Actually TL072 is generally a great choice for low hiss in guitar circuits.

Further optimization will depend a lot on the specific circuit.

Often the circuit sets the hiss level more than any decent chip.

[ElectricDruid]

If you're using high-gain tones, the noise won't be coming from the op-amps particularly, so as Paul says, you'd need to look at each individual circuit to try and get the best signal/noise ratio out of it. There *are* higher-spec op-amps available than the TL072 (at significantly higher prices) but they'll only offer a minimal improvement if all you do is swap the op-amp.

In general, the principles are to keep the signal level as high as you can going in (so that the signal is loud compared to any noise) and to minimise the required gain (since that boosts any noise that is present). In your situation, that might mean trying to boost your signal early in your effects chain, so you can drive later pedals harder and not need to add so much gain later on (since there will be more noise further down the chain).

Failing that, you're probably looking at noise gates or companding to help keep hiss under control.

HTH,
Tom

[PRR]

> There *are* higher-spec op-amps

Better for some things. Worse for others.

5532 is lower hiss for low source resistances like 5K. It is much worse than TL07x for high impedances like >100K.

There's no magic butter to make everything taste silky-smooth.

[Agung Kurniawan]

guys can you please explain to me the point of campanding circuit? i tottaly dont understand about companding...
and should using tantalum capacitor will reduce the noise?
well, im not disturb by noise cause im set the gain close to 1 o'clock. im manipulate the EQ to get the bold, tight and wide sound... i dont like noise gate. it cut my sustain...

[Keeb]

I'm stating the obvious here

but I think it's worth to add that circuit layout and wiring layout is something that needs more attention the more gain a circuit has. Usually the shorter wire the better and shielded wire (with only one side of the shield grounded to avoid ground loops) is helpful. A "dirty" power supply can also introduce noise into a circuit.

Throwing this in there since you said your circuits are your own design.

[Agung Kurniawan]

im sure there is no ground loop, but sometime my transformer can into very heat after playing for about 5-10 minute...
did this one affecting the pedals?

my PS have 9v and 12v output. regulated PS with CT transformer

[ElectricDruid]

I'm stating the obvious here

but I think it's worth to add that circuit layout and wiring layout is something that needs more attention the more gain a circuit has. Usually the shorter wire the better and shielded wire (with only one side of the shield grounded to avoid ground loops) is helpful. A "dirty" power supply can also introduce noise into a circuit.

Throwing this in there since you said your circuits are your own design.

This is a good point. Decent wiring and shielding is important.

T.

[ElectricDruid]

guys can you please explain to me the point of campanding circuit? i tottaly dont understand about companding...

Companding uses the fact that you get a better Signal-to-noise ratio if you have a louder signal. This is another way of saying you can hear the hiss more when you play quietly because you're not drowning it out.
What companding does is use a compressor to make quiet sections louder before the effect and then use an expander *after* the effect to return them to their original volume (which also decreases the level of any noise). If the compression and the expansion are closely matched, there shouldn't be any overall effect on the dynamics. In practice, compressors and expanders aren't perfect, and you will get noticeable effects - but it can reduce noise markedly.
I wrote a page about it over on my website:

http://electricdruid.net/noise-reduction-with-companders/

HTH,
Tom

[Agung Kurniawan]

ok, i get it now...
thanks everyone