Hi guys, I am planning on making a guitar effects unit, but as i want it to be 'customizable' i thought of not using one single op-amp but many between which i can switch. That means using some switches.. The op-amps are going to be in sockets.. And i was wondering - can the switches and/or the sockets and/or the wiring between them introduce extra unwanted noise, hum, etc. ???
If you put the switches too far from the circuit, then yes the long wires could pick up signals from the power supply or elsewhere, resulting in hum. So it depends on your construction layout really.
IC sockets are no problem but if you plan on doing a lot of swapping of ICs, then you should get good quality sockets, otherwise the contacts could become unreliable after too many remove/insert cycles.
IC sockets are no problem but if you plan on doing a lot of swapping of ICs, then you should get good quality sockets, otherwise the contacts could become unreliable after too many remove/insert cycles.
It's always a good insurance with any switches or socket to give a quick squirt of WD40 or switch cleaner, this helps to reduce any oxidation of contacts.
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Hi,
I cannot see it all, switching op-amps will make no difference to your
audience at all, basically a load of useless switches on your unit.
Yes all the extra wiring will cause issues, probably mainly with stability.
Pick your op-amps carefully and stick with them, concentrate on effects,
e.g. its easy to modify the over drive characteristics of any op-amp,
and this circuit will not care much about whatever op-amp is used.
rgds, sreten,
Good quality sockets (3 blades or more eg Samtec Tiger Claw) or ZIF (zero insertion force) should have no problem.
I didnt know sockets had a noise floor, most I've seen are passive devices, and apart fro adding a bit of stray (or parasitic) LCR into the circuit, thats it, they do not have a sound.
I didnt know sockets had a noise floor, most I've seen are passive devices, and apart fro adding a bit of stray (or parasitic) LCR into the circuit, thats it, they do not have a sound.
WD40 will get gummy with time -- it's not for electronics.
Some phenolic wafer switches seem to pick up a lot of dirt with time, so I've been using the sealed ones from Alpha -- SR2611F-0205 is double pole, 5 positon.
There are machined headers with 0.100" spacing which you can snap apart if you can't decide whether you'll be using 8 or14 pin IC's.
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Good point about WD40, also youd probably never be able to solder the board again. You can buy special contact greases etc, but not real good for what you have in mind and they are expensive.
I'll take back what I said about noise and IC sockets, we have found that the weakest link in any eletrical assemble are connectors and sockets. Sockets are OK for a few insertions, even then the added resistance can be milliohms. Even with good quality components after a few uses things get worse. This is not only down to the sockets or connectors, but how we shove things in, and out. Even with all the care in the world and the best tools; pulling an IC out of a socket it fun, you strain like mad, trying to pull it out square, and then as it releases you smack yourself in the face as you cant re-act to the change in force fast enought. Its this final movement that tends to damage the contacts, its off axis to the prefferered travel. Zif sockets over come this problem, but add thier own, less clamping force etc, you move a lever to bring the contacting faces together, whereas with claw type sockets you force the pin in, bending the metal contact, creating a bigger point contact force.
I'll take back what I said about noise and IC sockets, we have found that the weakest link in any eletrical assemble are connectors and sockets. Sockets are OK for a few insertions, even then the added resistance can be milliohms. Even with good quality components after a few uses things get worse. This is not only down to the sockets or connectors, but how we shove things in, and out. Even with all the care in the world and the best tools; pulling an IC out of a socket it fun, you strain like mad, trying to pull it out square, and then as it releases you smack yourself in the face as you cant re-act to the change in force fast enought. Its this final movement that tends to damage the contacts, its off axis to the prefferered travel. Zif sockets over come this problem, but add thier own, less clamping force etc, you move a lever to bring the contacting faces together, whereas with claw type sockets you force the pin in, bending the metal contact, creating a bigger point contact force.
Forgot, sockets also gets dirty, usually the PCB they are on is mounted horizontally with the sockets facing up, dirt, grease, nicotine etc all find their way into those tiny little sockets. So there OK for testing and general lab work, but for something that is get used a lot in not the most benign circumstances I'dd solder in the chips directly.
Have Fun
Marc
Have Fun
Marc
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