My Experience Building the Ruby/Noisy Cricket

[gaylerj1]

So here are my thoughts/experience on the Noisy Cricket MKII or the Ruby, some of this probably applies to everything.

1. BEWARE OF NTE PARTS!!! I cannot stress this enough. I don't know about their quality or whatever, but I cant tell you this for certain. Their product equivalents do not necessarily match with what you are trying to do. For example I wanted the obsolete MPF102 which is used all over this forum. I went to my local electronics supply store here in KCMO and said I want as many MPF102's that you have. Clerks says yes we got them and comes back with 3 or 4 little bags that say NTE457. I asked him what's this? He told me they're the NTE equivalent (which was at least a JFET anyway). I asked him if he had the data sheet for it. He told me that the only info he had is what was on the computer screen. I was like OK they're like 1$ apiece I'll try them. Long story short, I build the MKII. Would not work! Right away there was a sound like a pneumatic drill when I adjusted the gain. I would however get louder or quieter with the volume pot. Did all the normal stuff; checked my circuit like 20 times, flipped the fet just in case the pinout on the baggy was wrong, bridged solder joints. Basically everything people check before they pull their hair out. I finally pulled the fet out an replaced it with a J113 that I had in an assortment I bought from amazon. Soldered it in and guess what! I powered it on and touched the input jack, BEHOLD, IT SOUNDS LIKE AN AMP!. Plugged my guitar in and was blown away by the little 1/2 watt miracle. Point is, don't settle for what might work, get what has been proven to work. It will save you some serious frustration.
I can verify that the J113 works like a champ!

2. FLUX! I got into a bad habit a long time ago of just dipping the leads of my components in flux, putting a blob of solder on my iron and touching it to the component and pad. This method is quick and reliable especially if all you have is solder without a flux core. UNTIL YOU BUY THE WRONG FLUX! I recently purchased a jar of flux that the label stated was acid free and water soluble. I thought to myself "Hey this will work." Nope. After I built my Noisy Cricket that I finally got working, you can imagine my horror when the leads to my pots started breaking off my board. upon closer inspection there was green fuzz on most of the solder joints that had any stranded copper wire. I actually read the instructions on the flux at this point and step #4 said rinse inside of pipe thoroughly. Yeah not for electronics. So I changed the way I solder. I now use rosin core solder and no flux if I can avoid it. This will save you some heartache in the long run. Not to mention the fact that flux can become conductive and need to scrubbed off with solvent.

3. This was my first foray back into electronics building after about 15 years. I learned a lot during this build. As simple as it is, it's amazing how big of a pain in the butt it can be. I mean theoretically you could slap some pots on an LM386 add power and a coupling cap and it will probably work. But that JFET makes it sooooo much better. So please don't give up. It will eventually work, and there are plenty of people that will be happy to help if you reach out to them. Just remember....DON'T GIVE UP!

[cab42]

Great first post!

Welcome!

Edit: Use sockets for your transistors. This way you won't fry them when soldering and they are much easier to change.

[iainpunk]

hey, welcome to the forum, cool write up, i can certainly relate to some of the troubles you went through.

personally not a big fan of the LM386-based amps, but if you are happy with the results, more power to you!

cheers, Iain

[gaylerj1]

LOL! I registered in 2016 and my first post is in 2021! I should get an award for "Worlds Greatest Lurker".

[iainpunk]

i guess you qualify for the lowest post/day average score on this forum

cheers, Iain