Which IC makes the best amplifier?

[gary350]

Only problem I have with Google is, it is very slow some Forums have tons of advertisements that take 30 seconds to load. My son told me to try a new browser called IXQUICK it is much faster than Google. Ixquick seems faster than Google but the search engine is not as good. I am not finding the same things with Ixquick as Google. Ixquick is working great for all the places I typically go but not for searchs.

I have been watching YouTube videos on Op amp design and how they work. I need to take notes and learn the rules how they work so I can figure this out for myself. Take a look at this circuit I made some changes. Will this work?

**broken link removed**

 

[audioguru]

An electret mic is a condenser mic that has an extremely high input impedance with a 48V bias voltage stored in its electret material. There is a junction field effect transistor (Jfet) inside the mic to convert the very high impedance to a reasonable impedance. The Jfet must be powered. My circuit powers it from 1k and 47uF filter from +9V and a 10k resistor. This new filter also filters the bias to the input of the opamp to prevent low frequency oscillation called "motorboating (put, put, put ...)".

The 100 ohm resistor at the output prevents the capacitance of a shielded output cable from causing the opamp to oscillate at a high frequency.
Here is my fixed circuit:

 

[gary350]

Hey that looks good. I will build that when my parts arrive from China in about 3 weeks. Thanks for all the help.

The mail man is going to freak out I have 34 packages coming from China for this project and 2 other projects. LOL

 

[Nigel Goodwin]

Hey that looks good. I will build that when my parts arrive from China in about 3 weeks. Thanks for all the help.

If you looked in the sticky in the General Electronics Chat forum, then it's been there for a LONG time :

https://www.electro-tech-online.com/threads/basic-opamp-circuits.35258/

 

[audioguru]

Why buy parts from China with unknown quality (but we all know the quality will probably be absent) when you can order from Digikey or Newark and have name brand high quality parts delivered to you the next day? I hope you don't wanna save a buck.

 

[gary350]

I never heard of Digikey or Newark. I have not bought parts in 30 years. I have loads of parts just not what I need for these 3 projects. I go to the scrap yard all the time those people have no clue what that junk is it is just aluminum, brass and steel to them. I buy a lot of industrial parts for 15 cents a lb. NL7171 tubes are over $1000 each new and I paid about $1 each. I bought about 40 pancake diodes 600 volt 800 amps each paid $2 total. LOL, no project for them yet. I have 3 power supplies 5000 vdc with 3 caps in parallel 18,000. amp each high energy caps charge up to 270,000,000. watts. Discharge sounds like dynamite fun on the 4th of July. LOL I have lots of high voltage transformers 15,000. volts, Lots of SCRs and SCSs rated 400 to 800 amps 600 volts. I have about a dozen variacs or variable transformers some single phase and some 3 phase 15KW, 5KW and smaller. Lots of coffee cans full of salvaged resistors, capacitors, and misc parts. Lots of project I have built over the years on the shelves and under the work bench. On and off I been building a 270KW railgun. I built a coil gun accelerator it shoots a bullet through a 2x4 board. My neighbor calls the police every time I fire up my 12KW tesla coil, it makes 12 foot sparks from the 3 foot diameter sphere, 27 foot circle of sparks in the back yard. I have 8, NL7171 tubes. I have 100s of very large capacitors the size of a coffee cans in boxes waiting to be a project. I have more parts than I can think of. Now that I am retired I can build all the projects I have been wanting to build for the past 40 years. I need some cool ideas for new projects.

 

[Menticol]

Beautiful equipment. Thanks for sharing Gary

 

[carbonzit]

I can see the sign in front of your house: "Dangerous Stuff 'R' Us". Kewl.

 

[audioguru]

Yes, you have lots of good old stuff but you are buying more parts that are cheap with unknown quality from China.
"I will try this new Chinese part, nope it doesn't work. I will try that new Chinese part, nope it also doesn't work. But I bought MANY of them so maybe I will find one that works. But it might not work next week".

 

[gary350]

I always test my parts before I use them, I learned from experience if a project does not work it probably has a bad part then I have to find it and replace it. With a garage and storage building full of salvaged parts they all need to be tested before they get used. I wish I had more pictures of all the 100s of things I have built. I put a forklift motor on a go-kart once with a 750 amp car battery it would GO with the push of a button. The motor had full torque on take off so it would burn rubber like a rail dragster. LOL. Top speed was 35 mph but WOW the G force on take off was amazing. I built several go-karts with mercury outboard 4 cylinder 2 cycle engines with water cooling using 55, 65, and 80 hp engines. These are amazing G force on take off causes my eyes to cross so I have to close 1 eye to see. Hold on tight or it will pull my hands off the steering wheel. 0 to 87 mph in 3 seconds that is top speed with 3.7 to 1 gear ratio and no transmission. Total weight of go kart without my fat ass in there is 218 lbs. Did you know you can super charge a tiny speaker magnet with 1000 turns of #24 wire and discharge several large capacitors into the coil a tiny magnet that would only lift 1 lb before will now lift 2000 lbs but it has a half life of 3 seconds so the power drops very fast, you need to have it attached to a cable hoist ready to lift something to see how much you can actually lift. Here is a photo of my son on a bicycle I built with 2 pulse jet engines on the trailer pushing the bike. Pulse jets are 20 lb thrust each, 1 had argus valves like the German V1 the other had pedel valves. I told my son to take it out on the intestate highway and pass cars. LOL. I wont ride it faster than 45 mph not sure how fast it will really go these engines will do over 200 mph but drag is pretty high and the 2 engines too small for the mass so 80 mph might be top speed.

My computer is causing me all kinds of trouble I need to reboot before I upload more photos. I cant get to photobucket to get the links.

Here is the video.

 

[audioguru]

Weren't your pulse jet engines deafening? There is a video on YouTube of a pulse jet powered go cart that caused a tree to catch on fire. The engine glowed red hot.
When I was young my friends and I made bombs that all went up like rockets and we made rockets that all blew up. Luckily none of us were injured.

I worked for a Pro Audio manufacturer who had many dealers. Our products were so reliable that we did not have a service department.
I designed a fairly complicated equalizer circuit for a new speaker and had tens of thousands made using American ICs. They were all tested with tight spec's before being sold and only two failed.
One had a quad opamp IC mounted backwards and the other had a shorted electrolytic capacitor. The remainder were all sold and none were returned. That is extremely good reliability.
I did not dare to save a buck and use Chinese ICs.

 

[gary350]

This is a home project that is suppose to be FUN. If it works with china parts that is ok. If it were a serious project I need to depend on then I need to make sure I have good parts. I may have all the parts to build these projects but I just don't want to read all the number on 500 Mosfets then look up the numbers online then test them to see if they work. Not sure what I will do with all these old salvages part and I have no idea if they were made in USA or some other country. I have coffee cans, boxes and 5 gallon buckets full of parts. Too many parts to sort them they would take up 20 times more space and I don't have enough space now. It is frustrating to dump out a 5 gallon bucket of capacitors just to fine 1 certain cap then have to put all that back in the bucket. I am getting lazy in my old age. It seams easier to buy new parts they all come in the mail it is like having a KIT then all I do is build it. I can not tell you how many old TVs I stripped parts from 40 years ago. I have sold off a lot of my parts and sometimes I wish I had them all bad. I use to get all the free tubes from the local radio stations I had several 100 transmitter tubes still good but not much life left sold them all on ebay cheap I hope someone has fun with them, now I wish I had a few of them back. If I get serious about a project I can just buy parts on ebay. I like to build and experiment I use to build fireworks, rockets and play with explosives like they were large firecrackers that was 30 years ago. I like experiments that other people don't do except me and a few friends. New experiments are interesting, educational and FUN. I ran an electric fence around by yard 240 x 120 x 240 x 120 = 720 feet of wire then discharge my 270MW cap bank into it. The wire vaporized and the wire is gone in a cloud of gray smoke, it lights up the whole neighbor hood after dark and the BOOM loud as thunder. LOL. The neighbors all know me, they are always interesting in what I am up to so I invite them to see the show and they all enjoy it. If you invite the neighbors to the party they will never complain about the noise.

 

[carbonzit]

I never heard of Digikey or Newark.

I've gotta agree with others here; don't screw around with dubious parts from China, or even eBay. That's Mickey Mouse; you can do better (and it won't cost you much more either). eBay's OK for things like kits, but for components (resistors, caps, semiconductors), go right to the source rather than some random private seller.

Since nobody posted a link to Digikey, here it is. Very easy to find stuff there, especially if you use their parametric search feature; that's a fancy-schmancy way of saying you can focus your search for an item based on lots of different criteria (say, for an LED, you can specify color, voltage, physical size, whether it's surface-mount or through-hole, etc., etc.). Their minimum order amount isn't bad, they ship quickly, and they have damn near everything you'd ever want or need.

That way you know what you're getting. Some (not much, but some) Chinese stuff is even fake! (Not that some of the parts you'll end up buying from Digikey aren't made in China, but they're sourced through legitimate producers, not fly-by-night Web scammers.)

Of course, you should also make full use of all that stuff in your junk boxes, cans, barrels, etc.

Only problem I have with Google is, it is very slow [...]

It's not Google that's slow; it's your computah. Sounds like time for a new one (or maybe have someone look at your network connection or other problem that might be slowing things down).

 

[audioguru]

There is a Chinese manufacturer selling a photo of a protection circuit for a Lithium-ion rechargeable battery cell that looks identical to the real circuit.
But it is not needed for a fake Lithium-ion rechargeable battery cell anyway because the cell is too weak to need protection.

Here is a review of a Lithium-ion rechargeable battery cell from China bought on ebay:

 

[gary350]

I know China batteries are junk I bought some that would not hold a charge more than 2 hours. If I use them right away they are dead in 10 minutes. I complained and got a full refund.

Some of my parts arrived I am confused? Ebay AD says, China and Hong Kong but 2 packages shows they were mailed from Ohio and NC. Are people in the USA selling on ebay and claiming they are in China?

 

[audioguru]

Some people make a profit by buying cheap Chinese junk then selling it at a much higher price on ebay.