lumpy wafflesquirt
146 posts
Jan 15, 2010
12:26 PM
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For you techy guys.
I was looking into building an LM386 amp as suggested by Isaacullah and went into my local Maplins with the parts list only to find that they sell a kit for £4.99 although it needs augmenting to be the same as the noisy cricket. I didn't buy it as I then started to think about the other parts I'd need and what I might have knocking about at home.
I then thought about what speaker to use and would it run headphones.
There is lots of discussion here about microphones, but little about speakers. I would think that they must be almost as important as the mic and amp in getting the sound right. I guess most people use a combi amp/speaker, but the noisy cricket will plug into a speaker cab or I will find a speaker and build a box for the whole lot, but what sort of speaker should I look for.
8 ohms, but how big?
or do I get 2x 4 ohms in series ?
or 2 16 ohms in parallel?
Can I just rip a speaker out of an old TV or radio?
do I need woofers and tweeters or just a single cone?
TIA
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Kingley
603 posts
Jan 15, 2010
12:39 PM
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The speaker Ohms depend on the amp. If the amp was 8 Ohm then you could use either 1 x 8 Ohm speaker or 2 X 4 Ohm speakers.
They need to add up to the same Ohm as the amp to be correct.
I don't know the specs of the circuit by Isaac, but I'd suggest sending him an email and asking his advice on the best speaker for wattage, Ohms, etc.
Sorry I can't be more helpful than that. Hopefully one of the guys who knows more about the tech side will see the post and comment.
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isaacullah
579 posts
Jan 15, 2010
12:47 PM
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lumpy: The best 8" speakers I've found are from old organs. You can get them for next to nothing at thrift shops.
For an lm386 you can use big speakers or a cab, but they can also be used very well with small speakers, The beauty of this is that you can build it all into a little enclosure and have a very portable little amp. The best sources for small speakers that sound good for harp are old electronics. TV's are great, radios a little less so (designed for lower volume usually). Old radios will be better than new ones. The best speakers I've found come from old cassette recorders (the big flat ones). Look for 3 to 4 inch speakers. I've also used speakers from defunct computer surround sound systems. the bass drivers from them are really good. the tweeters, less so. Use one 8ohm speaker, or for slightly more volume (two small speakers have more surface area than one small speaker), try two 4ohm speakers in series (adds up to 8ohms). Two 16 ohm speakers in parallel will work too, but they are harder to find.
Good luck!
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The magnificent YouTube channel of the internet user known as "isaacullah"
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tookatooka
1003 posts
Jan 15, 2010
12:51 PM
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Hi Lumpy,
I would have thought that the Maplin K8066 Super Mini Mono 3WrmsAudio Amplifier would have been a better bet. It's only £6.99 for the kit and all you'd need would be battery (power supply 6 volts) and a speaker.
I think the cricket is only about 1W maximum.
You wouldn't need tweeters or woofers at that level of amplification and you'd more than likely get by with a speaker salvaged from an old radio T.V. etc. The majority are 8 ohm and would obviously sound better if mounted in a nice cabinet of some sort.
I'm assuming you are mainly thinking of using it for practice purposes.
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Last Edited by on Jan 15, 2010 12:53 PM
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lumpy wafflesquirt
147 posts
Jan 15, 2010
1:09 PM
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@tookatooka.
looks like it still needs jack sockets, switch, etc. it is an option though.
initially I am going to use an old PC speaker I have and see what it sounds like and then decide whether to house it in a small box with the speaker or have them seperate. possibly with a belt clip.
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tookatooka
1004 posts
Jan 15, 2010
1:13 PM
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Sorry Lumpy, yes it would need those. I wasn't sure whether you were an existing electronics hobbyist who may have had some of those bits already.
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rbeetsme
129 posts
Jan 15, 2010
2:21 PM
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BTW: a crap speaker can ruin a great amp.
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lumpy wafflesquirt
148 posts
Jan 15, 2010
2:31 PM
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@tookatooka
it's been a long time since I've done any electronics, but I think this would be a fun easy project. I have few odds and bits knocking around such as battery clip and a couple of LEDs.
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