Bass Guitar Amplifier (Possibly Portable And with a LM386) - Page 1
Forum section: electronics / projects

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 07, 2013, 01:38:41 pm
content: I am learning how to play bass guitar and i have seen many projects with the Lm386 amplifier.I found this onehttp://www.instructables.com/id/Portable-Guitar-or-iPod-Amplifier-Amp-9v-LM3/and i like it but 1st if you take a look at the schematic you will see a tone distortion circuit that uses capacitor and i have no idea how is this going to be connected at my project.Also i would like to know if i can use stereo jack with one speaker im a bit confused with the stereo and mono jacks.......Thank you

author: rsjsouza
author_rank: Super Contributor
timestamp: January 07, 2013, 02:49:37 pm
content: If you refer to the insert at the top right of the schematics (the black box with 5 white switches each connected to one capacitor), it most probably replaces the SPST switch in the circuit diagram.The black box is in fact five SPST switches assembled side-by-side in the same case, therefore allowing to select up to five capacitors. The number of distortion levels can also be increased to 32 by turning on switches simultaneously - which would make capacitors be connected in parallel where its capacitances are simply added.In the example below (taking the minimum and maximum levels on the schematics, and guessing the intermediate ones) you can enable each level or, for example, by turning on 2 and 3 you get a capacitance of 1.1uF./ 0.01uFSW1 |--o o----||---- -> to pin 8 of LM386||| / 0.1uFSW2 |--o o----||---- -> to pin 8 of LM386||| / 1uFSW3 |--o o----||---- -> to pin 8 of LM386||| / 2.2uFSW4 |--o o----||---- -> to pin 8 of LM386||| / 10uFSW5 |--o o----||---- -> to pin 8 of LM386||-> to pin 1 of LM386

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 07, 2013, 02:57:25 pm
content: Quote from: rsjsouza on January 07, 2013, 02:49:37 pmGot it Thank you!!!But will this project output a decent sound and not a farty one?(Thanks )

author: rsjsouza
author_rank: Super Contributor
timestamp: January 07, 2013, 03:18:39 pm
content: Quote from: ChrisGreece52 on January 07, 2013, 02:57:25 pmNo idea... The project is so simple that you can just assemble it and try. Several of these projects can be found everywhere on the net: as an example, check the MXR Distortionhere

author: Deepak
author_rank: Regular Contributor
timestamp: January 07, 2013, 04:50:09 pm
content: Quote from: ChrisGreece52 on January 07, 2013, 02:57:25 pmWhether it's farty or not is a function of the speaker/cabinet you hook it up to.If you're using this to practice in your bedroom it should sound ok - but I wouldn't expect this to keep up if you're planning on playing with other musicians.

author: SeanB
author_rank: Super Contributor
timestamp: January 07, 2013, 04:59:16 pm
content: LM386 is not exactly high power, not even close. It will do a half watt, enough to practice with in a quiet room. If you need more power you will need a more higher powered chip.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 07, 2013, 08:51:33 pm
content: Quote from: SeanB on January 07, 2013, 04:59:16 pmSo what do you suggest me to use for building my project (thank you) also i do not need it to be extra loud the speaker will be in front of me

author: SeanB
author_rank: Super Contributor
timestamp: January 07, 2013, 09:00:52 pm
content: It will be fine to practice with, but if you need more you will have to look into higher power units like a TDA2009 or a TDA2030.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 07, 2013, 09:07:11 pm
content: Thank you i will consider that.

author: mamalala
author_rank: Unknown
timestamp: January 07, 2013, 11:12:34 pm
content: The TDA2003 is also a nice, simple IC. Up to 10 watts, only requires a few parts. Don't forget the heatsinkGreetings,ChrisEdit: Forgot to mention that you can also use two of them in a bridged configuration to get a bit more power. Just google for "TDA2003 bridge".

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 08, 2013, 05:33:02 am
content: I think that the TDA2003 is more or less the same as the TDA 2009 correct me if i am wrong.

author: SeanB
author_rank: Super Contributor
timestamp: January 08, 2013, 06:34:10 am
content: they are part of a family with varying power and current ratings.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 08, 2013, 12:22:47 pm
content: Ok i think that a lm386 and a TDA2009 circuits will work fine for me . Thank you.

author: ivan747
author_rank: Super Contributor
timestamp: January 08, 2013, 01:29:39 pm
content: If you don't use a heatsink on those TDAs they blow up espectacularily.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 08, 2013, 02:45:22 pm
content: OK i will be carefull about this detail

author: SeanB
author_rank: Super Contributor
timestamp: January 08, 2013, 03:08:43 pm
content: They do that with a heatsink as well, the SOA and overtemperature protection on them is not very good, especially on the non SGS ones. The SGS ones still blow up, but will survive reverse voltage for at least a second so a fuse can blow.

author: Deepak
author_rank: Regular Contributor
timestamp: January 08, 2013, 03:43:34 pm
content: Here's a couple of links you might find interesting.http://sound.westhost.com/project27.htmhttp://electroschematics.com/1192/tda-amplifier-circuits/I'd skip the op-amp suggestion in the first link, but he does have suggestions for tweaking the preamp for bass (and other instruments).

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 08, 2013, 05:14:02 pm
content: Quote from: Deepak on January 08, 2013, 03:43:34 pmThank you for the first link (and the second of course but i am not looking for making a big amp but thank you because that sums up the contruction of one .

author: ivan747
author_rank: Super Contributor
timestamp: January 08, 2013, 06:16:32 pm
content: For reference, the Fender Frontman series use a TDA2003. That should give you a reference for how loud these TDA series can be. Schematics are published online, including a bass version.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: January 08, 2013, 06:34:19 pm
content: I found some fender amp schematics for bass guitar too take a lookhttp://www.drtube.com/guitamp.htm#Fender