Bass Guitar Amp IC Recommendation

Thread Starter

MasterG

Joined Jan 18, 2022
9
I want to power a "400w" 16 Ohm Speaker (is not 400w, that must be some branding trick, but at least is around 100w, see picture below).
This will be a simple bass amp project (maybe some 3-eq tuning diagram recommendation also) the imput is a passive bass guitar,
Already tested the speaker with a TDA2030, it handles bass frequencies well, but at low volume (TDA 2030 is not particulary good in that sense with a low input like a passive bass, and a preamplifer didnt help a lot) a parallel capacitor in the inverting input helps with that, but then is a Cheap Fuzz pedal+amp and i'm not aiming for that (sounds cool tho).
My only limit is the budget(low as possible, thats why i am using that speaker in the first place).
Any IC recommendation will be good with pro and cons if possible, but it has to be at least commonly available, 3rd world country.
I already have:
-110-12V 3A Transformer
-LM350K (Voltage regulator like the LM317T, but better, 3A,and in a TO3 package)

248302648_4700075736694677_5558445383975239605_n.jpg
 

Ian0

Joined Aug 7, 2020
5,113
A 12V transformer will give a rectified output of 17V. You might get 15V peak-to-peak output from an amplifier, that's 5.3V rms, which would would give 1.75W into 16Ω.
I have a complete bass guitar combo project in KiCad, which you're welcome to, but you will need a higher voltage transformer.
 

Thread Starter

MasterG

Joined Jan 18, 2022
9
A 12V transformer will give a rectified output of 17V. You might get 15V peak-to-peak output from an amplifier, that's 5.3V rms, which would would give 1.75W into 16Ω.
I have a complete bass guitar combo project in KiCad, which you're welcome to, but you will need a higher voltage transformer.
well if you can share it, it will be good.
The transformer is actually a 6 wire in this configuration

220----l l12
110----l l0
0-------l l12
So it should handle 24V at 3A right? i am not sure at all because well, as most of the parts (and the speaker itself) was found on the street/ taken from electronic waste
 

Ian0

Joined Aug 7, 2020
5,113
So it should handle 24V at 3A right?
That's better. Now you have 7W!
Reduce the values of R5 and R6 to 220k. They set the preamp supply voltage, and you don't have as high transformer voltage as I used.
You will also need a 1k resistor between Q7B collector and earth. I forgot it, and without it Q7B will overheat if the amp is driven into clipping.
I bet you won't have all the Kicad symbols and footprints that I have used, but I'm sure someone on this forum will know how to export the project with all its footprints.
 

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LowQCab

Joined Nov 6, 2012
2,045
I realize that You may not have many resources to choose from ........
Maybe You might run into a Home-Stereo-Receiver in the trash ???,
this would be my first recommendation.

The actual Amplifier is the easy part,
but the Power-Supply for the Amplifier is the expensive part.

Ideally, for a Bass-Guitar,
You would want a massive Amplifier that would never be driven into "Clipping",
then add Distortion and other Effects with Pedals, or,
a LapTop-Computer with Guitar-Effects-Software.
.
Here is a Schematic for a cheap High-Power Amplifier.
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100-Watt    Bridge Amp 1 .png


Or, these are in stock a DigiKey for ~$6.oo .........
https://www.digikey.com/en/products...B/3945921?s=N4IgTCBcDaICoBECCB2MA2ArAIRAXQF8g

This Chip will work in a Bridge configuration with a 16-Ohm Speaker,
( an 8-Ohm Speaker may cause it to smoke ), and produce approximately ~60-Watts.
You still need a Plus & Minus 30-Volt Power-Supply to go with it.
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Last edited:

MrChips

Joined Oct 2, 2009
26,089
You don't need voltage regulation for an audio amplifier. Also you can disconnect the HF speakers and the crossover. You don't need these.

I built a bass guitar amp from a car power amp. The dual channels are bridged for more output power to one speaker. You will need a preamp to boost the guitar signal to line input level. The beauty with a car amp is that it runs on 12V. You can use a sealed lead acid battery (SLAB) or a car battery for outdoor playing.

Buena suerte!
 

Audioguru again

Joined Oct 21, 2019
4,680
Your old 16 ohms speaker was designed to be driven by an old vacuum tubes amplifier that has an output transformer with a 16 ohms output.
A modern solid state amplifier does not use an output transformer so the output power into 16 ohms is low.

Your TDA2030 amplifier uses a 48V total supply voltage which might produce only 8W into 16 ohms at clipping.
The amplifier schematic you posted uses high current Mosfets for it to power 1 ohms, 2 ohms and 4 ohms speakers to a much higher output power.
 

Thread Starter

MasterG

Joined Jan 18, 2022
9
I realize that You may not have many resources to choose from ........
Maybe You might run into a Home-Stereo-Receiver in the trash ???,
this would be my first recommendation.
Actually thanks to this recommendation today i called a friend that does work at a E-Waste site, he wasn't there today(sunday) but he indeed told me that there is a vintage non-working (but it does turn on) Sony Audio Amplifier, he doesnt know the model but its something like this, i dont know prices but because it doesnt work it should be around $15
 

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MrSalts

Joined Apr 2, 2020
1,762
Actually thanks to this recommendation today i called a friend that does work at a E-Waste site, he wasn't there today(sunday) but he indeed told me that there is a vintage non-working (but it does turn on) Sony Audio Amplifier, he doesnt know the model but its something like this, i dont know prices but because it doesnt work it should be around $15
You might find that a cheap (used) subwoofer would work even better as a bass amp.
 

LowQCab

Joined Nov 6, 2012
2,045
You might find that a cheap (used) subwoofer would work even better as a bass amp.
.
Actually a Bass-Guitar-Speaker needs to have a wide Frequency-Response.
As bad as the Speaker is that we are currently talking about,
it might work-out just fine for Bass-Guitar, as far as """Tone""" goes, Piezo-Tweeters and all.
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MrSalts

Joined Apr 2, 2020
1,762
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Actually a Bass-Guitar-Speaker needs to have a wide Frequency-Response.
As bad as the Speaker is that we are currently talking about,
it might work-out just fine for Bass-Guitar, as far as """Tone""" goes, Piezo-Tweeters and all.
.
.
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Yes, but since he is interested in doing some work, adjusting the filters is the easy part, the beefy transformer and class D amplifier of most subwoofers will be a much better starting point than an old "Sony compact audio receiver" at 30W/channel. A bass amp is no fun at all unless you can feel some thump in your chest - 30W @ 8ohm amplifier into 16 ohm speaker will not make much fun.
 

Thread Starter

MasterG

Joined Jan 18, 2022
9
Update: these are the exact models, the top one does work (fully) but the bottom one doesnt even turn on, unless i buy them i can't open them, but for $20 at least the transformer is worth it isn't it?
I found the manual of the top one also with the diagram if any modification is needed.
 

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MrChips

Joined Oct 2, 2009
26,089
I would be tempted to buy the lower priced one (working or not) since you plan on gutting it in any case.
Before ripping out the transformer I would attempt to get it working first. You might learn something from the experience.
 

Thread Starter

MasterG

Joined Jan 18, 2022
9
both of them for $20
as far as """Tone""" goes, Piezo-Tweeters and all.
i already have a small true 15w bass combo amplifier (a proper branded one), but at high volume it lacks bright and clean high tones, it works pretty well if there is no drummer around, but if there is one, it will be impossible to hear the "bright part" of the bass, using both the "on project" bass amplifier + true 15w combo will give me the full range response, doesn't it?
 

LowQCab

Joined Nov 6, 2012
2,045
Sometimes "stacking-up" a whole bunch of different Amplifiers and Speakers can result
in a very interesting sound, ( "Tone" ).

Unless You will be using a Computer with Guitar-Effects-Software,
and You are looking for a particular "effect", or "Tone",
the actual Fidelity of the Speakers is not very important.
But You do need "something" that can produce the Higher-Frequencies of Sound.
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eetech00

Joined Jun 8, 2013
3,150
both of them for $20

i already have a small true 15w bass combo amplifier (a proper branded one), but at high volume it lacks bright and clean high tones, it works pretty well if there is no drummer around, but if there is one, it will be impossible to hear the "bright part" of the bass, using both the "on project" bass amplifier + true 15w combo will give me the full range response, doesn't it?
Does your combo have a horn tweeter? Are you using flat wound strings?
If the speaker doesn't have a horn tweeter, no way for the Bass guitar to sound bright.

Ampeg sells a nice small bass combo (2x10+horn) for about $350.00
 
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