DIY Amplifier for a beginner

[BassBron]

Hi everybody,

I am not sure if this is the right forum compartment to start this thread.

I have built a 15 inch speaker cabinet for my bass guitar.


I need an amp to go on top to drive the speaker.

The speaker is rated at 250 Watt PEP for what it is worth...
120 to 150 watts would be fine

Are there kits, or sites that sell kits, with parts in a 220 volt format??

Wouldn't mind bringing this to a good working unit.

Your input will be appreciated.

[vin*tone]

Tube? Mosfet? Class D module? Do you have any experience? Do you have lots of money and life insurance?

[BassBron]

Vin*tone, thank you for your reply. No valves at this stage. Mosfet, and preferably a pre-printed circuitboard, and components to solder into, which I can mount on an alluminium chassis, that i can bend and cut, and build a box around.
Insurance for what ? I have a tiny little experience.
The box dimensions are based on an old rotting Fender Amp. The porting was done using computer software and 110 mm sewer pipe cut to size. The box is carpeted on the inside.

[SolarMan]

The life insurance is incase you get zapped with hundreds of volts from the output capacitors - I think this applies mostly to tube amps, but I don't know for sure

Nice looking box there!

[Mr. Foxen]

SS amps have pretty low voltage filter capacitors. Can still connect yourself to the mains fairly easily, isn't a big deal if you have an RCD and a healthy heart, and it teaches you to not do that quite fast.

Gonna be loads cheaper to just buy an amp though. Maybe get a preamp kit to go with.

[mbelue]

41hz.com has poweramp kits, these are mainly stereo kits but a few can be bridged such as the amp 10 kit. 220v/110v is all dependant on what transformer you choose. You would still need a preamp though.

[seamonkey]

Have to say that the behringer iNuke is cheaper than DIY
And it's high enough quality that even audiophiles are jumping on them.

Build yourself a rack case to go along with the fine looking cabinet you've made.

You can spend your time in the pre-amp part where the voltages are low and rewards are the highest.

Books on op-amps have all kinds of pre-amp design information. So do spec sheets from chip makers.

PAiA Corporation - Analog Synths, Theremins, Preamps, and More
Has old but interesting designs

There's a lot of discussions on pre-amps and amps at
Solid State Guitar Amp Forum | DIY Guitar Amplifiers - Index

You can design you own pre-amp without touching a soldering iron by looking into ltspice. There's a yahoo group on it and several user contributed designs on many electronic gadgets.

And of course, software modeling is big these days. An iPad or small computer connected to the power amp can open up new possibilities over traditional heads.
Look at
SynthMaker - Modular VST and DSP Visual Programming Environment
You can build your own virtual pre-amp and if it's useful, sell it to others.

[BassBron]

Nice replies, and the pointers you have given me, with advice to consider buying instead of building.

In one of the emporiums, there are some old amplifiers heads (Ashdown) for sale (in good nick) in the 350 Euro range, with all sorts of little dials and meters. The rating of the Ashdown amp is 350 watts, which could be too powerfull and blow my speaker?

I did know that you can buy seperate heads, and I wonder why these amps are being sold without a matching speaker cabinet, nor do I know if those amps have pre-amps?? If I decide or am forced to take that route, what should I be looking out for???

There is a 2nd hand Line 6 spider ll head for sale on a gumtree site for approx 200 euro. The power rating of that amp is 150 Watts. Would this be too low for the speaker that i have built? Then there is the issue of matching the speaker to the amp, or is this a falacy? A lot of unknowns here for me at this stage.

Presently I have a small Line 6 110 compact unit that suffices when we play in the garage.

Regarding the pre-amp, that has been pointed out to me as well. Sea Monkey, thank you for the compliment, and the many sites that you've listed in your reply. Mr Foxen and Mr Belue thank you for your contributions.

[vin*tone]

Originally Posted by BassBron

Nice replies, and the pointers you have given me, with advice to consider buying instead of building.

Yeah - unless you are in for the thrill of building a bass amp from scratch - better to buy. Building would be more expensive.

In one of the emporiums, there are some old amplifiers heads (Ashdown) for sale (in good nick) in the 350 Euro range, with all sorts of little dials and meters. The rating of the Ashdown amp is 350 watts, which could be too powerfull and blow my speaker?

Not unless you crank it. Give the FAQ a read about matching speakers to amps - lots of good info in there.

I did know that you can buy seperate heads, and I wonder why these amps are being sold without a matching speaker cabinet, nor do I know if those amps have pre-amps?? If I decide or am forced to take that route, what should I be looking out for???

All bass amps include preamps. Heads are sold separately to cabs so people can get exactly the combination they're looking for.

There is a 2nd hand Line 6 spider ll head for sale on a gumtree site for approx 200 euro. The power rating of that amp is 150 Watts. Would this be too low for the speaker that i have built? Then there is the issue of matching the speaker to the amp, or is this a falacy? A lot of unknowns here for me at this stage.

Once again - read the FAQ's on power matching. I'd be more concerned that 150 watts may not be loud enough to be heard in your band.

Presently I have a small Line 6 110 compact unit that suffices when we play in the garage.

Regarding the pre-amp, that has been pointed out to me as well. Sea Monkey, thank you for the compliment, and the many sites that you've listed in your reply. Mr Foxen and Mr Belue thank you for your contributions.

[BassBron]

Tested my speaker cabinet for the first time yesterday at one of the local emporia.
The instrument was a Squier passive from the shop, and the head was the Ashdown.
The unit functions, but all the knobs and controls on the amp were intimidating, and the sales person seemed uninterested. So it could be the Squier, my speaker cabinet, the unit was not fully enclosed yet, and at this stage I am not sure whether buying that amp is going to make me happy? The problem with shops these days is that getting stock is risky if it does not move.....

[BassmanPaul]

What was not fully enclosed??

Amplifiers that have a lot of controls can be a bit confusing at first. You have to sit down with the amp and, reading the manual, find out just what each control does. Once you get familiar with the amplifier you'll have learned how to get the tone you want out of the system.

[dhsierra1]

electronic crossover, active crossover, discrete opamp, custom amplifier, passive preamp

have used their kits before, though for xovers. Posters above are right that it's simpler/cheaper to just buy the amp, though a preamp makes sense.

OTOH if you're looking for a learning experience, then by all means give the amp a go. Have done that in the past and learned quite a bit. And the amp turned out pretty good, too

[BassBron]

@ BassmanPaul. The cabinet had its backpanel off so I could monitor the speaker "breathing" when I connected it to the Ashdown Amp.

Ideally a speaker box needs to be fully enclosed to prevent "the wrong airflows/sounds" to muddle in " as it were.

@dhsierra1. Thank you for the link, and I will go and have a look there.

Regarding building the amp, I have recently found a chap who does electronic repairs for a music shop (his forte is mixing desks), who has made printed circuitboards of an amplifier layout. I think he's made six, and has one left, which he said I could have. I believe the design was not his, but "strongly influenced" by a well known brand.

Hopefully I can populate the circuitboard, and mount it on a chassis, and box it.

I think that should be a nice project to do ?

[Oobly]

Originally Posted by BassBron

@ BassmanPaul. The cabinet had its backpanel off so I could monitor the speaker "breathing" when I connected it to the Ashdown Amp.

Ideally a speaker box needs to be fully enclosed to prevent "the wrong airflows/sounds" to muddle in " as it were.

@dhsierra1. Thank you for the link, and I will go and have a look there.

Regarding building the amp, I have recently found a chap who does electronic repairs for a music shop (his forte is mixing desks), who has made printed circuitboards of an amplifier layout. I think he's made six, and has one left, which he said I could have. I believe the design was not his, but "strongly influenced" by a well known brand.

Hopefully I can populate the circuitboard, and mount it on a chassis, and box it.

I think that should be a nice project to do ?

That sounds like a great project! You will have a totally unique rig and the satisfaction that you made it all yourself Go for it.