| motocross_mike |
Hi all, my son is a bass player who dosn't earn a lot of money at his "real" job, and has asked me to make him a bass amp in the 200- 300w range. Although the purists would suggest a valve amp, I am more interested in buildig a solid state amp.
I am a radio electronics hobyist who has built and repaired many high powered transmitters etc over the last 25 years, so the construction of this amp should not be a problem, except for locating suitable circuit diagrams etc.
If you know of any suitable circuits could you please post the links for me here ..... many thanks in advance |
|
|
| tschrama |
Hi,
Check ww.sound.au.com for some ideas for such a project.
Regards,
Thijs |
|
|
| li_gangyi |
mike~! if ur son (like me) doesn;t really use the tone controls...coz it's a bass guitar...you could use a bridged parellel schematic...wire a few LM3875s together for 200W...check out ap note 1192 on national's webby...
http://www.national.com/an/AN/AN-1192.pdf
Look for 200W BPA |
|
|
| sreten |
I'll just note a good sounding transistor musical amplifier
for bass is is nothing like a good hifi amplifier in design
or construction.
The feature set you need is quite alien to a hi-fi designer.
TBH IMO its simply not worth trying to build an amplifier
with what is available out there second-hand, and I've
never seen decent published plans for a bass amplifier.
My Peavey mkIII bass head I bought for £120. Its great,
and built like a tank, with a massive heatsink (15"x4"x1")
and eight output transistors for its 175W/ 4 ohms rating.
It also has a seriously large overspecced transformer,
no wonder its still going strong after 20 years or so.
It also has a sound I like, but not remotely hi-fi in nature,
and also has an excellent feature set, input matching,
tone shaping, shelving tone controls + graphic EQ,
effect send/return and a mandatory feature for bass
amplifiers - a compressor to avoid clipping at high levels.
Buy something designed to to the job well, IMO.
:) sreten. |
|
|
| motocross_mike |
Thanks fellas for your replies. I will be looking around on the secondhand market to see what,s around, but failing that I will be making something to do the job. I have already looked at the
www.sound.au.com site and found a 100w amp schematic, but aparently more power is required. I will look into modifying this design for higher power output.
Again thanks for the help |
|
|
| li_gangyi |
| there is actually a 500W specifically desined for bass reproduction...runs class B... |
|
|
| motocross_mike |
| where would the circuit be for the 500w bass amp??? |
|
|
| phase_accurate |
I feel that there is a misunderstanding. An amp for the bass guitar was aked for. The thing from Rod Elliott is a subwoofer amplifier. Not exactly the same thing.
Regards
Charles |
|
|
| li_gangyi |
| I know it ain't but I suppose he could go a bit further and make one outta it...if you get what I mean...it just doesn't have the right processing and tone controls...which shouldn't be too difficult... |
|
|
| motocross_mike |
I have sent an email to rod asking if this amp is suitable as a bass amp, and if any circuit mods would be required for such a purpose. I will let you know what I find out.
I also propose to use the preamp (with the tone controls etc) from his 100w bass amp project infront of the big amp (whatever that turns out to be). |
|
|
| Optical |
Ive used a p3a (now a 500W version on rod site) 'subwoofer' amp with great results..
you will need a decent preamp to go with it though. |
|
|
| li_gangyi |
| the P3a is a hi-fidelity amp designed for use as a "normal" amp...the bass amp runs class B...which wouldn't be really good for "normal" speakers...for a bass amp it works good...u're right about the preamp... |
|
|
| motocross_mike |
| hey optical, would the preamp as part of rods project 27 be considered "good" or are there better designs about, sticking to sorry state (solid state) devices of course. |
|
|
| li_gangyi |
| try looking for a preamp that's based on a "Fender" tone stack...guitars have a different frequency for the tone controls...compared to a HiFi one of course...and yes...Project 27's preamp looks good...not so sure for a bass guitar though... |
|
|
| phase_accurate |
IIRC I have the schematic of an old HH bass amp somewhere.
Regards
Charles |
|
|
| Optical |
| The project 27 schematic looks ok, personally i use a 5 band eq with my preamp, 2 tones controls doesnt usually cut it.. |
|
|
| pessimissery |
I want to build my own bass amp and I cannot cope with tubes
In addition I will use it at home so I don't need a high power range
Can anybody link a transistor amp circuit schematic here
(If you've got a circuit with two inputs (guitar and bass) that would be great) |
|
|
| quasi |
Just a note of caution here when considering power amps. Many of the hifi amp schematics I have seen will simply not survive a bass guitar application. Even those rated at hundreds of watts would fail.
This is because ordinary music is nothing like a bass guitar note which is more like a sine wave coming from a signal generator. A sustained note at high power (even half power) would blow a seemingly robust amp. This is why the peavey rated at 175 watts has eight output transistors where a 175 watt hifi amp would only have three or four.
When testing the amps I have posted on this forum, I limit full power sine wave testing to a few seconds only. I imagine a young bass guitarist would exceed this "test" easily. It takes a lot of power to re-produce bass guitar notes cleanly (and they still want to crank it higher)
If you feel inclined, check this thread. There is an option for a power amp that can handle your need. You will definately need the 10 FET board for 500 watts.
http://www.diyaudio.com/forums/show...7022#post797022
Use this chart to determine the power configuration http://www.diyaudio.com/forums/show...4932#post794932
Cheers & Good luck |
|
|
| Nigel Goodwin |
For a preamp, you might have a look at This one which tends to get mentioned a lot!.
I think the suggestions of what's needed are perhaps getting a little complicated?.
It's really quite simple, you need a power amplifier that has a good frequency response - a HiFi one 'would' be fine, except for the sustained high power that it's likely to be subjected to. So you tend to need large heatsinks, lots of output transistors, large mains transformer, and big capacitors.
Preamp wise, it's really a personal thing, but as I see it, you want a flat response preamp, with adjustments available, that are approiate to a bass guitar - notice that the link I posted has a three band EQ (with selectable mid), plus a couple of switches as well. |
|
|
| motocross_mike |
Thanks for your input fellas, but the fire has gone out of this project. My son bought a 500w Bheringer Bass amp about 6 months ago. I have a lot of other projects on at the moment so will not be continuing with this one...
Again thanks for all the input.
By the way I picked up a little Lux ST77T/ 2 Stereo amp in very good condition. I dont know if I will keep it as yet. any iodeas what it may be worth? |
|
|
| pessimissery |
thanks for your replies
Quasi, I have wordered if you have got pictures taken during the building stages of your amp chasis and circuit |
|
|
| quasi |
| quote: | Originally posted by pessimissery
thanks for your replies
Quasi, I have wordered if you have got pictures taken during the building stages of your amp chasis and circuit |
This link will land you somewhere early in the thread.
http://www.diyaudio.com/forums/show...6105#post506105
Posts from;
#60 shows the PCB being made
#72 Heatsinks and rewound transformer
#143 My finished amp
#156 PCB Layouts used in my amp
#166 Final Schematic
#216 Slow turn on cct and PCB layout
#255 Zeonriders beautiful PCB
#285 Power selection guide
#301 high power version PCB
Cheers |
|
|
| pessimissery |
I really thank for your concern quasi
it seems that I will build it
so I probably get stuck more
hope you will go on answering me |
|
|
|
