1000W Simple PA Amplifier

[Blantozaur]

Hello. I build ba1200 width 4 output pair, supply 40V DC. Without input signal i got on output 2,3v DC

What is wrong ? Any suggest ?

 

[Blantozaur]

Error it's ba1000 !

 

[Blantozaur]

All works great. I think i've spotted a fake 1943 & 5200 . Sample 2sc2987 & 2sa1227

http://www.which.co.uk/consumer-rig...ted-a-fake-or-counterfeit-good-how-can-i-tell

 

[wiljj78]

All works great. I think i've spotted a fake 1943 & 5200 . Sample 2sc2987 & 2sa1227

Hello Blantozaur,

Good to hear it works!! also with some pictures would be great....

Regards,

 

[Blantozaur]

What i did:
- removed damaged amplifier section oryginal magnat 480
- mounted ba1000
- rewinded trafo up to +/- 40v at 14,4v 2x1x1.5
What i will do:
- sample output tranzistors to MJL in ba1000
- add subwoofer filters 20hz hpf and virable 30-100 lpf
- use amplifier protection circuit build in power supply
- add amplifier mute synchronizetd width power supply
- rewind trafo up to +/- 70v at 14,4v

 

[apexaudio]

What i did:
- removed damaged amplifier section oryginal magnat 480
- mounted ba1000
- rewinded trafo up to +/- 40v at 14,4v 2x1x1.5
What i will do:
- sample output tranzistors to MJL in ba1000
- add subwoofer filters 20hz hpf and virable 30-100 lpf
- use amplifier protection circuit build in power supply
- add amplifier mute synchronizetd width power supply
- rewind trafo up to +/- 70v at 14,4v

Nice work.
Regards

 

[nano nano]

[image][/image] hi apex I would ask that I love the arrows down how

 

[Vostro]

I guess he means what are the values of components

 

[dovizci]

I tried this circuit with mj15023 and 24. and as driver I used 2sc5200 ,I couldnt find 2sa5200. With doublle 60v testing there was an ossilation at the output. Have anybody an idea for dissolve..

 

[lawbadman]

So exactly how much power does this amp (B1000) produce at 8, 4 and 2 ohm?

Im trying to decide whether to build the B1000 or the 900H.


Thanks

 

[AndrewT]

Work it out from P = V² / Rload

The maximum V from a power amplifier must be less than {Vsupply Rail} / 1.5

eg.
supplies are +-80Vdc.
Maximum V < 80/1.5 < 53.3
Absolute maximum power is 53.3²/8 = 355W

 

[lawbadman]

so having a power supply of +-110 for either amp I would get 1300watts at 4 ohm and 2600 watts at 2 ohm.
But the question is, are either of the amps capable of producing all that power?

 

[tinitus]

I seem to remember Alex specced output on the safe side, and rated 8ohm and 4ohm power to be the same

so in my book you should probably calculate with less power in a 2ohm load

 

[AndrewT]

Assess the SOA capability of the output stage by using the relationship:

Maximum Output power is ~ Total output device power rating divided by 4.

This applies to normal ClassAB amplifiers.
The switched rail type are quite different.
I don't have a rule for them.

eg.
for classAB
using a 4pair output stage of 250W devices equates to total device power rating of 2000W.
Maximum power is ~ 500W.

 

[lawbadman]

hmmmm ok

so MJL4281 350 watts
so with 9 pairs
6300/4=1575watts......

 

[AndrewT]

mjl4281 is 230W
9pair is 4140W
At very high supply voltage I would aim for divide by 5. If they are to run hot as well then divide by 6.

But switched rail amplifiers do it differently.
That divide by 4, or 5, or 6 does not apply.

 

[tinitus]

just a general interest regarding diodes

D2/D3/D4/D5/D6 are all 1N4007, and D7/D8 are 1N5408

what is the reason for using different diodes ?

 

[AndrewT]

different duty requires different device parameters.

D3 & D4 should be small signal diodes, try 1n4148.

D2, D5 & D6 may be OK to leave as power diodes, 1n4002 or above.

D7 & D8 must be power diodes.
But the back emf and the resulting current coming from the speaker and it's crossover components cannot be that high, that 1n540x devices must be used.

I use 1n4003 or above here. But I don't drive 1kW speakers. Maybe the peak transient currents from really big speakers can exceed the short term peak capabilities of the 1n400x series.

 

[tinitus]

ok, great, thanks

I might have a combination use for this amp
as bass guitar amp driving 18" woofer
and as a mono sub amp with EQ, driving the same woofer for hifi music

and it might do both at the same time, when I figure out how

 

[AndrewT]

Can a direct drive 18" woofer dump enough current back into a 110Vdc supply rail such that a 1n4003 cannot cope?