1000W Simple PA Amplifier

wattaniya · 2014-11-01 9:53 am

hi apex sir,
these days i am buissy,
now i am free to work with amp.
supply dcv 95v,
dc offsett 20mv,
today i checked with 10 ohm 10 watt resistor instead fuse and i measured the dc volt for bias, it showing 0.485vdc, is it bias very low,(u mentioned 15ma per pair, so totally 1.35vdc on 10 ohm) am i correct?
output base to gnd volt showing 0.420vdc and other side 0.460vdc.
9 pair outputs and with bd681, bias resistor 8.2k.

wattaniya · 2014-11-02 6:35 pm

hi apex sir,
today i give 50vdc with 8 pair outputs,
it clips at 30vdc,
dc50v sag to 46v,
load 4 ohm,
100hz sinewave feed input.
outputs are 45degree celcious,
basevolt is 220mv.

wattaniya · 2014-11-02 6:40 pm

and another testing with 70vdc,
8 output pair
base volt is 120mv,
clips at 40v, 70v sag 57vdc
outputs 70ddegree, at clips.
sound is clear .
100hz sinewave, and music tested

K-amps · 2014-11-02 6:54 pm

Seems pretty normal to get 200 watt clip at 70v, although looks like your power supply is merely adequate. You might need something larger to get more power... Sagging a bit too much, but still depending on the size of your trafo (350-450va?) it looks normal.

wattaniya · 2014-11-02 7:37 pm

for output c5200 and a1943 what is the safety voltage? is it 95v ok ?

wattaniya · 2014-11-02 7:39 pm

clips at 40v ac out,
70vdc supply,
70vdc sag to 57v dc.

K-amps · 2014-11-03 1:32 am

C5200/A1943 can take 95v rails, but you will need bazillions of them, since their SOAR is limited. You are better off with MJ21193/94 or MJL43281 types

wattaniya · 2014-11-03 4:35 am

if i add more output of c5200 and a1943 for 95vdc.
how many output need for 95vdc?

AndrewT · 2014-11-03 9:55 am

wattaniya said:
hi apex sir,
today i give 50vdc with 8 pair outputs,
it clips at 30vdc,
dc50v sag to 46v,
load 4 ohm,
100hz sinewave feed input.
outputs are 45degree celcious,
basevolt is 220mv.

this does not make sense.

Supply is +-50Vdc
Supply sags to +-46Vdc when full power is delivered into 4r0 test load.
So far, am I interpreting your data correctly?

it clips at 30vdc,

What is this?
Do you mean an output voltage?
Do you mean 30Vpk?
Dop you mean 30Vac?

outputs are 45degree celcious,

What does this mean?
Is this a temperature?
Measured where?
On the device plastic case?
On the device backplate that you can't access?
On the heatsink very near the device?
On the heatsink 10mm away from the device?

basevolt is 220mv.

What does this mean?

AndrewT · 2014-11-03 10:03 am

wattaniya said:
if i add more output of c5200 and a1943 for 95vdc.
how many output need for 95vdc?

Have you looked at the datasheet?
What is the maximum (25°C) current the device can pass for one shot 100ms? or continuously?

I'll tell you:
~0.45A @ 95Vce for Tj=150°C, continuous.
~0.75A @ 95Vce for Tj=150°C, one shot 100ms.

How much capability is left for signal delivery when the device is not held at Tc=25°C?

K-amps · 2014-11-03 10:13 am

wattaniya said:
if i add more output of c5200 and a1943 for 95vdc.
how many output need for 95vdc?

If you want to run this thing into 4 ohms, I'd go with 20 pairs (40 devices) at 95v rails.

As Andrew says, at 150C, the C5200 is about a 40watt device. Your Output stage should be able to deliver about 1800watts (assuming a nice safety margin) this means about 40 devices or 20 pairs.

This is why no manufacturer uses these devices with high rails...

sajti · 2014-11-03 10:29 am

I would not go over+/-80V with simple class AB. Class G/H is more comfortable for higher voltage...

Sajti

AndrewT · 2014-11-03 10:33 am

K-amps said:
If you want to run this thing into 4 ohms, I'd go with 20 pairs (40 devices) at 95v rails.

As Andrew says, at 150C, the C5200 is about a 40watt device. Your Output stage should be able to deliver about 1800watts (assuming a nice safety margin) this means about 40 devices or 20 pairs.

This is why no manufacturer uses these devices with high rails...

except in ClassG/H topologies where the transistors are switched in to deliver the peaks for VERY SHORT transients and are kept cool/cold by enormous capability heatsinking.

wattaniya · 2014-11-03 11:48 am

AndrewT said:
this does not make sense.

Supply is +-50Vdc
Supply sags to +-46Vdc when full power is delivered into 4r0 test load.
So far, am I interpreting your data correctly?What is this?
Do you mean an output voltage? yes ac volt
Do you mean 30Vpk? yes
Dop you mean 30Vac?What does this mean? 30v ac at clip
Is this a temperature? yes
Measured where? front of the output
On the device plastic case? not plastic its ceramic
On the device backplate that you can't access?
On the heatsink very near the device?
On the heatsink 10mm away from the device?What does this mean?

wattaniya · 2014-11-03 11:55 am

sajti said:
I would not go over+/-80V with simple class AB. Class G/H is more comfortable for higher voltage...

Sajti

hi sajti,
how many pairs u recommend for 80vdc? for full volume.
with 80 vdc how many watts into 4 ohm?
what is clip level on output volt ac?

AndrewT · 2014-11-03 2:46 pm

Post734

wattaniya said:
...........

What is this?
Where is your comment?
DON'T put your words inside the quote. It will be interpreted as editing the contents of a quote
I was binned for changing (just slightly) a quote !

wattaniya · 2014-11-03 3:30 pm

the answer is after the question mark of ur qusetions.

sajti · 2014-11-03 5:30 pm

wattaniya said:
hi sajti,
how many pairs u recommend for 80vdc? for full volume.
with 80 vdc how many watts into 4 ohm?
what is clip level on output volt ac?

I would use MJL21193/94, and 6-7pairs. 500-600W looks possible for 4 ohms.

Sajti

wattaniya · 2014-11-03 6:01 pm

thank u sajti for the reply

apexaudio · 2014-11-03 7:50 pm

16LED VU for amps. PCB size 100x35mm

1000W Simple PA Amplifier

Member

Member

Member

Member

Member

Member

Member

Member

R.I.P.

R.I.P.

Member

Member

R.I.P.

Member

Member

R.I.P.

Member

Member

Member

Member

Attachments