350w plate amp,whats this wire!

[mikee12345]

hey all

just got a 2nd hand plate amp

Firstly=the output seems unfiltered
secondly-the output is quiet

using a 2226 with 20w i know how loud my jbl can go,so im not really sure whats up

what are these wires,they look FAT and like suspiciously like something i need!!!!

its connected near the output transistors, speaker out connectors?

am i just hearing line level stuff ?

Help!

next time i might just buy it fullprice from jaycar to avoid the online auction hassle.....

at first i thoht perhaps that my Sources speaker outputs were not BLACK (-ve) earth based,because i thoht perhaps i was hearing the tiny flow through there so i switched that, and the output was still the same! (ofcourse i risked the first amp to test this but it seems to work still)

yes i can model horns and ported boxes,but this is just annoying!

[mikee12345]

+ its night time and our lights seem to be less than 100w so its hard to see minute details on the boards...

[hunter audio]

hi

thats the positive supply

form the power supply to the out put transistors

this is some thing you can do about it

measure the voltage on the power supply - at the bridge rectifier

- follow the - ve and + ve lines from it - see where the - ve wire goes

it should most probaly run to the out put transistors - opposite to wher the red wire is connected to the out put board

if so trace out how the - ve is connected to the power supply - points (near the rectifier)

now measure the voltages - of the - ve terminals with respect to earth - measure at the rectfier point and the out - put transistor board

then measure the + ve terminals - if you find the +ve voltage not reaching the out put transistors

connect the red wire similarly as they have connected the - ve (black wire to the supply)

protection

place a 500 ma fuse on the red wire line - that way any wrong connection or shorts will not damage any component

suranjan

[mikee12345]

Thanks,i cant find my meter though its in storage !,surely theres a VERY obvious connector someplace!

Cheers

[djQUAN]

if the black wire goes to the filter cap's center tap, and the red wire connects to all those ceramic resistors, then it's the speaker output.

[mikee12345]

hah,some one i know thinks it COULD be the sub out

note,on the front it doesnt actualy SAY 'sub out' it says 'high level in,out' and line in and out....





infact im beginning to think it is the SUB OUT ,because the amp is meant for mounting on the box,il double check when i find my meter,il have to go search and see if its in a box at a relatives house.

+40v Dc on the old jbl mite wake it up abit !

just thoht some one would know outright

[hunter audio]

hi

if ure 2226 is performing low - then most probably the - ve supply is connected and what u are getting is a half signal out put at the spk lines - there fore the spk is playing a bit low

as for a sub out - it will be a line level out - then the wire should be a screen cable (with the earth shielding) and it wont be such a heavy duty guage wire like the one that is disconnected

yet the best would be to actually check the voltages ,

also the sub out will never run from the out put tranny board - it will run from the input control circuitry board from a small ic - op amp ,

yet its best that you take all precautions , please insert a fuse (mentioned before)

at my end i am not only a transducer design engineer - i have designed a lot of these plate amps (i do audio pcb designing too)
for my customers who use my drivers - and end up asking me to improve their amps ets

you can run a back up check on me - search for hunter audio in the - solid state section ,

suranjan

[mikee12345]

i actualy cant tell where any of the tracks are,i cant remove the pcb easily , and the blops of black goop cover up where exactly the wires go....

Cheers!

[hunter audio]

hi

man - one sec do you have - 1 red wire that is not connected or

2 wires that is not connected

intially you mentioned there is 1 (red)

if they are two and (the red ) runs to the emitter resitors on the out put tranny board - and not to the output transistors itself

and the black wire you are showing now runs to the filter caps

then this is the speaker out wire

suranjan

[djQUAN]

the connector is a slide "quick disconnect" often used to connect to speaker terminals.