HI !
I try to find the easy solution to use my balanced PREAMP for my lm4780 and I don't know if this type of shematic diagram work or not ?
thanks in advance!
nicK
You don't want that ground connection on the speaker - that will short out the nearest amplifier!!
http://www.ti.com/lit/gpn/lm4780
Have a look at P. 6 for output configuration.
It is safest to leave the Zobel networks (series R+C from each output to ground) in as shown as they affect the inherent stability (same is true on all IC amps I've dealt with so far...).
I know you're trying to go minimalist but view these as "safety feature" and you won't regret it.
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OOPS I missed that.
Yes, remove that ground connection...Look at Fig 3 on page 6 of pdf linked by blu_glo.
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It will work...just don't connect the ground to the - side of the speaker.
It will work better if you follow fig 3 of pdf...not many changes.
-As Dug suggested, check for DC path to ground in the preamp outputs?
You should really have 18K-22K ohm resistor between RCA signal and ground terminals on + input and same again on - input.
You are feeding in a balanced input to all this - you said your preamp had balanced output?
By which I choose to assume each channel has two outputs and ground, one output being INVERTED in phase?
If you feed same phase signal into both inputs on your above circuit your speaker will get the difference - which will be pretty close to zero!!
A schematic or link to your preamp circuit might shed some light...
You should really have 18K-22K ohm resistor between RCA signal and ground terminals on + input and same again on - input.
You are feeding in a balanced input to all this - you said your preamp had balanced output?
By which I choose to assume each channel has two outputs and ground, one output being INVERTED in phase?
If you feed same phase signal into both inputs on your above circuit your speaker will get the difference - which will be pretty close to zero!!
A schematic or link to your preamp circuit might shed some light...
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BTW at 11A peak output I have to say you've done a stirling job of choosing the best IC for bridging! most of the others won't do much of their max power onto 4 ohms bridged (= equivalent to 2 ohms single ended - SPiKEs galore!!!).
Give it generous heatsink and don't take supply rails much over that +/- 25V needed (P. 5 "Po" figure) for max power onto 4 ohms!
With bridging and adequate supply caps you should be able to get 100W into 8 ohms and close to 200 into 4!!!
Give it generous heatsink and don't take supply rails much over that +/- 25V needed (P. 5 "Po" figure) for max power onto 4 ohms!
With bridging and adequate supply caps you should be able to get 100W into 8 ohms and close to 200 into 4!!!
PRE-AMP
Hello again !
my preamp is OUTLAW 970 OLD 7.1 PRE-AMP
the problem is in RCA version the opamp sound "THE SH*T!" because this company use very cheap chinese opamp.
But when I open my case I view the very good sound quality use for balanced section !
this is the reason, but I don't know if it's a "TRUE" inverted phase of not I don't test it for the moment.
THANKS GUYZ !
nicK
Hello again !
my preamp is OUTLAW 970 OLD 7.1 PRE-AMP
the problem is in RCA version the opamp sound "THE SH*T!" because this company use very cheap chinese opamp.
But when I open my case I view the very good sound quality use for balanced section !
this is the reason, but I don't know if it's a "TRUE" inverted phase of not I don't test it for the moment.
THANKS GUYZ
!nicK
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