View Full Version : Bridging the amp9?
I know that normally people is told that this can't be done and the way to get more power out is to parallel and run lower impedances.
I've read that you can bridge a "non-bridgeable" amp by inverting 1 of the signal inputs (180 degrees phaseshift)and then you can bridge it.
Can this be done with the amp9?
Not according to the "Overview" page: http://41hz.com/main.aspx?pageID=124
Br column says N :(
Yes I know, but isn't that only according to "normal" bridging? Not taking into account that you can invert 1 of the signal inputs?
Isn't the problem with the amp9 that one of the rails isn't inverted and then you cannot bridge like normal?
I don't understand it, but I think it has something to do with the single-supply amps being "already bridged internally".
One-channel-inverted is how I understood the definition of bridging.
You can think of the Amp9 chips as having an inverting opamp inside. It inverts a signal so that there are 2 out of phase signals to amplify and bridges them at the output. You can see at the outputs that it is bridged since the speaker is never directly attached to ground. In short, it already does what you are asking about internally.
The TA3020 chips such as the Truepath and Amp7 have single ended outputs (one speaker terminal is grounded), so they can be bridged in the manner that you are talking about.
ahh okay... so the amp9 is actually a 8 channel bridged at 4 channels?
Yep...
Indeed the amplifier overview clearly shows this...
------X-max. can be several meters on any driver, too bad it can be done only once...------
okay.. i'll study it some more :)
Anyone know the answer to my other question regarding dropping the voltage just a bit by using a diode?
Havoc, you can do that. You can lose as much power in diodes as you want :) (I hear it may be noisy sometimes but probably not a lot.) You may not need it, I'm not sure. Try to find out exactly what voltage the transformer puts out unloaded, and how much voltage that is after rectification, and check the exact max spec of the Amp9 ... 18 V * 1.414 = 25.5V ... if the transformer gives you an extra 10% when it's unloaded, that's 28V ... isn't the Amp9 max 27V? Then the question is: Am I calculating this correctly? - And how much does the transformer really rise? And is it every 100% unloaded when connected to the Amp9? Doesn't the Amp9 take around 300mA or something when doing nothing?
The TAA4100A can handle some more voltage, no problem... 27,6Vdc is rendered safe max continuous operating voltage. Plus it draws more idle current than for instance an QAMP3 or AMP6, so the voltage will most likely drop well within the safe margin...
The one transformer has better voltage regulation than the other. R-cores are for as far as I know the best regulating transformers. Toroids some of the poorest, but on the other hand they can pretty easily be unwound a bit to lower the voltage...
------X-max. can be several meters on any driver, too bad it can be done only once...------
okay thx guys... I'll check with a meter to see what idle voltage is.
If too much I will drop with a diode or unwind a bit.
The 2.1 project is coming along. Hivis have been bought and I found and bought an active filter that devides to sub at 150hz so that is perfect for bi amping.
Cases for fulltones is almost finished for testing and sub unit is purchased :)
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