mini aleph

[vivanco]

Hello everyone, this is my first 3D, I have a problem with my mini aleph, this is exactly the lack of input sensitivity;
Let me explain, I have created two integrated amplifiers in which the preamp section is based on a circuit fet in single-end type, with a gain of about 15 db, while the final section, is formed in the first a pair of mini aleph version in single end and the second is a card with Tripath TA2024 Class T;
during testing I noticed that the TA2024 amplifier generates a sound power much higher than the mini aleph;
from this I deduced that it is probably a matter of input sensitivity, because more or less power in the final game of the two systems are similar (9 + 9 watts for the TA2024 and 10 + 10 watts for the mini aleph), then wonder how I can correct this, thanks.
ps: I had decided to reduce the resistance value R1 (10K) and increase the value of the resistor R2 (100K), if this is correct, what are the values most appropriate to use?
thanks for your replies.

[Bill Fuss]

Can you show us a schematic.

[d to the g]

Don't forget that the mini aleph is balanced. To get appropriate gain from a single ended connection, you need to ground the - input.

[vivanco]

Originally Posted by d to the g

Don't forget that the mini aleph is balanced. To get appropriate gain from a single ended connection, you need to ground the - input.

my mini aleph was built through the use PCB's produced by Brian's chipamp.com,,, I connected the input unbalanced directly on the pad's dedicated;
from what you say, I understand that I should connect the pad of the input (-) balanced on earth, right?
if not mistaken, this should not affect on increasing the power output, but only to ensure that they are not picked up noises from the outside, at least so it seems to me to understand by looking at the circuit,,problem that may arise, leaving the floating input (-)

help me please

[MEGA-amp]

Originally Posted by vivanco

the input (-) balanced on earth

you want to connect (-) to signal ground, not earth ground, provide a picture or crude drawing to clarify.

[d to the g]

On Brian's boards, there are three input pads. Since you are using it single ended, just put in a wire jumper input "-" to input "ground" and you'll be good to go.

[vivanco]

ok I understand, but I can tell you now that the amp is playing very well, just to get a decent sound pressure on my 102db speakers, I have to turn the volume control more than 3 / 4, there is no presence hum or noise;
now I wonder what happens when I connect the signal (-) to ground? increases the gain? if not, how can I make the final section of the most sensitive input? thanks for your time, greetings.

p.s.:I apologize for my bad English, unfortunately, as an Italian I help with a simultaneous translator, so I do not know if it is expressed correctly.


Giovanni

[Bill Fuss]

The gain should increase dramatically when you ground the neg input.

If you have changed the resistors at the input you have changed the global feedback network. Please return the resistors to their correct values as designed.

Have you looked at the original mini A thread?

Best, Bill

[vivanco]

Your words comforted me greatly!
I did not change the values of the input resistive network, I thought of it, but after reading your thoughts, I think you should solve my problem.
for now thanks and greetings to all