[precsmo]

oh btw, if I ever upgrade, it is if Meier comes out another even better amp, I really hope if he was able to reduce the amp size by much. That's considerably an upgrade to me

 

[audionewbi]

My only issue is the lack of charging circuit.

 

[wormsdriver]

My only issue is the lack of charging circuit.

amen, brother!

 

[audionewbi]

This is why i think if it as "my special occasion amp", 9 volt battery isn't really cheap but when i plug in the er4s and turn the knob on i forget all about it.

 

[ClieOS]

If you have to ask for a charging circuit, might as well as ask for Li-ion battery as that will really slim thing down a bit.

 

[audionewbi]

  If you have to ask for a charging circuit, might as well as ask for Li-ion battery as that will really slim thing down a bit.

It has a few large caps inside it ( i think they are caps), I guess he might have to redesign those parts as well. 

 

[ClieOS]

  It has a few large caps inside it ( i think they are caps), I guess he might have to redesign those parts as well. 

 
Caps are easy to deal with, just don't use big electrolytic and you can instantly slim the design down. Battery / power section is a much more tricky issue.

 

[audionewbi]

If anyone can do it will be the Dr himself, I wonder if he is working on few projects as I am typing this. 

 

[pietcux]

Maybe the caps he uses sound best?

 

[ClieOS]

Maybe the caps he uses sound best?

 
They are power caps, not directly in the path of the signal (and thus don't directly affect the sound). Electrolytic is good choice for power caps, but there are suitable replacement as well.

 

[Mad Max]

They're there because he considered them best for the circuit despite whatever other options he had.
 
I wonder how much more battery life he could have given the amp by designing it to run off of a pair of AAs.  Then we could use Eneloops (or their Amazon rebranded variety).  My rechargable Tenergy 9V block doesn't have as much capacity as one of those, let alone a pair, and it seems that the LT1054 voltage converter/regulator doesn't use that much current itself, which I assume is what supplies the amp with the power that it runs on if it isn't just for the unique volume control.

 

[ClieOS]

  They're there because he considered them best for the circuit despite whatever other options he had.
 
I wonder how much more battery life he could have given the amp by designing it to run off of a pair of AAs.  Then we could use Eneloops (or their Amazon rebranded variety).  My rechargable Tenergy 9V block doesn't have as much capacity as one of those, let alone a pair, and it seems that the LT1054 voltage converter/regulator doesn't use that much current itself, which I assume is what supplies the amp with the power that it runs on if it isn't just for the unique volume control.

 
The choice of 9V is because 9V is high enough voltage to run most opamp properly and battery is generally considered a very clean power source, as long as you don't have to mess with the voltage by much. To use AA, anything less than 5V is not going to be enough (generally speaking), and 6V (4x AA)is borderline, while 9V (6x AA) is going to be heavy and bulky. If you are only going to use just one pair, you'll have to use a step-up circuit, which it creates noise / ripple that requires extra circuit to smooth down (which is the main reason why Dr. Meier has been avoiding step-up circuit all these time, I would believe). So if these extra circuits are unavoidable, then the smarter choice will be to go straight to Li-ion as it is far more efficient and higher capacity than NiMH of the same size. There are quite a few ways to get there, but unfortunately none without problem of their own.

 

[Mad Max]

   
... you'll have to use a step-up circuit...

 
That's LT1054's job.

 

[ClieOS]

   
That's LT1054's job.

 
If my measurement over the LT1054 (in StepDance) is right, it is not a step-up convertor but a step-down convertor / regulator actually. It takes either battery or DC input (from the socket), regulate it down to about 7V, then follow by a transistors based split circuit that creates a +/-7V supply rail to the opamp. It also explains why StepDance requires a regulated 15V adapter as LT1054's input rated only up to15V.
 
p/s: I would also think a step-down is more energy efficient than a step-up circuit. You might get more capacitance from a pair of AA, but boosting 3V to 7V will take more power than down regulating a 9V to 7V.
 
[See below] Cool, I stand corrected.

 

[Jan Meier]

Hello guys,
 
the LT1054 takes the +9V powerline of the battery and creates an additional -9V battery. Thus the effective supply voltage is doubled. The opamps run at +/- 9V.
 
Cheers
 
Jan