Ventus is a mostly discrete opamp. 
This is a circuit designed for some DIY fun. It is based on the Diamante circuit I published a while back.
The front end is a folded cascode design and runs into a LME49600 buffer. The buffer is in the feedback loop.
A schematic is worth a thousand words.
It sounds excellent. It can drive low impedance headphones exceptionally well.
As shown it is a BAL/SE converter and take balanced input from DACs such as Buffalo or Opus.
I would suggest when using it in this way (Balanced to SE) you use a relay to shunt output to GND on turn off to prevent any turn off thump. The thump buster works well in this role.
The Ventus can also easily be setup as a classic non-inverting amplifier with single ended input. It also can be setup as an in inverting amplifier with single ended input.
Each module is a mono channel so It takes two for stereo, and they stack easily.
There is a pot to null output offset.
We have boards tested and parts are en route so these will be available very soon.
The board is tested and proven, and I love it. I have been listening to it for a week now.
Take a look.
Cheers!
Russ
This is a circuit designed for some DIY fun. It is based on the Diamante circuit I published a while back.
The front end is a folded cascode design and runs into a LME49600 buffer. The buffer is in the feedback loop.
A schematic is worth a thousand words.
It sounds excellent. It can drive low impedance headphones exceptionally well.
As shown it is a BAL/SE converter and take balanced input from DACs such as Buffalo or Opus.
I would suggest when using it in this way (Balanced to SE) you use a relay to shunt output to GND on turn off to prevent any turn off thump. The thump buster works well in this role.
The Ventus can also easily be setup as a classic non-inverting amplifier with single ended input. It also can be setup as an in inverting amplifier with single ended input.
Each module is a mono channel so It takes two for stereo, and they stack easily.
There is a pot to null output offset.
We have boards tested and parts are en route so these will be available very soon.
The board is tested and proven, and I love it. I have been listening to it for a week now.
Take a look.
Cheers!
Russ
Attachments
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Both ccts works very well for the task. Ballsie lite will be a bit easier to use since it has an output shunting relay built in.
My first choise for driving headphones would be Ventus.
My first choice into another amplifier would be Ballsie Lite.
Cheers!
Russ
I am getting these kits ready, and am trying to decide on what to do with the LME49600.
Getting it properly mounted with a soldering iron is possible, but not easy, unless you are really good at SMD soldering. The large metal tab needs to be soldered completely to give good thermal conduction to the ground plane.
I could pre-mount them using solder paste and a reflow oven, but want to get some feedback from interested party's first.
Anyone?
Getting it properly mounted with a soldering iron is possible, but not easy, unless you are really good at SMD soldering. The large metal tab needs to be soldered completely to give good thermal conduction to the ground plane.
I could pre-mount them using solder paste and a reflow oven, but want to get some feedback from interested party's first.
Anyone?
Thank you, Russ. Can we get an estimated release date for the Ballsie Lite?
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A couple of points I need to put in the manual (which I will try to get up soon).
1) Make sure you use the closest together pads for RVCC and RVEE unless you plan on reversing polarity of the LEDs and C5/C6 as well as swapping NPN/PNP transistors. I figured some people may want to experiemnt by using PNP input pairs etc. So I made the board support that option.
2) For non-inverting use: Reduce R2 to 221R and make R4 47K (this will set the input impedance). Connect -IN to GND. Then adjust R5 and R3 set the gain. Gain = 1+(R5/R3). For unity gain simply omit R3. For example. Using R5 of 1K and R3 of 1K would get you a voltage gain of 2, which is 6db.
3) For inverting use: Omit R2 and optionally decrease R4 (A range from 0R(jumper) to 1K should work fine). Then wire your input to -IN and GND. The gain is R5/R3. So using 1K for each R3 and R5 would get you unity gain inverted(-1). Remember that R3 will now set the input impedance of the cct. In this example 1K.
I hope that helps.
Cheers!
Russ
1) Make sure you use the closest together pads for RVCC and RVEE unless you plan on reversing polarity of the LEDs and C5/C6 as well as swapping NPN/PNP transistors. I figured some people may want to experiemnt by using PNP input pairs etc. So I made the board support that option.
2) For non-inverting use: Reduce R2 to 221R and make R4 47K (this will set the input impedance). Connect -IN to GND. Then adjust R5 and R3 set the gain. Gain = 1+(R5/R3). For unity gain simply omit R3. For example. Using R5 of 1K and R3 of 1K would get you a voltage gain of 2, which is 6db.
3) For inverting use: Omit R2 and optionally decrease R4 (A range from 0R(jumper) to 1K should work fine). Then wire your input to -IN and GND. The gain is R5/R3. So using 1K for each R3 and R5 would get you unity gain inverted(-1). Remember that R3 will now set the input impedance of the cct. In this example 1K.
I hope that helps.
Cheers!
Russ
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They simply are not needed. It is not a problem at all in terms of causing any instability. While the capacitance can reduce the effectiveness of the shunt it is not a big deal. Brian is simply stating that if you plan on using placid you might as well omit them to get the best out of the placid. Keep the supply wiring as short as possible.
You can also RVCC and RVEE jumpers and omit C5 and C6 if you are using placidBP.
Cheers!
Russ