Hi Gents,
With the PALADIN Small Signal Controller project nearing finalization, I though I would share my next idea so long. We already have the controller with volume control, input selector, LCD display, Remote control, etc. This then allows you to make a passive pre-amplifier.
The logical next step would be to make some boards that would allow you to make an active pre-amp using all PALADIN parts, and with the same level of quality throughout.
The idea is the same as with the other project - I will solder all the parts to the boards and test them before sending them out, so you shouldn't need to have to solder and fault-find anything - just connect up and enjoy.
So far, I am leaning towards a fully discrete buffer / line stage. This would typically have zero voltage gain, but have a good amount of current gain. It further allows you to isolate bits from each other because the buffer would have high input impedance and low output impedance.
My current pre-amp I am using at home is exactly that - a discrete zero gain buffer which accept the incoming signal, then the volume control (PALADIN Attenuator), then followed by another discrete zero gain buffer which drives the output.
The sound and detail I get out of it is damn impressive for what it is (no matched transistors or resistors, and built on a quick and dirty home-brew PCB). I therefore can't help but wonder how good a well engineered version could be. Something with dual transistors (in a single case) to ensure matched gain structure, etc.
I have been looking through lists and lists of dual transistors to try and find workable parts. There are many options out there - the one that obviously draws my attention is the Analog Devices (AD) SSM2220 and SSM2212 packages. The datasheet specifies a current gain match of 0.5% between the 2 transistors in a package, very low voltage noise, offset voltage drift, and 200MHz gain bandwidth which all looks great to me.
Obviously you pay for those specs - the devices go for between R 90 and R 110 ex VAT each, and you would need a couple of them to make a decent buffer stage, so I am not sure whether they are the correct devices to use or not.
The alternative is to use through-hole 3 pin transistors but then match them up by hand. Much cheaper, but a hell of a lot more schlep too...
This project has not started in any official capacity yet, but I have been thinking about it and tinkering with ideas around this for quite a while, so I thought I would open a discussion around this.
1. What do you think of the general principle?
2. Is this something you would be interested in?
3. Is the zero voltage gain a problem for you?
Please feel free to share your thoughts and / or opinions on this? The more input, the better :2thumbs:
Kind Regards,
Ian.
With the PALADIN Small Signal Controller project nearing finalization, I though I would share my next idea so long. We already have the controller with volume control, input selector, LCD display, Remote control, etc. This then allows you to make a passive pre-amplifier.
The logical next step would be to make some boards that would allow you to make an active pre-amp using all PALADIN parts, and with the same level of quality throughout.
The idea is the same as with the other project - I will solder all the parts to the boards and test them before sending them out, so you shouldn't need to have to solder and fault-find anything - just connect up and enjoy.
So far, I am leaning towards a fully discrete buffer / line stage. This would typically have zero voltage gain, but have a good amount of current gain. It further allows you to isolate bits from each other because the buffer would have high input impedance and low output impedance.
My current pre-amp I am using at home is exactly that - a discrete zero gain buffer which accept the incoming signal, then the volume control (PALADIN Attenuator), then followed by another discrete zero gain buffer which drives the output.
The sound and detail I get out of it is damn impressive for what it is (no matched transistors or resistors, and built on a quick and dirty home-brew PCB). I therefore can't help but wonder how good a well engineered version could be. Something with dual transistors (in a single case) to ensure matched gain structure, etc.
I have been looking through lists and lists of dual transistors to try and find workable parts. There are many options out there - the one that obviously draws my attention is the Analog Devices (AD) SSM2220 and SSM2212 packages. The datasheet specifies a current gain match of 0.5% between the 2 transistors in a package, very low voltage noise, offset voltage drift, and 200MHz gain bandwidth which all looks great to me.
Obviously you pay for those specs - the devices go for between R 90 and R 110 ex VAT each, and you would need a couple of them to make a decent buffer stage, so I am not sure whether they are the correct devices to use or not.
The alternative is to use through-hole 3 pin transistors but then match them up by hand. Much cheaper, but a hell of a lot more schlep too...
This project has not started in any official capacity yet, but I have been thinking about it and tinkering with ideas around this for quite a while, so I thought I would open a discussion around this.
1. What do you think of the general principle?
2. Is this something you would be interested in?
3. Is the zero voltage gain a problem for you?
Please feel free to share your thoughts and / or opinions on this? The more input, the better :2thumbs:
Kind Regards,
Ian.
