@Will - it looks like there are some parts in there that are different than NwAVGuy's spec, and I worry this is violating the original license. From a post on reddit:
You can see a 5% tolerance resistor at R25, non-Alps potentiometer, non-standard MOSFETS Q1 and Q2, and non-standard passives.
R25 is critical to proper turn on/off operation (1% tolerance recommended). The potentiometer choice affects channel balance and its taper impacts volume adjustment.
The blue LED is a nice touch, but that also requires circuitry changes - and NwAvGuy's specified red LED was to avoid an uneven battery draw).
Substituting Q1/Q2 can alter power delivery to the opamps. It will be interesting to see how this pans out.
Also the case isn't the standard b2-080.
millifooHey Everyone,
Thanks for all your posts, especially @millifoo, really appreciate the specificity and succinct nature of your response. You bring up understandable concerns regarding the parts used to construct these prototypes and I should have clarified this in my first post. These prototypes were constructed using parts immediately available. That’s why there are some deviations from the original design.
We are still adjusting the design (those details I mentioned in my original post), and we will be updating the group with any major revisions here in the discussion. Those final design elements will be decided shortly before the drop ends (we’ll release the changes in an email to all participants . This means every piece feedback we receive has a very real chance of making into production. Given that, be vocal! Let us know what you want and we’ll make it happen as best we can. Endorse posts you agree with, debate the ones you don’t.
We are huge fans of NwAvGuy’s design here at Massdrop. The intention with our take on the Objective 2 amplifier is to make the product accessible to more people while honoring the spirit of the design as well as the licensing terms as much as we possibly can.
To cover a couple of questions posed by other folks:
From @TenryuuQ: Will this cost $70?
A: That's what we're planning if you’re in the united states. If you’re overseas (or imaginary land borders to the north and south) you’ll have to kick in an extra $10 to cover international shipping. Getting some final quotes tomorrow so this could change slightly.
From @SithQ: Any way we can get a drop of the ODAC + O2?
A: Would love to, sadly ODACs are published under a different license and this will take some time to arrange. If there’s enough interest we’ll definitely reach out to yoyodyne consulting (the company that makes the ODAC) and see about proposing this to our partner.
These O2s will have a two year warranty through Massdrop.
Thanks again for your posts, I’ll be around to keep answering questions and reading your feedback.
You can see a 5% tolerance resistor at R25, non-Alps potentiometer, non-standard MOSFETS Q1 and Q2, and non-standard passives.
R25 is critical to proper turn on/off operation (1% tolerance recommended). The potentiometer choice affects channel balance and its taper impacts volume adjustment.
The blue LED is a nice touch, but that also requires circuitry changes - and NwAvGuy's specified red LED was to avoid an uneven battery draw).
Substituting Q1/Q2 can alter power delivery to the opamps. It will be interesting to see how this pans out.
Also the case isn't the standard b2-080.