rebone,
Happy New Year 2024!
That's a nice pair of mono blocks you got there. I see you that your chassis is 100% hand build using aluminum angle bars and sheets; from experience I understand that building a chassis from ground up requires quite a bit of work, and kudos to you on the successful completion of the project.
Now if you want to take it to the next level, probably need to upgrade your speaker.
What cabinet do you have the Alpair 12P in?
Happy New Year 2024!
That's a nice pair of mono blocks you got there. I see you that your chassis is 100% hand build using aluminum angle bars and sheets; from experience I understand that building a chassis from ground up requires quite a bit of work, and kudos to you on the successful completion of the project.
Now if you want to take it to the next level, probably need to upgrade your speaker.
What cabinet do you have the Alpair 12P in?
Thanks guys
I don't have the alpairs in a cabinet at the moment, just using them while I'm waiting for some new ones I have ordered.
I would have liked to build a pair of monkey coffins but they are to big for my situation.
mbrennwa; this one is not as compact as your cube, which I thought was very cool.
I don't have the alpairs in a cabinet at the moment, just using them while I'm waiting for some new ones I have ordered.
I would have liked to build a pair of monkey coffins but they are to big for my situation.
mbrennwa; this one is not as compact as your cube, which I thought was very cool.
Thanks fab.
Yes, the amplifier boards went smoothly.
I had to change R13 and R14 to 10Ω to be able to set the driver bias to 50mA.
Re damping factor, well spotted. I have recalculated these.
( some number confusion in the chaos )
I used 3x 25Ω in parallel to get 8.33Ω and recalculated DF to 54.4
I used 4x 25Ω in parallel to get 6.25Ω and recalculated DF to 39.7
rebone
Yes, the amplifier boards went smoothly.
I had to change R13 and R14 to 10Ω to be able to set the driver bias to 50mA.
Re damping factor, well spotted. I have recalculated these.
( some number confusion in the chaos
)I used 3x 25Ω in parallel to get 8.33Ω and recalculated DF to 54.4
I used 4x 25Ω in parallel to get 6.25Ω and recalculated DF to 39.7
rebone
You are welcome rebone.
Glad it was easy for you to build.
you have a relatively low output bias current for such a class A amp. That may explain why you had to reduce R13/14 values. Based on you heatsink size you may consider increasing the bias current if the resulting temperature is no more than 50C. Driver current can go as high as 100ma without bad side effects.
In general, more driver and output bias current increase “smoothness” and a bit the DF of the amp if this is what you are looking for .
keep us posted on the burn-in and consider trying increasing the bias current
Fab
Glad it was easy for you to build.
you have a relatively low output bias current for such a class A amp. That may explain why you had to reduce R13/14 values. Based on you heatsink size you may consider increasing the bias current if the resulting temperature is no more than 50C. Driver current can go as high as 100ma without bad side effects.
In general, more driver and output bias current increase “smoothness” and a bit the DF of the amp if this is what you are looking for .
keep us posted on the burn-in and consider trying increasing the bias current
Fab
