Yes, of course when you are putting the PSU inside it can only be for the AC. I was thinking about which connector to use when making an external 24V PSU for the ACA.....and here the SpeakCon could be a good choice.
Some switching supplies will not want to charge a large cap. There is
a way where you can charge the cap more slowly but take the charge
out quickly. Try something like this circuit in parallel with the supply.
Use a bigger diode if think you need it. A Schottky will give you less drop
if you want it as a peak current reserve.
Attachments
I have two 69.1K resistors left over. I don't see them in the circuit diagram on first post? Did I miss a step?
Thank you!
I will do that.
Checking my parts, I only have a 15-ohm 5-watt resistor and 1N5818.
Can anyone confirm if this will work?
It's written on the piece of paper that came with the kit. 39K for higher gain and 68k for lower gain or when using a preamp.
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That slip was missing from the parts pack I received - but then the package had already been opened by Dave, so maybe it fell out?
Anyway mystery solved.
Anyway mystery solved.
Done! Took my time - 9 hours to complete. Only one burnt finger. Bias set 10.0V +/- 0.01V No untoward smells or sounds, and no smoke! 🙂 Couple issues with the case and screws no lining up exactly, but still looks great.
Is it possible to add a 1/4 headphone jack with a switch to turn off the speakers when headphones are in use?
Is it possible to add a 1/4 headphone jack with a switch to turn off the speakers when headphones are in use?
Using the 39k will give 10 dB of gain and 68k will give 14 dB of gain (as in the original ACA). There is more NFB using the 39k. It gives a higher damping factor. So lower gain using 39k and higher gain using 68k.
Then you can use a preamp with lower gain if you use 68k than with 39k.
I didn’t put whole Mepper’s post just his part
Quote from clowkoy is oposite than Meppers post
Originally Posted by clowkoy View Post
It's written on the piece of paper that came with the kit. 39K for higher gain and 68k for lower gain or when using a preamp.
Originally Posted by MEPER View Post
Using the 39k will give 10 dB of gain and 68k will give 14 dB of gain (as in the original ACA). There is more NFB using the 39k. It gives a higher damping factor. So lower gain using 39k and higher gain using 68k.
Then you can use a preamp with lower gain if you use 68k than with 39k.
Quote from clowkoy is oposite than Meppers post
Originally Posted by clowkoy View Post
It's written on the piece of paper that came with the kit. 39K for higher gain and 68k for lower gain or when using a preamp.
Originally Posted by MEPER View Post
Using the 39k will give 10 dB of gain and 68k will give 14 dB of gain (as in the original ACA). There is more NFB using the 39k. It gives a higher damping factor. So lower gain using 39k and higher gain using 68k.
Then you can use a preamp with lower gain if you use 68k than with 39k.
I think it is correct what I wrote. If it is written "oppsite" other place it may be wrong. The gain of the amp is lowered using the 39k resistor in the "new" ACA (more NFB introduced to get lower gain).
The top and bottom plates are not symmetrically drilled. They have a front/back orientation where the lips will be flush with the front and sit on top of the back plate. If one comes up short to the back plate, rotate the panel 180°.
It's easy enough to add to the existing amp. Find a switch you like and drill a hole in the front.
That said, it's being considered for future kits.
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