R12 sets the AC gain so the supply voltage makes no difference to that one. Omitting R12 sends the gain from 10.5db to 28db with corresponding big decrease in bandwidth and an increase in distortion.
Upping the supply and omitting R15 imo negates using a higher supply voltage.
Omitting R15 reduces quiescent current and so reduces available output voltage swing into real loads.
Upping the supply and omitting R15 imo negates using a higher supply voltage.
Omitting R15 reduces quiescent current and so reduces available output voltage swing into real loads.
I just thought of something in regards to the zerozone.
On the original ACA the positive speaker connection is grounded and the negative is not, why is that?
And is it the sake on the zerozone?
Because I have the speaker terminals connected directly to the board without any ground at the positive connector (or the negative one for that matter).
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Yes the speaker +ve is grounded the same as the ACA. Look at the tracks on the zerozone, the OUT+ thick track goes to the GND terminal.
Because the ACA is a 'common source' amplifier and inverts the signal.
See here: Amp Camp Amp #1
That's fine as long as they are all insulated from a metal chassis. The negative leads from your power supply 'join' them together anyway.
Ah, ok!
I couldn't look at the board so I just used the DMM instead.
Then I need to look elsewhere for the source of the buzzing.
I hoped it was just a matter of putting a direct connection between the PSU and speaker but since Thea are connected at the board that shouldn't make a difference.
I couldn't look at the board so I just used the DMM instead.
Then I need to look elsewhere for the source of the buzzing.
I hoped it was just a matter of putting a direct connection between the PSU and speaker but since Thea are connected at the board that shouldn't make a difference.
Quick easy question hopefully:
I'm building the ACA and the wires that came with the kit are colored differently than those in the guide.
One length, however, is thicker and a multi-stranded wire compared to the other lengths provided.
Which connections should this thicker wire be applied?
Thanks,
Mario
I'm building the ACA and the wires that came with the kit are colored differently than those in the guide.
One length, however, is thicker and a multi-stranded wire compared to the other lengths provided.
Which connections should this thicker wire be applied?
Thanks,
Mario
In this photo Bare, Black, and Blue are thick.
The rest are thin.
The power wiring (red and black in this photo) are thin. Twisted wires to the LEDs are also thin.
Substitute what colors you have in a manner that is logical to you.
The wire colors will change over time with the various packings of the kits.Also, it's really not super critical, so if you have to use thick where it's supposed to be thin, or vice-versa, it's really not going to make much difference at all.
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Ok, back again with the humming.
I have found the source but not the solution.
If I power up with no source connected the humm is much lower but as soon as I connect a source the humm is back.
I don't own a preamp yet (got parts and board for a BOZ and jFet BOZ) so I am limited to Chromecast audio and misc phones/tablets but battery or line powered doesn't matter.
I tried a starground with some alligator clips but that didn't do anything.
I then tried to elevate the signal ground by adding a 10R resistor (in series) between the RCA ground lug and the signal ground connector on the board but that didn't help either.
I have found the source but not the solution.
If I power up with no source connected the humm is much lower but as soon as I connect a source the humm is back.
I don't own a preamp yet (got parts and board for a BOZ and jFet BOZ) so I am limited to Chromecast audio and misc phones/tablets but battery or line powered doesn't matter.
I tried a starground with some alligator clips but that didn't do anything.
I then tried to elevate the signal ground by adding a 10R resistor (in series) between the RCA ground lug and the signal ground connector on the board but that didn't help either.