I new to this forum.
Can someone kindly offer help?
Previously built ACA version 1.1 Worked fine from the get go.
Just completed ACA version 1.6 Not so lucky
Only a little sound is coming through the right channel.
Set bias to 10 on each side, no problem there.
Any suggestions where to look first?
Can someone kindly offer help?
Previously built ACA version 1.1 Worked fine from the get go.
Just completed ACA version 1.6 Not so lucky
Only a little sound is coming through the right channel.
Set bias to 10 on each side, no problem there.
Any suggestions where to look first?
I just finished building two of these little amps this afternoon. Used Belden 9497 though out the internal. very very happy with the result.
It has truly an interesting sound signature for SS. high is there, low is there, details are ok, but it has one of the smoothest mid range, especially vocal are really fantastic, smoother than some of my tube amps, at same time the ACA somehow still sounds clean. Impressive. I am using high sensitive full ranges only.
Highly recommended. Thank you for making this available.
It has truly an interesting sound signature for SS. high is there, low is there, details are ok, but it has one of the smoothest mid range, especially vocal are really fantastic, smoother than some of my tube amps, at same time the ACA somehow still sounds clean. Impressive. I am using high sensitive full ranges only.
Highly recommended. Thank you for making this available.
the 39k resistor on the back panel
Curious: what is the consequence of not attaching the 39K resistor between the RCA and the back panel switch? I appear to have lost that resistor. I can order another, obviously, but given the backups at Digikey who knows when it will arrive. Just would like to know if I need to chase that part or can just leave it out.
I plan to run mono blocks if that makes a difference to my situation.
Bonesthrower
Lincoln, Nebraska
Curious: what is the consequence of not attaching the 39K resistor between the RCA and the back panel switch? I appear to have lost that resistor. I can order another, obviously, but given the backups at Digikey who knows when it will arrive. Just would like to know if I need to chase that part or can just leave it out.
I plan to run mono blocks if that makes a difference to my situation.
Bonesthrower
Lincoln, Nebraska
ACA 1.8 build issues
Hello,
I just finished building the ACA 1.8. It powers up and works, but there is noticeably bad distortion in the upper mid frequencies at virtually any volume.
I haven't really done any trouble shooting yet other than to check all my cables.
Hopefully someone can steer me in the right direction to try and solve my problems.
I'm using a pair of Tekton Compact Enzos that are supposedly about 94dB efficiency.
I can take pics of everything if that will help, soon I'll start taking measurements.
Thanks for any help or ideas!
Hello,
I just finished building the ACA 1.8. It powers up and works, but there is noticeably bad distortion in the upper mid frequencies at virtually any volume.
I haven't really done any trouble shooting yet other than to check all my cables.
Hopefully someone can steer me in the right direction to try and solve my problems.
I'm using a pair of Tekton Compact Enzos that are supposedly about 94dB efficiency.
I can take pics of everything if that will help, soon I'll start taking measurements.
Thanks for any help or ideas!
You only need that resistor for running the amp in bridge mode. It feeds the output of one channel to the input of the other when selected via the switch.
Four basic checks.
1/ Is the supply voltage correct.
2/ Is the midpoint voltage correct. This is the voltage on the Plus end of the speaker coupling cap.
3/ Is the voltage between Q1 Drain and Q2 Source approximately 0.9 volts give or take.
4/ Are the output FET's getting hot. They should.
Not sure if I'm measuring correctly.
I measured voltage from the positive pole of the large cap to chasis ground. It seemed to fluctuate a lot. Going from 0 to around 9 volts with occasional excursions past 14 volts.
I didn't want to measure for very long as I was concerned that the mosfets would get too hot not attached to their heat sinks.
Power from the PSU is pretty much exactly 24V.
Thanks!
I measured voltage from the positive pole of the large cap to chasis ground. It seemed to fluctuate a lot. Going from 0 to around 9 volts with occasional excursions past 14 volts.
I didn't want to measure for very long as I was concerned that the mosfets would get too hot not attached to their heat sinks.
Power from the PSU is pretty much exactly 24V.
Thanks!