F6 Amplifier

[buzzforb]

ah! more pics soon. I may try to fire it up after all. Gotta get some other stuff done. Just depends on the progress.

[Zen Mod]

@flo

1u is way too much

been there , erred almost the same

[flocchini]

thanks ZM for the info and table
dont know what I was thinking - in fact, I was'nt thinking

[Antoinel]

Originally Posted by buzzforb

ah! more pics soon. I may try to fire it up after all. Gotta get some other stuff done. Just depends on the progress.

buzzforb. Are you interested in a procedure to turn on your balanced diyF6 for the first time?

[buzzforb]

What do you mean? I had planned to bias each side individually and then connect together. I will check out the bias arrangemnts and FR before adding the output fets. I will use laterals instead of the SS to make sure I dont cook anything.

[buzzforb]

Originally Posted by Zen Mod

@flo

1u is way too much

been there , erred almost the same

Where is the rest of the table and what was the calculation. Way too busy and lazy to look for myself. Are we talking snubbbers here, or just bypass caps? I have heard some folks dont like snubbers, whats your opinion. Gotta go finish tapping sinks. I hate tapping, even with drill.

[Antoinel]

Originally Posted by buzzforb

Where is the rest of the table and what was the calculation. Way too busy and lazy to look for myself. Are we talking snubbbers here, or just bypass caps? I have heard some folks dont like snubbers, whats your opinion. Gotta go finish tapping sinks. I hate tapping, even with drill.

buzzforb. This is a suggested procedure. Your pcb shows that power to both amps is applied simultaneously.

• Separate the turn-on of the amps
• Cut with razor the +Vc and -Vc traces to left channel. Ideally, each channel may have had its +/-Vc lines independent from the other.
• Ground the bridge resistor; the one [low value] connected to the primary winding of the Left Amp. Is this 18 Ohms? I only see one resistor bridging R and L amps.
• Bias this R amp l like you've done with diyF6 .
• Disable power to the R amp [razor cut the traces].
• Lift the feedback resistor off ground.Connect its other side to ground.
• Repeat the above for the L amp tyo bias the left amp.
• Disable power.
• Lift the bridge resistor off ground.
• Now you are ready to apply power to both amps.

[buzzforb]

No need to cut trace. You can do each half, just grounding resistor and leaving out opposites sides power fets.

[Antoinel]

Originally Posted by Antoinel

buzzforb. This is a suggested procedure. Your pcb shows that power to both amps is applied simultaneously.

• Separate the turn-on of the amps
• Cut with razor the +Vc and -Vc traces to left channel. Ideally, each channel may have had its +/-Vc lines independent from the other.
• Ground the bridge resistor; the one [low value] connected to the primary winding of the Left Amp. Is this 18 Ohms? I only see one resistor bridging R and L amps.
• Bias this R amp l like you've done with diyF6 .
• Disable power to the R amp [razor cut the traces].
• Lift the feedback resistor off ground.Connect its other side to ground.
• Repeat the above for the L amp tyo bias the left amp.
• Disable power.
• Lift the bridge resistor off ground.
• Now you are ready to apply power to both amps.

buzzforb. Here is a much simpler procedure [than above] to start up.

• Cut with razor blade the traces emanating from the outputs to the 100 Ohm feedback resistor of each amp.
• Thus, both amps are no longer bridged, and each operates open loop, and independently for biasing..
• Apply power. Adjust the bias and stabilize the operating point of each amp like in diyF6 [one hour].
• Preheat the soldering iron
• Turn power off to the balanced diy amp
• Give yourself one minute to solder the traces that you cut.
• Power up.

If the above is not done, there is the probability that the series connected feedback resistors can see ~45 V, and thus overheat.

Best regards.

[buzzforb]

Ok. Thanks. Probably will not get to it today.