You would use 1 fuse only for the primary circuits. As I stated above, when properly implemented, the transformer is the most reliable major component in your power supply. I have replaced hundreds of shorted power supply caps and many blown rectifiers over the years, but only twice have I seen a transformer fail. One was abuse and the other was likely a manufacturing defect.
The answer is to use a speaker protection board. That way you are insured against blowing an expensive speaker regardless of failure mode.
The answer is to use a speaker protection board. That way you are insured against blowing an expensive speaker regardless of failure mode.
This was my thought as well.
As long as everything is behind a single fuse, risk is not really higher than a standard build. And risk in that case is very low, as evidenced by the fact that the FW commercial build doesn't have a protection circuit.
And at risk of sounding like a broken record. I continued to just love this addition to the design all night. Absolutely no way I'm going back to a single transformer per channel. Better imaging, clarity, and precision with a more holographic presentation.
As long as everything is behind a single fuse, risk is not really higher than a standard build. And risk in that case is very low, as evidenced by the fact that the FW commercial build doesn't have a protection circuit.
And at risk of sounding like a broken record. I continued to just love this addition to the design all night. Absolutely no way I'm going back to a single transformer per channel. Better imaging, clarity, and precision with a more holographic presentation.
Thanks for everyone's insights. Assuming equal risk of unlikely failure, and assuming DC protection, is there a compelling reason to go with one solution or another:
1) PSU for each rail?
2) PSU for each phase?
cal3713, thanks for letting me hop onto your question. I hope I didn't muddy the waters. Sounds like it was well worth the experiment.
1) PSU for each rail?
2) PSU for each phase?
cal3713, thanks for letting me hop onto your question. I hope I didn't muddy the waters. Sounds like it was well worth the experiment.
Thanks for everyone's insights. Assuming equal risk of unlikely failure, and assuming DC protection, is there a compelling reason to go with one solution or another:
1) PSU for each rail?
2) PSU for each phase?
cal3713, thanks for letting me hop onto your question. I hope I didn't muddy the waters. Sounds like it was well worth the experiment.
Ha! Not at all... that's what the thread's for.
As for your question, clearly you need 8 transformers!
(Wish I knew the answer to your question... if I had to guess, I'd say each phase because it provides more isolation than the rail setup)
LOL! I hope I wouldn't need 8.
Currently the set up is dual mono stereo amps.
Chassis 1 / Amp 1
Left Channel: 1 PSU, Both rails one donut
Right Channel: 1 PSU, Both rails one donut
Chassis 2 / Amp 2
Left Channel: 1 PSU, Both rails one donut
Right Channel: 1 PSU, Both rails one donut
What I had considered would only require changing the input stage wiring from SE to balanced per the normal design. I can also make it 'user switchable' from Bal to SE. The front end shares the same PSUs.
Chassis 1 / Amp 1
Left Channel (-) Balanced OR Left Channel stereo SE: 1 PSU (dual rail)
Left Channel (+) Balanced OR Right Channel stereo SE: 1 PSU (dual rail)
Chassis 2 / Amp 2
Right Channel (-) Balanced OR Left Channel stereo SE - 1 PSU (dual rail)
Right Channel (+) Balanced OR Right Channel stereo SE - 1 PSU (dual rail)
It's the most simple change, but I was curious re: one donut per rail (shared between phases) vs. one donut per phase. For simplicity's sake, I think the one PSU per phase is likely best, but I am curious.
Currently the set up is dual mono stereo amps.
Chassis 1 / Amp 1
Left Channel: 1 PSU, Both rails one donut
Right Channel: 1 PSU, Both rails one donut
Chassis 2 / Amp 2
Left Channel: 1 PSU, Both rails one donut
Right Channel: 1 PSU, Both rails one donut
What I had considered would only require changing the input stage wiring from SE to balanced per the normal design. I can also make it 'user switchable' from Bal to SE. The front end shares the same PSUs.
Chassis 1 / Amp 1
Left Channel (-) Balanced OR Left Channel stereo SE: 1 PSU (dual rail)
Left Channel (+) Balanced OR Right Channel stereo SE: 1 PSU (dual rail)
Chassis 2 / Amp 2
Right Channel (-) Balanced OR Left Channel stereo SE - 1 PSU (dual rail)
Right Channel (+) Balanced OR Right Channel stereo SE - 1 PSU (dual rail)
It's the most simple change, but I was curious re: one donut per rail (shared between phases) vs. one donut per phase. For simplicity's sake, I think the one PSU per phase is likely best, but I am curious.
Extremely helpful insight that I had not considered. I have the the existing CL-60 thermistors typical to most First Watt builds in each "PSU" section. However, I have been investigating not only "beefier"/alternate thermistors from Mark's awesome thread, but various combinations of relay-based / time delay soft starts with DC protection as all-in-one units. I definitely realize that those can add complexity, but they may offer me a better sleep, to steal a phrase from the mighty ZM.
Thank you!
Thank you!
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I've tried with my builds the difference between 'plain' stereo power supply and dual mono power supply - a couple of times. Last time with a F7 build.
The difference is not small.Definitely, always dual mono if possible. No going back to stereo PS.
So true.
F4 Power Rating into Lower Impedence
Can someone tell me the power rating for the F4 when in balanced mono and parallel mono?
"In mono balanced operation, you can achieve up to 100 watts output into an 8
ohm load."
Can it go higher into 4 ohms in balanced mono?
"It will do 50 watts into 4 ohms,
and as a mono-block amplifier with parallel inputs and outputs, it will do about
100 watts into 2 ohms."
The above pretty much answers the question about parallel mono.
I'd like to try the Magnepan LRS which is 4 ohm at 85-86db.
Thanks.
Can someone tell me the power rating for the F4 when in balanced mono and parallel mono?
"In mono balanced operation, you can achieve up to 100 watts output into an 8
ohm load."
Can it go higher into 4 ohms in balanced mono?
"It will do 50 watts into 4 ohms,
and as a mono-block amplifier with parallel inputs and outputs, it will do about
100 watts into 2 ohms."
The above pretty much answers the question about parallel mono.
I'd like to try the Magnepan LRS which is 4 ohm at 85-86db.
Thanks.
It will be fine. F4 has lots of output devices and can send plenty of current to grumpy speakers, so lower than 8-ohm loads present no challenge.
Remember that power in W is a mathematical construct, Vrms^2/R, where the R is speaker load in ohms. Obviously if the divisor becomes smaller the quotient gets bigger. (If, in our case, the amp can push the current into the lower impedance, which F4 can...)
Remember that power in W is a mathematical construct, Vrms^2/R, where the R is speaker load in ohms. Obviously if the divisor becomes smaller the quotient gets bigger. (If, in our case, the amp can push the current into the lower impedance, which F4 can...)
Speaker protection boards are normally single channel in layout and on a single pcb. But, fleabay has lots of cheapies that work but you need to change the relays to Omron or other quality ones.
UPC1237 Dual Channel Speaker Protection Circuit Board DC 12-24V Boot Mute Delay | eBay
UPC1237 Dual Channel Speaker Protection Circuit Board DC 12-24V Boot Mute Delay | eBay
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