Awesome work on your F4 builds, 2 picoDumbs. As they say... No pain, no gain. (Pun intended? idk...)
And Norrlands Guld, page 8 of the F4 manual states the following:
"For parallel operation of the two channels as one, you must connect the outputs left positive to right positive either at the connectors themselves or by “bi-wiring” the loudspeaker with two sets of cables. Remember that the positive outputs have a red band.
The black banded output connectors are already connected together to ground, so you can make this connection externally or not as you please."
No mention of any extra resistors.
And Norrlands Guld, page 8 of the F4 manual states the following:
"For parallel operation of the two channels as one, you must connect the outputs left positive to right positive either at the connectors themselves or by “bi-wiring” the loudspeaker with two sets of cables. Remember that the positive outputs have a red band.
The black banded output connectors are already connected together to ground, so you can make this connection externally or not as you please."
No mention of any extra resistors.
Thanks!!
I was just confused with all write ups on the net:
Paralleling Amplifiers Increases Output Drive | Analog Devices
Bridged and paralleled amplifiers - Wikipedia
As close to 300 as you can get without making your heat sinks too hot to hold your hands on!
I ran mine at 400mV for many hours in a 3U (lid off) No problems. But, I dialed it back to 300. I just think it sounds a tiny bit smoother at 300 over 200mV. Once it’s had some run in time, it may sound exactly the same at 200 vs. 300.
I always make an initial bias at startup, then 15 minute intervals (with lid on),checking it. I don’t make any final adjustments until 1 hour.
David,
You can check page one of this guide and 6L6’s other guides for guidance.
A separate psu chassis IMHO is overkill. This is a simple design that needs a simple, clean psu layout with a star ground. Just add a chassis with enough heat dissipation to the mix, that’s it. A deep 4U is plenty.
I have a dual-psu in external chassis. You can use a four-lead cable with Neutrik connectors, +/-/0/chassis ground. I use shielded 3x2.5mm and extra ground to chassis. PSU as a general Pass. 0 to PSU ground and chassis ground to PSU ground star. In amp chassis you can boost with caps between rails and ground with short cables. ZM suggested motor runs 65uF or more. If I may add F4 is fantastic with or without external PSU. An external PSU makes me try more amps at less cost.
