Pictures of your diy Pass amplifier

A 50W Dale RH series in free air does 20W at 25C ambient.
The 50W rating at 25C requires a heatsink surface that shouldn't be underestimated.

(btw, the Dale RH-50 and RH-100 have been around for many decades. When i first used them in the mid '80s, Dale was the single ready available industrial power resistor brand available overhere)

This is correct, and what I believed I had learned long ago was wrong...Thanks for setting me straight!
But I guess I proved those Dale RH-50 are tough!?
 
Add up all the dissipations of all the components making up your amplifier.
That should exactly equal the Power Input from the Mains.
...
Everything else is dissipated inside the chassis ...
And what about the power dissipated on the speaker coil?


Yep. Those "metal jacket" power resistors are intended for heat sink mounting, and should be significantly derated if not used that way.
I have managed to push 150W on a 25W resistor for a long-term period keeping it at 50-60º. I am using one of these heatsinks placed next to a 14cm industrial high CFM (and noise!) fan.
 
..More photos

I've tidied-up the wiring a bit, Plain F5 not yet TURBONIZED :)
 

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Last edited:
making progress

I wanted to share a pic of my current set up, I am very pleased with it. The baffles are 24" by 36". I have a diy f5 on the bass, and a diy f3 on the treble, and a diy xbzls pre. I have a b5 xover and a rotel rcd-02 with a new mclock and a class a analog stage. I have another f5 and zenv4 on the bench in progress.

I am adding slot loaded bass to the wings of the baffles, and will experiment with 4 or 8 ohm total bass load.

after using only one amp and single drivers for so long, this sounds pretty awesome.
 

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