Pass Labs B4 crossover questions

[Dennis Hui]

Lots of happy folks.

 

[Eslheadphone]

Cant wait. A BOM would allow us to order materials now. I will start laying out a chassis.

 

[WBS]

Thanks Nelson, I can't wait! You can't have too many excellent crossovers after all...

The funny thing is last week when I ordered a Mean Well 24V power supply from Mouser for my H2, I thought to myself, "I should probably order a couple more of these."

I should've listened to myself.

 

[wg45]

Looks like it might be time to put my SAE 4000 crossover out to pasture.

Thanks, Papa.

 

[feds27]

Awesome. Thanks Nelson!

 

[RogerGustavsson]

Is that +24V unregulated? A pity there is not a symmetric power supply (+/-) so that we could get rid of the coupling capactiors.

 

[Zen Mod]

that's bloody optimistic, counting on fact how many series connected capacitors one need to have in active xover stages

 

[WBS]

All you need:

Triad WSU240-0500-13

or

Mean Well GS06U-6P1J

 

[RogerGustavsson]

I mean the interstage coupling capacitors that are electrolytic. These cannot easily be replaced by film caps. The capcitors setting the slope/frequency of the crossovers must be film caps anyway.

 

[Zen Mod]

wait for Pa's schematic , then introduce bipolar supply, taking all Vref points to GND

remove interstage coupling caps

easypeasy

 

[Gyuri]

And how's about B5?
Would be my my greediest welcome.

 

[Nelson Pass]

wait for Pa's schematic , then introduce bipolar supply, taking all Vref points to GND

remove interstage coupling caps

easypeasy

There are only input and output coupling caps, no "interstage"

 

[planet10]

And how's about B5?

Isn’t that essentially what we already have in the diyAudio Store.

Analog Crossover Network – diyAudio Store

Aimed at the LX-mini but very versatile.

dave

 

[Zen Mod]

There are only input and output coupling caps, no "interstage"

me dunno

that's what Son of Gustav presumed ....

ZM Knows Station

 

[WBS]

Glad you know!

 

[ZUM911]

Isn’t that essentially what we already have in the diyAudio Store.

Doesn't look as versatile to play with various drivers as the B5 would be. I could be wrong but it looks like component values need to be changed to alter the crossover. With the the B5 you flick switches.

I'd be keen to see a DIY B5.

 

[planet10]

I believe that this simplification is also in the one we are talking about here as well. If you want to flic switches i think you will need to get a real Firstwatt one.

dave

 

[Giallograle]

Just logging on in the hope of a heads up when these arrive.

 

[R-K Rønningstad]

I tried to reverse engineer the B4. My guess is attached. The Rs have values ", 2R, 4R, 8R, ...
For the LP part of the B4 crossover, opening all DIP-switches will open R9 - R12 (see attachment). This means no signal will reach the inputs of U5 and U6. (Likewise, opening R1 - R4 will the audio straight to the positive inputs of U1 and U2. I guess maybe the gates are grounded via 1Meg?)

/RK

 

[Nelson Pass]

The Gates are provided with 2 Meg to ground to insure that there is no
excitement when switching or if the resistors are left open.