A guide to building the Pass F4 amplifier

can you grasp this?

I know it demands some work ......

on the other hand ....... I presume that's dual primary Donut , so check with continuity test am I on right track :

Yellow One and Red One are one Primary

Yellow Two and Red Two are next Primary

if yes , for UK mains ( aroundish 230Vac?) , connect Yellow one to Phase , then together Red One and Yelow Two ( insulate that connection) ,then Red Two to Neutral

if you're using regular fuse (750VA/230Vac = approx 3A15T) , nothing catastrophic can't happen , except maybe some heart palpitation 🙂

well , all this counting that your're speaking about primary colors , while secondaries are ignored this time

just in case - secondaries are always having much fatter wire , while primaries and shield are having skinnier
 

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Would somebody be kind enough to clarify whether the TL-431ACLP is a suitable part to use in the F4 build please?
It seems there are more versions of the TL-431 than there are fish in the sea! Mouser don’t have a “regular TL431” as ZM suggests we use (in F4 power amp thread -post 4399), they all have a string of letters after the 431 and the data sheet doesn’t make it clear what those letters mean.
Dennis Hui said (post 4400) “The F4 schematics, with TL431 shows an adjustment range of around 7 to 9.4V”
The 431ACLP datasheet says “The output voltage can be set to any value between Vref (approximately 2.5 V) and 36 V, with two external resistors”, so I assume (always a dangerous thing) that the TL-431ACLP will work just fine in the F4 circuit with the standard resistors for R8 and R9. Is that a correct assumption? Thanks.
 
First, disconnect the amplifier boards from the PSU. You don't need to have them attached until the PSU is sorted and working. 🙂

Which secondary leads are mates? Each secondary is a single piece of wire looped around the core, that wire has a beginning lead and an end lead. Continuity test will show which is one end and which is the other.

Check your PM
 
@Belmondo - Follow the advice provided. I made the error of ordering a close, but not quite part. TLV431ILPR... This wonderful community helped me realize and correct the error of my ways after my MOSFETs wouldn't kick in. Low Voltage version ... nope... nope... nope. Oops 😀
 
Thanks again for all the advice, much appreciated, especially by ItsAllInMyHead. I did read about you prefix problem which is why I started paying attention to the types of TL-431. 6L6’s recommended part is now in my BOM

I’m now at the last hurdle with my BOM. Trim-pots. Bourns has different pin configuration - straight and offset - all have 3 pins but there are 4 holes on the pcb for the trim pots. Little things like this completely throw a beginner!

Are there 4 holes so I can use trim pots with either the 3 pins in-line or those with the pins off-set? I don’t want to buy the wrong ones as they are relatively expensive and then there’s the carriage cost on top for a re-order if I'm wrong! I’m looking to buy this: 3296W-1-502LF Bourns | Mouser Российская Федерация
and the 500 ohm version. Thanks again for your help. I’d be lost and pulling out what’s left of my hair without it!
 
@belmondo - if you're so inclined. If I had it to do over again, I'd have put in the pots with the adjustment on the side. I can't remember if the F4 boards have both in-line and Y configuration, but something like this makes it so much easier to adjust the bias and offset. I couldn't find the exact part I was looking for, but someone with better Mouser-Fu skills may be able to jump in with the exact part number for both pots.

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