Hi all
Can someone tell me
- the mouser/RS reference for the 8 posts terminal blocks : got lost there 🙂-)
EDIT : got it : barrier terminal blocks ref Cinch Connectors 5-140 https://befr.rs-online.com/web/p/barrier-strips/2508740475/
- recommended type and avg for the F4 cables input/output
Thks
Jean-Louis
Can someone tell me
- the mouser/RS reference for the 8 posts terminal blocks : got lost there 🙂-)
EDIT : got it : barrier terminal blocks ref Cinch Connectors 5-140 https://befr.rs-online.com/web/p/barrier-strips/2508740475/
- recommended type and avg for the F4 cables input/output
Thks
Jean-Louis
Last edited:
Pass DIY Addict
Joined 2000
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Jean-Louis: for output wiring between the PCB and the speaker terminals, use heavy gauge stranded wire such as 12-14ga. For input wiring between RCA and PCB, use thin gauge, solid core wire, such as 24-30ga. A single twisted pair from telephone/CAT5 wire will work well. A few here will advocate for 30ga silver wire, which also works well.
Thanks a lot Eric ! Should receive missing components in few days, got 3xF4 to build + 3xBA3, hope I succeed the whole multi-amp system without burning the house (;-).
BR
BR
Would a 5U big chassis be enough for a "mono block" F4 build? Two F4 boards per side, with parallel/balanced inputs?
It is quite smaller and somewhat cheaper than a true mono block construction.
With a balanced BA3 preamp we could have a nice 50-100W class A system in a "compact package."
Would the BA3 power amp be able to supply the same power output as such a solution?
It is quite smaller and somewhat cheaper than a true mono block construction.
With a balanced BA3 preamp we could have a nice 50-100W class A system in a "compact package."
Would the BA3 power amp be able to supply the same power output as such a solution?
Yes. it will be a fairly tight fit, and your PSU requirements obviously double, but it's possible.
You may need slightly reduced bias.
Yes.
Yes. The BA-3 is a F4 with a gainstage in front of the power stage.
I'f I were looking for a preamp that would accept SE and BAL input and always output balanced ( I will have a balanced DAC but SE phono stage), tubes and transformers come to mind. I believe the impasse does such a trick, any solid state options?
Zen Mod's "Pumpkin" preamp is SE or Balanced in to SE or Balanced out. And has enough gain to run balanced F4.
Perfect.
🙂 🙂 🙂
Perfect.
🙂 🙂 🙂
Of course.
But the question remains, what will you use for voltage gain? (Or depending on your source, attenuation...)
But the question remains, what will you use for voltage gain? (Or depending on your source, attenuation...)
As I'm waiting for PE to get more parts in I thought I'd start making a BOM for an F4. That way if I really the ACA amps I can start gathering bits. A couple of questions on the F4 though. I'll be using the PSU board from the store and see that I most likely do not want/need to use input/output snubbers. Is that correct? I'll be shooting for the Antek AS4218 trafo and using monolithic rectifiers along with the soft start/protection pcb's.. Also, I noticed a difference between Mr. Pass's schematic and the store schematic for R8. Any suggestions there?
No snubbers required.
Soft start is not necessary.
IIRC R8 can be within quite a range. Use the one listed in the BOM in the store.
Soft start is not necessary.
IIRC R8 can be within quite a range. Use the one listed in the BOM in the store.
A few weeks back I was trying to correct big DC offset numbers. It was suggested I increase R7 to 5k pot... Worked like a charm 🙂
I built mine exactly as in the F4 production manual, 27.4k instead of 22.1k, 10r instead of 22.1r, 150r instead of 100r. Worked perfectly for me, but as they say your mileage may vary.
The only thing I had to change was 22.1k which limited me to 70mv. 27k sorted that out nicely. Currently running everything else stock.
I've just built my f4 and got it up and running.
My psu rails are +-24.5v.
I've biased to just over 200mv.
Do these amps take a while to burn in?
Whilst on my bench the heat sinks went up to just over 50C but don't seem to be getting anywhere near that warm whilst playing.
Possibly because on my bench it was up on end in the front panel. But wouldn't think it would have made as much difference as it seemed.
Was wondering what people thought I should bias this to. The stock spec is 200mv but most people seem to be running these much hotter. The build guide suggests 270mv to 300mv was optimum but that was with a 22.5 v supply.
My g&w t2.6f headphone/preamp will go loud enough to listen to music but enough to go loud in case any ones wondering. So will order the impasse kit.
My psu rails are +-24.5v.
I've biased to just over 200mv.
Do these amps take a while to burn in?
Whilst on my bench the heat sinks went up to just over 50C but don't seem to be getting anywhere near that warm whilst playing.
Possibly because on my bench it was up on end in the front panel. But wouldn't think it would have made as much difference as it seemed.
Was wondering what people thought I should bias this to. The stock spec is 200mv but most people seem to be running these much hotter. The build guide suggests 270mv to 300mv was optimum but that was with a 22.5 v supply.
My g&w t2.6f headphone/preamp will go loud enough to listen to music but enough to go loud in case any ones wondering. So will order the impasse kit.