Aleph J illustrated build guide

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astromo

astromo

Member
Joined 2017
Extreme_Boky said:
I think that the toroids can work above 40degC with no issues. I personally never had a problem with them overheating in class A amplifiers. Once again, the only problem with open-style toroids (non-potted) is if the plastic wrapping may become loose and allow windings to vibrate. Potted transformers seem like a great idea, especially if they are supposed to be supplying constant currents of around 2-3-4 amps. I'd call this a great long-term investment.

Re rating, I remember Nelson mentioned that there is no point in wasting VA rating; however, he had his transformers made as per VA requirement, BUT the iron was speced a level-up; If Aleph J requires 300VA transformer, he would go for 300VA windings, wound on iron speced for 400VA.
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Nice. Nelson has a few advantages over simpletons like me with single unit purchasing power. In my case, I spent the extra and opted for a potted transformer. Undoubtedly OTT but at least it's built to last and I have this uncanny ability to pick up annoying buzzing sounds - so, I was happy to pay for the insurance.
 
S

spryor

Member
Joined 2013
Zen Mod said:
1.with this load , you'll get around 1.25x more DC Volts than inputting AC Volts , so you're good with 35Vdc caps

in any case , don't go lower than 60mF as sum of all caps , per channel

2. these are good quality ones

3. personal preference ; I'm using metal diode bridges almost always

4. I=U/R ; 20mA to 30mA is enough ; calc dissipation as P=I^2 x R , go for 3-times declared power of resistor
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6L6 said:
I agree with everything Zen Mod says.

1) You are fine with the caps you have.

2) Nichicon are great.

3) Simple is good. It's also less expensive. There may be an advantage to the fancy diodes and such, but I've built plenty both ways and can't tell much difference. I've been using discrete lately.

4) 2.2k 3W. :). But anything 2K-20K 3W will work great, It just drains the capacitor bank when powered off.
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Thanks Zen Mod and 6L6 for your replies a few days back. I just saw that Antek has the 4218 transformers back in stock so I went ahead and ordered a couple to have on hand for the eventual dual mono build :)

One more minor parts question: Will this do for a terminal block for wiring the primaries?

Thanks!
 
S

spryor

Member
Joined 2013
Thanks! I think that's the final piece for my Mouser cart...

Well... one more question since I'm writing: I used 22 gauge wire throughout my BA3 FE pre and that seems to be working well. Can I stick with that gauge for the Aleph J? Specifically I'm wondering about the PSU connections. I recall reading somewhere that Nelson and others like small wire for signal and heavier gauge wire for the power supply. And any preference between solid vs. stranded in each of these applications?
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
energy lines - everything you can squeeze in pads , and that would be 1-2mm Dia , fatter the merrier , stranded of course

solid core good when you have eyelets and terminals , but when dealing with pcbs , solid core is critical from multiple reasons

for input signal I'm using twisted solid core , 0.15mm Dia
 
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