Aleph J illustrated build guide

Official Court Jester
Joined 2003
Paid Member
Public Apology to Andy

.... for so freely used term "idiot"

well, Court Jesters and Village Idiots are my fave characters, so that's probably reason why that term is not having so negative implications for me

not excuse, just stating the fact



VIkings are dumbidiots, still thinking about that**

'Talians are artists, 'nuff of them selling that sort of Drek to Vikings and rest of Population

Peppe replied you adequately

btw. 'Talians had Marco Pantani, too ; King of the Mountain

go figure

still remember - was watching both Giro and Tour that year , when he won both

he drove it with Pure Will


**most recent confirmation being - my Polish Guy having Babelfish Aleph XJ , decided to waste some greens od Adiophoolfuses
his own Verdict - he wasted those greens

if in doubt - use nails ..... or skip fuses all-together

invest money on proper insurance

:devilr:

Public apology to
 

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Official Court Jester
Joined 2003
Paid Member
Hi, can I get some help with the PSU for this build? I FINALLY started getting parts out of bags and working on the PSU board. I am following the build guide here (meaning I am using the off-board rectifiers). I ended up with (8) 35V 22,000uF caps and have the 400VA 18V Antek transformer.

For the 8 filter resistors (R1-R8), have the 0.47 ohm 3 watt ones I see for all these builds. No issue (unless there is an issue based on the parts I mention above!)

For the 2 bleed resistors (R9-R10), on the first page of this thread I see the diagram and 6L6 reference 2.2Kohm (2,200), however I ended up with 22kohm (22,000) resistors based on a saved cart I used. To be blunt, should I put these aside and buy 2.2Kohm resistors?

For the 2 LED resistors (R20-R21), using 10Kohm and this LED (I have a red/green set, but same electronic values): TLHR5400 Vishay Semiconductors | Mouser - are these resistors the appropriate value for the board voltage and LEDs I have? I have played around with some calculators but not 100% sure.

Thanks!

buy 2K2 for bleeders

for LEDs, everything from 10K-22K will work properly

Collecting parts for the build… Well, time for noob questions deluxe🙂

What is the green and yellow connected to inside the transformer? To some shielding or to the core? Center tap???

We have got 230V here in Sweden.

Should i connect green/yellow to the safety ground in the Aleph chassie?

yeah, that's so called "static shield"; connect it to same screw on chassis, where safety GND lead from IEC is connected
 
For AC line fuses, I use the ceramic sand filled variety. I’m not worried about audio performance at the input to the power transformer. Sand filled fuses are intended to prevent the fusible element from reconnecting after being open by an over-corrupt condition.
Fuses in supply rails are a different matter, as they are now part of the drive current path for the amplifier. I have not experimented with these, as I prefer to not use fuses here to begin with.
 
Member
Joined 2016
Paid Member
I typically do fuse the B+ rail in my tube amplifiers, and I see that the small fuses (like 50 mA or 100 mA) do indeed have a few Ohms of resistance. In line with my thinking of low-impedance PSUs, I try to have the fuse before the last buffer capacitors.



Regards, Claas
 
To chime in on the 'cleaner' power side of things. I use a Monster Power HTS1600 (Isolation filter and surge) only because you can find them for next to nothing on the likes of Craig's list and such. Not sure if it really helps, but at the very least its interesting to watch the line voltage sag change throughout the day while the tunage plays.

If you hunt around, eventually you'll catch someone cleaning out a house and dump it for $15 near you. :) I wouldn't pay more than an arbitrary 45 buckazoids.

Monster Power Surge Protector | Stereo Systems & Home Theatre | Ottawa | Kijiji

https://www.ebay.ca/sch/i.html?_nkw=HTS1600&_sop=12

++ POWER SURGE OUTLET ++ - electronics - by owner - sale
 
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Official Court Jester
Joined 2003
Paid Member
pretty much any non- already-bridged amp can be bridged

and even some already bridged amps can be bridged again ( having 2 of same)

so, yes - Aleph J can be bridged, and worth mentioning - these made as already properly intrinsically bridged Alephs are known under name Aleph X

there were even projects on forum done in past - to make Aleph X from two channels of Aleph J

but - Aleph is tricky - not being able to leave Class A - one must not forget that in bridged arrangement current in two halves is the same/one , while each half is seeing half of load , so working twice hard

with that, you must increase Iq, stepping in Mucho Heat territory

still at first half of morning coffee, I know I could write it in less words .......... :clown:
 
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j175

It was probably beaten to death, but what about j175 for input stage?
It is not biased by Idss, so i am not worried about it.
Did some spicing in ltspice, but pretty sure j175 model must be broken, it gives too low H2 for paralleled 175's..

I know this is not discovery of warm water or anything, and worse than Toshiba parts for sure, but how much worse can it really be for a junkbox build? Maybe j176 or 177 would be better, but 175 is what i have on hand..
Why is p-channel jfet world so dead in 2021? Born too late to explore the world, too early to explore the stars, but just the right time to watch pch jfets dissapear.

Put the images and sim file in attachments

Cheers
 

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