Aleph J illustrated build guide

Hi members,
I think I did it.....first adjustments done.....seems to run fine.
I went with adjustment guide from 6L6 on the thread start setting bias to 0,4v and zero dc offset.
Now powered on bias is up over 4,5v settling down to 0,4v.
Highest temp on device just under 65C and 55C heatsink.

But I found another post with adjustments posted by ZenMod that needs to put 10r,100r or 1k for R30.......i still have jumper at R30....should I change?!

Another question......I’m still not sure with the fuses.....I’m running 240v 400va transformer
What fuse value makes sense?!

Thanks
Gregor
 
Member
Joined 2016
Paid Member
Hallo Gregor,

congratulations!
Fuse value should be the lowest that doesn‘t blow on start-up. ;)

A good starting point is half the value that the folks with 120 V AC mains use.
In my Aleph J build, I have 1.25 or 1.6 amp rated fuse. I use a single CL-60 in series with the mains for slow-start.

Best regards, Claas
 
Here it is .... :)

Hope image shows up ....
 

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Hi all, just wondering if anyone has run Q Acoustics 3050's with the Aleph J. I can get a pair for a great price. Only concern is they are 6ohm nominal, but 92db sensitivity. I can't imagine I will run the amp into clipping with the level I listen at, not trying to recreate concert volume, but want to be sure. I know the amp is rated at 13watts 4ohm on the First Watt site and thought it said Mr Pass doesn't know of a load that will damage it. A newbie question I know...
 
First Aleph J listening tests....make me smile....
....this amp sounds BIG and SWEET...great imaging and focus...
I run it first of all with my 100k passive preamp....

But I have a audible hum on the right channel .....any suggestions how to locate the problem.....?

Thanks all .....Papa Nelson....6L6....ZenMod.....DIY Audio....and all members sharing their ideas, knowledge and passion for no profit!!!

Gregor
 

6L6

Moderator
Joined 2010
Paid Member
First swap input wiring L-R and then output wires L-R and make sure it's the amp channel and not something else.

Does it hum with nothing connected? Does it hum with a different preamp?

Does it hum with the input shorted?

Is the hum mains frequency (50hz) or 2x mains (100hz) ?
 
First swap input wiring L-R
.....Hum stays at right channel

and then output wires L-R
......hum moves to the left

and make sure it's the amp channel and not something else.

Does it hum with nothing connected?
No hum.....just very little....same level on both channels

Does it hum with a different preamp?
.....no other preamp available at the moment

Does it hum with the input shorted?
.....both channels dead quiet

Is the hum mains frequency (50hz) or 2x mains (100hz) ?
I would say it’s typical 50hz
Can I measure somehow?!

Thanks