Aleph J illustrated build guide

[dehaai]

Hi guys,
just a quick question, does you're Aleph J produce any hum when its not connected to a pre-amp/buffer or some other kine of equiptment?

 

[Zen Mod]

nope

 

[tonistefanovski]

Dead silence

Hi guys,
just a quick question, does you're Aleph J produce any hum when its not connected to a pre-amp/buffer or some other kine of equiptment?

 

[dehaai]

@Zen Mod & tonistefanovski,
thanks.

then its back to the workshop for me .

ps. without any drawings....... i connected the ground of the inputs to GND3 instead of the GND next to the +in and -in, does this cause any problems?

 

[Zen Mod]

question for guys involved in exact pcb design

 

[tonistefanovski]

@Zen Mod & tonistefanovski,
thanks.

then its back to the workshop for me .

ps. without any drawings....... i connected the ground of the inputs to GND3 instead of the GND next to the +in and -in, does this cause any problems?

Maybe this would help

 

[2 picoDumbs]

If you have dual mono in a single chassis then a thermistor per channel is a good idea.
You should also have input signal ground going to star ground. I think that's what you have shown but need to confirm it.

 

[tonistefanovski]

If you have dual mono in a single chassis then a thermistor per channel is a good idea.
You should also have input signal ground going to star ground. I think that's what you have shown but need to confirm it.

In my recent Aleph J build I’ve connected signal ground to main board… I’ve did that several times without problems… Always “dead silence”….
Tony

 

[dehaai]

I do have a dual mono setup attached to one power supply (diyaudio power supply).
I attached the PSU with one thermister to the chassis with a bolt on that same bolt i wired the savety earth.

thanks for you're answers so far. next week a collegue will help me with a scope to search for the hum.

 

[ElectroNick]

Please also check your inputs (RCA or XLR); no direct connection to ground.

Pictures could help, if you have some.
Please post 'em.

Good luck !

 

[dehaai]

only RCA, and no connection to ground, i've put the fotos in an album on onedrive:

http://1drv.ms/1LK79gs

at the moment only the aleph J boards are connected, the photo's also show a Mez B1 board but it is disconnected at the moment for the sake of troubleshooting. when i short the inputs of the aleph J the hum disappears.

 

[dmtparker]

Placeholder post because I will probably need one here as well...

Comments, questions, etc... Go right ahead!

What gauge wires did you use for PS-> board? Also for audio signal (in/out)?
I have a distinct tendency to use wires that are much larger than necessary and I would like to avoid that. But, of course, I don't want them to be too small either!!
Thanks

 

[audioexplorations]

deHaai - is the hum equal in both channels? is it a low frequency hummm or more of a higher frequency hiss?

 

[6L6]

What gauge wires did you use for PS-> board? Also for audio signal (in/out)?

I use whatever I have on hand, and closest to what fits in the holes of the PCB.

For input wiring, coax or twisted pair is best. If you have an unused CAT-5 cable, open that up and you will find many strands of twisted pair perfect for signal wiring.

 

[jdg123]

I'll second 6L6. I have built with 15ga and 18ga and I can detect no difference.

 

[wdecho]

I'll second 6L6. I have built with 15ga and 18ga and I can detect no difference.

Me too, 18 gauge is so much easier to work with so I am using it for all builds now.

 

[dehaai]

deHaai - is the hum equal in both channels? is it a low frequency hummm or more of a higher frequency hiss?

Low frequency, definitely a hum.

 

[dehaai]

I do have a dual mono setup attached to one power supply (diyaudio power supply).
I attached the PSU with one thermister to the chassis with a bolt on that same bolt i wired the savety earth.

thanks for you're answers so far. next week a collegue will help me with a scope to search for the hum.

today we diagnosed the hum problem with a scope and found that there is 0,4v of AC on the DC side of the psu, is 0.4v enough to cause a hum?

 

[rtirion]

What was the frequency of the hum? 100Hz means supply born. 50 Hz means input born.
If its input born 50Hz simply make sure to use a piece of shielded cable between input and PCB. Or try to relocate the transformer.

 

[dmtparker]

For input wiring, coax or twisted pair is best.

I've always used twisted pairs for PS wiring as well - 24/0 as pair and 0/-24 as pair, but I see you just ran straight wires for 24/0/-24. Any advantage / disadvantage for twisted pairs on the POWER side. (obviously very important for input)
What about OUTPUT? I usually twist them as well. I guess it looks neater, but does it really matter?