Aleph J illustrated build guide

[6L6]

Neutral really shouldn't be fused. If there is a 10A fuse in the kit, put that on the Neutral and make absolute sure it's on the Neutral. And then double check that the proper size fuse is on Live.

 

[e_fortier]

This seems like an odd kit...there’s 2 different fuses value?

 

[6L6]

I think some of the back panel kits that have a dual-fuse drawers in the power entry module there is a quite large fuse intended to go on the Neutral (in 110v countries) that effectively places the entire fuse duty on the Live, as it needs to be. Perhaps I'm thinking of the Whammy kit...?

 

[Vunce]

I believe tizman is using his own parts, not a kit from DIYA store.

 

[tizman]

If your product only has one fuse on the primary side, it must be installed on the Live side, not neutral.

The inlet has one fuse, that is on the live side, and I will put the other added fuse on the neutral instead of on the ground.

 

[tizman]

I believe tizman is using his own parts, not a kit from DIYA store.

Yes. I added the extra fuse and connected it to the ground instead of to the neutral. I am correcting that now.

 

[tizman]

As Andy mentioned, twisting of wires to minimize loop area is beneficial. To each channel, the V+, V-, and Gnd should be tightly twisted together. The Gnd should follow the V+ and V- wires to their connection points on the board, and then the Gnd goes to its connection point.

Rotating the transformer to find the quietest orientation is also beneficial. If your transformer is an Antek, I have found that they "leak", and the quietest orientation is with the location of the AC in and out of the toroid pointing towards the front and back of the case.

How much capacitance do you have in your power supply? In my experience with my 103dB speakers, a 44mF - 0.1R - 44mF CRC filter will still have a very low level of hum that is audible with my ear against the speaker. This is after taking care minimizing loop areas and EMF emissions.

To further minimize ground loops, all components of the sound system should be plugged into the same wall AC receptacle. Use a power bar if necessary.

I am using the DIY Audio Power Supply board, and it has a 8X 33000 uF. 264000 uF in total.

 

[tizman]

Thank you all for the help with my build. Here are a few photos of my progress this evening…

I relocated the rectifiers closer to the front of the amp and further away from the signal boards. I also tightly twisted the wires from the rectifiers to the power supply board, and positioned them further away from the amp boards, and to the middle of the amp.

I also connected the ground from the two sides of the power supply board on the same side that the V+ and V- are on, rather than on the side that the rectifiers feed. I’m not sure if I understood what was required and did it correctly in this case.

 

[Extreme_Boky]

Looking good.

To experiment with the ground lift resistor (this will reduce the buzz pretty much completely), see the attached photos: before and after ... self-explanatory...

Once you are happy (try to find the minimum ohms that will work for you, start with 10 ohms), implement it in full/permanently 🙂

 

[Extreme_Boky]

Just in case you'll need the photo of the permanent ground-lift implementation (I used 10 ohms resistors with RCAs single-ended input.... but later moved to a fully balanced topology - dead silent... no buzz and no hiss - amazing):

 

[tizman]

Looking good.

To experiment with the ground lift resistor (this will reduce the buzz pretty much completely), see the attached photos: before and after ... self-explanatory...

Once you are happy (try to find the minimum ohms that will work for you, start with 10 ohms), implement it in full/permanently 🙂

View attachment 1098952

View attachment 1098953

Will do. I’m going to try to minimize hum through a more thorough approach to lead dress, and then try the ground lift resistor once I’ve done all that I can inside the chassis.

 

[tizman]

This is the fixed power inlet with the second fuse moved from ground to neutral.

 

[Vunce]

Where does the wire thats soldered to the AC inlet Gnd tab connect? Picture if you can.

 

[tizman]

It may be just me, but two of those three connections look as if they were made with an iron that wasn't man enough (or hot enough?) for the job.
GND in particular.

It was okay, but I reflowed it and it looks better now.

 

[tizman]

Where does the wire thats soldered to the AC inlet Gnd tab connect? Picture if you can.

I took it off the fuse and put it directly to chassis ground.

 

[tizman]

As Andy mentioned, twisting of wires to minimize loop area is beneficial. To each channel, the V+, V-, and Gnd should be tightly twisted together. The Gnd should follow the V+ and V- wires to their connection points on the board, and then the Gnd goes to its connection point.

Rotating the transformer to find the quietest orientation is also beneficial. If your transformer is an Antek, I have found that they "leak", and the quietest orientation is with the location of the AC in and out of the toroid pointing towards the front and back of the case.

How much capacitance do you have in your power supply? In my experience with my 103dB speakers, a 44mF - 0.1R - 44mF CRC filter will still have a very low level of hum that is audible with my ear against the speaker. This is after taking care minimizing loop areas and EMF emissions.

To further minimize ground loops, all components of the sound system should be plugged into the same wall AC receptacle. Use a power bar if necessary.

I am twisting the V+ V- and ground wires together now. I am running the wires across the board as it places the wiring further from the rectifier. Twisting is hard to do with the Teflon coated wire I am using. This is a photo of where I’m at. Should I braid or simply twist the three wires at this point?

 

[Ben Mah]

Twist is better than braid - smaller loop area.

 

[tizman]

One side’s power wiring done.

 

[tizman]

Both sides done.

 

[tizman]

I tested the amp on my Khorns. It still hums. The hum sounds exactly the same in both channels. Its lowest in volume when one channel has an RCA cable plugged into it. Adding the second increases hum. This is true for a source and for shorted plugs.

I’m glad I went through and reduced the potential sources of hum. Moving wires around doesn’t seem to affect the hum’s volume level anymore, so I m calling the lead dress good.

Next is Boky’s ground mod. Is it best to desoldering the transistors from the PCBs in order to remove the PCBs? Is it better to unscrew the transistors from the heatsink??