My new Aleph ONO Phono Section

[Algar_emi]

Case laquer

Here the suspension plate with MinWax Laquer Red Mahogany.

 

[Algar_emi]

Laquer Details

A few close shots of the laquer.

 

[Algar_emi]

Case Metal just starting

I completed the cutting of all the aluminium plates for the case. Don't forget there is 2 cases for just one ONO. One for the transfos and unreg supplies, the other for the reg psu and ONO Preamps pcb. I cut 2 complete sets, one case for the ONO the other for my SuperDAC.

 

[Algar_emi]

Unreg Supply Schematic

I just forgot to post the last schematics. Here the Unregulated power Supply with Soft Recovery Diode and Black Gate snubber cap.

 

[Algar_emi]

And the Reg PSU

And the regulated Supply.

 

[Alain Dupont]

Algar,

You cited: Electrosonic in "My new Aleph ONO Phono Section"

could you give us the link to their site, please.

Regards.

Alain.

 

[Algar_emi]

Supply Enclosure Done

Here a picture of the Supply Enclosure. All the metal is cut. Still doing the assembly. Should have the main enclosure done too this week-end.

 

[Algar_emi]

A better view of the assembly. The quality of craftmanship is not too bad 😀

 

[Algar_emi]

Inside detail. The case is made of 1/8 inch aluminium. I used 3/8 bar in each corner. All the screws are 4-40 Stainless Steel.
The finished enclosure a pretty rigid but the top cover rings like a bell. I will cover all inside surfaces with bitumen type pad to kill the vibration. I used a piece of scrap alu for the bottom. This is why there is scratches on it...

 

[Algar_emi]

Oups.
An other user found a small error in my schematic. The Positive Output was not connected to the output connector.

Here the corrected schematic.

 

[Algar_emi]

Oups, a few errors (around SW2) and parts name addition.
I hope these are the last corrections, sorry Guys. 🙄

 

[nagard]

Hi !
......,you forgot R5 going to the positiv power supply on one side, and to the D5 anode at the other side...

 

[Algar_emi]

😎 I guest that with all your help, I found and corrected all the errors now. I added voltages and current test point values to help you test your Ono. Here the last version I hope.

Bye...

 

[VS]

Hi,

I've found a new schematic error...I hope is the last one!

C5 is not 0.027uF but 0.0027uF

Regards,
VS

 

[Algar_emi]

Here the latest version. Corrected C5 and there was 2 C1, renamed correctly 4.7uF C28.

 

[Algar_emi]

Working toward the completion of this project. I bought a really nice ONO original style enclosure from an other user on this forum.
It looks just like the real thing. I'll install the 2 main preamp and regulated PCB inside it.

Using the same wood decoupling platform as discussed ealier, I'll place the new ONO enclosure on top, and I'll keep my separate power supply under it.

Since I'm also working on an Aleph X preamp clone, I wanted to use the same connectors and connector pins pattern as used into standard PassLabs power supply products. Their power supply can supply a X1 preamp and an Ono at the same time. The PS supply +/-40V and +/-10V for the digital, all unregulated, are available on both DB25M connectors

To be able to do so, I design a new PCB for my power supply section. Both +/-40 Unreg Power supply will connect there. There is also a new +/-10V Unreg Digital supply added on that PCB. Finally it can supply the PS front blue led. All supply voltages are available on both DB25M connectors. Since I'm using fully dual mono supply, I made each L and R power supply bigger traces (lower impedance) on each L and R connectors. So I'll be able to use this supply for my X preamp if I wish to.

Here this PCB

 

[tmblack]

Can someone tell me how well matched do the JFET's 2SK170 need to be? What are there Vp?

Thanks

Tom

EE

 

[Alain Dupont]

tmblack,

>> how well matched do the JFET's 2SK170 need to be? What are there Vp

PS with 8/12 volts DC and a serie resistor of 22 Ohms, 4 resistors matched at 0.5 ohm
JFET's 2SK170 are gettind 2.5 mA each so you have to match them at 2.5 mA
and the error delta v accross the fet's from 0.1 to 0.05 Volt would be very good 🙂

Alain.

 

[tmblack]

and the error delta v accross the fet's from 0.1 to 0.05 Volt would be very good

Alain.

Hi Alain,

how many 2SK170 did you go through to find 4 matched jfets?

Tom

EE

 

[Alain Dupont]

tmblack,

>> how many 2SK170 did you go through to find 4 matched jfets?

If i recall correctly:
about 32 * 2SK170-GR to get 2 sets of 4 matched at better than 0.1 volt .

Alain.