Aleph Ono Project (from PCB group buy)

[pquadrat]

ERROR on power supply PCB !!!

There is a small error in the power supply PCB: D11 has to be changed in direction, and the connection between D11 and D11 has to be changed to reflect this.

Without this fix, the relay will not switch.

-Peter

There are still boards available.

 

[Raka]

We lazy...

That means that actually none of us had built the unit, had we?
I'm still busy sourcing the components, and reichelt have just told me that the 10uF of wima is no longer available
Besides, a rega B250 is looking for place in my TD160 and my motor hasn't a pulley, and the ps is still in progress (see my thread in analog). So, I have an excuse, but you all?

 

[ARAD]

Ono project - P2 boards

pquadrat,

I am in the process of building the Ono based on your boards - should have all the parts by end of this week (hopefully getting the 10uF WIMAs...)

What would be the value for R19 when using the MEDER relais (24V) ?

Thanks & regards,
Andreas

 

[wuffwaff]

Peter,

thanks for the info!


Raka,

I´m also waiting for the parts to arrive but I already started building the cabinets wich always seems to be the most labour intensive part when building an amp. I´ll post some pictures when they´re ready.

william

 

[martinschki]

Hi all,

if there is someone in this group who is from US or canada:
i just moved to the US and i would need some sources for parts here.

Thank You!
Martin

 

[ststone]

www.mouser.com
www.digikey.com

 

[mjounot]

Martin

Digi key , Newark, Mouser, Welborne, Parts Connection,Michael percy. They are all listed in diyaudio.com links.

Mike

 

[TheMyxin]

Re: We lazy...

That means that actually none of us had built the unit, had we?
I'm still busy sourcing the components, and reichelt have just told me that the 10uF of wima is no longer available

Its really hard to find the 10uF WIMA
FKP10 or MKS4 especially in tolerance
with 5%. So its easier to get the Epocs
ones at RS-Components.
These are the same as Peter (Pquadrat)
has used (the blue big ones)

 

[Raka]

EPOCS

Hey, Thanks for the epocs hint. I intend to buy some components at RS so that helps a lot to reach the minimum value for free shipping. I was a little lost with those caps value. Until now the components I used were kind of very standard for my non-top-units, so I looked more like a Holmes with the pipe than an electron.

 

[Billc]

Hi, I have my circuits boards built and ready to go except for the 2sa991 and 2sc1844 transistors. Does anyone know if these are so important that I should not substitute them? Are any of the Zytex transistors adequate as substitutions?? I think that they may be since they are used in the pearl phono. Thanks, Bill

 

[wuffwaff]

Bill,

I will use 2sa970 /2sc2240 but I think you can even use BC550/560 without any problems.

william

 

[Cobra2]

Need some help!

I cannot find C2A in the BOM(C2A=?), and also wonder how to get space for it....(under C10).

Will also use the RS relay, that makes R19=?

Arne K

 

[Peter Daniel]

You are aware, that you don't have to use 10u output capacitor (C7). Just increase the value of R4 (collector of Q1) and place a trimpot in parallel with R4. You'll be able to adjust the output offset to 0V and it will stay that way. That setup worked succesfuly in my Ono for many years.

 

[fschlenk]

I built the ONO board. It sounds very good. I meassured the voltage over R53 and R67.
I got 1V over R 53, fine.
But 1,35 V over R67.
Did anyone encounter this problem before, any ideas ?
I also only got 11,6 V over the MC JFET input. Instead of 15 V on the drawing.
Ideas ?

Best Regards

 

[D.Achenbach]

I built the ONO board. It sounds very good. I meassured the voltage over R53 and R67.
I got 1V over R 53, fine.
But 1,35 V over R67.
Did anyone encounter this problem before, any ideas ?
I also only got 11,6 V over the MC JFET input. Instead of 15 V on the drawing.
Ideas ?

Best Regards

1.
That the voltage over R67 is too high should be a result of a too high voltage over D5. Is D5 of this channel shining much brighter than that on the other channel?
If the Voltage over D5 is too high, remove th LED and check it out in a test circuit. Let a current of about 5mA flow through the diode an meassure the voltage over the diode. Should be about 1.7V.

2.
Meassure the voltage on Emitter of Q24. Should be 26V as in the circuit diagram. But this confuses me a little bit because the 26V are divided by the two resistors R18 and 16 into about 13V. The Output of Q14 ist about 0.7V below this at 12.3V.
Let's calculate this back with 15V supply on the MC transistors. 15 + 0.7 = 15.7 * 2 = 31.4V at emitter of Q24. This should be the correct voltage. Also the divider R75/R76 at the base of Q24 will result in the range of about 31V. I think this is the correct value, not 26V.
Mayby one can measure this out.

Best Regards
Dieter Achenbach

 

[D.Achenbach]

I built the ONO board. It sounds very good. I meassured the voltage over R53 and R67.
I got 1V over R 53, fine.
But 1,35 V over R67.
Did anyone encounter this problem before, any ideas ?
I also only got 11,6 V over the MC JFET input. Instead of 15 V on the drawing.
Ideas ?

Best Regards

The higher voltage over R67 is normally the result of a higher voltage over D5. If this is the reason, remove and meassure the voltage over the diode in a testcircuit with a current of about 5mA. If it's over 1.7 replace it. Bevor you insert the replacement diode checkt the voltage.

The values given in the circuit diagram are a little bit confusing. 26V on Emitter of Q24 are divided into half with R16/R16. So the voltage behind Q14 should be about 12V.
I think, that the given value of 26V is not correct. The calculated value with reference to the divider R75/R76 should be around 30 to 31V (36V*10k/11.5k minus BE voltage of 0.7V).

Hope thid helps.

Best Regards
Dieter Achenbach

 

[TheMyxin]

Connection for the Relais

Hello
I have successfully run my PCB-Ono-Board
but i am not sure hot to connect correctly
the Relais on the Supply-PCB to the Ono-
PCB due that there are no polarity marked.
So i have measured the voltage on the
Supply-PCB on the Relais 4 pin connection.
it has a screw-connector and numbers
1,2,3,4 from left to right (right of this
connector there are the other 4 pin supply
connectors).
I get - 40,9V DC when i measure 1 to 3
or 1 to 4 or 2 to 3 or 2 to 4. So 3,4 seems
to me GND and 1,2 the connection for + V
DC voltage unregulated right ?

So how is the connection on J7 due to the
polarity ??

 

[D.Achenbach]

Re: Connection for the Relais

Hello
I have successfully run my PCB-Ono-Board
but i am not sure hot to connect correctly
the Relais on the Supply-PCB to the Ono-
PCB due that there are no polarity marked.

I get - 40,9V DC when i measure 1 to 3
or 1 to 4 or 2 to 3 or 2 to 4. So 3,4 seems
to me GND and 1,2 the connection for + V
DC voltage unregulated right ?

So how is the connection on J7 due to the
polarity ??

Correct, 1 and 2 plus, 3 and 4 minus.
Unless the relay is a nonpolarized type the polarity does not matter. As I saw it in the specs of the relay it is unpolarized.

Regards
Dieter

 

[fschlenk]

As I am short of 2SC1844 I have to replace them.
Or does anyone in Germany still has 2-4 left.
This would definetly be of great help !
Please let me know.

There were several suggestions in this list.
Has anyone tried sofar ?
As I only need to replace the input of the 2SK389 I plan to use Philips BC 550. Of course, the pins are not directly compatible. But I can live with that.
Any suggestions to this replacement.

 

[fschlenk]

I am looking for 2-4 2SC1844 pref. in Germany.
Does anyone know where these items are still available.

I plan to replace them with BC 550 in the diff. input of the 2SK389 stage. Of course, these means changing the pins. Any suggestions ?

Best regards