Re: Epcos?
Raka said:Hi all,
I'm still late on sourcing components.It takes time to save money...
I have almost finished the order to RS, I only have to include the famous 10uF caps. Somebody told me that Epcos was available at RS, but I can't find them !!
The Epocs Caps have the Order-Number
191-2948 in the new cataloge (the yellow one). They are the blue big squared ones.
Finally just completed the Aleph ONO. Every works fine except for one problem.
When the ONO is switched on, there's a pulsating beat going from low to high pitch for about 5 secs. Something like like 'boop..........boop........boop.....boop....boop...boop.boop". After that everthing would be fine.
Anyone experiencing this? Is this normal?
When the ONO is switched on, there's a pulsating beat going from low to high pitch for about 5 secs. Something like like 'boop..........boop........boop.....boop....boop...boop.boop". After that everthing would be fine.
Anyone experiencing this? Is this normal?
Just had a new observation.
When I switched on ONO when cold, I don't have this problem. But after I switched off and on again immediately, the problem arises.
If I allow the capacitors to discharged fully, by observing the LED diminished completely and switched on again, the problem goes away.
When I switched on ONO when cold, I don't have this problem. But after I switched off and on again immediately, the problem arises.
If I allow the capacitors to discharged fully, by observing the LED diminished completely and switched on again, the problem goes away.
I've just "finished" mine!!
Almost done, well, it's only fitted in a timber plate, and the connectors dancing everywhere, and a resistor of the inverter made smoke, and the caps for the MC stage are missing, but the MM works fine.
I had also some problems with "ploooo plooo" but was due to the poor solder of the phono connectors. Waiting for the carpenter for the casing.
Otherwise the sound is kind of wonderful. I compared quickly to my ESP and the question is clear as the sound of the pass unit. Extended in the highs and clear. The warm here is not needed and is not present.
Switching back to the ESP, there are a lot of grey clouds.
One thing surprising is that there was a obvius running in period of 2 minutes. Until then, the cellist didn't know where to sit, after that, he couldn't stand up.
Thanks Nelson/Wayne, for allowing me/us to enjoy your design.
Almost done, well, it's only fitted in a timber plate, and the connectors dancing everywhere, and a resistor of the inverter made smoke, and the caps for the MC stage are missing, but the MM works fine.
I had also some problems with "ploooo plooo" but was due to the poor solder of the phono connectors. Waiting for the carpenter for the casing.
Otherwise the sound is kind of wonderful. I compared quickly to my ESP and the question is clear as the sound of the pass unit. Extended in the highs and clear. The warm here is not needed and is not present.
Switching back to the ESP, there are a lot of grey clouds.
One thing surprising is that there was a obvius running in period of 2 minutes. Until then, the cellist didn't know where to sit, after that, he couldn't stand up.
Thanks Nelson/Wayne, for allowing me/us to enjoy your design.
In looking over the specs for the hard-to-find transistors 2SC1822 and 2SA991, I recalled some very low noise transistors in my stock and checked their spec sheets.
The 2SA1084 (-90V) or 2SA1085 (-120V) have the same low noise at 0.5 nV/Hz^0.5. The complement part is 2SC2545 - 2547 (rated at 60, 90 and 120V). All other specs are virtually identical. Below is the zip file containing the pdf for both devices.
I've bought them in the past from www.bdent.com
Regards, Robert
The 2SA1084 (-90V) or 2SA1085 (-120V) have the same low noise at 0.5 nV/Hz^0.5. The complement part is 2SC2545 - 2547 (rated at 60, 90 and 120V). All other specs are virtually identical. Below is the zip file containing the pdf for both devices.
I've bought them in the past from www.bdent.com
Regards, Robert
Thanks, Peter, your boards are very nice. I finished them up this weekend.
****
I tried Peter Daniel's suggestion of changing R4 to a larger value and bypassing it with a 5K potentiometer. It works well, and does allow the removal (jumpering) of C7. Thanks, Peter.
In an effort to remove the remaining caps, I also did the same with R59 on the inverter differential, using 1k5 instead of 475R for R59 (placing this on the bottom of the board) and again bypassing with a 5K potentiometer (placing this on the top component side).
This mod allows removal (jumper) of C38 and C9. Now the only signal path cap is between the MC and the MM sections (which cannot be easily avoided due to the single ended power supply for the MC section).
To set the DC offset, it seems best to first adjust R25/P, then adjust the new R4 pot, and finally, the new R59 pot. DC on each output leg now varies between +/- 10 mV.
****
I tried Peter Daniel's suggestion of changing R4 to a larger value and bypassing it with a 5K potentiometer. It works well, and does allow the removal (jumpering) of C7. Thanks, Peter.
In an effort to remove the remaining caps, I also did the same with R59 on the inverter differential, using 1k5 instead of 475R for R59 (placing this on the bottom of the board) and again bypassing with a 5K potentiometer (placing this on the top component side).
This mod allows removal (jumper) of C38 and C9. Now the only signal path cap is between the MC and the MM sections (which cannot be easily avoided due to the single ended power supply for the MC section).
To set the DC offset, it seems best to first adjust R25/P, then adjust the new R4 pot, and finally, the new R59 pot. DC on each output leg now varies between +/- 10 mV.
wrong voltage
I finished my Ono and I took some measurement that they dissapointed me.
1)After R43 I have 32,5V instead of 30,
2)on Q24 I have 32 instea of 26V
3)on the 4 2SK170BL I have 9,8 instead of 15V
4) on R67 and R53 I have 1,4V instead of 1V
I'm the only one with those numbers?
I would like to get the proper voltage, I performed a search on the subjects and I found an answer only for point 4 : try different led, is this correct what about the others?
Giorgio
I finished my Ono and I took some measurement that they dissapointed me.
1)After R43 I have 32,5V instead of 30,
2)on Q24 I have 32 instea of 26V
3)on the 4 2SK170BL I have 9,8 instead of 15V
4) on R67 and R53 I have 1,4V instead of 1V
I'm the only one with those numbers?
I would like to get the proper voltage, I performed a search on the subjects and I found an answer only for point 4 : try different led, is this correct what about the others?
Giorgio
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