My friend is seeking PS supply cap for refurbishing this amplifier, Is RIFA a good choice since both are made in scandinavian.
Any good option??
Any good option??
Hello Tube747,
Forgive me but I don't quite understand this. I can think of two possibilities:
"PS supply cap" Do you mean the power supply electrolyte capacitors ?
If you do, those are Philips capacitors. In fact, every electrolyte in the original two-channel is Philips. For the filters, Styroflex-red is used. Decoupling: Wima red or blue.
..
But I can also imagine that you mean "Powerswitch" with "PS" and the capacitor that is mounted over it. It doesn't quite matter much as long it's not the "old" transparant series.
"Is RIFA a good choice since both are made in scandinavian. Any good option??"
What do you mean with both ?
Cheers!
Johan
Forgive me but I don't quite understand this. I can think of two possibilities:
"PS supply cap" Do you mean the power supply electrolyte capacitors ?
If you do, those are Philips capacitors. In fact, every electrolyte in the original two-channel is Philips. For the filters, Styroflex-red is used. Decoupling: Wima red or blue.
..
But I can also imagine that you mean "Powerswitch" with "PS" and the capacitor that is mounted over it. It doesn't quite matter much as long it's not the "old" transparant series.
"Is RIFA a good choice since both are made in scandinavian. Any good option??"
What do you mean with both ?
Cheers!
Johan
Hi
I refurbished two of the 25 watt amps some years ago. Both amps needed attention to the same areas.
The emitter resistors on the output transistors, that were fitted by electrocompaniet, needed replacing by ones of the same ohm value but 5 watt instead of 2 watt. Also the pcb around those resistors needed attention due to overheating around those resistors. I also reduced the bias slightly so that I could just keep my hand on the heatsinks when the amp had fully warmed up.
I found that the electrolytic capacitors on the pcb's needed replacing but not the power supply capacitors for the amp output or amp front end supplies.
I also found that a number of joints on the pcb were cracking and needed resoldering.
At one time Electrocompaniet suggested it might be worth experimenting with more modern output transistors ( I think this might help a lot ) and improved input transistors possibly using jfets on the front end.
Don
I refurbished two of the 25 watt amps some years ago. Both amps needed attention to the same areas.
The emitter resistors on the output transistors, that were fitted by electrocompaniet, needed replacing by ones of the same ohm value but 5 watt instead of 2 watt. Also the pcb around those resistors needed attention due to overheating around those resistors. I also reduced the bias slightly so that I could just keep my hand on the heatsinks when the amp had fully warmed up.
I found that the electrolytic capacitors on the pcb's needed replacing but not the power supply capacitors for the amp output or amp front end supplies.
I also found that a number of joints on the pcb were cracking and needed resoldering.
At one time Electrocompaniet suggested it might be worth experimenting with more modern output transistors ( I think this might help a lot ) and improved input transistors possibly using jfets on the front end.
Don
Don,
Can I replace those 5W emitter resistors with either Mills MRA-5 or MRA-12?
Mills MRA-5 Resistors
Mills MRA-12 Resistors
Thanks!
Can I replace those 5W emitter resistors with either Mills MRA-5 or MRA-12?
Mills MRA-5 Resistors
Mills MRA-12 Resistors
Thanks!
Hi Johan!
Thanks!
Yes, I'm talking about power supply electrolytic cap. But Philips getting hard to find. My friend told me it's under BC components instead of Philips logo now.
What is Styroflex-red? Can I replace all Wima red and blue with Wima Black box series??
Sorry, I mean "both" RIFA and EMC Otala amp also made in Scandinavian.
At first I suspects someone has modded the amplifier from Rifa to Philips since the amplifier I get is not from the original owner. I always think the Otala amplifier "should" have RIFA there. The reason is that just like some Italian equipment like to put Kendeil cap there and British gear has BHC cap. So I assume the Otala amplifier should have RIFA in the power supply.
Thanks again!
Thanks!
Yes, I'm talking about power supply electrolytic cap. But Philips getting hard to find. My friend told me it's under BC components instead of Philips logo now.
What is Styroflex-red? Can I replace all Wima red and blue with Wima Black box series??
Sorry, I mean "both" RIFA and EMC Otala amp also made in Scandinavian.
At first I suspects someone has modded the amplifier from Rifa to Philips since the amplifier I get is not from the original owner. I always think the Otala amplifier "should" have RIFA there. The reason is that just like some Italian equipment like to put Kendeil cap there and British gear has BHC cap. So I assume the Otala amplifier should have RIFA in the power supply.
Thanks again!
Tube 747
I checked my notes on the electro rebuild to make sure I am giving you the correct information.
I find that in I replaced the 1 ohm 5 watt resisters on the output transistors with 1 ohm 12 watt resistors. These seem to work fine and I would recommend the 12 watt resistors.
I also found that I increased the value of the resistence of the variable potentiometer that sets the bias current by 50%, from 300 ohms to 450 ohms. ( This is only given for guidance. You will need to check the value on the potentiomer on your amp. I reset the value of the potentiometer to lower the temperature of the heatsinks . )
Hope this helps
Don
I checked my notes on the electro rebuild to make sure I am giving you the correct information.
I find that in I replaced the 1 ohm 5 watt resisters on the output transistors with 1 ohm 12 watt resistors. These seem to work fine and I would recommend the 12 watt resistors.
I also found that I increased the value of the resistence of the variable potentiometer that sets the bias current by 50%, from 300 ohms to 450 ohms. ( This is only given for guidance. You will need to check the value on the potentiomer on your amp. I reset the value of the potentiometer to lower the temperature of the heatsinks . )
Hope this helps
Don
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