Philips CD104 tweaks

[poynton]

Originally posted by JeroenR



Yep, That's the one.

I used 47mF/160V caps as I was expecting 100V, not 150. Bit tight this way but at least it keeps the supply small. The red wire is the V-out. It is slightly boxed (alu) because it is close to outputs and the decoder/servo boards.

The decoder board is now empty where the opamps etc were. I hope to have just enough space for the tubes, caps and more caps...... and let's not forget the 6.3V supply.

Hi.

It may be necessary to add a regulator to ,say, 125V to reduce off load voltage and voltage droop in use.

Andy

[JeroenR]

Originally posted by poynton



Hi.

It may be necessary to add a regulator to ,say, 125V to reduce off load voltage and voltage droop in use.

Andy

Why do you think that is necessary to add the regulator? Not enough head-room? I expect the tube circuit to draw about 1W (two time about 5mA at 100V) max.

Would someting like a 24reg and 100V zeners do the trick? But would that not require extra caps (space again)?

[poynton]

Originally posted by JeroenR



Why do you think that is necessary to add the regulator? Not enough head-room? I expect the tube circuit to draw about 1W (two time about 5mA at 100V) max.

Would someting like a 24reg and 100V zeners do the trick? But would that not require extra caps (space again)?

Exactly what I had in mind. The extra caps do not need to be huge - 47uF again

[JeroenR]

Originally posted by poynton



Exactly what I had in mind. The extra caps do not need to be huge - 47uF again

Could I put a dummy load on the supply to simulate the power consumption and so see what voltage drop I can expect before I install the reg? I expect the tube-circuit will draw somewhere between 5 and 10mA per channel so perhaps a 20Kohm/5W to see what happens? Or will this do bang again?

I'm asking because I'm afraid that if I set the output to high (150V) then there will be not enough "room" for the reg and when I set the output too low (at 100V) there will be too much dissipation in the reg.

So perhaps the question is : how do I find out what the best value for the zener is?

Thanks,

Jeroen

[poynton]

Try without the reg. to start.

It may be necessary to revise the power supply if too much hum.

Andy

[JeroenR]

Originally posted by poynton
Try without the reg. to start.

It may be necessary to revise the power supply if too much hum.

Andy

I certainly will try this weekend. After the supply there will be a resitor and one more cap directly connected to the plate of the top tube so perhaps if I take a good cap, add a choke somewhere.....

I'll get back again with diagram and photo's later.

Thanks,

Jeroen

[JeroenR]

Here's the circuit I'm going to try.

Let me know if something looks odd.

[JeroenR]

No tubes yet, just the 6.3V.

[JeroenR]

Found a spot.....

[JeroenR]

Deforrestation........ room for the tubes.