power supply reassignment problem

[chopchip]

i reassigned the "zen dual parallel single ended triodes with paralleled cathode followers" preamp to the duty of phono preamp.

the two circuit diagrams and the power supply diagram are shown below

i thought i could just stick with the old power supply and there would be no difference. wrong. now im getting only 80 volts B+ and low gain rather than 250 volts and too much gain.

i was getting 250v before but now it has all changed.

what do i need to do. change the resistors between the smoothing caps? any ideas?

thanks

[20to20]

A centertapped rectifier cathode circuit supplying B+ from the CT? Show us the original diagram you're using to build from.

[chopchip]

Originally Posted by 20to20

A centertapped rectifier cathode circuit supplying B+ from the CT? Show us the original diagram you're using to build from.

im not sure which original diagram you mean. those are the schematics for the one phonopreamp and the other is the diagram for the original preamp that was in the chassis.

[chopchip]

Originally Posted by 20to20

A centertapped rectifier cathode circuit supplying B+ from the CT? Show us the original diagram you're using to build from.

this is the PS that the designer suggests for this project. i thought one would be much like the other

[20to20]

Originally Posted by chopchip

im not sure which original diagram you mean. those are the schematics for the one phonopreamp and the other is the diagram for the original preamp that was in the chassis.

Power supply diagram. Did you draw that from your own wire tracing?

[20to20]

Originally Posted by chopchip

this is the PS that the designer suggests for this project. i thought one would be much like the other

Your hand drawn PS diagram shows a directly heated K rectifier like a 5U4 or 5AR4 and your official diagram lists a 6CA4 type. And your hand drawn diagram shows you tapping the B+ from a CT on the 5V heater circuit for the 5U4. Aint no such thing.

[chopchip]

Originally Posted by 20to20

Your hand drawn PS diagram shows a directly heated K rectifier like a 5U4 or 5AR4 and your official diagram lists a 6CA4 type. And your hand drawn diagram shows you tapping the B+ from a CT on the 5V heater circuit for the 5U4. Aint no such thing.

this is the complete schematic of the zen power supply that is in the original preamp.

the other PS schematic is the one recomended by the designer of the phono preamp

[20to20]

Originally Posted by chopchip

this is the complete schematic of the zen power supply that is in the original preamp.

the other PS schematic is the one recomended by the designer of the phono preamp

So you are trying to use the RJM PS with the Zen preamp? Correct?

[chopchip]

Originally Posted by 20to20

So you are trying to use the RJM PS with the Zen preamp? Correct?

nope the zen preamp PS with RJM phono preamp

[20to20]

Originally Posted by chopchip

nope the zen preamp PS with RJM phono preamp

The Zen PS drawing shows the rectifier output tied to a centertap of its own 5v circuit. Get that checked out. There should not be a centertap of the 5v. You may have some tranny legs crossed.