Hi Salas, I replaced both the ccs and the shunt and now everything is back to working, thank you very much, I noticed only one thing, I have a rectified voltage of 300V when empty, connecting the two shunts and setting them for 200v out with an absorption of 35mA per shunt I can't have the same setting in one of the two, if the first septum at 350mV the second I can't make it go more than 250mV and the input voltage drops to 200V,
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I have a rectifier valve with anodic characteristics of 2x300v @ 2x75mA, if I use two shunts in parallel one per channel with a single transformer, and if each channel absorbs 15mA, what must be the correct current to set?
When we like 20mA spare per channel then setting 20+15=35mA CCS in each is OK. As an experiment you could use 25mA CCS each. It would worsen Zo spec of regs a bit, but to see if that's the issue with Vin dropping. What is max Cinput for the rectifier in its spec sheet? Maybe it drops voltage because of small Cin after loading more than 50mA constant draw?
Hi Arto I'd like to improve the psu of the old project with 6N1P and 6N13S. The BC638 could be suitable as PNP transistor into the shunt circuit?
Hi Salas,
I don't know if the topic has already been posted in the long 3d, if so, I'd appreciate a link to the post number.
I'm using two indipendent hvshunt reg on an amplifier which uses an input stage (6j5 srpp) dc coupled with a 300B output stage.
Everything works but the two regs reach the desired working voltages really slowly (about 40 minute ).
In this time the 300B' s circulating current never becomes dangerous but its desired working point is reached with great delay.
What can be done to make sure the regs reach the desired voltage in the shortest time possible.
Thanks
Luigi
I don't know if the topic has already been posted in the long 3d, if so, I'd appreciate a link to the post number.
I'm using two indipendent hvshunt reg on an amplifier which uses an input stage (6j5 srpp) dc coupled with a 300B output stage.
Everything works but the two regs reach the desired working voltages really slowly (about 40 minute ).
In this time the 300B' s circulating current never becomes dangerous but its desired working point is reached with great delay.
What can be done to make sure the regs reach the desired voltage in the shortest time possible.
Thanks
Luigi
Hi
How many Volt it climbs in about 40min after the initial Vout? Looks like positive thermal drift? In that case, its the JFET heating up giving out more current to the Vref resistors as its ambient temperature changes enough. That can be few Volt only if the system is correctly set and not overheated.
Try distance the regs from the main heat sources, if the tubes are near to them, and/or use bigger sinks when those are the worst radiators to the JFET area if they are saturated with MOSFET dissipation.
So you could watch when setting an initial Vout if and how closer the final Vout results. If it remains as before it could be something else than thermal drift. Maybe not enough CCS setting.
How many Volt it climbs in about 40min after the initial Vout? Looks like positive thermal drift? In that case, its the JFET heating up giving out more current to the Vref resistors as its ambient temperature changes enough. That can be few Volt only if the system is correctly set and not overheated.
Try distance the regs from the main heat sources, if the tubes are near to them, and/or use bigger sinks when those are the worst radiators to the JFET area if they are saturated with MOSFET dissipation.
So you could watch when setting an initial Vout if and how closer the final Vout results. If it remains as before it could be something else than thermal drift. Maybe not enough CCS setting.
Salas have you seen this: PCB Tube Anode Adjustable PSU Regulator Salas V2 from stereo24 on Tindie
Hi
I bought a pcb to make a tube preamplifier based on ls26 cat-sl1
The high voltage is 260 V 80 mA. I purchased two shunt regulators because the PCB has two B + and a 260 V earth.
I have some questions:
First: is a shunt regulator sufficient?
Second: how can I set the current and V output from the shunt controller?
Third: what is the value of the resistor for the checks before connecting it to the pcb?
I bought a pcb to make a tube preamplifier based on ls26 cat-sl1
The high voltage is 260 V 80 mA. I purchased two shunt regulators because the PCB has two B + and a 260 V earth.
I have some questions:
First: is a shunt regulator sufficient?
Second: how can I set the current and V output from the shunt controller?
Third: what is the value of the resistor for the checks before connecting it to the pcb?
80mA for one 12AU7 section, two 12AX7 sections, one 6DJ8 section, per channel? That's 20W B+ power draw per channel at 260V. Sounds like way too much. 10mA per channel is far more likely.
SSHV2 can go at least up to 100mA CCS each. Post#1 has link to the SSHV2 circuit description. There is a PDF manual attached under the description also. In the manual its explained how to set it. Its actually very easy because it has trimmers both for CCS mA and Vout.
For test load resistor use 27k 5W. Start with setting 30mA CCS per channel. Read 300mV at TP for that. Then take it to 260V output.
If the preamp uses much much more than 10mA per channel, unlikely, the rail voltage will drop significantly lower than 260V when you will connect it. Then up the CCS slowly until it gets to 260V on the preamp. Add another 20mA CCS and leave it at that.
SSHV2 can go at least up to 100mA CCS each. Post#1 has link to the SSHV2 circuit description. There is a PDF manual attached under the description also. In the manual its explained how to set it. Its actually very easy because it has trimmers both for CCS mA and Vout.
For test load resistor use 27k 5W. Start with setting 30mA CCS per channel. Read 300mV at TP for that. Then take it to 260V output.
If the preamp uses much much more than 10mA per channel, unlikely, the rail voltage will drop significantly lower than 260V when you will connect it. Then up the CCS slowly until it gets to 260V on the preamp. Add another 20mA CCS and leave it at that.