#26 pre amp

[merlin el mago]

Attached schematic how I wired the Lundhals LL1660, help will welcome?

 

[vgeorge]

Your schematic looks to have a 229V transformer with a choke input. If you look at your simulation, it shows 202V at C3, if I am not mistaken. Is C1 value as shown?
I use a similar arrangement with 220V transformer with choke input and I have around 190V before the regulator.
Are you sure?

 

[merlin el mago]

C1 is a Russian teflon FT-3 01,uF 600V

Only different is I have between the tx and the AZ1 100R

 

[iko]

Remove C1 so you have a proper choke input filter.

 

[merlin el mago]

OK

 

[vgeorge]

And put somewhere a resistor in series - like 10R - in the power supply to calculate current draw. Just to be sure that tubes are working.

 

[iko]

Why do you have a 100R between the transformer and the AZ1? Normally you want the lowest output impedance you can get.

 

[andyjevans]

Attached schematic how I wired the Lundhals LL1660, help will welcome?

I don't know if it matters, but I think you have the outputs the wrong way round on the LL1660. Plus should go to plus.

 

[merlin el mago]

AZ1 needs to see the impedance more of 100 ohms or doesn't work properly (verified).

 

[stajo]

Why do you have a 100R between the transformer and the AZ1? Normally you want the lowest output impedance you can get.

To protect AZ1 maybe. But where do you see it?

I don't know if it matters, but I think you have the outputs the wrong way round on the LL1660. Plus should go to plus.

An anodefollower inverts.


What is the last 2,7k/100nF for?

 

[vgeorge]

What is the voltage drop on the 2,7K?

 

[merlin el mago]

To protect AZ1 maybe. But where do you see it?


told me Rod Coleman

An anodefollower inverts.


What is the last 2,7k/100nF for?

2K7 to low the voltage 100nF not used

 

[stajo]

If you have 306 something B+ you must have put something larger as the first cap then 100 nF. Check that, or remove it as earlyer said. Then you need a cap after the 2,7k. 100 uF:is I would say worx.

 

[merlin el mago]

What is the voltage drop on the 2,7K?

I have removed the CCS+Gyrator, I guess I need a dummy load in place of Gyrator and tube to measure, wich value?

 

[merlin el mago]

If you have 306 something B+ you must have put something larger as the first cap then 100 nF. Check that, or remove it as earlyer said. Then you need a cap after the 2,7k. 100 uF:is I would say worx.

1rst 100nF removed, I don't have 100uF I have 220uF could I use after the 2K7?

 

[stajo]

I have removed the CCS+Gyrator, I guess I need a dummy load in place of Gyrator and tube to measure, wich value?

for 300 V 5 mA 60k
for 250 V 5 mA 50k
for 200 V 5 mA 40k
for 150 V 5 mA 30k

 

[stajo]

1rst 100nF removed, I don't have 100uF I have 220uF could I use after the 2K7?

Yes you can.

 

[vgeorge]

Update your simulation on PSUD with the new data. Calculate 6mA current draw for the tube. You will find the correct resistor value.
Put what Stajo suggested as a start value. You will have to get around 150v on your load.

 

[merlin el mago]

Using 2k7 for R1 changing last cap for 220uF with a dummy load of 30k psud gives 229V?

 

[merlin el mago]

psud simulation