Hello
the last few days i have make some changes to my 4P1L pre..
mounted the new gyrator instead of my Trafo output
mounted Rod Coleman v5 heater
it gave me many hours off problem ,,and i will like to Thanks Rod Coleman (He knows why..)
but in all the problems ,,i will say it is worth while..good learning also
about the sound,,(i use a 4.7uf mundorf silver in oil for output).i have got more of everything--nore clear,,better bass..a feeling of the music is closer to me
a super pre is now even better,,,will not for know return to Trafo.
next step will be v7 from Coleman..and i have order some riken 0.47uf Q cap..will try them out
Best Bjarne
the last few days i have make some changes to my 4P1L pre..
mounted the new gyrator instead of my Trafo output
mounted Rod Coleman v5 heater
it gave me many hours off problem ,,and i will like to Thanks Rod Coleman (He knows why..)
but in all the problems ,,i will say it is worth while..good learning also
about the sound,,(i use a 4.7uf mundorf silver in oil for output).i have got more of everything--nore clear,,better bass..a feeling of the music is closer to me
a super pre is now even better,,,will not for know return to Trafo.
next step will be v7 from Coleman..and i have order some riken 0.47uf Q cap..will try them out
Best Bjarne
Hi Andy...
It is working properly now. Listening to it and it's definitely better than
my old simple one.
I only have some very few things different than Ale.
Zener diodes 15volt across the lower DN2540. If not you'll damage it
if you try with a resistor load.
4.3M resistor instead of the 4.7M.
1K as anode load instead of 470R.
Trimmer is 1K instead of 2K.
I'm still on 8R cathode here we go.
PS! Please ignore the voltage,wattage,amps values on the schematic. Lt-Spice does not work properly anymore..
On my 8R 1 have 1.55volt on the filament and 108volt on the anode. Which equals 30mA. I can adjust from 21.36 mA to 36.48 mA on my trimmer. Lower the R11 330R with of course raise the current.
/Michael
What's the output impedance?
Gain is 20dBs?
Can drive 300 ohms headphones like Sennhs HD600-650?
How many VA & volts for Rod Coleman DC heaters transformer?
Last edited:
Simulation:
Gain: 18.2dB
Rout: 220R. IMHO too high for 330R headphone.
Raw supply AC voltage is 6.3V....with V7 regulator and without filament bias.
I see. You should try the LL1671! The preferences and tastes are different so I guess
you found your ticket!
Enjoy...
I haven't built this active load version, but it's on my to-do list. The first thing I would say from a fair bit of experience with 4P1L, 01A, 26 etc preamps using filament bias and shunt regs is that the circuits are fairly complex and the voltages take a lot of working out in them. I know this is a DIY forum and we all like to experiment, but some of the design work here isn't simple.
So when guys like Ale have done all the work and measurements to construct these circuits and guys like Rod Coleman have done all the work in making the filament regs, I'd say build all these circuits exactly as they have been designed in the first instance. If you have the design ability of guys like Ale or Rod (which in most cases is a big ask) then you might have sufficient knowledge to try some alternative solutions but otherwise, my own viewpoint would be to build it as it is and get it working first. Ale's PSU is here for guidance.
http://www.bartola.co.uk/valves/wp-content/uploads/2014/04/Siberian-Gen3-Preamp-HT-Supply..png
So when guys like Ale have done all the work and measurements to construct these circuits and guys like Rod Coleman have done all the work in making the filament regs, I'd say build all these circuits exactly as they have been designed in the first instance. If you have the design ability of guys like Ale or Rod (which in most cases is a big ask) then you might have sufficient knowledge to try some alternative solutions but otherwise, my own viewpoint would be to build it as it is and get it working first. Ale's PSU is here for guidance.
http://www.bartola.co.uk/valves/wp-content/uploads/2014/04/Siberian-Gen3-Preamp-HT-Supply..png
Well, that's a start. That's the PSU for the Gen 3 version, 235v. The schematic you posted was closer to the Gen 1b 250v.
http://www.bartola.co.uk/valves/wp-content/uploads/2015/02/4P1L-Siberian-Gen1b-v01.png
http://www.bartola.co.uk/valves/wp-content/uploads/2015/02/4P1L-Siberian-Gen1b-v01.png
The only question I can answer is the DC voltage for Rod Colemans board.
On my 8R I have the following.
AC 8.3 volt
DC to Coleman , works for ver (5,7) 9.32 volt.
DC out Coleman, works for ver (5,7) 5.96 volt.
/Michael.