Then I suggest OPT, choke or gyrator. Resistor voltage drop will skate you our of the loadline.
Gyrator like Iko used? It seems to complicated for me, could you please post a schematic how can be used with VR150?
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In my mind, 150v is far too low a B+, because it doesn't allow you to use a proper load on the 26. Even if you want to use an active load such as a CCS or a gyrator, these work best with 70-100V headroom. If you want to operate at ~150V on the tube, I suggest having 220V B+ at least.
I would suggest increasing the B+ and using a VR150 and VR75 in series to get 225V, followed by a CCS set to 6-7mA. Alternatively you could also use a resistor or go back to your transformer load.
The only way you could possibly have a circuit from a 150V DC supply would be to have a low DCR anode choke of 150H up and output the anode signal with a capacitor.
It's what I have, a VR150 in series with a VR75 for B+. Gyrator as load, and I end up with 150V DC on the plate of the 26.
Felipe, I think you giving up too soon.
Using anode resistor and cap. coupling (B+:220V, Ra:10K) the easiest method, but the poorer sound.
If you compensate OPT, you get much better result.
Using an anode resistor is a very poor idea. I would forget it. Various solid state anode loads are interesting - I tried these at some point and preferred the OPT, but haven't revisited this lately. I would simply use the transformer and forget about output caps. Try it as it is first.
My experiences with the 26 is that it has good sound at several different operating points. I have run it at 90v and 3mA and it sounds surpringly good at that operating point. You are not going to have poor sound within the range 90-180v
Filepe - you have now practically built your 26 preamp. I think this is the time to stop agonising over possible choices and just listen to it. You will need a reference listening test for any future modifications anyway. Experiment later and then see if it sounds better or worse or the same as it is with the OPT and VR150. This is exactly what I'm listening to as I write, and it's a perfectly good sound. Have a good Easter and enjoy your build. Play some music!
Andy
My experiences with the 26 is that it has good sound at several different operating points. I have run it at 90v and 3mA and it sounds surpringly good at that operating point. You are not going to have poor sound within the range 90-180v
Filepe - you have now practically built your 26 preamp. I think this is the time to stop agonising over possible choices and just listen to it. You will need a reference listening test for any future modifications anyway. Experiment later and then see if it sounds better or worse or the same as it is with the OPT and VR150. This is exactly what I'm listening to as I write, and it's a perfectly good sound. Have a good Easter and enjoy your build. Play some music!
Andy
Thanks for kind advice Andy, I will folow your advice, I wish you happy Easter.
Felipe
Listened the 26 with OPTs, no hum only sound, for my Borbely monos 75W enough power: my loudspeakers 94dB/W/m🙂
Yes, very different I used SS Borbely balanced preamp, the 26 is silent like a tomb, I was afraid that it did not have sufficient gain but now I believe still can play vinyl with TT and 26: that's will do tomorrow.
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VR150 is very low noise I'm not sure when installed, 26 is the most musical preamp I have listened🙂 and I listened several (40 years).