hello Felipe
For cathode bias, you can use this general diagram to connect the filament (or look at the manuals for my regulator).
Ignore the grid and anode connexions.
For the 26, with about 9V bias For Ia= about 5mA:
R1=1.8K (Welwyn W21 or other vitreous wirewound, o Mills MRA5 or MRA 12 if you can get them).
C1=100µF 25-35 or 50V Nichicon VR Panasonic AM or special audio type (to your taste)
For cathode bias, you can use this general diagram to connect the filament (or look at the manuals for my regulator).
Ignore the grid and anode connexions.
For the 26, with about 9V bias For Ia= about 5mA:
R1=1.8K (Welwyn W21 or other vitreous wirewound, o Mills MRA5 or MRA 12 if you can get them).
C1=100µF 25-35 or 50V Nichicon VR Panasonic AM or special audio type (to your taste)
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Many thanks Rod for your kind support, what's the difference in sound quality: less thin/analytic & more warm/body sound?
I posted a populated (by Ale) set of Ale's Gyrator boards in Swap Meet if anyone is interested ...
Ale what's the output impedance using the hybrid mu-follower & what's the gain?
Thanks
Felipe
Thanks
Felipe
Hi Felipe,
Answers to both of your questions are on the lecture. Just follow the link and sit down to read through. A nice drink will help 🙂
Ale
Answers to both of your questions are on the lecture. Just follow the link and sit down to read through. A nice drink will help 🙂
Ale
Thank you for posting this Ale, a fantastic read.
I bet you had a great time at ETF, I'm hoping to go sometime in the next few years. It looks like a wonderful experience.
Cheers,
Gable
Long interconnects
Can I run long interconnects between the pre and my amps (2M or 3M) with no deleterious effects?
I'm currently using Plate chokes (225H) that couple any 60HZ floating around the room. This would get away from that. I have a set of Ale's gyrator boards ready to go in that I want to try later. I apologize if this has been answered before.
Best Regards, Mark
Can I run long interconnects between the pre and my amps (2M or 3M) with no deleterious effects?
I'm currently using Plate chokes (225H) that couple any 60HZ floating around the room. This would get away from that. I have a set of Ale's gyrator boards ready to go in that I want to try later. I apologize if this has been answered before.
Best Regards, Mark
Sorry my ignorance I have several doubts:
1/ I'm using the attached schematic, my question is: the opt is 4:4.5 so if I use power amps of 100K input impedance the tube have reflected 100K x 0:88 = 88k888, not optimum (optimal 2-3 times plate resistance 7K600 at 135V?
2/ Using opt 15K : 600R the 26 can drive well 300R load, 300R x 25 = 7K5?
1/ I'm using the attached schematic, my question is: the opt is 4:4.5 so if I use power amps of 100K input impedance the tube have reflected 100K x 0:88 = 88k888, not optimum (optimal 2-3 times plate resistance 7K600 at 135V?
2/ Using opt 15K : 600R the 26 can drive well 300R load, 300R x 25 = 7K5?
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That's an old schematic of mine where I was using the 26 as a driver tube. For a preamp you need the LL1660 in step-down to lower the impedance and match to the amp. Lundahl have all the wiring alternatives on their site for you to choose from. How much step-down you want is up to you.
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Hello Gents,
Slghtly OT question pls as the current draw for the 26 or 01A is very low, would there be any benefit of running the tube with a regulated PS ?
Thanks
Slghtly OT question pls as the current draw for the 26 or 01A is very low, would there be any benefit of running the tube with a regulated PS ?
Thanks
0.88 square 2 = 0.774 x 100 = 77K440?
Wow Andy what a big difference using all the primary of LL1660 connected togheter to use as plate load for 26, is day & night, thank you very much for advice. As output cap used Auricap 0.47uF 1.500V, tomorrow I will try FT-3 0.47uF 200V and rapport.
Next: time to try amorphous choke load & Sic for cathode.
Cheers
Felipe
My 26 preamp
Just wanted to share my #26 preamp. This is my third 26 preamp that I have made, but I used Rod's regulators in filament bias in this one, and I have to say that it sounds way better than my other builds! The filament supply is in a seperate box and uses Electraprint chokes in CLC. The power supply is in the main amp case with chicago potted power transformer and chokes in LCLC into 3B28 rectifiers (they look bad ***!). I used Lundahl Ll1660 10ma outputs. Power supply is also regulated two Vr75 fed by a CCS. I love the sound of this preamp even though it is still burning in! Oh, and I powerder coated the chassis.
Just wanted to share my #26 preamp. This is my third 26 preamp that I have made, but I used Rod's regulators in filament bias in this one, and I have to say that it sounds way better than my other builds! The filament supply is in a seperate box and uses Electraprint chokes in CLC. The power supply is in the main amp case with chicago potted power transformer and chokes in LCLC into 3B28 rectifiers (they look bad ***!). I used Lundahl Ll1660 10ma outputs. Power supply is also regulated two Vr75 fed by a CCS. I love the sound of this preamp even though it is still burning in! Oh, and I powerder coated the chassis.
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