JJ (in Slovakia) makes 6SN7, 6SL7, 12BH7, 5751, EF806 . . . And JJ at the same location makes ECC equivalents of the 12AX7, 12AT7, and 12AU7. Long plate, short plate, regular pins, gold pins, etc.
I purchase all my JJ tubes from Eurotubes in the USA where I reside. I just drive over and pick them up. Eurotubes does additional testing when they get them from JJ. I have not had a JJ tube failure that I purchased them from Eurotubes.com
And look at the large JJ selection of power tubes, and rectifiers too.
Go forth and build that amplifier.
I purchase all my JJ tubes from Eurotubes in the USA where I reside. I just drive over and pick them up. Eurotubes does additional testing when they get them from JJ. I have not had a JJ tube failure that I purchased them from Eurotubes.com
And look at the large JJ selection of power tubes, and rectifiers too.
Go forth and build that amplifier.
Yes I am aware. You have not read the entire reply. The reason that I want to use a noval tube is because my OCD for symetry. Two octal tubes? Looks great. One noval next to one octal? Lets say im tripping hard 😀 .
I am ware that JJ makes tubes and its quite the selection but for me as a student and that the amplifier is rather just an experiment then I will figure something out, I go for the cheapest possible tubes. Shuguang. Now Im wondering how can be something from the other side of the planet end up 20 bucks cheaper than something local.
Shuguang also makes 6SN7 valves but I said, its not really the availability of the original tube, its the visual side of thing.
Yeah I am aware that JJ manufactures but as in the previous reply, it is the visual appearance.
Also JJ ends up way more expensive than Shugunag from the other side of the planet
2X noval 2X octal.
EF86/806 is a noval tube from the beginning. The 6SN7 however, obviously isnt. I already built the mullard 20W amp and to be honest it looks amazing the way I set it up (two novals in the front, EF86 front right 12AX7 front left and the EL34s in the back everything simmetricallly spaced out and spaced out to also not be too difficult to remove the tubes. (Its a PCB based amp, Exactly what I plan to do with this second amp too)
EF86/806 is a noval tube from the beginning. The 6SN7 however, obviously isnt. I already built the mullard 20W amp and to be honest it looks amazing the way I set it up (two novals in the front, EF86 front right 12AX7 front left and the EL34s in the back everything simmetricallly spaced out and spaced out to also not be too difficult to remove the tubes. (Its a PCB based amp, Exactly what I plan to do with this second amp too)
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ok,and what is the problem?
all the tubes AX AT AU and SN SL and SJ are still produced or easily found especially in Russia for octals
all the tubes AX AT AU and SN SL and SJ are still produced or easily found especially in Russia for octals
The original schematic utilises a 6SN7 as the phase inverter. I would prefer if I could use a 12AX7 in the circuit. The 6SN7 and 12AX7 have very different electrical characteristics. It is obvious that a modification as such requires a chenge in the circuit- resistor values and such.
Now im not a proffesional that has years long experience with vacuum tube gear, I mostly restore stuff but I have not gotten that much in depth. I cannot do the modifications on my own an what is why I would like someone to help me if possible to modify the circuit so it accepts the tube I want to.
Now im not a proffesional that has years long experience with vacuum tube gear, I mostly restore stuff but I have not gotten that much in depth. I cannot do the modifications on my own an what is why I would like someone to help me if possible to modify the circuit so it accepts the tube I want to.
ok,I understand better now.
have you read the pages of the site "the valve wizard"?
you will probably find there a beginning of answer.
How to design valve guitar amplifiers
have you read the pages of the site "the valve wizard"?
you will probably find there a beginning of answer.
How to design valve guitar amplifiers
If you really want to use a 12AX7 in the phase inverter (instead of a 12AU7 which as previously mentioned would work with the same component values as for the 6SN7 and is the easiest option), then just copy the phase inverter from the Mullard 5-20, again as previously mentioned. The voltage at the ECC83/12AX7 grid in the 5-20 is 85V, same as the HF-52 so should work OK with Mullards component values. The 5-20 phase inverter is fed from 405V compared to 310V for the HF-52, so the power supply RC chain will need to be modified.
I have decided different, I am going to use the HF50/60 schematic. Will the phase inverter of the 20W mullard amp work with this? WIll it give enough drive? (22V sine on the grids of the EL34 as according to the HF50/60 schematic?
Also the phase inverter on the HF50/60 gets 422V on the anode resistors. That goes to 355V on the anodes themselves and acros the tube we have 300V in the original circuit. I dont think higher voltage on the inverter of the 20W would be hurt if I give it a couple more volts. But then again, im no professional .
It did give me some of the stuff I need. The difficult thing for me is to get it correct in my head because most of the information is rather from a guitar amps perspective. Im looking for HIFI. All tho its almost the same I need to look out for some stuff I guess.
Thank you very much
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