Congratulations
Any pictures of the preamp build you can post?
I can't right now because a friend decided to keep it for now. I wonder why?😉
Alright, did some more scooting around- the mounting holes near each socket are 40mm spacing m3 holes, and the socket centers are 45mm from the top edge of the board, 20mm from the board edge. I don't have access to a printer just now to mock up a printout of the PCBs but I think that there should be plenty of room for most reasonable audiophile output caps. I want to redo the silkscreen labeling of the output terminals and I'm trying to think of the most clear way to do so.
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Missed a trace between the anode load resistors and the anode pin on the sockets while rearranging, fixed it 😱
Alright, now we have the seven pin socket nested inside the footprint (surprisingly easy, really) for the octal socket, so the board will now support the 6AQ5 and other tubes that share the same pinout 🙂
I just want to redo the labels on the terminal strip and I think we are basically done!
I just want to redo the labels on the terminal strip and I think we are basically done!
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Nice! I tend to put the B+ and heater heares on the opposite side of the signal, but it's not a phono stage so I see no reason to really...
I would appreciate any comments on more clear markings for the terminal strip that all the offboard connections are run off of, so I took a break from that and decided to try a different part of the project.
I went ahead and worked on the nine pin version as well. This one is set up for the EL84 pinout, with jumpers to allow the 6p15p to work as well. This will allow you to use a bunch of great affordable tubes for this design, such as the 6p14p, 6CW5/EL86/PL84/UL84, and the 6p43p (my personal favorite I'd like to try). For quick reference, a mu of 20 can be had with the EL84 with a bypassed cathode, and the 6p43p could make a mu of 6 like the 6V6 design but can do it even with only a 150 volt supply!
I will also do a 6p1p version as well, once these look good. I think we're almost done!!!
I went ahead and worked on the nine pin version as well. This one is set up for the EL84 pinout, with jumpers to allow the 6p15p to work as well. This will allow you to use a bunch of great affordable tubes for this design, such as the 6p14p, 6CW5/EL86/PL84/UL84, and the 6p43p (my personal favorite I'd like to try). For quick reference, a mu of 20 can be had with the EL84 with a bypassed cathode, and the 6p43p could make a mu of 6 like the 6V6 design but can do it even with only a 150 volt supply!
I will also do a 6p1p version as well, once these look good. I think we're almost done!!!
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Put 3mm holes in the centre of each tube socket -- it makes a stencil for layout (cutting the hole for the tube - I assume the parts are on one side and the sockets on the other?)!
Also if you move the electro in the centre you can place a 5th screw hole there...
Also if you move the electro in the centre you can place a 5th screw hole there...
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Great idea, it'll also let folks slap an LED under there if they so chose. 🙂
I think I'll put another screw terminal on the top for alternative supply of power too. Maybe a few extra holes for ground, power, etc in a few places for experimenters too.
I think I'll put another screw terminal on the top for alternative supply of power too. Maybe a few extra holes for ground, power, etc in a few places for experimenters too.
Especially if blue like in cheap low voltage "tube" headphone amps that everything is done by a fake 5532 op-amp and the tubes are decor. Super -Eww 😀
Could go green to play pretend like the new Mcintosh stuff 🙂
Alright- here's the semi-final octal/seven pinner version- we now have a mounting hole in the center of the board, inline with the centers of the tube sockets at 45mm from the bottom edge of the board. With the holes at 20mm from the center on top and bottom of each socket we should have plenty of support, in addition to the corner mounting holes! There are now holes centered under each socket for easy chassis drilling layout, and they also serve double duty for anyone that wish to place an LED under the socket for seven pin applications. The supply capacitor is now up at the top of the board right next to the feed to the anode resistors, with an alternate feed of power on this side of the board for those that would prefer it. I also found a better way to label the terminal strip for in/out/power that I think is much more clear.
Alright- here's the semi-final octal/seven pinner version- we now have a mounting hole in the center of the board, inline with the centers of the tube sockets at 45mm from the bottom edge of the board. With the holes at 20mm from the center on top and bottom of each socket we should have plenty of support, in addition to the corner mounting holes! There are now holes centered under each socket for easy chassis drilling layout, and they also serve double duty for anyone that wish to place an LED under the socket for seven pin applications. The supply capacitor is now up at the top of the board right next to the feed to the anode resistors, with an alternate feed of power on this side of the board for those that would prefer it. I also found a better way to label the terminal strip for in/out/power that I think is much more clear.
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And here is the noval/El84 version. All of the features of the octal version, but set up for EL84 pinout tubes. Also features support for the 6p15p tube as well via jumper to allow connection of pins 1 and 3 to tie the G3 and cathode together. I'm particulary interested in this version so I can build one up with 6p43p-e tubes for low voltage 🙂 Interesting note is that you can build your chassis to accept either board, and then freely dismount one to swap to the other. Interesting feature of doing the boards all at once 🙂
Silkscreen still says "6v6" on it for now, I'll let Salas decide what we call that version. "EL84 line preamp"? "Noval line preamp" is what I'm calling it for now.
Next up once we are happy with these two will be a pinout change to the noval/EL84 version to work with the 6p1p tube. I'll call that one the "6p1p line preamp" on the board.
I might order a batch of beta PCBs by friday? 🙂
Silkscreen still says "6v6" on it for now, I'll let Salas decide what we call that version. "EL84 line preamp"? "Noval line preamp" is what I'm calling it for now.
Next up once we are happy with these two will be a pinout change to the noval/EL84 version to work with the 6p1p tube. I'll call that one the "6p1p line preamp" on the board.
I might order a batch of beta PCBs by friday? 🙂
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Great to have the novel option. Speaking of which has anyone built an el84 version? Would one expect more or less noise and distortion or less vs a 6V6?
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I have a LTP, SE😛P linestage running EL84 and EL86. I like the EL84 better...and gain for my amps is just about right. Triode strapped in all cases.
cheers,
Douglas
Great job, thank you! But do we actually need that B+ next tot the signal outputs and inputs? Just a safety precaution... Are you gonna order both 6v6 and novel versions?