A power supply schematic showing the batteries would be awesome! Thank for sharing! I want to build one but didn’t understand how the battery bank is grounded with respect to the chassis grounds. Cheers! 🎉
The negative terminals for 90V B+ and 1.4V A+ go to the chassis. The positive terminal for the -4.5V C- goes to the chassis as well. For B+ you can use ten of the cheapest 9V carbon batteries you can find in series. For A+, a 1.5V D cell battery will work. For C- you can use three AAA batteries in series and they should last an eternity.
Thanks, I did a preamp design for AudioXpress a few years back that I have since refined using 1T4 tubes. You can reduce the current of the final tube using a buffer unity gain amp like the LM49600 instead of a tube. Have you tried the 3V4 or the 3S4 as an output tube? They are the miniature tubes that designers used back then with the 1T4's. Also you can reduce the plate voltage to 50 or 60 and they still run well. Lots of fun!
What a great idea! I would like to see the schematic as well. It looks like the screen is internally connected to the cathode on the 1t4 tube so they cant be triode strapped. Their transconductance is pretty low too but the sound it promising. I wonder what the primary inductance is of that output transformer? Thanks for posting this project! it is very inspiring. I've got an 82 Candy apple red Standard - Metallic red on a les paul is freaking awesome!. What year is your les paul? Thanks again!
My Les Paul is from 1975. It came with mini-humbuckers but they were a bit shrill sounding for my liking, and microphonic, so I swapped them out for P90's as they are my favourite pickups. The 1T4 has its supressor grid connected internally, not its screen grid, so they are able to be triode strapped. In my circuit they are run as true pentodes. One can also use the 1U4 as it's pin compatible, or the 1U5 if you ground the diode on pin 4 which is unused on the other two pentodes. A link to the schematic is in the video description.
@@snarfusmaximus Thanks for the thoughtful response! I have parts on order. I might try a push pull as well. I used to have a 77 wine red deluxe that I also put p90's in because, ah, well... P90's! Thanks again.
Oh, I forgot to mention, the impedance of the transformer is 10k on the primary. That PA transformer is made for 8 ohm speakers, hence why I change taps on the primary rather than the speaker side. The 1Q5GT requires an 8k load at a B+ of 90V but 10k seems close enough. It also keeps things pretty cheap using such a generic transformer.
What if you used regular valves instead and just used more batteries in series? I assume the battery valves are more efficient, but which ones are better overall. The battery or regular valves
You could run regular valves on batteries but you'd need more batteries and they'd die quicker. Standard valves have a heater to heat the cathode and generally require way more current to do so. The heater in battery valves is the cathode and they require much less current to work. They were made for portable radios before transistors took over so they were designed to be efficient and not eat through batteries. Neither valve type is better as they are designed to serve different purposes. Obviously battery valves won't ever deliver the power of a Marshall stack.
@@snarfusmaximus are the battery valves just as good with a similar lifespan compared to the regular ones that run on mains power or are they a compromise with maybe less lifespan in exchange for longer battery life? Today we have lithium batteries compared to the batteries they used back then. Just asking because i am thinking about building a vacuum tube bluetooth speaker and would rather have more battery storage in exchange for longer valve lifespan and better quality. If all is equal i will go for the battery versions but if not i will go with the regular valves and just battery up the thing. I already have a bunch of batteries just sitting on the shelf that were good and being tossed so i rescued them.
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A power supply schematic showing the batteries would be awesome! Thank for sharing! I want to build one but didn’t understand how the battery bank is grounded with respect to the chassis grounds. Cheers! 🎉
The negative terminals for 90V B+ and 1.4V A+ go to the chassis. The positive terminal for the -4.5V C- goes to the chassis as well. For B+ you can use ten of the cheapest 9V carbon batteries you can find in series. For A+, a 1.5V D cell battery will work. For C- you can use three AAA batteries in series and they should last an eternity.
I'm not sure why I'm getting a striketthrough when I type minus 4.5V and C minus. The smart formatting sucks.
Thanks,
I did a preamp design for AudioXpress a few years back that I have since refined using 1T4 tubes. You can reduce the current of the final tube using a buffer unity gain amp like the LM49600 instead of a tube.
Have you tried the 3V4 or the 3S4 as an output tube? They are the miniature tubes that designers used back then with the 1T4's. Also you can reduce the plate voltage to 50 or 60 and they still run well. Lots of fun!
Legend! Nice work & entertaining as usual. Ricky B.
Been too long since we caught up on the air, KF. We should do so again soon.
very neat i am building class A stereo amp using 2 x 807 and ef37A for hifi
Please post a video when it's done. I'd love to hear it.
@@snarfusmaximus here's my email i will send you photos eletrontube42@gmail.com
looks great
What a great idea! I would like to see the schematic as well. It looks like the screen is internally connected to the cathode on the 1t4 tube so they cant be triode strapped. Their transconductance is pretty low too but the sound it promising. I wonder what the primary inductance is of that output transformer? Thanks for posting this project! it is very inspiring. I've got an 82 Candy apple red Standard - Metallic red on a les paul is freaking awesome!. What year is your les paul? Thanks again!
My Les Paul is from 1975. It came with mini-humbuckers but they were a bit shrill sounding for my liking, and microphonic, so I swapped them out for P90's as they are my favourite pickups.
The 1T4 has its supressor grid connected internally, not its screen grid, so they are able to be triode strapped. In my circuit they are run as true pentodes. One can also use the 1U4 as it's pin compatible, or the 1U5 if you ground the diode on pin 4 which is unused on the other two pentodes. A link to the schematic is in the video description.
@@snarfusmaximus Thanks for the thoughtful response! I have parts on order. I might try a push pull as well. I used to have a 77 wine red deluxe that I also put p90's in because, ah, well... P90's! Thanks again.
Oh, I forgot to mention, the impedance of the transformer is 10k on the primary. That PA transformer is made for 8 ohm speakers, hence why I change taps on the primary rather than the speaker side. The 1Q5GT requires an 8k load at a B+ of 90V but 10k seems close enough. It also keeps things pretty cheap using such a generic transformer.
Very nice project. All the caps are polyester? Thanks!
Yes, except for one ceramic in the tone circuit.
@@snarfusmaximus thanks!
What if you used regular valves instead and just used more batteries in series? I assume the battery valves are more efficient, but which ones are better overall. The battery or regular valves
You could run regular valves on batteries but you'd need more batteries and they'd die quicker. Standard valves have a heater to heat the cathode and generally require way more current to do so. The heater in battery valves is the cathode and they require much less current to work. They were made for portable radios before transistors took over so they were designed to be efficient and not eat through batteries. Neither valve type is better as they are designed to serve different purposes. Obviously battery valves won't ever deliver the power of a Marshall stack.
@@snarfusmaximus are the battery valves just as good with a similar lifespan compared to the regular ones that run on mains power or are they a compromise with maybe less lifespan in exchange for longer battery life? Today we have lithium batteries compared to the batteries they used back then.
Just asking because i am thinking about building a vacuum tube bluetooth speaker and would rather have more battery storage in exchange for longer valve lifespan and better quality. If all is equal i will go for the battery versions but if not i will go with the regular valves and just battery up the thing. I already have a bunch of batteries just sitting on the shelf that were good and being tossed so i rescued them.