Here's a final schematic of my 12AV5GA amp which was inspired by George of Tubelab from his page on beating the poop out of the 6AV5GA.
The bias control is one of these: Electron Tube Amp Negative Grid Bias Power Supply Adjustable 4channel for PP SE | eBay
The boost converter is one of these using the 200V AC output into a Delon circuit: DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter Boost Board Transformer | eBay
The 12V SMPS is one of these: AC 110V-220V TO DC 5V 12V 24V 2A 10A 15A 20A 40A 60A Switch Power Supply Adapter | eBay
This complete build cost about $300 CAD, and as some of you know, the 12AV5GA is essentially a 2A3 when connected in triode mode. Find me a 2A3 amp for $300 CAD
EDIT: The extra SMPS is powering the boost converter in this amp due to it being an afterthought.
Thanks,
Koda
The bias control is one of these: Electron Tube Amp Negative Grid Bias Power Supply Adjustable 4channel for PP SE | eBay
The boost converter is one of these using the 200V AC output into a Delon circuit: DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter Boost Board Transformer | eBay
The 12V SMPS is one of these: AC 110V-220V TO DC 5V 12V 24V 2A 10A 15A 20A 40A 60A Switch Power Supply Adapter | eBay
This complete build cost about $300 CAD, and as some of you know, the 12AV5GA is essentially a 2A3 when connected in triode mode. Find me a 2A3 amp for $300 CAD
EDIT: The extra SMPS is powering the boost converter in this amp due to it being an afterthought.
Thanks,
Koda
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Bro, are you me? We seem to have similar ideas lol.
Nice build! Coincidentally, I've got sixteen 12AV5GA in my tube bin waiting for a screen drive or crazy drive build. I like your cathodyne into differential amplifier setup, and the individual cathode resistors are a nice touch for increased linearity and lower odd harmonics. I've found that to be a great way to go when swinging even huge voltage for some nutty experiences in the past.
Nice build! Coincidentally, I've got sixteen 12AV5GA in my tube bin waiting for a screen drive or crazy drive build. I like your cathodyne into differential amplifier setup, and the individual cathode resistors are a nice touch for increased linearity and lower odd harmonics. I've found that to be a great way to go when swinging even huge voltage for some nutty experiences in the past.
I've done it with 6N8S and 6CG7 in the past, load the follower with a CCS, and run 275~300 or so volts on the plate, and a negative rail at least twice your bias voltage for the outputs. Otherwise simply wire it up as you usually would for fixed bias and adjust as usual. Less voltage is needed for twin/crazy drive, but I haven't yet played with that too much.
Personally I found that it was less hassle and slightly less work to use the IRF820 instead of cathode followers, but then you don't get the same bragging rights
Personally I found that it was less hassle and slightly less work to use the IRF820 instead of cathode followers, but then you don't get the same bragging rights
I've done it with 6N8S and 6CG7 in the past, load the follower with a CCS, and run 275~300 or so volts on the plate, and a negative rail at least twice your bias voltage for the outputs. Otherwise simply wire it up as you usually would for fixed bias and adjust as usual. Less voltage is needed for twin/crazy drive, but I haven't yet played with that too much.
Personally I found that it was less hassle and slightly less work to use the IRF820 instead of cathode followers, but then you don't get the same bragging rights
Fair point
But I trip over getting the DC coupling voltages to line up in my mind. I don't use SPICE.
Thank you. To be fair though, it's just a standard Williamson front end basically copied from the Acrosound catalog. If I was building this amp from scratch again, I'd probably use a 6F12P instead of 2 6SN7
6F12P is very unstable. I had an experience about 10 years back. Any good pentode tube will be better for the IPS.
It sounds like, "Your Caruso is bad singer. I did not hear him personally, Moisha by phone sang like him".
What Unstable means? The best tube for input stages of power amps. Period.
The circuit listed above has been built and used without issue. It is triode connected though.
It is using roughly a 3k Ra-a. It's effectively the same tube in this circuit. I think the 6F12P will drive it to full output. I get about 150V P-P from the circuit I added in the third post.
Just eyeballing it I figured it was around 60 volts. Sounds like it should work pretty well with what I have on hand. I have a couple no-name 6K:8 ~20 watt output transformers that I will use, power output won't be huge, but this isn't meant to be a spec buster rig anyway. I may even rig up some 4 ohm speakers to them to run them a bit harder.
When are you going to regulate them' screens and run it pentode connected? The 6AV5 types are a very nice pentode in their own right, without having to play pretend with triode connection
When are you going to regulate them' screens and run it pentode connected? The 6AV5 types are a very nice pentode in their own right, without having to play pretend with triode connection
I prefer triodes I guess, although my latest build uses a pentode input... My speakers are 95db in room so I don't need a lot of power. My 6P45S in push pull triode makes 80W into 1k3 (Triad VPT18, series), or about 25W into 4k3 (Hammond 1650N), the latter being class A.
I run the 12AV5GA in triode with a 3k Ra-a... (Triad VPT12, series) and it's good for about 30W Class AB1.
I run the 12AV5GA in triode with a 3k Ra-a... (Triad VPT12, series) and it's good for about 30W Class AB1.
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