40W from pair of Russian military tubes with 10W dissipation?
An externally hosted image should be here but it was not working when we last tested it.
I am playing with this schematic for several days. I know that the 4P1L is "only" 10W, but I am curious why I get this result. Because of schematic? Because of tube model? Or beause LTspice does not work 100%?
A few mounts ago I build PP with 4P1L and I got around 4W. For driver and splitter I used 6N23P.
A few mounts ago I build PP with 4P1L and I got around 4W. For driver and splitter I used 6N23P.
Models fail to detect faulty start conditions. Thats where the users intelligence is essential to understand the limitation of the model. Spice doesn't understand power limits - it simply amplifies within the parameters of the valve stages and the input conditions. As was pointed out - your mistake was to input far to much signal to the outputs.
Shoog
Shoog
What load resistance did you have a few months ago?
3.5K, I got 4W peak. My mistake in previous post.
Models fail to detect faulty start conditions. Thats where the users intelligence is essential to understand the limitation of the model. Spice doesn't understand power limits - it simply amplifies within the parameters of the valve stages and the input conditions. As was pointed out - your mistake was to input far to much signal to the outputs.
Shoog
I did not know that. Thanks for info.
I am playing with this schematic for several days. I know that the 4P1L is "only" 10W, but I am curious why I get this result. Because of schematic? Because of tube model? Or beause LTspice does not work 100%?
As already pointed out you cannot drive the 4P1L's with 260V signal. As it is a simulator valves will not get red hot and the amplifier won't disintegrate. This is not a fault of LTspice but yours. It will work as long as you feed it with sensible numbers....
Also 1K8 load is just too low.
I don't know if Ale has refined the model for positive grid region but it should be fine up to +10V grid voltage (except for the driver requirement of power drive). It is surely based on real curves. This means that if your bias is -24V you should only apply no more than 78V peak-to-peak signal to the grid not 260!
Last edited:
As already pointed out you cannot drive the 4P1L's with 260V signal. As it is a simulator valves will not get red hot and the amplifier won't disintegrate. This is not a fault of LTspice but yours. It will work as long as you feed it with sensible numbers....
Also 1K8 load is just too low.
I don't know if Ale has refined the model for positive grid region but it should be fine up to +10V grid voltage (except for the driver requirement of power drive). It is surely based on real curves. This means that if your bias is -24V you should only apply no more than 78V peak-to-peak signal to the grid not 260!
Something like this (14W)?:
Attachments
I don't know if Ale has refined the model for positive grid region but it should be fine up to +10V grid voltage (except for the driver requirement of power drive). It is surely based on real curves. This means that if your bias is -24V you should only apply no more than 78V peak-to-peak signal to the grid not 260!
I haven't refined the model for A2 operation as I don't have(yet) grid current traces. I have recently refined a model for the 814 and 4-65a in triode mode as transmitting valves generally have grid current curves available. Dmitry refined the grid current model replacing the classic diode one with a better curve model which matches the exponential grid current at lower anode voltages.
I will publish these new models when I get the time.
The new 4P1L model performs more accurately than Dmitry's at larger voltage swings, but clearly will not represent A2 operation well...
Ale
I was getting 5W from one paralleled pair in A2. You can't get more.
Soviet push-pull amp that used one 4P1L as a driver with interstage transformer driving a pair of 4P1L was rated for 10W output. However, it was battery powered, so I don't expect high idle current.
КРУ-10
Schematic on page 21, including details of transformers: http://piratbooks.ru/file/_zhurnal_Radio_Radio_1952_09.djvu
Soviet push-pull amp that used one 4P1L as a driver with interstage transformer driving a pair of 4P1L was rated for 10W output. However, it was battery powered, so I don't expect high idle current.
КРУ-10
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Schematic on page 21, including details of transformers: http://piratbooks.ru/file/_zhurnal_Radio_Radio_1952_09.djvu
Found this kit in Thailand of all places... DIY µé¹áºº»ÃÕËÅÍ´
In one of the pictures, it mentions the OPT is 3.6K, for 2 tubes, so 1.8K for 4 tubes is not completely out of the question. BTW, that's a lot of tubes to get 14W ;-)
Jaz
In one of the pictures, it mentions the OPT is 3.6K, for 2 tubes, so 1.8K for 4 tubes is not completely out of the question. BTW, that's a lot of tubes to get 14W ;-)
Jaz
It is a lot of tubes for that but they are amongst the most linear of valves about. Do you really need more? I have a 100W pair of valve amps that I built but rarely use more than 5W plus some headroom. So 14W is probably about all that's needed with the right speakers.
Cheers Matt.
Cheers Matt.
Here's a question for you Wavebourn - when searching Ebay for transformers there seems to be a dirth of Russian offerings. What search terms are likely to bring up Russian OT.
I never heard about good Russian OT production.
Thats unfortunate.I never heard about good Russian OT production.
Shoog
Thats unfortunate.
Why OTs would be needed in struggle for liberation of working class of the planet from capitalist exploitation?
Power transformers, though, were great. ТА, (Anode Transformers), ТАН (TAN, Anode and Filament Transformer), ТН (TN, Filament Transformer), ТПП (TPP, for powering of semiconductors)
An externally hosted image should be here but it was not working when we last tested it.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Tubes / Valves
- 4P1L triode PP (40W!!?)