I prefer parallel-connected 4P1L filament (2.1V 650mA), and for SE or PSE you can use 6.3V 4A transformer. But, as Euro21 says, we need to know if you are using Filament Bias. Please post the schematic, if you have filament bias.
With any DHT, please use a separate 6.3V 4A transformer winding for L-channel and R-channel.
When halves of the filament are connected in parallel distortions are lower. 4П1Л is a directly heated tube, so the voltage drop on the filament in each articular point adds to the control grid bias. You can view each wire in the grid as a separate triode, so the more the difference between bias points is, the better they match each other. However, they are pretty linear in this particular tube, so the difference would not be audible, but still, theoretically it is better to connect halves of the filament in parallel.
It makes total sense then to build the first stage and output stage in separate chassis, pre amp/power amp set up, I think Andy Evans advocated that.
I did that, works very well. For me now it's 01A in one case, 4P1Ls in two small monoblocks
It has been published by Andy Evans in various places. Do a basic search and you find the schematics. Basically everything to the right of the 100K resistor (including it) is the "power amp" Common bias point is 20V, so you need a pre-amp/driver that swings this voltage (40Vp-p) or just short of it to use the full power if 4P1L's
It's fun to understand the operation of the circuits you are building, and these low parts count designs are great to get insights into tubes. And there is a special beauty in the simplicity (power supplies left aside) of these curcuits
It's fun to understand the operation of the circuits you are building, and these low parts count designs are great to get insights into tubes. And there is a special beauty in the simplicity (power supplies left aside) of these curcuits
Hi, I found this thread while considering to build 6C4C SE or 4P1L PSE amp.
Glad that you love product from Vietnam. Phuong Nguyen - NP Acoustic - is my friend, but he is not good at English, just in case you have difficulty in reaching/communicate with him, can send me a PM, I can explain/forward to him. I am more than happy to help both sides
Glad that you love product from Vietnam. Phuong Nguyen - NP Acoustic - is my friend, but he is not good at English, just in case you have difficulty in reaching/communicate with him, can send me a PM, I can explain/forward to him. I am more than happy to help both sides
I communicate with Phuong Nguyen on Facebook Messenger which is his preferred medium. But good to have an English-speaking alternative.
I'm a fan of his amorphous plate chokes and just ordered another two. I have a small one 15mA and a big one 40mA. Very similar sound, the small one is a touch smoother and the large one a touch more detailed. Both good. His OPTs are good to have but I'd also make a case for his plate chokes, since amorphous cores work nicely here.
I'm a fan of his amorphous plate chokes and just ordered another two. I have a small one 15mA and a big one 40mA. Very similar sound, the small one is a touch smoother and the large one a touch more detailed. Both good. His OPTs are good to have but I'd also make a case for his plate chokes, since amorphous cores work nicely here.
2.5K is more optimal for a parallel 4P1L with 250V B+, to get 5W in class A2.
My not too good looking monster amp just got finished and up running. It's sound really good if compare to the other amps I have finished the last twenty years. It measures good too, -3db 11.3hz to 45.5k...
Thanks Andy for his valuable advices and also thanks Rod for his guiding me along.
Thanks Andy for his valuable advices and also thanks Rod for his guiding me along.
Attachments
Andy,
Thanks for your help.
Ale,
I was inspired by your ideas and your enthusiasm to the diy community. You're really generious to disclose all your findings with those Russian tubes.
Eh... I almost forgot to thank Wavebourn for his contributions.
Albert
