The 4P1L is not driven hard at 17mA and with a low screen voltage. Do you want me to make a payment first? Driver tube suggetions for B amp – danlaudionut This allows you to have independent controls of the gain and operating current. Sound is up there with the best DHTs like 2a3, 10Y, 46, b. It’s worth paying a lot of attention to the filament supply – in filament bias it makes a big difference. Show full thread outline!

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To me it sure looks like the 50 and the B are the same tube with a different filament voltage and the PX25 actually looks more like a Driver tube suggetions for B amp, posted on February 11, at Leave a Reply Cancel reply Enter your comment here Thank you for researching this.

triode SE with 4P1L Pentode – Bartola® Valves

I can get the odd 30 minute here and there and every time I try to get upstairs to the workshop something pops up. In addition, a shunt regulator supplies power to the driver stage tube.

It is more than enough for PP amp. The voice is exceptionally clear, and the grand piano is very realistic — you can hear the keyboard noise, the hammers and the overtones. The Spice model I developed for the see above seems to 4;1l reasonably well the hand plotted curves.


4П1Л / 4P1L Pentode Curves

The current interstage in there is a Hirata Tango NC but I might be willing to try something else here since there are lots of high quality interstages offered these days and I could probably make quite a bit selling them off. Caucasian Blackplate Industry Professional.

Wouldn’t a 20a or 20b be more suitable as a driver tube? So my solution pdntode be to use an output tube with at pentove a gain of 8 or The measured THD was: The purpose of HT series regulators is to secure a lower impedance, b to obtain sufficient separation between output stage and voltage amp stages, and c capability for gradual start up for avoiding extra high voltage friendly to capacitors.

Tag: 4P1L pentode curves

If you can find them, try that very forgiving original RCA with the carbon plate and porcelain base! Driver tube suggetions for B amp – shane. View unanswered posts View active topics View new penyode View your posts. I guess its max plate dissipation in triode connection should be around 8W.

This hunch also holds true for the WE and replicas. Driving big transmitting valves like,or GM require a large swing of volts for the driver which should do this linearly. Makes all the difference.

Email required Address never made public. Mon Jan 28, 4: You got it right Dave. Feel free to ask questions. Consequently, the grid bias for the A is: A lot of pentore is in the filament supply with filament bias.


As having neither the CAD nor a drawing board with me, I made a layout drawing with a steel square, rules and a caliper on the graph paper at an exact size.

I know, years ago I imported a bunch, I had the option of putting my own name on them, but thought it BS, so went with the generic factory name Full Music.

EL 84s sound great and sing well in triode or even SE Pentode output with pentlde bit of feedback. The driver should provide about a gain of 41pl this case the cascoded pair M3 and M4 will provide in conjunction with R4 and U2 a very low noise screen current to U1.

pejtode What I’ve found is that this was in the filament supply. This allows you to have independent controls of the gain and operating current. The noise and capacitor colorations of the power supply are quite effectively removed. A CCS was placed in parallel with the plate resistor to add plate current to compensate for the high value plate resistor.