Creating a Tube Amplifier with 2xPCL86, EM84 Indicators and Transformers TG2.5-1-666 & TS40/29/670

Regarding the capacitor - in the MV3 diagram, which I've linked earlier, it's done differently and so I recommend. Capacitor between the slider and the wire mesh. That's how you did high tones are embossed (especially at low settings).

With regard to hum, 50 Hz should not be troublesome with proper location of everything. You can also raise the potential of the filament 10-15V above the cathode potential.

Excitation - it's not really a "positive ear", it would connect almost all the time. The question is whether this is not a case assembled on the table, no screening, etc. If it is better without the ears, it must be corrected - phase shifts cause the formation of positive feedback around the upper end of the band.
Although, the diagram looks good in this respect.

noe1 wrote:

"the question of choosing the value of the capacitor (so that it does not cut the bass, but without exaggeration with the value) I shoot at 100n". After all, at a low volume in this senseless arrangement, you will win the bass so that the listening session will be hopeless.

In MV3 it is and it is ok - there is no exaggeration in the bass. But everything is a matter of constant time. This is sometimes seen in the diagrams, only the voltage divider on the input, not the sweat. - the tube hifi power tubes themselves do not have volume control.
Nevertheless, I shot at the value (giving only the maximum). But such a system has several advantages, including the fact that the grid of the first lamp has a leakage resistor connected in a permanent way (and not, for example, a potentiometer zipper).

The natural brake of the bass are other elements here and below a certain value it will be difficult to come down with the band.

Hmm, what "stripes" are you talking about? I do not think I have seen such capacitors yet - what is this designation?

Probably it is about foil capacitors coiled with a marked stripe leading out the outer cladding.

He wanted a reg system. the volume I suggested, but yesterday I looked for a moment in the evening and wrote back only on it. And today is the new day.

1. Will the placement of transformers in metal cans offset their work and affect the entire system.

Probably yes, only: there are 2 types of interference from the transformers. Magnetic and electric fields. The electric field can be easily shielded with a piece of grounded conductor - typical ubiquitous "screens". The magnetic field is more difficult - you need a screen of soft magnetic material - the field wipes energy on the flow of eddy currents. This is more difficult to shield, therefore transformers are properly set - middle columns at an angle of 90 degrees, especially when the transformers are close to each other.

This type of impact decreases with the square of distance - that is why "the farther the better".


2. Should shielded transformers be connected to a common point of mass.

Both the core and the screen - to ground, can be at the chassis at the fixing point, are not sensitive zones and there is nothing to combine.


3. When I have it all connected, do I still have to make the filter on the anode power supply and lamp glow as shown in the picture

Anodic - do you associate the concept of the ripple factor? If you go down to 0.05% for the final pentode and 0.02% for the triode, it will be great. If you feel like it, anode triodes can even be stabilized.

As for the glow - the minimum is the symmetrization of the resistors to ground (R23, R24). DC can be fun - only the rectifier must be solid, diodes blocked with capacitors, etc. Badly made solid can give worse interference than variable - you get rid of "brumu" and you get "ticking".