wonderful ! You did a fine work, a tried a similar circuit with the polytronic-system of the ex-GDR, all filters are homemade, too. It workes fine, too. You can do the coupling to the filters with splitting the capacity, too, the filter coil can have only one (tapped) winding in this case, Keep it going !!
But I'm afraid if use auto-transformer the coupling between windings will be higher having sharp cone right in the middle of sound frequency and much lower at the low and high end so sound will be more distorted. Isn't it?
@@alexloktionoff6833 Hello, I did not mean autotransformer-coupling between the stages ! I meant the coupling the next stage on an resonant circuit: here is the autotransformer principle possible as well, if you build a IF-Amp with single resonant-circuits. This can be done, too and it is seen in the shematic above, too, in the demodulator-stage for instance. But if you want to built a bandpass-filter (seen on the left side in the shematic above), you can couple the secondary resonant-circuit with autotransformer (tapped) winding or by splitting the capacity oft the secondary resonant circuit ! Splitting the capacity is more comfortable for homemade-filters And yes, the coupling will be very high, but this is, what you want, because the selectivity is done by the coupling oft the primary and secondary resonant-circuit ! In case oft the single-resonant-circuit there is only the single resonant circuit itself to get selectivity, the coupling oft the next transistor stage has to be with low damping oft the resonant-circuit, like it has to be in the secondary-circiut of an band-pass-filter. - Splitting the capacity is good for homemade IF-Amps, but it is impossible to make IF-Amps for AM/FM together, thats the disadvantage. But today transistors are so damn cheap, I would build 2 seperate IF-Amps if I want AM/FM in one radio together. You asked for circuits, unfortuately the GFGF-schematics are down, but you can find examples in many radio-circuits of the 70's, some brands did this many times in AM-IF-Amps, too, FM was in TBA120-like ICs. I did this C-splitting-thing in Vision-If-Amps with stagged tuning one-resonant-circuits, it work fine. Hope, it helps, greetings
@@alexloktionoff6833 ...addendum: The autotransformer only transformes impedances as well as the splitted capacitor does, I think, I got you wrong a little bit ^^ but its just about that: transforming impedances in consequence of the low-impedance of a transistor circuit. A seperate couple-winding is useful, too, it can be does in series to the BIAS-resistor... But a seperate couple-winding (10...20 turns) directly over the main-winding is magnetical nearly the same like autotransformer-tap...
@@perianmarcel2059 I see they’re needed to be rewound. But on Aliexpress I can find only complete kits with all components pcb and case. Do you use a cheap only coils kit? Can you help to find it? Thank you in advance
wonderful ! You did a fine work, a tried a similar circuit with the polytronic-system of the ex-GDR, all filters are homemade, too. It workes fine, too. You can do the coupling to the filters with splitting the capacity, too, the filter coil can have only one (tapped) winding in this case, Keep it going !!
Tnx!
@@hql400 interesting method, can you provide a link to schematics?
But I'm afraid if use auto-transformer the coupling between windings will be higher having sharp cone right in the middle of sound frequency and much lower at the low and high end so sound will be more distorted. Isn't it?
@@alexloktionoff6833 Hello, I did not mean autotransformer-coupling between the stages ! I meant the coupling the next stage on an resonant circuit: here is the autotransformer principle possible as well, if you build a IF-Amp with single resonant-circuits. This can be done, too and it is seen in the shematic above, too, in the demodulator-stage for instance. But if you want to built a bandpass-filter (seen on the left side in the shematic above), you can couple the secondary resonant-circuit with autotransformer (tapped) winding or by splitting the capacity oft the secondary resonant circuit ! Splitting the capacity is more comfortable for homemade-filters And yes, the coupling will be very high, but this is, what you want, because the selectivity is done by the coupling oft the primary and secondary resonant-circuit ! In case oft the single-resonant-circuit there is only the single resonant circuit itself to get selectivity, the coupling oft the next transistor stage has to be with low damping oft the resonant-circuit, like it has to be in the secondary-circiut of an band-pass-filter. - Splitting the capacity is good for homemade IF-Amps, but it is impossible to make IF-Amps for AM/FM together, thats the disadvantage. But today transistors are so damn cheap, I would build 2 seperate IF-Amps if I want AM/FM in one radio together. You asked for circuits, unfortuately the GFGF-schematics are down, but you can find examples in many radio-circuits of the 70's, some brands did this many times in AM-IF-Amps, too, FM was in TBA120-like ICs. I did this C-splitting-thing in Vision-If-Amps with stagged tuning one-resonant-circuits, it work fine. Hope, it helps, greetings
@@alexloktionoff6833 ...addendum: The autotransformer only transformes impedances as well as the splitted capacitor does, I think, I got you wrong a little bit ^^ but its just about that: transforming impedances in consequence of the low-impedance of a transistor circuit. A seperate couple-winding is useful, too, it can be does in series to the BIAS-resistor... But a seperate couple-winding (10...20 turns) directly over the main-winding is magnetical nearly the same like autotransformer-tap...
Interesting I see Germanium npn transistor, even Poland could not produce such and had to export from Soviet Union.
Which year of manufacturing?
Misto video! 👍
That's good; thanks
Is there only the coils kit being sold on Aliexpress? Can you provide exact title, or link?
@@alexloktionoff6833 No, you need to rewind all the IF transformers. That's why I am providing the infos about turn no and inductance.
@@perianmarcel2059 I see they’re needed to be rewound. But on Aliexpress I can find only complete kits with all components pcb and case. Do you use a cheap only coils kit? Can you help to find it? Thank you in advance
@@alexloktionoff6833 Try this: www.aliexpress.com/item/1005003757706854.html