EL34/KT88/6L6 Tube Amplifier Construction: DIY Audio Projects, Symphonic Metal & Classical Music

I warmly welcome,
I'm planning to build a tube amplifier. I am looking for a fairly simple system that, if properly performed, will give back with sound (I mainly listen to symphonic metal and classical music). I was interested in the diagram and the short description of the structure on the website diyaudioprojects.com . Does this scheme have any reasons at all - the author writes that EL34 / KT88 / 6L6 tubes can be used interchangeably in it? How much truth is there? Maybe someone has some better suggestions for me?
Best regards,
Peter

Hello. And here my friend looked. https://www.elektroda.pl/rtvforum/topic1565468.html#7647341

Ok, I understand - I do not insist on the single ended configuration - anyway, I was afraid that this configuration might provide me with too little output power. As for the diagram from bonavolta.ch, although it looks friendly, there is no information on how to start the circuit. In any case, I am more and more willing to undertake the construction of the PP system, even though it is more complicated.

EDIT: if we are talking about PP, is it an amplifier Mr. Sławicz which has much better documentation (better available anyway) wouldn't be a better option? ] Link [/url]

http://www.electronicasi.com/wp-content/uploads/2013/04/GPE.pdf

Added after 4 [minutes]:

https://serwis.avt.pl/manuals/AVT5446.pdf

cefaloid wrote:

In practice, it may turn out that a push pull system is not much more expensive. Because you will need a housing, power supply, loudspeaker transformer, etc. And such a 30-40W is good power and you would not have to think about high-efficiency loudspeakers.

Of course, SE amplifiers with a power greater than 5-6W are already aberration. It is not a coincidence that in the factory equipment from the era when transistors were not yet or just crawling There were practically no lamps stronger than the EL84 in this configuration, regardless of the fact that the catalog cards of lamps such as EL34 also provided their SE applications for formalities. The only advantage of SE amplifiers is their simplicity: one end tube is enough, no tubes are needed for phase inverting circuits (and such systems, regardless of the configuration, cost at least one additional tube that does not provide any amplification), and finally the speaker transformer is easy to wind up. Besides, there are only disadvantages: the need to work in class A, which is associated with low efficiency and low output power, not exceeding half the admission power of the final lamp, high average power consumption from the power supply, sensitivity to hum, high harmonic content, especially even-order. The situation becomes even more complicated when we strive to obtain the highest possible quality of the amplifier: due to the anode current under-magnetization of the tube, a gap in the output transformer is needed, which in turn requires an increase in the number of turns if we want to get good bass transmission, as a result of the above, the dissipation inductance increases, so to prevent weakening sopranos, you need to divide the windings into many sections, which in turn requires enlarging the core to accommodate insulating spacers etc. Finally, it may turn out that the PP transformer will be cheaper, and certainly smaller and lighter than the SE transformer, of identical quality and power, regardless of the requirements for symmetry of the anode winding halves. The same will be true for the power supply: the PP circuit will require less power, regardless of the presence of two output lamps in each of the channels. Especially the parallel connection of lower power tubes in the SE configuration is completely pointless: the same tubes used in the PP configuration will provide several times more power (of course in class B or AB) with less distortion. Today's popularity Hi-End SE amplifiers can only be explained a false ideology made by smart producers of this type of equipment, and naivety audiophiles giving each other all sorts of stuff.

Quote:

For example, this circuit is popular:
http://www.bonavolta.ch/hobby/en/audio/el34_8.htm

But definitely overcomplicated. The first stage with a dedicated EF86 audio pentode is there extremely correct , it was even remembered that the grid blocking capacitor C6 of this tube should be connected to the cathode and not to ground, since serial CVT is used. But the way to use another tube, the ECC83 duotriode, is complete from the cap. One of the halves is used as a cathode follower (thus the basic value of this lamp in the form of a high gain factor is not used). The second - is the phase inverter in the system cradles where yes, high tube gain is very desirable (regardless of the fact that the resultant stage gain is only -1) but here it is reduced by a nonblocking resistor in the cathode. The possibility of improving the frequency properties was not used here cradles through auxiliary coupling between the cathodes of the triodes, but then the follower would have to be replaced with a stage in the WK system, and the amplification of the whole would turn out to be so great that after closing the CVT loop, excitation would occur. But why not be here anyway cradle? The EL34 tube is characterized by good sensitivity (like most dedicated audio end pentodes, from ECL86 through EL84 and ending with the now forgotten EL503, in contrast to beam tetrodes designed primarily for pulse operation, from PCL805 through EL81, PL504 and ending with ruby Therefore, the 6?45C does not require a particularly high control voltage, even in the UL configuration. This reveals the voltage distribution on both triodes: the follower will definitely not provide a voltage higher than 41V, cradle and - 60V, but without taking into account the aggravating effect of the divider resistors cradles (R13 + P1 - R14). Such voltages would be easily obtained from the simplest and most reliable inverter in the system cathodines (with shared load) requiring only one triode, and half of the cheaper ECC82 tube would do even better than the ECC83. The other half would be used in the second channel, and if someone is afraid of crosstalk - an ECC85 equipped with an intersystem screen can be used. The simplicity will turn out to be even greater when the EF86 pentode's operating point is slightly adjusted, so as to lower the voltage on its anode and screening mesh to about 70V (in which conditions it works perfectly), thanks to which there will be a possibility of galvanic coupling of the triode mesh with the pentode's anode. The entire invertor will then be reduced to one duotriode half and twoidentical resistors in the cathode and anode, without any potentiometer correcting the asymmetry, because there will be nothing to correct here, maybe only with the exception of the spread of parameters of both resistors, if they will have a tolerance of 20% instead of 1%. There is nothing original about it, that's how Polish amplifiers were built, including W-600f and W-701:
https://www.elektroda.pl/rtvforum/topic1538046.html

Quote:

Here are a few other designs, including single ended:
http://www.bonavolta.ch/hobby/en/audio/el34.htm

The first Dynaco Stereo 70 - and again recommended by me above, a practical configuration of a triode phase inverter with a shared load, galvanically coupled with a pentode voltage stage. Only the tube is different: a combination triode-pentode 7199 was used, corresponding to our ECF82 apart from a different electrode base. I do not see any reason why other similar tubes, such as the popular Soviet 6?1? (equivalent to the ECF80), should not be suitable for this role, regardless of insignificant differences in some parameters.