The choice was for a Single Ended all triode amp, with simple but not stupid schematics. Moreover the maximum attention was devoted to the choice of every component and specially to the transformers (output and power).

The tube used in the amplifier is the PCL82/ECL82 or 16A8/6BM8 (American names). The difference between ECL and PCL type is only the heather requirements (16V for the PCL, 6,3V for the ECL); this amplifier can use both types by multiple heather voltage in the power supply transformer.

Oh, yes, the PCL82 is a little, poor tube, used in audio stage in television receivers in the ’60, not a noble direct heated tube like the 211. Someone perhaps forget that the 211 is a general purpose tube, while the PCL82 is a Triode-penthode SPECIFICALLY designed for audio. It is a double tube, with an input low power triode (mu=70) and an output power penthode. One tube is used in each channel. In the Scherzo amplifier the output perthode is triode connected for best sound results: this is the official configuration. But if you need more power or you want to experiment other solutions you can connect the output stage in ultralinear configuration. With the Scherzo you can verify and experience a lot of ways. 

The Scherzo is an amplifier with many uses and many configurations. Here they are.

Uses. You can use The Scherzo as:

1) An Integrated Amplifier with an output power of 1,6 W per channel. It could seem low but you can discover how loud it can sound and not just with high efficiency loudspeakers, although this choice is the preferred one. 

2) A Power Amplifier: you can use it without the volume control, as a power amp.

3) An Headphone Amplifier: you can drive by the Scherzo any kind of headphone, without the limitations that usually afflict headphone amp, like current or impedance limits. It has a true SE triode output transformer power stage.

Configurations.

You can use the Scherzo to experience directly many "rumours" diffused in the audio world. One of this rumour regards the power needs: are you sure that under 100W you can not drive your speakers? But there are many other ones, for example the sound of triode vs. penthode or the importance of the feedback.

In my opinion the power that you REALLY need in your home for a real music reproduction is much less than that you can imagine; of course a very low power like the Scherzo’s one suggests the use of high efficiency loudspeakers to reach very high pressure levels, but you will be really surprised listening how loud 1,6 W can sound. And pay attention, the need for quality is like a virus, if you taste a real high quality amp you risk to change many other parts of your chain (loudspeakers...) in order to maintain "that" quality.

About other rumours, in my vision the triode is ever the best choice and the feedback increases technical performances but damages the sound. I use a lot of measure instruments but I listen by my hear, not by my loved Tektronix. So when I have to choose for the music, I avoid feedback at all and I use only triodes and transformers (usually my design transformers). Are you sceptical? Well, I am satisfied, because I prefer that you DO NOT BELIEVE ME and EXPERIENCE all that directly by your hands (and by your hears!). For this reason the Scherzo allow you to choice between many solutions.

The output stage permits a multiple configuration:

A) Triode. In this case the power is 1,6 W from a true single ended triode output stage. This is the official configuration of the Scherzo.

B) Ultralinear. In this case the power is 3 W from the single ended ultralinear output stage. If you need more power, but you must abandon the purity of the triode. With the Scherzo you can experiment this solution too.

Feedback: you can insert or not insert 4 dB of feedback, to verify the damage that this solution causes to the music. Surely the electrical performance upgrades but the musical performance falls down. If you do not believe me you have just to try. The feedback can be useful for the music result just in ultralinear configuration, when it allows to better control of low frequencies, but even in this case the total musicality is damaged. The official configuration is triode without feedback at all, of course.

The schematics and the components.

The electrical scheme is simple. The first stage is an anode follower with a gain of about 58. This stage is RC coupled to the power stage. The power stage has an automatic bias and is triode connected, the tube dissipate about 5,3 W where the max dissipation is 7W (anode + g2). There is nothing of special, simply each part is very well "tuned" with others so I suggest to avoid any modification. If you want, you can build the Scherzo amplifier simply form that schematics, with the parts (and specially transformers) that you prefer. In this case I suggest good quality electrolytic capacitors ( Elna Cerafine, Rubycon Black Gate, nichicon Muse,etc.), a good polyester coupling capacitor (0,1 to 0,22 microfarads 400V, Solen, Mit,Infinicap etc. Or for best performance the JENSEN Paper in oil aluminium or copper foil ); use good quality carbon resistors, avoid metal film ones. The critical parts are the output transformers (and power trans too): you can use any OPT that you like (primary impedance between 3,5 to 5 kohm are good, secondary as you need), although in this case I suggest to choice in the Tamura catalogue. But I must tell you very clearly that in this way you are not building the original Scherzo and there are few probabilities to reach the best music performance: you are building your amplifier with the Scherzo’s scheme. For maximum musical performances the BEST CHOICE IS to use all the parts supplied with the component sets and specially the original transformer set. At least you can use only the original transformers. Both power and output transformers are very important in the sonic result. I spent many month to set up them, using all my experience in transformer design: remember that it is relatively simple to get high result form an expansive design, but it is hard to give a high quality result when you have a limited budget. These transformers were developed specially for this design and offer best results. I tried to condense in this simple and very cheap amplifier all the experience in the design of amp and transformers that I usually apply in my finished amplifiers (reference level, not DIY, I’m sorry) and the result is very satisfying, as report many hundred of people that built it, but everyone is a free man, so the choice is your...