[retailer]

Some guitar amps do have distortion built in, one of the amps that I copied the 1965 Fender Deluxe (21 watts output) was not made with built in distortion Fender amps from that era are known for their clean head room, they can be overdriven which is where the distortion comes from and can also be used to give a clean non overdriven sound, depends on the skill player. Guitar amps have a tone stack that alters the frequency response from being linear but does not introduce distortion.

I have the calcs I used for the output transformer - the core was 25.4mm x 32mm, using a variacI determined that the turns per volt would be 6 turns per volt, I went with same anode load that Fender used so primary impedance was 6600ohms. To acheive 21 watts output with 6V6's I needed around 350-360 volts so 6 x 350 = 2100 turns, this was the number of turns I used for the primary. With no load my B+ anode voltage was 415v, at clipping that dropped back to around 395v, output measured into a dummy 8 ohm load was just over 13 volts, pushing it just past clipping I had just over 14 volts - near enough to 21 watts. I didn't mention inductance, as it may have added an extra thing to think about, I recall agonising over this for a long time before I actually wound a transformer.

There are many ways to design your transformer, this is just one of them, it may not suit everyone but it does give me the results that I want.

With regard to the total number of turns, it would be 1350 and will need to be split with a centre tap so 675 turns for each half of the primary, with my Fender transformer I split it into 2 windings of 525 turns each and a 3rd winding of 1050 turns.