Massimo, I checked my other manuals sources and these guys seem to be the only one who have this particular manual. I don't see that manual in our forum'S collection of available manuals but even if we did have it, the forum unfortunately has a rule about giving out manuals to people with less than 50 posts.

OBI56 wrote:Massimo, I checked my other manuals sources and these guys seem to be the only one who have this particular manual. I don't see that manual in our forum'S collection of available manuals but even if we did have it, the forum unfortunately has a rule about giving out manuals to people with less than 50 posts.

Thank you for your reply. Another user helped me in e-mail, he gave me a link where I found the service manual of 'PT-1250 amplifier and I discovered that it is substantially different from older brothers, who between them are almost equal.So I made a step forward, but I have to try again!As for the 50 post slowly write them ...

OBI56 wrote:Massimo, I checked my other manuals sources and these guys seem to be the only one who have this particular manual. I don't see that manual in our forum'S collection of available manuals but even if we did have it, the forum unfortunately has a rule about giving out manuals to people with less than 50 posts.

Thank you for your reply. Another user helped me in e-mail, he gave me a link where I found the service manual of 'PT-1250 amplifier and I discovered that it is substantially different from older brothers, who between them are almost equal.So I made a step forward, but I have to try again!As for the 50 post slowly write them ...

The PT-1250, PT-1800 and PT-2400 share a common users manual, but apparently different Service manuals. Which specific model are you looking for information on? If it is the PT-2400, then that is similar to the TFM-75 amplifier (identical main boards, power supply but different meter and protection circuit boards). As for the PT-1800, it does not seem to have an equivalent in the regular series.

Ok, I have a pt1800 and pt2400, are internally identical. Changing only the values of voltages, perhaps the value of some resistance, and if I remember correctly the pt2400 has 4 transistors in the final more than pt1800 for each channel.I checked the pattern of the TFM-75, the end of the plate is the same, but I believe that there is some resistance of different values.I did not understand where the power supply section is, I have to study it better.Anyway I hope to find the original layout of the two amplifiers in my possession ...

That power supply is different than normal transformer power supplies, which is why it is a magnetic field amplifier. The duty cycle of the current going into the transformer (actually a field coil) is adjusted by a triac, which gets feedback from the voltage rails. When the voltage starts to sag on the high rails, the duty cycle is adjusted upward (but never to 100%). The power is never flowing into the field coil during the zero crossing of the A/C cycle.

Thanks for the welcome. Thanks also for the explanation on the operation of 'amplifier, even though in reality I know well how they work. Bob Carver has materialized in a circuit that many have tried to achieve, but always with poor results. He made it work 100% without using any electronic component dedicated to the course the very special power transformers!O.T. but you managed to understand in depth what I write? To read your answers I make use of Google's online translator, but leaves much to be desired. Fortunately, I understand a little English. To write the same way I do and if I do not like to fix the way I do.

hi guys....since we are on topic of manual for 1250...i have a pdf of it but i need to know if you can bridge this unit cuz there is nothing in manual about that ....and if you can than how to positive ?...one negative one positive from both chanells ?...how ?....thx

I got a PT2400 but its fan is quite loud for home audio listening. Since the PT2400 is very similar to the TFM75 which doesn't need a fan for cooling, I'm hoping that it will be ok to disable the fan for home use. Have anyone tried this or have any relating info?