An old Forte' model 3 made new

 This is an odd topic just because what I will be discussing is an old Forte' model 3 power amp that has been completely rebuilt and designed differently than the original. Years ago, it started with a loud popping noise in one channel. That was enough to take a look inside. I found out that this model uses a chip for the input and the chip had a reputation for this problem. When looking inside the unit, I decided it was time to change out the power caps, replace the bias setting pot, and hope for the best. Shortly thereafter, I knew that I was in over my head, and looked for a tech out there that would be of assistance. Almost by accident, I ran into John Dee, a former engineer at Sudgen? audio located in Europe. Point being John was just the right person for the job. It took a long time to complete the project due to personal reasons, but now the amp is up and running in my system. John converted it to class A bias, and also reduced the number of output transistors. Probably close to all the transistors were changed out due to catastrophic failure (you can thank me for that). A better diode bridge was installed, faster caps replace throughout, and numerous other parts I am sure were dealt with as well. Since my speakers are quite efficient at about 94 db, I had John set the bias for a mere 20 watts class A. It sports a damping factor of 600, has a much faster rise time, and electrolytic caps were all bypassed with Wima caps IIRC. The sound? Well, as expected the bass is to die for, the midrange has power that makes the music 'right there', and truthfully, I do have the hearing to give an honest opinion of the treble, but I feel that it is a bit light. I suppose that I could rig up an adapter and use headphones, giving me the chance at hearing more accurately what the signature of the amp is. Probably sometime soon, I will do that. I just felt that this sort of project is more common amongst some of us and would like to hear your impressions of said projects.

Showing 1 response by robkimsj

This might be a bit off topic, but I have a model three and was looking at a Nakamichi PA-7. Can anyone comment on the similarities or differences between these two amps. I was thinking that I might have the model three modified more toward class A, and have the Nakamichi for higher power needs. Plus, I love the look of the Nak'.