Re: Allen Wright Differential Amp
Yes, i'm working thru an EL84 amp now, with a Dyna ST70 in the queue...
I'm not a wise mentor.... i'm where you are, i do have a couple good mentors to help me already thou.
dave
DrDeville said:Seriously, do you think it would be possible to start with a relatively straighforward PP design and then, with the help of a wise mentor, slowly modify it into something like Wright's design, or something equally cool?
Yes, i'm working thru an EL84 amp now, with a Dyna ST70 in the queue...
I'm not a wise mentor.... i'm where you are, i do have a couple good mentors to help me already thou.
dave
Hey Dave,
I respect you for helping others even though you are still learning. I try to do the same.
Well, I'll keep learning, and try to identify a straighforward starter amp, that I can build/restore, and then modify into something really special. I need at least 50WPC, so I am thinking PP, and debating between triode and pentode (straight triode, versus ultralinear with option of triode operation
).
I have some books on order, so maybe once I learn some basics my path will become clearer.
Thanks again for your help, and good luck!
George Ferguson
Yep, you saw where I was headed.
I respect you for helping others even though you are still learning. I try to do the same.
Well, I'll keep learning, and try to identify a straighforward starter amp, that I can build/restore, and then modify into something really special. I need at least 50WPC, so I am thinking PP, and debating between triode and pentode (straight triode, versus ultralinear with option of triode operation
).I have some books on order, so maybe once I learn some basics my path will become clearer.
Thanks again for your help, and good luck!
George Ferguson
Its an old thread, however I built a few years ago a mono-block amp with a 'super-triode' circuit, I still try to make it all right. It runs into stability issues at low signals levels, have some strange high frequency noise and performs not good.
Just the new transformer sounds way better, CFB is like the enemy of GNFB, it causes a lot of problems here and you have to rethink everything.
You have some high feedback from the UL , then another 6 + db from the CF, then another 10 + db from the GNF to make the amp a winner. All this has to work perfectly and the driver has a lot of trouble, the transformer too has a lot of trouble cooping with all this. So you probably need to design a resonator to damper the ringing in the CF+UL local feedback, then another for the GNF resistor, and you have to get a bullet proof driver stage. It is not easy!!!
But it is the sound I always wanted to have.
I never liked the sluggish low detail and low micro details of triodes. UL cleans everything and makes it more lively but it has a shouting haze which is annoying, you lose the warmth of tubes and much low level is lost in the sound stage, it sounds like a transistor amp in some aspects.
Then a good 'toroidal' transformer in UL gives you all this, and in CF you don't lose the micro-details, which is awesome, but again all the problems, I am currently boosting the power supply to 50uf - 10H choke - 250uf -- B+ and a 4.5k --- 100 uf for the driver stage and their respective caps.... before it ran 50uf 10H 100uf , and 50 uf for drivers (drivers have also another 100uf + 100 uf and resistor for each tubes)
Redoing all the heaters wiring too and power supply wires, trying to cut the 120 hz noise and other stuff.... We will see soon.
Just the new transformer sounds way better, CFB is like the enemy of GNFB, it causes a lot of problems here and you have to rethink everything.
You have some high feedback from the UL , then another 6 + db from the CF, then another 10 + db from the GNF to make the amp a winner. All this has to work perfectly and the driver has a lot of trouble, the transformer too has a lot of trouble cooping with all this. So you probably need to design a resonator to damper the ringing in the CF+UL local feedback, then another for the GNF resistor, and you have to get a bullet proof driver stage. It is not easy!!!
But it is the sound I always wanted to have.
I never liked the sluggish low detail and low micro details of triodes. UL cleans everything and makes it more lively but it has a shouting haze which is annoying, you lose the warmth of tubes and much low level is lost in the sound stage, it sounds like a transistor amp in some aspects.
Then a good 'toroidal' transformer in UL gives you all this, and in CF you don't lose the micro-details, which is awesome, but again all the problems, I am currently boosting the power supply to 50uf - 10H choke - 250uf -- B+ and a 4.5k --- 100 uf for the driver stage and their respective caps.... before it ran 50uf 10H 100uf , and 50 uf for drivers (drivers have also another 100uf + 100 uf and resistor for each tubes)
Redoing all the heaters wiring too and power supply wires, trying to cut the 120 hz noise and other stuff.... We will see soon.