I was expecting same suggestions on how to improve the A75 maybe like this:
"New bias circuit – A newly developed bias generator has eliminated three sources of variation in bias current in the output stage. It also allows approximately 20% greater power output for a given supply voltage."
Papa You know from where this came from Is not my work if inapropiate to use in this way You have my most sincere apologies.
Or maybe suggestion regarding the replacement of the power mossfets with T03 dudes
I will eventually build the A75
Tanks for your kind offer of support.
It will take me along time to get there as I am planing on
F5 aleph x aleph x100 first
At present I am collecting data and modifications.
I have made inquiry about the transformers those will be custom Jobs
1000VA with twin outputs at 24 volts taped at 20 volts this to give me flexibility with the regulated voltages.
I will try to approach the construction in a modular way same as for the Burning amplifier.
I will also try a different approach to the heat sink problem.
Papa Nelson keep saiing that the Moss fet runs much better at hieger bias.
But this is outside the scope of this tread
As you notes in one of my posts Papa wrote that one day he may be having a go at fixing the A75
The idea of this post is to collect suggestion in what we would like to improve on the A75
Which improvement would you like to see on the A75?
Please send me a PM with your address. The boards are yours ...........hopefully we will see the results of your experiments one day. I went thru the process of building most of Mr.Pass's designs and all I can say is that you are in for a treat.
I own Mr.Pass a lot for his advice, help and encouragement over the years ,he is truely a great man who is willing to share his designs and ideas with us. I hope you will enjoy the experience as much as I did.
I just read the A75 PDF today and enjoyed the very clear explanations about everything in the front end. The way you can play with the folded cascode looks very attractive. Definitely a very appelling front end.
Are those audioXpress boards or did you make your own? I am in the slow process of building a pair of A75 monoblocks. Chassis are done, and I have audioXpress boards, one populated, one not.
I was wondering if you might have more boards that you might wish to give away, or sell, or perhaps trade?
Also, I guess you have looked at using jfets in the front end of the A75. I think I can just stick them in for the input fets and perhaps adjust the bias resistors to get them to work. But perhaps you already know the answer as to what is required?