Goldmund Mods, Improvements, Stability

Jump to Latest
#1,603
This is a PM I sent to another member. Some of you have given me a lot of help to get this project done, so I intend to finish it eventually (thanks!). However it would be a disservice to the project to rush into things, so I would like to take some time to get used to prototyping and troubleshooting real circuits.

keantoken said:
Hello.

I have not been able to put the circuit together yet. 🙁

I started this project but I didn't really have the ability to complete it immediately.

I graduated from HS on the 4th, so I have more time on my hands now. After I have done some experimenting on real circuits, not just simulations, I will probably make some amendments to the circuit and then build it.

I regret that I haven't done anything in a reasonable amount of time but I don't feel very good about leaving this project after so many showed interest and helped me along. So it will be done. However I must take this slowly, since electronics isn't the only thing on my mind, and economy troubles, yada yada.

Please be patient,
- keantoken
Click to expand...
 
#1,605
I've discovered that masking tape will do fine for my new style of groundplane prototyping:

http://www.diyaudio.com/forums/solid-state/190115-ground-plane-prototyping.html

I've learned that the 2SC5171/SA1930 Toshiba datasheets are are loaded, they are nothing like the real devices. It is better to use the 2SC4793/SA1830, which are actually about as good as the datasheets suggest.

I think signal ground will just be a wire suspended above the board, away from the ground plane.

With this kind of construction I will be able to use one board for both channels, assuming I have a compatible heatsink.

- keantoken
 
#1,607
here
 

Attachments

  • ngm ken.GIF
    ngm ken.GIF
    39.8 KB · Views: 1,198
Last edited:
#1,608
It's probably been discussed before in this thread but it's late and I don't want to read through it at this time!

For the driver stage if it's low current draw I thinking just implement a regulated voltage doubler circuit like the original. There's nothing really wrong with doing this right?
 
#1,611
That schematic lacks a miller compensation cap for some reason, and will surely oscillate. Furthermore, the values are unrefined since it has never been tested. Base and gate stoppers should be optimized, as well as the output zobel, driver stage bias current, and pretty much all other operating points. Degeneration should also be optimized. This should be done by someone with a good signal generator, fast oscilloscope, and good speakers.

Also, I don't know if Digora means the schematic for my design, he may be meaning a different schematic.

I will get to this in the future, believe it or not. I still have all the stuff I've been sent.

- keantoken
 
#1,615
Goldmund module A1 modify to A2

Hi All,

Adapted from NagysAudio how Goldmund A1 module modify to A2 version :

2.) On T6 (the now new MPSA42), short C-B instead of E-B. This can be easily accomplished without any modifications to the PCB. BC182B's leg pin out is CBE and MPSA42's leg pin out is EBC. Simply solder in the new transistor facing the same way.

According to my enclosed circuit , if follow above changing, I think the T6 will completely reverse the polority so the collector will via R12 going to GND. Does it work ?

CK
 

Attachments

  • goldmund_a1_connection.JPG
    goldmund_a1_connection.JPG
    41.5 KB · Views: 1,383
You must log in or register to reply here.
Top Bottom