Wot's The LED Calcs for Gilmore Amp .... ?
post-763774
Thread Starter
Post #1 of 2

qbe

Head-Fier
Joined
Feb 22, 2003
Messages
87
Reaction score
0
Joined
Feb 22, 2003
Posts
87
Likes
0
I know my English is somewhat mangled, but I don't know what the real question is ...

I want to start on the Gilmore amp soon, but I can't get 1.6V LED's. The basic LED's here in Oz vary from 1.8V to about 2.1V.

So what are the formulae/calculations/changes to be made to the components? I presume the LED is trying to achieve a bias voltage on the base of the 2SA1015 and the 2SC1815 but what is that voltage (is it 16 - 1.6?), how do I calculate the changes and what components are to be changed?

I know Sijosae has a schematic on Headwize which uses 1.85V LED's but he is also using a 12V supply rail.

Help, please.

qbe
 
     Share This Post       
post-763902
Post #2 of 2

Glassman

Headphoneus Supremus
Joined
Mar 22, 2003
Messages
1,830
Reaction score
11
Joined
Mar 22, 2003
Posts
1,830
Likes
11
look, the current flows from +16.4V through one LED, then two 7k5 resistors in series and then through the second LED to -16.4V.. now if we know the dropout of the LEDs is 1.6V each, we can calculate 32.8V-3.2V=29.6V - let's assume 30V.. 30V/15k=2mA flowing through the LEDs, so if you are measuring the dropout, do it under the same condition, because if you vary the current, the dropout will vary too.. red colored LEDs should give you about 1.6V with 2mA flowing through them..
 
     Share This Post       

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top