[sphinxllama]

Hello diyers,

Since I have two more weeks from college of, I want to build a portable solution for my headphones. So I already got a cmoy but want to build a Sijosaes amp.

I just wanted to ask if you could check my layout. It is from Sijosaes Simple ClassAB amp.

Link from Sijosaes amp is HIER.

My layout looks like that:

To match the hFE values from the transistors used I use this circuit from Sijosae HERE.
Especially the transistors from the current must be match, like I got told.

Here is my layout from the PairmanII:

What do you think, will both protoboard layouts work?

Thanks for checking.
kim

 

[heatmizer]

Has no short circuit protection say 4.7 ohm resisters on the outputs.
Check for dc offset on source circuit has no input caps.
I would recommend something else for the rail splitter opa551,buf634 etc
If you are going to power from single 9volt change the 2k bias resistors to lower value say 1.4K to 1.6K. you want roughly 3 mA for bias current


and have fun its a good amp

3channel config

 

[sphinxllama]

@heatmizer

thought about using buf634 for the rail splitter but the buf634 is hard to get here. I would have to mailorder it from digikey or so and that is really expensive. also found a rail splitter on tangentsoft.net (HERE) with a TLE2426 but it is the same problem. think the easiest would be to use the resistor divider like in my cmoy but thought that sojaese configuration would be better if the hFE values are matched closly.


the short circuit protection resisters on the outputs look like that?:

just putting the resistor from output to ground?

Quote:

Check for dc offset on source circuit has no input caps.

should I use some caps to go from input to where???

 

[heatmizer]

take a look at this thread especially "the doctors" posts and pictures

http://www.head-fi.org/forums/showth...=sijosae+class

even matching transistors i had a hard time with discrete rail splitter
high output opamp was my answer especially with only 9volt supply

and the pairman thing what is testing the hfe of the transisters in the circuit?
"Steichen's" circuit for transistor matching
http://www.diamondstar.de/transistor_matching_bjt.html

 

[sphinxllama]

hi,

spent some time on gathering information about rail splitter and also about buffers. having not a lot of knowledge about electronics I understood only few things but what I figured out is, that I should use this

(it is from the headfier thedoctor posted in this thread HERE #39) as a rail splitter with the ic as a groundchannel, right?

i am going to post a layout tomorrow. I think that is the easiest way, so I can build the amp exactly like the layout.