Treble booster Ge

[fuzzo]

Hi,

Today I made a Ge treble booster using an Ac127.

Works perfectly but I haven't a correct boost, the level is same with my clean channel. I've to turn up at max the level to have signal. Plus, when the range pot is at bass side, the sound looks like a really crappy fuzz but not a boost.

I plugged a BC550C to see if my veroboard was wrong, nothing. The BC550C boosts like hell But the Ge trannie gives a very low signal. Here's the schematic I made :




The HFE is 137

Any suggestions ? (I'm little bit desapointed about that, Every time I work with Ge I failed ! )

[Brossman]

If it's any help, your schematic is not complete...

Your 4k7 pot, and your 100k pot do not have a third connection...Now I'm not very good at this stuff yet, but my best guess would be to take the remaining lugs and ground them.  Then ground to the In/Output jacks.

But honestly, I can't tell you much more than that. (if anything, this could be used as a bump so, maybe, just maybe more people will see this and put in their two cents 

[soggybag]

Try connecting your output cap to the collector and put a 10K between the collector and V+. Put the volume pot after the output cap with one end to ground and the wiper to the output jack.

Funny you should post this, I just started building a Rangeblaster tonight. With an AC127. It's almost exactly what you have, using the variable input cap. It leaves off the gain pot and 47u cap. And uses a 47K instead of the 68K.

[Solidhex]

Did you use the emitter resistor to bias the transistor correctly? You should get something between 6.8v to 7.2v on the collector. Or else just go with what sounds best. You also need to post transistor voltages if you want people to help.

--Brad

[fuzzo]

Hi guys.

I supect the AC127 transistors to be dead or not very good. I plugged a 2N3904 and that works perfectly, good gain et good sound.

It's over, I give up with Germanium stuff , too many debugg too realize your transistors are crappy.