- This topic has 4 replies, 3 voices, and was last updated 5 years, 5 months ago by
.
-
Posts
-
Hello! New to the forum.
Bought and roughly put together a Dr Phybes, with the intent to do a couple mods on it so I hooked everything up on a breadboard. I’m getting just my clean signal and no phasing whatsoever.
I am using a tl071 instead of a tl061 because that’s all I have at the moment. The LFO seems to be working, I connected an LED and it was blinking.
The transistors I’m using are 2N5457s in a surface mount package. I know these work because they’re the same ones I used in a breadboarded phaser not too long ago and they did fine. I even tried some matched 2N5458s and still nothing. I also subbed the output transistor with a 2N5087.
All of my voltages on the ICs are 8.5-9 and the transistors are around 4v.
Im using a 3362 bourns style trimpot.
I had all the grounds connected together, even the extra ground.
In the pictures I have R10 and R17 in their modded state, i just soldered the wire ends together for now until I figure this out.
Truly stumped. Anything I could’ve possibly missed?
Edit: I have not tried reversing the transistors, didn’t realize that the pinouts are backwards. I will try that out at a later time.
Hi James – While the TL071 sub for the TL061 is fine, the “Dr Phybes” build requires “matched” 2N5952 JFETs. Did you match them? And it’s not likely the 2N5457s will work well – especially if they are not matched. The “matched” 2N5952 JFETs are quite important in this build.
Reversing them is the correct thing as they are not the same pinout.
+1 Cybercow per Mark Hammers notes here:
https://www.diystompboxes.com/smfforum/index.php?topic=56187.0
Yeah I did match them. I put them in the correct way and I have phasing now. Oops! It’s still very weak though. I do not have the 2N5952s on hand unfortunately so I will have to grab a handful and try to match them.
<hr />
Hello! New to the forum.
- You must be logged in to reply to this topic.