I plan to recheck voltages this evening. Thanks.
This Week on the Breadboard: The Tube Bender Deluxe
- Thread starter Chuck D. Bones
- Start date
szukalski
Well-known member
Is your JFET through hole or SMD? It may just be out of spec for the circuit. I used SMD and it rocks right out of the box.
it is through hole. I plan to swap it out later and see it that is the culprit.
I did have to work through a few errors on my vero to get to this point, so Chuck's comment was well taken.
Chuck D. Bones
Circuit Wizard
Check the voltage on Q2-C. The bias is definitely wrong on Q1 & Q2.
Possible causes:
R4 not connected or wrong value.
Q1 S or D not connected.
Q2 B shorted to Q2-E.
Reinspect solder joints, part placement and Vero cuts BEFORE replacing or resoldering anything. It is too soon to replace Q1.
Possible causes:
R4 not connected or wrong value.
Q1 S or D not connected.
Q2 B shorted to Q2-E.
Reinspect solder joints, part placement and Vero cuts BEFORE replacing or resoldering anything. It is too soon to replace Q1.
Thanks Chuck --
I rechecked the parts you noted --
R4 not connected or wrong value. --- corrections are as shown in schematic and value confirmed
Q1 S or D not connected. ---- Q1 S and D connected as shown in schematic
Q2 B shorted to Q2-E. ---- no short between Q2 B and E
Also -- voltage on Q1 D socket is same with or without Q1 inserted in the socket.
R5, R6, R7 and R10 are correct values and connected as shown in schematic
Q1 S connects to Q2 C as shown
Q1 D connects to Q2 B as shown
The marked values on the caps for that part of the circuit match the schematic.
I am going back over the vero. No unplanned shorts on the board between rows or where the row was cut. Will check again for layout errors in that part of the board.
I rechecked the parts you noted --
R4 not connected or wrong value. --- corrections are as shown in schematic and value confirmed
Q1 S or D not connected. ---- Q1 S and D connected as shown in schematic
Q2 B shorted to Q2-E. ---- no short between Q2 B and E
Also -- voltage on Q1 D socket is same with or without Q1 inserted in the socket.
R5, R6, R7 and R10 are correct values and connected as shown in schematic
Q1 S connects to Q2 C as shown
Q1 D connects to Q2 B as shown
The marked values on the caps for that part of the circuit match the schematic.
I am going back over the vero. No unplanned shorts on the board between rows or where the row was cut. Will check again for layout errors in that part of the board.
Chuck D. Bones
Circuit Wizard
And the voltage on Q2-C is???
Chuck D. Bones
Circuit Wizard
If you have eliminated short from Q2-E to Q2-B as a cause, then it's most likely that either Q1 or Q2 are bad or not connected correctly.
Have you tried breadboarding the first stage? It's a convenient way to test parts.
Have you tried breadboarding the first stage? It's a convenient way to test parts.
Are you going to post the gerber file for the board on your github account?
I never did track down the errors on my vero build for this, but Dave was kind enough to share his build files so I ordered the board and assembled it without issue. Really nice design that matched well with some pedalpcb drill guides. I am really happy with the sound. It is tighter and crisper than a Tube Bender I built a while back, and the turbo switch adds a lot of punch. Looking forward to playing with this one some more.
Chuck D. Bones
Circuit Wizard
Wow! Just beautiful. Nice job, Man.
Chuck D. Bones
Circuit Wizard
My opinion: A footswitch should have a knob associated with it that varies its effect. Otherwise, you may be hard-pressed to find knob settings that provides the desired tones & volume with TURBO on and off. My intent with the TURBO switch is that it is "set & forget." With TURBO off, all of the distortion happens in Q3 & Q4. With TURBO on, Q1 & Q2 are easily driven to saturation. My advice is breadboard it and see for yourself before you drill the enclosure.
