Schaller Tremolo / Hearthrob Tremolo

geiristudio · Post by **geiristudio** » 07 Jan 2012, 14:59

Hey, I'm gonna build this. What's the SPDT switch for ? If it's nothing important, how would I remove it from the vero layout ?

rocklander · Post by **rocklander** » 07 Jan 2012, 20:27

changes the speed range ... it has a slow range, and a fast range.

geiristudio · Post by **geiristudio** » 13 Jan 2012, 21:26

This is weird, I put it together and double checked if everything is correctly wired up, which it is. The guitar goes through but no tremolo effect. I wired everything straight through with out the 3pdt switch. The dwell knob lowers the output but the speed knob does nothing.

Any ideas ?

Edit: One of the transistors was facing the opposite direction. I fixed that but nothing changed. I count 14 cuts in the vero, is that right ?

mirosol · Post by **mirosol** » 11 Mar 2012, 17:20

I have the same situation as geiristudio. Dwell seems to act as volume. Someone had this same problem earlier on, but this thread had no clear explanation. I'm going to try debugging this more today.

I'm using lvlark's vero layout from yesterday..

IvIark · Post by **IvIark** » 11 Mar 2012, 17:53

I've been over the layout and can't see any deviation from the schematic. This is the scheme I did it from:

does anyone have any other scheme for this that I can compare it to?

IvIark · Post by **IvIark** » 11 Mar 2012, 18:11

One thing I have noticed is that if you're using 2N5088's the transistors need to face the opposite way.

IvIark · Post by **IvIark** » 11 Mar 2012, 18:27

Just trying to compare MarkM's PCB with the schematic I posted above, and I notice that the negative legs of C6 and C8 are connected on the PCB, but not in the schematic. Could someone who's built this give that a try to see if it solves it? You can do it easily by linking the centre lug of the switch to that hole on the 3rd row between the 2 x 22u caps

rocklander · Post by **rocklander** » 11 Mar 2012, 19:08

IvIark wrote:Just trying to compare MarkM's PCB with the schematic I posted above, and I notice that the negative legs of C6 and C8 are connected on the PCB, but not in the schematic. Could someone who's built this give that a try to see if it solves it? You can do it easily by linking the centre lug of the switch to that hole on the 3rd row between the 2 x 22u caps

my layout also does this (must have copied that from MarkM's layout unwittingly) and I can confirm that my one works too... (it's on my 1590a board)...

mirosol · Post by **mirosol** » 11 Mar 2012, 19:44

IvIark wrote:Just trying to compare MarkM's PCB with the schematic I posted above, and I notice that the negative legs of C6 and C8 are connected on the PCB, but not in the schematic. Could someone who's built this give that a try to see if it solves it? You can do it easily by linking the centre lug of the switch to that hole on the 3rd row between the 2 x 22u caps

Yup! That does it.

I turned all four transistors around and wired the center lug of the spdt switch to the middle of those caps. And it gives the tremolo now.

But... It's nowhere near unity gain. It's really quiet. I've checked everything so many times that i may be missing something.

So after these fixes, the effect works, but it's really quiet.

mirosol · Post by **mirosol** » 11 Mar 2012, 21:01

My bad. Started probing, and it started to work right. I've stumbled on this before. Biasing thing maybe.

So. One wire and flip the transistors - It's perfect! Thanks lvlark! Your layout made it possible to fit this in 4site B enclosure - Just had to shave one column off from both sides.

Now i'm just thinking that maybe i should make the led blink...

IvIark · Post by **IvIark** » 12 Mar 2012, 10:31

Here's the altered layout, and fixed schematic in case anyone needs it.

Post by **jmwreck** » 18 Jan 2013, 04:39

is it possible to put a sine or square wave switch on this pedal?

dan.schumaker · Post by **dan.schumaker** » 04 Mar 2013, 17:58

This is my first vero build. It wouldn't be fun if it worked the first time....

Running through my test box, I get signal through the circuit. Not trem signal, just signal. Currently the speed knob is acting as a volume control and the dwell and switch do nothing. I am using 2N5088 transistors, and the only change was using a 20k LIN Dwell pot instead of a 25k LIN.

Here are the voltages I am getting:

9V 9.51

Q1C 0
Q1B .32-.51 moves with dwell knob
Q1E 0

Q2C 3.15
Q2B 2.17
Q2E 1.57

Q3C 9.54
Q3B .06-1.13 moves with speed knob
Q3E 0-.64 moves with speed knob

Q4C 5.80-9.53 moves with speed knob
Q4B .07-.64 moves with speed knob
Q4E 0

I would think a part of the issue is that the voltages are too high on Q4C, almost like the resistor isn't working in that position. The multimeter reads 2.2K though. Also I think there is an issue with Q3B & Q3E going to zero. That is probably why the speed is acting as a volume control.

Does anybody have any suggestions on things I should look for?

Thanks