solderman tremolo breadboard issue

[ugly_guitar_guy]

Ok, I've decided to breadboard solderman's Red Rooster tremolo because I want a 1590A tremolo and the tiny trem is just a little too difficult to dial in.

Solderman posted his build pdf here: http://solderman.fatabur.se/Mini_trem/Little%20Read%20Rooster_project_file.pdf

and here's the schematic:



Now, I've breadboarded this and I get no tremolo. The LED doesn't blink, it just stays solid, and varies in brightness when I turn the depth knob. I'll note that I had to use NTE substitutes (NTE133 for the BF245B and NTE123AP for the BC547B). I'm pretty sure I got the pinouts correct.

Here's a pic of my breadboard:



Any thoughts?

[PRR]

> LED doesn't blink, it just stays solid, and varies in brightness when I turn the depth knob

That's not right. Check depth pot connections. Or replace pot with a 10K resistor (no connection to the 1uFd cap to FET gate). Does that wag the LED?

What DC voltages on oscillator transistor pins? Are they steady or goofy?

[ugly_guitar_guy]

> LED doesn't blink, it just stays solid, and varies in brightness when I turn the depth knob

That's not right. Check depth pot connections. Or replace pot with a 10K resistor (no connection to the 1uFd cap to FET gate). Does that wag the LED?

What DC voltages on oscillator transistor pins? Are they steady or goofy?

If I put a 10k resistor in place of the pot the led barely lights up at all. Here's what I'm getting:

Q1:
G: 0
D: 2.47
S: 7.68

Q2:
G: .38
D: 0
S: 0

Q3:
E: 6.86
B: .62
C: 0

(9v battery tested @ 8.82 volts)

No varying voltages here. Where should I go from here?

[PRR]

> Q3:
> E: 6.86
> B: .62
> C: 0

E and C appear to be switched.

I agree it "looks" right in your image and the NTE123AP datasheet.

Still, turn it around and see if collector comes off of 7V.

[ugly_guitar_guy]

> Q3:
> E: 6.86
> B: .62
> C: 0

E and C appear to be switched.

I agree it "looks" right in your image and the NTE123AP datasheet.

Still, turn it around and see if collector comes off of 7V.

If I turn it around I get:
E: 0
B: .65
C: 5.71

[PRR]

> NTE123AP for the BC547B

These are not very equivalent; and 1-transistor oscillators can be fussy.

Try an additional 1Meg in parallel with the 1meg near Q3.

Try another transistor. Aron's or SmallBear's 2N3904 should be suitable.

[ugly_guitar_guy]

> NTE123AP for the BC547B

These are not very equivalent; and 1-transistor oscillators can be fussy.

Try an additional 1Meg in parallel with the 1meg near Q3.

Try another transistor. Aron's or SmallBear's 2N3904 should be suitable.

Well, I had some 2N3904's and tried them, and then after a 10th look I realized that my 1uf caps weren't placed correctly, so I fixed them and now it works.

My new question is can it be possible to make the speed go any faster? Which components control that?

[smallbearelec]

...can it be possible to make the speed go any faster? Which components control that?

The time constant is set by the 1 mf caps, the 15K resistor and the combination of the 2.2K resistor and speed pot. Lowering the value of the caps or lowering the 2.2K will increase the top speed. However, with this type of LFO, control of the speed tends to "bunch up" at the high end when using a linear taper pot. You will probably be happier with a reverse audio pot (my SKU 1007). If you use smaller caps, try .68 mf film.

[ugly_guitar_guy]

...can it be possible to make the speed go any faster? Which components control that?

The time constant is set by the 1 mf caps, the 15K resistor and the combination of the 2.2K resistor and speed pot. Lowering the value of the caps or lowering the 2.2K will increase the top speed. However, with this type of LFO, control of the speed tends to "bunch up" at the high end when using a linear taper pot. You will probably be happier with a reverse audio pot (my SKU 1007). If you use smaller caps, try .68 mf film.

It looks like a 1K resistor where the 2.2K is gets closer to what I want. Anything less than that seems to make the LFO lock up when it goes that fast. Its just seems like the range of speed is kinda of narrow overall. I'm looking at the EA Trem schematic over at GGG and see it's very similar, but with a slightly wider range. Looks like I might just have to call this one close enough and get a board made tomorrow.

[ugly_guitar_guy]

...can it be possible to make the speed go any faster? Which components control that?

The time constant is set by the 1 mf caps, the 15K resistor and the combination of the 2.2K resistor and speed pot. Lowering the value of the caps or lowering the 2.2K will increase the top speed. However, with this type of LFO, control of the speed tends to "bunch up" at the high end when using a linear taper pot. You will probably be happier with a reverse audio pot (my SKU 1007). If you use smaller caps, try .68 mf film.

Hey Steve, Thanks for the info. I'm actually "stuck" with using log or audio taper pots in values of 5K, 10K, 20K, 50K, and 100K, because that's the only values I can get clear shaft pots in unfortunately, otherwise the reverse audio would be the way to go here for sure.

[smallbearelec]

I'm actually "stuck" with using log or audio taper pots in values of 5K, 10K, 20K, 50K, and 100K, because that's the only values I can get clear shaft pots in

I see. Yeah, I may get Alpha to make a 100K rev audio in that style specifically for this job, but will not be till next year. Good job you got the thing working!

[ugly_guitar_guy]

I'm actually "stuck" with using log or audio taper pots in values of 5K, 10K, 20K, 50K, and 100K, because that's the only values I can get clear shaft pots in

I see. Yeah, I may get Alpha to make a 100K rev audio in that style specifically for this job, but will not be till next year. Good job you got the thing working!

If you carried clear shaft, reverse log pots you would make every project of mine so much more successful. I just ordered some clear shaft pots from you that I need for now though. Thanks, and hope to see those in the inventory next year!

[DavenPaget]

Sorry but what the heck is a clear shaft pot 

[smallbearelec]

what the heck is a clear shaft pot

http://www.smallbearelec.com/Detail.bok?no=1186

Use an acrylic knob, stick a 3mm LED inside the shaft and illuminate. What I don't know is if they will make a Dual 100K reverse audio in this style. Would be really good for these LFO apps. I will inquire.

SD

[ugly_guitar_guy]

Sorry but what the heck is a clear shaft pot 

I really dislike surface mounting options for LED's, so clear shaft pots is a great fix for that! Like this:



The left pot flashed with the trem rate, the right one is the depth and indicates on/off.

[deadastronaut]

@chris: nice build....

ive just designed a pcb layout from the schematic above...did you use the schematic as it is...or did you change any values etc..?

[ugly_guitar_guy]

@chris: nice build....

ive just designed a pcb layout from the schematic above...did you use the schematic as it is...or did you change any values etc..?

@deadastronaut: Thanks, actually that pic is still your "Tiny Trem" for showing how the clear shaft pots can work. I haven't yet assembled this new one.

I just used solderman's pcb because it fits in a 1590A. Would like to check yours out if it fits as small.

The only differences are the 2.2K resister connected to the speed knob I changed to a 1.2K for slightly faster rate, and the 1uF electrolytic connected to the depth knob I changed to a 100uF. You can also change the input cap to a .47uF like solderman did. I was fine with the .01uF.

Looking forward to see what you'ce come up with!

[deadastronaut]

ahhh i thought i'd seen it before!...

my layout won't fit a 1590a,  1590b only at the moment...

is unity volume ok on it?...

i'll bread it and see what happens, and try your specs...cheers chris,  rob.

[ugly_guitar_guy]

ahhh i thought i'd seen it before!...

my layout won't fit a 1590a,  1590b only at the moment...

is unity volume ok on it?...

i'll bread it and see what happens, and try your specs...cheers chris,  rob.

On my test amp (Micro Cube) the volume was pretty good. Very slight high-end loss, but nothing more than most tremolos. I've got to drill and cut my pcb today, so I'll report back a little later with some more pics.

[deadastronaut]

cool, yeah i have a micro cube too...great for testing stuff!....