RoseyRay Build Help - Thanks

[yalesmith]

Hello.  I built this pedal and I am not getting any sound.  Any help would be greatly appreciated.

Thanks

Build Instructions can be found here:  http://tagboardeffects.blogspot.com/2013/01/the-roseyray.html

IC1 JRC 4558
1 8.93
2 8.84
3 8.78
4 9.10
5 8.85
6 8.68
7 8.71
8 9.15

D1 1n914
A 8.98
K 9.25

D2 1n914
A 9.10
K 9.00

D3 1n4001
A 8.75
K 8.75

D4 Led
A 8.75
K 8.75

D5 Led
A 9.44
K 9.17

[nick d]

       All the voltages are  close to 9V - pin 4 is the ground connection for the IC and should be at 0V .
         Check you ground connections .

[Kipper4]

Yer here's the schematic
http://hammer.ampage.org/files/Roseyray.gif
It has a common or garden voltage divider. So pins 1,2,3,5,6,7 should be around 4.5v
Pin 4 0v grounded
Pin 8 should be around 8.5 to 9 v
Check your ground and voltage divider voltage.
Solder bridges?
Cuts?
Do you have an audio probe to check where the signal stops? It's a handy little gizmo.

[Kipper4]

To check the voltage divider use you multi meter to measure the voltage at the node (junction) of the 47k and 470k. It should be around 4.5 volts

[yalesmith]

Hello.  Thanks for the responses.  okay i found 1 mistake and fixed that now Pin 4 is at zero volts.  At the junction between the 47K and 470K is 6.8 volts, but the odd thing is at the other end of the 470k the voltage is 7.4 volts.  Does this makes any sense?  why did it increase?

Thanks

[Kipper4]

Whats your IC voltages now and does the pedal work?
Best to start a full debug thread maybe.
Look up for the "what to do if it doesnt work " thread and please give us more info.

[yalesmith]

Updated Voltages and I am not getting any sound.

Thanks

Build Instructions can be found here:  http://tagboardeffects.blogspot.com/2013/01/the-roseyray.html

IC1 JRC 4558
1 8.26
2 7.51
3 7.44
4 0
5 7.44
6 7.88
7 8.35
8 8.93

D1 1n914
A 7.36
K 6.86

D2 1n914
A 6.86
K 7.36

D3 1n4001
A 8.38
K 7.89

D4 Led
A 8.36
K 7.89

D5 Led
A 9.45
K 8.94

[yalesmith]

Also I don't understand why there is no voltage drop across the 470K resistor going to Pin 3, instead voltage increases!!!  

Thanks

[slacker]

Have you made the connection of pin 4 to the jumper under the IC, shown by the blue spot?

[yalesmith]

Yes.  The blue spot just means it (in this situation goes to ground).

Thanks

[bluebunny]

At the junction between the 47K and 470K is 6.8 volts, but the odd thing is at the other end of the 470k the voltage is 7.4 volts.  Does this makes any sense?

Yep - that's Ohm's law at work.  If there's current I flowing through a resistor R, then there's a voltage V (difference) across it.  V=IR.

If there were no voltage difference across the resistor, then there would be no current flowing through it.

[Kipper4]

It might just be me missing something but I can't see how the 240k in the second feedback loop goes from pin 6 to 7 in the layout.

[slacker]

There's a jumper under the opamp Rich.

[Kipper4]

You are of course correct. My eyes deceived me. Because of the ic writing I for some reason thought the jumper went right up the top. Thanks for that. I get it now

[yalesmith]

hmm.  Okay the voltages for pins 1,2,3,5,6,7 work if I pull the the jrc4558, I have tried another one ant the voltages jump around like crazy.  I am thinking that the IC runs like a tube were if installed there is a voltage drop across a resistor rather than a voltage increase.  Does this make sense that a voltage increase when the IC is in?

Thanks, I am a dummy when it comes to this.

Dave

[Mark Hammer]

The schematic linked to is incorrect, or rather, incomplete.

There should be a 1uf cap between the junction of the diodes and those 10k resistors, and the 6k8 resistor, with the plus side going to the diodes/10k resistors and the negative to the 6k8 side.  There should also be a 1uf cap between the output of the second op-amp and the midscoop filter, with the + side at the op-amp output, and the - side going to the 22k resistor and .001uf cap.  These caps are crucial for preventing DC from getting where it shouldn't.

Taking a cue from the FY-2 I modded recently, I would also suggest installing a "shift" control, to re-tune the midscoop.  In this instance, replace the 22k and 10k resistors with the following, in order, a 2k2 fixed resistor (going to one outside lug), a 25k linear pot, and a 4k7 fixed resistor (from the other outside lug).  The whole thing adds up to roughly 32k, or the same series resistance as 22k+10k.  The .1uf cap to ground is connected between the pot's wiper and ground.  This allows you to retune the lowpass portion of the midscoop so that it consists of only the very deep bass, or more of the lower midrange as well.

[yalesmith]

That is pretty awesome tip, sort of like a contour control of sorts......now only if i can get it to work. I understand what u are saying but i dont understand IC and how they work  go figure:)

Dave

[Mark Hammer]

It'll come.  Don't worry. 

[yalesmith]

I got it!! it was a combination of 2 things.... First it was 2 bad op-amps!!!! That is unbelievable!!! To be sure I tested the in a ts808 i built a while ago and wouldn't you know it  they both did not work.   And the second problem was the 2.2uf cap at the output was in the wrong hole. I really like the pedal alot but the tone control trows me, it feels like a second gain control of sorts.  I will definitely incorporate that shape control tomorrow. 

Thanks again,

Dave

[Mark Hammer]

Yeah, it's a bit of a weird one, isn't it?  It's not a tone control as much as a "morph" control, since one is moving between two different worlds: a more normal warm overdrive, and a searing high-gain pedal.

But I'm very glad you got it to work.  I hate to see that sort of effort expended without reward when someone has expended  on my recommendation!