Road rage and dirtbag problem.

[djaaz]

I had to find a 1 ohm resistor because my DMM would not take any mA measure and because i'm lazy.
I'm reading 21,5 mV which means 21,5 mA.

[gitaar0]

Hi Djaaz,

Thanks for doing that.
My built reads a little higher 23 ma, but that is maybe because of the bypass led I am using.
I will try to get that other regulator then.

[gitaar0]

Well, this keeps bugging me for a while now!! I can not seem to get this right.

I have build and rebuild the road rage, breadboarded it and ordered different regulators.
I ordered the same regulator Djaaz used and I still have the same problem.

The road rage give 14.88 volt and as soon as I connect the Dirtbag the voltage drops to 11.90 volts. This happens in every version I tried. I have tried this also with different wall power supplies (9volt 500ma)

My Dirtbag works fine and sounds good at a 15 volt power supply. No change in voltage when connected.
So now I start thinking that I have to start checking the Dirtbag.
These are the voltage readings of the Dirtbag when used with the 15 volt power supply:
IC1
1) 7.16
2) 7.23
3) 7.01
4) 0
5) 6,51
6) 7.23
7) 7.17
8 ) 14.79

IC2
1) 1.10
2) 1.79
3) 1.79
4) 0
5) 1.81
6) 1.78
7) 10.18
8 ) 1.80
9) 1.80
10) 7.88
11) 6.17
12) 1.81
13) 14.79
14) 1.79
15) 1.79
16) 0.17

IC3
1) 7.10
2) 7.11
3) 6.97
4) 0
5) 6,89
6) 7.11
7) 7.11
8 ) 14.79

IC4
1) 14.75
2) 7.41
3) 6.74
4) 6.74
5) 0
6) 7.41
7) 8.14
8 ) 0

IC5
1) 14.75
2) 7.41
3) 5.03
4) 5.02
5) 0
6) 7.41
7) 8.14
8 ) 0

IC6
1) 8.15
2) 8.14
3) 7.92
4) 0
5) 6.65
6) 6.82
7) 6.70
8 ) 14.80

IC8
1) 7.10
2) 7.10
3) 6.88
4) 0
5) 7.18
6) 7.90
7) 7.90
8 ) 14.79

What seems odd is the voltage at IC2 pin 16 and the voltages at IC5 pin3 and pin 4. Is this odd or not and what does it tell me?


Any suggestions?

Thanks, Marc

[gitaar0]

I swopped IC4 and IC5 and then the readings are changed with the IC. So there is something strange with IC5 with a low voltage at pin 3 and pin 4. Deffective chip? (That would be strange as the dirtbag is working and I have a good sound)

What creates the 0.17 volt at pin 16 of the IC 2?

[gitaar0]

bump?

[djaaz]

Josh posted its voltage here:

http://www.madbeanpedals.com/forum/index.php?topic=3701.msg33203#msg33203

Ok the charge pump was worth a try.    I was thinking maybe you were not getting enough mA for the circuit but you should have no problem with the LT1054.

Here are my voltages in an effort to help you and those in the future.  The input voltage is 14.75V.  I omitted IC7 since thats the modulation section.

Josh

IC1
1) 7.14
2) 7.14
3) 7.12
4) 0
5) 7.07
6) 7.14
7) 7.14
8 ) 14.74

IC2
1) 1.18
2) 1.78
3) 1.78
4) 0
5) 1.78
6) 1.78
7) 10.12
8 ) 1.78
9) 1.78
10) 7.73
11) 6.02
12) 1.78
13) 14.74
14) 1.78
15) 1.78
16) 0

IC3
1) 7.14
2) 7.14
3) 7.12
4) 0
5) 7.12
6) 7.14
7) 7.14
8 ) 14.74

IC4
1) 14.7
2) 7.29
3) 6.28
4) 6.27
5) 0
6) 7.29
7) 7.82
8 ) 0

IC5
1) 14.7
2) 7.29
3) 7.33
4) 7.33
5) 0
6) 7.29
7) 8.94
8 ) 0

IC6
1) 8.95
2) 8.83
3) 8.8
4) 0
5) 6.96
6) 6.98
7) 6.83
8 ) 14.74

IC8
1) 7.14
2) 7.14
3) 7.12
4) 0
5) 7.66
6) 7.73
7) 7.73
8 ) 14.74

I had a few mv on PIN16 as well when i troubleshooted my Dirtbag, my issue was not at all like yours and i solved it by changing the compander.

[harpplayer]

Hi!

I am having (yet another) problem with my Dirtbag.

It is working quite alright now with the v3205, but since I got MN3005´s and I´ve socketed all the critical values, I changed the IC´s.

I am using a nice 15V power supply, but I only get a loud hum and a tiny signal. If I use the 9V, then I get clean signal just ok (haven´t tweaked the trimpots to see if I can get any delay, but it would probably be just too distorted).

The power supply is working just ok with all my other effects, so I really have no idea what might have happened here. Does anyone?

Thanks!
André

[spaceboss]

I haven't built the Dirtbag yet. But from reading the build doc, there is more to the change between 3205s and 3005s than swapping ic's: jumpers, component values, etc.

Have you done all that?

SB

[harpplayer]

Yep, changed all the components, moved the traces next and below the IC´s, and removed the diodes and cap mentioned on the doc.

I was afraid I might have fried the MN3005´s, but I tested them on my DM-2 and they are ok. Funny thing is that on 9V it worked (clean signal at least). That´s odd...

[harpplayer]

Finally! Apparently it was something to do with the feedback pot.

Thank you very much Brian and everyone that helped me for giving me the oportunity to build such an incredible effect! I am absolutely amazed by the sound!

[gitaar0]

Back on the oiginal topic, if that is possible please.

I solved my problem.
The current the dirtbag draws (24 ma and slightly higher on startup) is on the edge of what the charge pump delivers. That is why it is dropping the voltage.
Apparently the combination of diodes, lt1054 and the 15 volt regulator ( i used a L7815CV) is more specific then I tought.
I breadboarded different combinations of different samples of the same part and noticed that this could make a difference of almost 1 to 2 volt!
Finally found the right combo that gives me a steady 14.95 volt with the dirtbag connected.
One to remember.

Thanks Djaaz for thinking wih me.
It is working fine now.
With 250k time pot (250k resistor parallel to that) instead of he 100k and a 270pf instead of the 250pf at the clock I have 560 ms of delay time.

Marc

[gitaar0]

Back on the oiginal topic, if that is possible please.

I solved my problem.
The current the dirtbag draws (24 ma and slightly higher on startup) is on the edge of what the charge pump delivers. That is why it is dropping the voltage.
Apparently the combination of diodes, lt1054 and the 15 volt regulator ( i used a L7815CV) is more specific then I tought.
I breadboarded different combinations of different samples of the same part and noticed that this could make a difference of almost 1 to 2 volt!
Finally found the right combo that gives me a steady 14.95 volt with the dirtbag connected.
One to remember.

Thanks Djaaz for thinking wih me.
I
It is working fine now.
With 250k time pot (250k resistor parallel to that) instead of he 100k and a 270pf instead of the 250pf at the clock I have 560 ms of delay time.

Marc

[alanp]

I had wondered if it was current draw (dropping voltage is a good sign of this), but figured that if it was, wiser heads than me would have said 

[hoyager]

Back on the oiginal topic, if that is possible please.

I solved my problem.
The current the dirtbag draws (24 ma and slightly higher on startup) is on the edge of what the charge pump delivers. That is why it is dropping the voltage.
Apparently the combination of diodes, lt1054 and the 15 volt regulator ( i used a L7815CV) is more specific then I tought.
I breadboarded different combinations of different samples of the same part and noticed that this could make a difference of almost 1 to 2 volt!
Finally found the right combo that gives me a steady 14.95 volt with the dirtbag connected.
One to remember.

Thanks Djaaz for thinking wih me.
I
It is working fine now.
With 250k time pot (250k resistor parallel to that) instead of he 100k and a 270pf instead of the 250pf at the clock I have 560 ms of delay time.

Marc

Hey Marc, just wondering what that final combination was?

I am getting different results every time I build a supply using the LT1054. The voltage drop of the 1n4001 seems to change results the most. I've also found for some reason LM7815 seems to work alot more consistently than 7815CV?

Andy

Andy

[gitaar0]

I am using LT1054, regulator is L7815CV diodes are 1n5817(2x) and a 1n4001.

Somehow I found that sometimes this combination works and sometimes it does not...probably a variety of the parts and the fact?
I still have no clue. My solution is that I breadboard the roadrage first and select the best suitable parts that way. It is strange as I have the impression that most others are not running into this problem.

Maybe it is the parts that I get here...who knows