Hi i built the pedal and have no sound output. Cant see any bridges or cold solder joints and diodes are in the right direction. Im wondering if i have dodgy IC's. These are the measurements i got when i measured across them. I put the black probe on 1-4or 1-8 and then the red on the other side. Multimeter is set to 20v range
There is no output and knobs have no effect thru the front of the amp. When put thru the FX Loop the Volume knob has the usual effect (changing Volume) but there is only a screech instead of the guitar sound. any help on things to look at much appreciated
I'm afraid I can't help you with the voltages for this one since I'm not too familiar with OTA chips. Here is the schematic. https://www.pedalpcb.com/docs/PedalPCB-LoFinator.pdf
So comparing the Schematic to the layout it looks like the 240K resistor that connects to pin 9 of IC2 should connect to the 27K resistor in column 14 but not to pin 9 of IC2. That pin should connect to the 100k resistor to pin 13 and 10k Resistor to ground.
also wondering if the 10k resistor on pin 6 of IC4 (U24-W24) should pin 6-7 (T24-U34) and I think the link on Pin 9 of IC3 (L25) should be down 2 places (to N25). I could be very wrong but I cant see how 1.2nf Cap links to the 1uf
Hmmm, as far as I can see regarding pin 9 connections it matches the schematic. 240k goes from pin 9 to pin 7. 100k goes from pin 9 to pin 13. 10k goes from pin 9 to ground. 27k goes from pin 9 to pin 3 of IC3.
For IC 4...there is two 10k resistors connecting to pin 6, one is connected to vref and the other is connected to pin 7 via jumper under the IC, it is a feedback resistor.
As for the connection from pin 9 of IC3....can't spot any difference. Pin 9 is connected to ground via 10k resistor and there is a jumper which connects to the 1uF cap. The other side of the cap is connected to a 10k resistor that goes to pin 3 and 12nF cap.
Ah yep, now i trace what you says it makes sense, But Should the 1.2nF also connect from pin 5&7 to the 1uF Cap as well as pin 9 or is that done from the link? Also i have no output from pin 9 of IC3 but have got from 10 & 12, not sure if I am meant to or not
There a problem i encountered after pilot test of my newlybuilt lf7 Primarily on low control which sounds like an airplane when knob fully clockwise.what i did was soldered a 1.5M resistor on lug 2.now it sounds like it should be.more power fuzzhead sir!
awesome ! Thank you !
ReplyDeleteWhat are D2 and D3?
ReplyDeleteIt is 1N4148's. Notes updated.
DeleteAlso just wondering where LED- gets wired to?
DeleteLED is your bypass LED so cathode leg should go to your bypass switch. Which lug to use depends on how you wire up the switch.
DeleteCheers thanks
ReplyDeleteHi i built the pedal and have no sound output. Cant see any bridges or cold solder joints and diodes are in the right direction. Im wondering if i have dodgy IC's. These are the measurements i got when i measured across them. I put the black probe on 1-4or 1-8 and then the red on the other side. Multimeter is set to 20v range
ReplyDeleteIC1
1-8> 7.26
2-7> 0.09
3-6> 0.08
4-5>1.36
IC2
1-16 > 0
2-15> 0
3-14> 0
4-13> 0.02
5-12> 1.79
6-11> 9.1
7-10> 1.79
8-9> 2.14
IC3
1-16 > 0
2-15> -0.01
3-14> -.06
4-13> 0
5-12> 0
6-11> 9.1
7-10> 0
8-9> 1.06
IC4
1-8> 7.27
2-7> -0.01
3-6> 0.01
4-5> 1.81
Any info would be appreciated
Im using LM13700 for IC2 and IC3
DeleteHave remeasured voltages now I have more of an idea of what i am doing.
DeleteIC1 (4558)
1- 3.57
2- 3.58
3- 3.25
4- 0
5- 2.48
6- 3.65
7- 3.65
8- 9.05
IC2 (LM13600)
1- 1.3
2- 0
3- 3.55
4- 3.57
5- 4.85
6- 0
7- 4.86
8- 3.73
9- 7.81
10- 9.06
11- 9.06
12- 9.06
13- 3.6
14- 3.56
15- 0.01
16- 1.3
IC3 (13600)
1- 1.27
2- 0
3- 3.6
4- 3.59
5- 8.25
6- 0
7- 8.25
8- 7.05
9- 6.96
10- 8.3
11- 9.06
12- 8.3
13- 3.48
14- 3.59
15- 0
16- 1.27
IC4 (4558)
1- 6.95
2- 6.89
3- 3.54
4- 0
5- 6.59
6- 5.9
7- 8.3
8- 9.05
There is no output and knobs have no effect thru the front of the amp. When put thru the FX Loop the Volume knob has the usual effect (changing Volume) but there is only a screech instead of the guitar sound. any help on things to look at much appreciated
Just wondering if you had the schematic link that you used? Thanks
ReplyDeleteI'm afraid I can't help you with the voltages for this one since I'm not too familiar with OTA chips.
DeleteHere is the schematic.
https://www.pedalpcb.com/docs/PedalPCB-LoFinator.pdf
Thanks heaps. Ill keep debugging :)
ReplyDeleteSo comparing the Schematic to the layout it looks like the 240K resistor that connects to pin 9 of IC2 should connect to the 27K resistor in column 14 but not to pin 9 of IC2. That pin should connect to the 100k resistor to pin 13 and 10k Resistor to ground.
ReplyDeletealso wondering if the 10k resistor on pin 6 of IC4 (U24-W24) should pin 6-7 (T24-U34) and I think the link on Pin 9 of IC3 (L25) should be down 2 places (to N25). I could be very wrong but I cant see how 1.2nf Cap links to the 1uf
DeleteHmmm, as far as I can see regarding pin 9 connections it matches the schematic. 240k goes from pin 9 to pin 7. 100k goes from pin 9 to pin 13. 10k goes from pin 9 to ground. 27k goes from pin 9 to pin 3 of IC3.
DeleteFor IC 4...there is two 10k resistors connecting to pin 6, one is connected to vref and the other is connected to pin 7 via jumper under the IC, it is a feedback resistor.
As for the connection from pin 9 of IC3....can't spot any difference. Pin 9 is connected to ground via 10k resistor and there is a jumper which connects to the 1uF cap. The other side of the cap is connected to a 10k resistor that goes to pin 3 and 12nF cap.
Ah yep, now i trace what you says it makes sense, But Should the 1.2nF also connect from pin 5&7 to the 1uF Cap as well as pin 9 or is that done from the link? Also i have no output from pin 9 of IC3 but have got from 10 & 12, not sure if I am meant to or not
ReplyDeleteGot it working. had a dud Q1. looking forward to exploring all I can do with this pedal in my setup :)
ReplyDeleteThank you for the layout. It works really well now that I know to put it AFTER my drives.
ReplyDeleteIf im lucky ill finished it next week.hopefull.
ReplyDeleteThere a problem i encountered after pilot test of my newlybuilt lf7
ReplyDeletePrimarily on low control which sounds like an airplane when knob fully clockwise.what i did was soldered a 1.5M resistor on lug 2.now it sounds like it should be.more power fuzzhead sir!