| Author |
 Topic  |
|
kriwil
Copper Member
Indonesia
17 Posts |
 Posted - 02/18/2010 : 04:59:11
|
Hi all, i am new member here from Indonesia. I have an old Japanese DD3 with large chip with problem of delayed sound.
The delayed sound is distorted, while the clean sound is perfect. It also have problem with feedback setting. If I open feedback pot, the delay become infinite and getting loud and louder until its totally only feedback sound.
I try to tap into input of compressor (part of NE570), and yes! the sound is distorted there, but if I take out the NE570 then it sounds normal. I swap the IC with new one, it comes the same issue...
I got confused now.. anyone can help me? |
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/18/2010 : 05:35:20
|
| Replace C31. Should fix it. |
 |
|
|
kriwil
Copper Member
Indonesia
17 Posts |
Posted - 02/18/2010 : 06:56:12
|
| thanks, will try and update the result. |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/18/2010 : 15:03:55
|
Let us know... I've had two long-chip DD-2/3 pedals on the bench with that exact symptom. When C31 fails the compressor stops compressing so that every time the signal passes through the delay circuit it gets expanded without being compressed - hence the "distorted...infinite and getting loud and louder until its totally only feedback sound".
PS: Welcome to the forum! |
|
|
|
kriwil
Copper Member
Indonesia
17 Posts |
Posted - 02/19/2010 : 03:09:02
|
Did replace C31 and the delayed sound gone (sound very low). I traced it from input A/D, output D/A until LPF before expander. It sounds fine.. after the expander its gone..
So i replaced tantalum cap in expander circuit... and it works!!
But its not perfect yet (i feel), compared to my other Japanese DD3 the delay sound slightly lower and the feedback also slightly shorter.
I thinking to replace all polar cap around NE 570 to get the sound perfect... what do you think? |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/19/2010 : 03:45:15
|
| Yeah. For some reason in some long-chip DD-3s those caps fail with age. Replace them all around the 570 and see how it sounds. |
|
|
|
kriwil
Copper Member
Indonesia
17 Posts |
Posted - 02/21/2010 : 14:40:56
|
bad news! the delayed sound now gone. not totally gone, but very low. I traced it back, it sounds normal until expander input and gone after expander output. Did replaced all cap around expander but its not help...
The strange thing is feedback is working very well, it gives delay repeated when i tapped it into expander input..
I have no clue what should i do with it... any idea? |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/21/2010 : 16:10:29
|
| Can we please see some crisp close-up pics of the area around the compander? Front and back of the board? Thanks! |
|
|
|
kriwil
Copper Member
Indonesia
17 Posts |
Posted - 02/22/2010 : 04:43:57
|
| Ok, will take some pics from the board. Will update you soon |
|
|
|
kriwil
Copper Member
Indonesia
17 Posts |
Posted - 02/24/2010 : 06:31:37
|
did not have a chance to upload the pic yet, but i did some voltage probing on C32,C33 and compared it with my normal DD3. i got different voltage on C33.
I suspect that D5 is fail, but i'm not sure what is the function of D5 there? why it needs to connect to flip flop ? |
|
|
|
kriwil
Copper Member
Indonesia
17 Posts |
Posted - 02/24/2010 : 14:00:13
|
Here is the pic
Image display code added by Moderator.
|
Edited by - Dr. Bob on 02/24/2010 14:42:51 |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/26/2010 : 14:35:24
|
quote:
Originally posted by kriwil
did not have a chance to upload the pic yet, but i did some voltage probing on C32,C33 and compared it with my normal DD3. i got different voltage on C33.
I suspect that D5 is fail, but i'm not sure what is the function of D5 there? why it needs to connect to flip flop ?
D5 mutes the expander. I've never seen a signal diode fail in this pedal. D5 failing would simply make the expander "always on", not stop the sound.
Can we have clearer, closer pics of the board around the 570? The blurry ones don't really help  |
|
|
|
kriwil
Copper Member
Indonesia
17 Posts |
Posted - 02/27/2010 : 03:25:13
|
laurie, sorry for the blur pic. It taken with bold 9000 cam.
Anyway, it works now, i replaced all 10uf/16 cap (i have 2 DD3 having problem with all 10uf cap, may it defect cap at that time??)
Current problem only the "plop" sound when i pressed the pedal on.. i suspect cap arround the FET switch... what do you think? |
|
|
|
Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 02/27/2010 : 03:38:02
|
Hi kriwil
That's good news.
Seems more & more early DD-'s are having Cap problems.
I don't doubt that we will see more.
I wonder if has anything to do with the higher temperatures in your part of the world?
Regards Dr. Bob  |
Edited by - Dr. Bob on 02/27/2010 03:40:40 |
|
|
|
Dirk_Hendrik
Copper Member
Netherlands
28 Posts |
Posted - 02/27/2010 : 19:02:50
|
quote:
Originally posted by Dr. Bob
Hi kriwil
That's good news.
Seems more & more early DD-'s are having Cap problems.
I don't doubt that we will see more.
I wonder if has anything to do with the higher temperatures in your part of the world?
Regards Dr. Bob
Nope. It's purdy cold around here and the probem is just the same ;) But yes, this problem is one of the most common I see too with DD2/s's. Usually when doing repairs on DD2/3's as well as DSD2/3's I replace all 10uF's. Even if they weren't the cause of the problem. It might just be that Boss bought a very large batch of poor quality caps and, considering the age of these delays, not even that bad. Something has to fail eventually. Happy it's often the same |
|
|
|
Pedal Dan
Silver Member
USA
419 Posts |
Posted - 02/28/2010 : 02:00:22
|
Hi Dirk Hendrik, and Kriwil,Welcome to the forum from Phillytown! Dirk, are you the same chap with the Ibanez pedal web site? If so I enjoyed looking at your collection, and your comments about your pedals. |
|
|
|
Topic |
|
DD3 Japan not working properly
