After reading through previous posts and trying many of the "fixes" I still can't get a clean repeat, in fact I can't get it even tolerable. I still have oscillation runaway too when using the Feedback knob, even with T1 all the way down.
Powered by Road Rage 2015, LT1054 and 7815.
Clock set at 7Khz with Delay pot maxed.
D1, D2 & D3 omitted. IN5817 used in place of R58
8k2 - R50 & R51 (VTL5C3)
R55 & R27 jumpered (Could this be related to the distortion issue?)
Currently have 3 unresolved issues:
1. Biasing BBD1 - distortion and high pitched whine
2. Distorted repeat
3. Can't turn feedback pot past noon or oscillation begins.
Biasing per build doc:
With IC4 removed and audio probing IC3 Pin3 I get a loud high pitched whine over the signal unless I turn the clock trimmer way counterclockwise. So when I'm trying to bias BBD1, I can't get rid of the distortion and I get a high pitched whine on top of the guitar signal (with clock set at 6.5Khz) Is that normal?
Here are the "mods" I have in place at the moment:
Compander biasing
(14.6V Pin 13-NE570)
Increased R13 & R14 to 42k. Gives 7.25V on pin 7-NE570
Decreased R37 to 8k2. Gives 7.33V on pins 10,11 - NE570
Loud Repeats:
Increased R38 to 68k to tame the volume of the repeats a bit.
Other changes:
20k Trimmers for Bias 1 and Bias 2 (Started with 30k)
100K Trimmer for T1 (Started with 50k)
Other "mod" tried:
Lower gain of BBD 2, tried 33k for R28 & R29. This resolved the oscillation issue but not the dirty repeats so I put them back to 100k for now.
Here are my voltages:
IC1 - LF353 IC2- NE570 IC3-MN3008 IC4-MN3008
1. 0.0 8. 14.6 1. 1.03 16. 1.05 1. 14.11 8. 0.95 1. 14.11 8. 0.95
2. 7.29 7. 7.29 2. 1.84 15. 1.84 2. 7.09 7. 7.94 2. 7.09 7. 7.21
3. 7.29 6. 7.29 3. 1.84 14. 1.84 3. 6.40 6. 7.09 3. 6.73 6. 7.09
4. 0.0 5. 7.29 4. 0.0 13. 14.6 4. 6.38 5. 0.0 4. 6.75 5. 0.0
5. 1.84 12. 1.84
6. 1.84 11. 7.33
7. 7.25 10. 7.33
8. 1.84 9. 1.84
IC5 - MN3101 IC6 - TL062
1. 14.11 8. 0.95 1. Varies 8. 14.60
2. 7.09 7. 6.91 2. 7.36 7. Varies
3. 0.0 6. 7.13 3. Varies 6. Varies
4. 7.09 5. 6.79 4. 0.0 5. Varies
Q1 14.6/6.55/6.24
Q2 14.6/7.19/6.6
Q3 14.6/6.70/6.12
Q4 14.6/6.10/5.52
Last note, I'm playing a Les Paul with Tone Zone pickups.
Please help, thanks!
Do you really have 0V on IC1 pin1. That looks like a problem -- I would expect to see your op amp reference voltage (VB, 7.29V in your case) there.
Your IC2, IC3 (MN3008 BBD) and IC6 (TL062 dual op amp LFO) voltages look good.
Your voltages are looking ok expept pin1 of IC1 which probably is a measurement error.
Despite that your compander and bbd voltages looks correct.
While turning the bias pot you should find a spot where the delay is without any distortion if your mn3008 is legit.
One time I had a couple of mn3008 which where fake and I could bias them at any point of the bias control.
Do you have any other bbds to try a different one?
Thanks, unfortunately those are the only 2 BBDs I have.
So frustrating.
I'll order a couple more. Is Polida a valid source on EBay?
If I was you I will probably avoid any Chinese e-bay seller.
Paul is offering MN3008, and most mebers here have buy from his shop, including me and never had any issues.
They are tested and legit.
http://www.diyguitarpedals.com.au/shop/index.php?main_page=product_info&cPath=4&products_id=123
cheers,
Panos.
Any delay coming through at all and the BBD works to a point, certainly not fake, although perhaps ESD damaged.
Use an audio probe to find the source of distortion, sounds like there's too much signal at some point, quite possibly an incorrect value or bad solder joint.
Thanks for your help, feeling optimistic again. Although I am going to order a couple MN3008s from Paul as I'm sure once I have this one sorted I'll be building another.
Will audio probe again in about 3 hrs or so, but last night I was getting a high pitched whine on top of the distorted signal while probing IC3 (MN3008) pins 3-4. Is that normal?
Should the signal coming into IC3 pin 7 be clean and without a whine?
Audio probe NE570 pin 6, clean pin 7, more gain, sounds slightly overdriven, but no ugly distortion. Swapped with another NE570, same results. Is this slightly overdriven sound expected?
BBD 1 MN3008 pin 7 same as NE570 pin 7, MN3008 pin 3 ugly distortion and a high pitched whine.
Hoping for something to try, maybe lowering gain of BBD 1 via R21 & R22? Or trying something in R55?
Tried 100k for R55, didn't help just seemed to limit the amount of rotation when adjusting the bias trimmer.
I just powered with 9V rather than 15V and even though the NE570 is biased high (around 7V on 7,10,11), the distortion seems better. It also allowed me to tame the runaway oscillation with the 100k trimmer I have in there. I'm assuming there must be less gain through the BBDs with the 9V supply. I'm now wondering if I should re-bias the NE570 for the 9V supply and see what happens. Defeats the purpose of the MN3008s but if it sounds better...
Guess I should try adjusting the BBD gain with the 15V supply 1st by decreasing R21 and R22.
No go with R21 and R22, just lowered the gain/volume from BBD 1, distortion remained.
Went with option 2, re-biased NE570 for 9V supply, distortion is much better.
Don't understand why, but may have to stick with the 9V supply.
Going to stop for now until I get some pointed suggestions as I'm just going around in circles.
Thanks,
Mike
Hi,
I had some troubles that sound similar. Did you check those posts?
What are you using to test the delay? Might be that your signal is very hot. Humbuckers are driving BBDs easily to distortion. Did you check and reflow your soldering as Scruffie was suggesting?
I was very precise in what Inwas looking for and thus worked quite a bit on the distortion. Biasing is very critical, up to the point that I even made sure that the cancel pot was right, not by ear or sight but with a scope. It does matter, at least too me it did. The same goed for biasing the compander at half powersupply ( thank you Scruffie) . That makes a big differences. Did you try to change R 15 too as that might temper a too hot signal.
In my case I found out that it did matter a lot at what voltage I was running the build. Lower then 14.8 for the bbds was just not as clean as I wanted. My problem was with the roadrage that I could not get to deliver 15 volt to the Aquaboy. It would always drop too much. I worked with a dc-dc converter that keeps the voltage at what you choose and that worked way better with a cleaner signal. Problem with that was that I got clock heterodyning with my delay and the Delaytion tap tempo module that I combined it with. The roadrage did not have that problem. In the end I found the regulator for the roadrage that did keep the voltage to 14.8 minimum. Maybe it had to do with the parts I can get here. I have had that problem with other builds in combination with the roadrage before. I think you can find my posts about that. I did not work with mn3008 but maybe this info helps.
It is worth the effort so keep working at it.
Succes, Marc
Thanks Mark,
I did refow solder around BBD1, but not the entire build. Will do that today.
I'm using a Les Paul with Tone Zone humbucker, I did notice early on if I set the bias pots in the middle of their passing delay range and picked lightly the distorting wasn't noticeable, so a hot signal may be the culprit. I'll increase R15 too today.
Unfortunately I don't have access to a scope.
I'm sure I read your previous post, but will reread to be sure I didn't miss anything.
R15 or R55 to tame hot signal?
What's your value of R55?
You should jumper or R55 and R27.
R15 purpose is only for filtering.
Quote from: Maoriente on March 07, 2015, 03:28:30 PM
I'm using a Les Paul with Tone Zone humbucker
That is a very hot pickup afaik 8)
Maybe work with a less powerfull pickup first to see if you get your aquaboy right.
Hey Maoriente,
i had distortion issues with the aquaboy for such a long time...i was using v3205's and there was NOTHING i could do to stop that distortion. I frankensteined my build to the point of almost self-destruction...
The second i put mn3008's in, the distortion was gone. Now i know you said you are using mn3008's, just wondering if they have been relabelled. Where did you get them if you dont mind me asking?
The only noise you will get from mn3008's will be good noise, but i guess more like 'darkness' (no treble).
The whine sounds like the clock is still in the audio range, make sure you are biasing it properly.
This was the first video i made of the aquaboy (where it wasnt working properly), see if the sound samples sound the same as yours:
And here is where its working successful. Again, point of reference for you and your build:
Hope that helps!
Paul
Thanks Paul, I watched your 1st Aquaboy vid yesterday, sounded like you were working with my PCB.
I bought the MN3008s from Sharpseller off EBay. They supposedly offer refunds, we'll see.
I also just purchased a set of MN3008s from you 2 days ago, hoping they will save the build.
Questions,
With legit MNs, when audio probing BBD 1 pin 3, is the signal completely clean or do you just bias for lowest distortion on pin 3? And then the circuit filters out the rest?
Also, the signal going in to the NE570 is completely clean, but comes out on pin 7 sounding a bit overdriven. Is that normal? Same result with 2 different NE570s.
Thanks,
Mike
Quote from: Maoriente on March 08, 2015, 12:35:05 PM
Questions,
With legit MNs, when audio probing BBD 1 pin 3, is the signal completely clean or do you just bias for lowest distortion on pin 3? And then the circuit filters out the rest?
Also, the signal going in to the NE570 is completely clean, but comes out on pin 7 sounding a bit overdriven. Is that normal? Same result with 2 different NE570s.
Thanks,
Mike
When audioprobing on pin3 of BBD the signal is never completely clean, thats why you need to bias it to find the "sweet" spot with the lowest distortion.
Also are you using jumpers for R55 and R27?
When you have the delay pot on max and try to bias it you will always have a little bit of distortion when you hit hard your guitar.
Try to bias it with the delay pot halfway up and see how it goes.
Cheers,
Panos.
Quote from: chromesphere on March 08, 2015, 04:04:39 AM
Hey Maoriente,
i had distortion issues with the aquaboy for such a long time...i was using v3205's and there was NOTHING i could do to stop that distortion. I frankensteined my build to the point of almost self-destruction...
The second i put mn3008's in, the distortion was gone. Now i know you said you are using mn3008's, just wondering if they have been relabelled.
Interesting... If they were relabelled v3205s would they work at 15v? I just built an aqua puss on vero (similar to aquaboy right?) and had horrible distortion using 2x v3205's. Put in two working mn3205s from an old ad3208 build and it worked perfectly. The v3205s work fine in my ad3208 too! Funny how this circuit is sensitive to the v3205s. Hope you get this sorted Maoriente it's a good delay. Some legit mn3008's may do the trick.
When audioprobing on pin3 of BBD the signal is never completely clean, thats why you need to bias it to find the "sweet" spot with the lowest distortion.
Also are you using jumpers for R55 and R27?
[/quote]
Thanks, good to know there is going to be some distortion on pin 3. I was thinking there should be no distortion on pin 3. I did have the delay pot 1/2 up and had varying degrees of distortion when biasing with the trimmer, I would usually set the trimmer in the middle of both extremes.
I originally had R55 and R27 jumpered, then tried 100k in R55 and 470k in R27. Didn't help, but left the sockets in place and currently have 1K in both R55 and R27.
At one point I did have the Aquaboy sounding fairly good with my humbuckers in split coil mode and when picking lightly in full humbucking mode. But if I hit an a chord, I still got ugly distortion on the 1st repeat.
The strange thing is it seemed to sound better running at 9V rather than 15V. I've since re-biased the NE570 for the 9V supply.
Question; should the output of the NE570 sound a bit overdriven? It's not an ugly distortion but it sounds like an overdriven sound to me. The input to the NE570 is perfectly clean.
Now that I know there is going to be some distortion on pin 3, I'm going to try a reset things for 15V and give it a go again.
Half the 570 is working as a compressor, that means signal after it may be noisy and yes possibly overdriven sounding as it's bringing lower signal levels up.
There's no chance of a 3205 or 3208 being relabeled as a 3008, just wouldn't work.
An ESD damaged BBD could distort and be excessively noisy, that's quite possible and if you didn't properly handle the chips could be on the seller or buyers side.
The v3205 is not a drop in with a lot of stuff we build, it's an option and can work fine for some which is why it's nice to have the option on builds but firstly there have been a few batches of bad chips (high biasing point, hot outputs) and secondly a circuit specifically designed for them is going to sound better.
The issue of distortion could also be tracked down to an incorrect value, bad solder joint etc though, everyone is always quick to blame the BBD as it's the most expensive part and the heart of the circuit but there's a lot that goes in to a delay that can go wrong and the BBD is a small part. It can also just be down to expectations.
You're running at 9V sounding better suggests it may be your pickups, 15V does increase the headroom of the BBDs but 9V means there's less signal swing. But it could be that there's another issue that just means while that still holds true, it's less apparent.
The series resistance before the BBDs isn't really ideal for distortion reduction... it's not how i'd have done things but it is what it is.
Hello again, I received the MN3008s I ordered from Paul so it's time to give this a go again.
I've re-flowed the solder for the entire board and have double checked all part values.
Unfortunately, after replacing the MN3008s and re-biasing, the end result is the same.
At this point I have to assume the Dimarzio Tone Zone output may be causing the distortion, if I back off the volume knob and/or pick lightly the distortion isn't noticeable. But at the same time it's hard to believe this build can't handle a Tone Zone pickup...so I'm not convinced.
I'm going to get an Air Norton for the neck position, 270mv output as opposed to 375mv for the Tone Zone.
More later...
My Gibson SG is my go to, its got humbuckers, not sure how that compares to your guitar as far as output goes but it doesn't distort my aquaboy.
The mn's should sound "dark" (lacking of treble) and maybe a little dirty, but not distorted (overloaded transistor or broken speaker cone distorted if you know what I mean), or "clipped", that's not working correctly.
Have a listen to those videos of mine to work out if its the same sounding as the 'success' video. If its not, im not sure. Assembly error (bridge, component value, etc), dead / fake compander, etc??