Dirtbag Troubles

[LaceSensor]

Not sure.

[tenwatt]

I don't mind being the guinea pig.  Makes me feel like I'm a part of the solution.  Let's keep it positive and get it wrapped up.  Negative vibes aren't going to help at all.

[andersom]

Thanks for all the hard work you guys are doing

[madbean]

I didn't get the time I needed yesterday to work on this, but I'm on it now. Anyone who is experiencing problems just hold on, take a deep breath and wait another day. I'll have some comments by tomorrow. Distorted delay actually only has a couple of culprits, so I think this is actually something very minor. I'm also really puzzled over why my prototype build did not have this problem. Anyway, more as soon as I have it!

[LaceSensor]

I didn't get the time I needed yesterday to work on this, but I'm on it now. Anyone who is experiencing problems just hold on, take a deep breath and wait another day. I'll have some comments by tomorrow. Distorted delay actually only has a couple of culprits, so I think this is actually something very minor. I'm also really puzzled over why my prototype build did not have this problem. Anyway, more as soon as I have it!

really appreciate you popping by to update.
my anguish is only cos I know how lovely thisll end up

Looking forward to hearing your analysis

[madbean]

One thing I'll be looking at is how BIAS2 and GAIN2 might be over-amplifying the delay line signal into the second BBD. It's possible that tying R23 to VB instead of ground or adding a cap in series to ground might solve the problem. I actually did the same thing with R17 (which goes to ground in the stock DMM).
REF:http://www.freestompboxes.org/viewtopic.php?p=166963#p166963

As Scruffie mentioned in another post, these two trimmers are somewhat interactive.

I'm going to experiment with the compander section a little more, too. Basically, I'm populating one of the production boards to compare to my prototype, with several key components socketed. The prototype is about 99% the same layout, but there were a few "bottom side" fixes for small errors on that layout, which makes it a lot harder to swap out resistors, etc.

I expect everyone to have some beautiful delays happening before you know it!

[RonaldB]

After posting at FSB.org i was pointed in this direction 

I will measure my Dirtbag board an post voltages.

Is there anything that can be done right now?

RonaldB

[RonaldB]

I was just looking at the schematic for the AD3208 over at GGG.com
And in the compander section they used 2x 22K instead of 2x 47K.
And i noticed that they had 100pf on pin 9 and 8.
I have no experiance on these compander circuit's but maybe it's usefull.

RonaldB

[dwstanford]

This will not be a problem if I use MN3005's right?

Not certain, but i built the 3005 version and didn't have this problem.  I was very strict to the BOM (no part subs) and it fired right up.  You may want to socket any subs or parts you may suspect need tweeking.  But it is most likely a difference betweem the two versions from what I can tell.

[madbean]

Should not be an issue with MN3005. I expect that the higher supply voltage plays a part in that

[RonaldB]

I tried tying R23 to VB last night and it cleaned the  delay line up.
Not all the fuzz is gone but you could here it getting better.

Off course i had to rebias the thing.

RonaldB

[the3secondrule]

Confirmed w/ 3005's - finished mine tonight. It fired up first time, and sounds great. and I haven't even touched the trimmers yet!

Should not be an issue with MN3005. I expect that the higher supply voltage plays a part in that

[madbean]

So I worked all yesterday afternoon, got my new build together. Fired it up and damn if it did not have the worst whining I ever heard. I was really stumped since I was very careful in populating and soldering. After 10 minutes I realized I had swapped the pots for delay and level. Ack!

Anyway, I will definitely wrap up this afternoon and have the solution for our extra dirty repeats.

[tenwatt]

I can barely wait.  It's good to hear that even the Mighty Bean makes rookie mistakes sometimes too.  

The real question is...were you getting fizzy, fuzzy, delays?

[LaceSensor]

So I worked all yesterday afternoon, got my new build together. Fired it up and damn if it did not have the worst whining I ever heard. I was really stumped since I was very careful in populating and soldering. After 10 minutes I realized I had swapped the pots for delay and level. Ack!

Anyway, I will definitely wrap up this afternoon and have the solution for our extra dirty repeats.

Thanks for the update. I look forward to the conclusion of your findings.

LS