Dirtbag 3205 distorted repeats. What else to try besides listed in doc?

[octa805]

Howdy,

Couple questions here.

Question 1--I built up the v3205 dirtbag about a month back using all of the updated revisions per the build doc. Still getting pretty hissy repeats and can't seem to bias it out. Did a lot of research on here and then I read this post by bean:

http://www.madbeanpedals.com/forum/index.php?topic=3332.0

where he says to remove R14 as it it is the greatest source of distortion. Was that the latest revision? That still accurate? Would that help here? If not, what would?

Question 2 --When playing there is a significant delay from when I strike the note until it is processed and spit out by the dirtbag. Is this a function of all dirtbags or just the 3205 version? My memory boy and carbon copy do not seem to have the same issue. (Well they do, just not to such a great degree). If it is a symptom of only the 3205 would a conversion to a 3005 at a higher voltage alleviate this?

Again, great build, love it. Just want to refine it further. Thanks!!!

[octa805]

Bump

[octa805]

I'll just keep talking to myself until someone else wants to jump in.

I went back to rebias it per the build doc last night to see if I could get it a bit cleaner. I had mixed results.

First, I followed the audio probe instructions of tapping into each delay chip separately to try and get the cleanest signal possible by manipulating the 2 bias trimmers.

Then I went back and adjusted the gain trimmers.

This ended up in some pretty distorted repeats.

I went back and just by listening (no audio probe) did some micro-adjustments of the bias trimmers and got a better signal coming through. This allowed me to go back and dial down the 2 gain trimmers quite a bit which helped clean up the signal.

End result, it's better. Especially on slow, signal note playing. Also better on slow chord work.

If you get it going too fast it feels like it can't keep up and gets muddled up and distorted. I'm guessing this is the compressor running at 9v not being able to keep up and provide headroom? eh?

Still lots of white noise/hiss when you play regardless of short or long delay time.

It is fun and do-able but it's just not quite there.

Anything else that can be done here would be great. I'm even considering trying to convert it to another version that I can run at a higher voltage if that would help. Thanks for any input.

[LaceSensor]

Its just the nature of the shitty v3205s Im afraid from what I can gather off peoples experiences, and my own build with v3205s. I found it unusable.

Other people are happy with it, but then everyone has their own ears and distortion on the repeats can be seen as a "feature" of the Memory Man..

What I would suggest is turning both gain trims to Zero and getting the cleanest repeat you can (probe or ears method), then keeping blend and Level at 12 o clock turn up gain 1 nly first, with t feedback at full. Get the point of runaway delays where you can handle it. Then use gain 2 to get a but more level in the repeats, you will ikely get runaways so turn gain 1 down a tad.

Your mileage may vary
No warranty implied or expressed

Good luck!

[octa805]

thanks! I've been dying for any feedback over here.

are they that bad? Hmm. That's a bummer.

I'll give your method a shot.

What I'd love to know is if the issues I'm seeing with the 3205's (distorted repeats, white noise/hiss, slow compressor speed) would all go away if I ran different chips at a higher voltage?

I'm thinking of perhaps using the MN3005 fakes from smallbear at 15v. Would that do it?

Thanks again.

[GhostofJohnToad]

I'd start with trying BL3208 first. Cheaper and direct drop in for 3205.  Lesser delay time though.   This is the route I'm going with mine.

[octa805]

hmm. if they're cheap enough it might be worth a test. good idea.


where do you find them w/ the correct size/spacing?

[GhostofJohnToad]

Smallbear has them for $3.75 a piece

[octa805]

ah, well snap. thanks. that's easy enough.

if you do it first let me know what you think.

[octa805]

hey, I was researching this a bit more. You might want to be careful w/ that swap. Found this bean comment below:

I've got a DM-2 built up with 2x 3208s. There is a problem with it though that I have not been able to solve. The expandor portion is not operating correctly and killing the delay signal with much prejudice. So far I have not figured out why---I don't think it has anything to do with the different BBDs.

Point is, I can't intelligently comment yet on the differences between that and the v3205. I am less inclined to do a hybrid digital/analog at this point, mostly because I have at least three or four more unreleased delay ideas I'm still in the process of finalizing.

[GhostofJohnToad]

well, that certainly does dampen that idea. 

[LaceSensor]

thanks! I've been dying for any feedback over here.

are they that bad? Hmm. That's a bummer.

I'll give your method a shot.

What I'd love to know is if the issues I'm seeing with the 3205's (distorted repeats, white noise/hiss, slow compressor speed) would all go away if I ran different chips at a higher voltage?

I'm thinking of perhaps using the MN3005 fakes from smallbear at 15v. Would that do it?

Thanks again.

I found with using MN3008s you can get it to sound great but youll get about 250ms of delay out of it only.
You can use double delay boards (4 x mn3008) but then the biasing gets trickier again, not impossible of course, but I found the clock noise to be quite high.

You can run 2 x 3008s from small bear (the M3005 fakes) with a larger clock capacitor (up the 240pf to something like 330pf or less) and get some more delay time, with a bit of clock whine at the upper reaches.

Definitely will sound better than the v3205s, run it at 15v
The main benefit to 15v from what I gather is headroom, so yes less inclined to distort the repeats with hotter input signals.

[apollo]

Has anyone tried using the mn3205? Is it any better?

[Scruffie]

hey, I was researching this a bit more. You might want to be careful w/ that swap. Found this bean comment below:

I've got a DM-2 built up with 2x 3208s. There is a problem with it though that I have not been able to solve. The expandor portion is not operating correctly and killing the delay signal with much prejudice. So far I have not figured out why---I don't think it has anything to do with the different BBDs.

Point is, I can't intelligently comment yet on the differences between that and the v3205. I am less inclined to do a hybrid digital/analog at this point, mostly because I have at least three or four more unreleased delay ideas I'm still in the process of finalizing.

No reason that should be the case, 3208s and 3205s should swap over fine, well, as long as you make sure to get the 14-Pin version of the 3208 or the 8-Pin wouldn't fit.

Has anyone tried using the mn3205? Is it any better?

I believe I have read of this being the case... certainly people saying the v3205s seem to be 'hotter' but i've never compared.

There is some stuff that can be done to make the v3205s work quite a better actually, but by the time I tested it all out, it just didn't really seem worth doing it on the Dirtbag boards, too many changes.

[octa805]

Anyone try the BLs yet?