Aqua Boy with v3205 's

[hoyager]

I'm in the same boat here, there is more headroom in a pt2399 echo base I've made which is running on 5v. I have 2 more of these to make with the ddt boards so appreciate your research efforts.

Perhaps interestingly, I've read the mpsa18 is quite a high gain transistor and have read suggestions of peeps using (mostly reported in making wah pedals sound more vintage) bc109c and bc550 which have lower hfe? values resulting in a softer and perhaps noisier but less edgy sound. Grain of salt though because the circuit may not accept different values, and so may or may not help. I will know in a couple of weeks, Brian maybe know. I'm going to try an OPA2134 in one of these too

Andy

[gtr2]

If I remember right Andy, I think you had some posts with the double delay distortion issue.  Were you able to clean up the repeats at all?  I'm thinking we may have two issues here, one being the headroom issue.  The other being the current clock driver being unable to support the two v3205's BBD's.  I'm unsure of where to go from here so hopefully Brian will have some good insight based on my info in the previous post.  The best solution would if there was another clock driver we could use,  but I bet in any case we're going to have to add a clock driver or a clock driver buffer (I don't know if that's the right term or not  )  I wish I had an oscilloscope, because I think that would really help with checking out the clock driver issue.  But then again, I'd have to learn how to use it first  .

Josh

[hoyager]

Yes, 2 out of 3 that I've made, that seem to work properly (as good as can be), are very dirty but its not a bad sounding dirt, the filters take the harshness off nicely. Its a different league compared to the AD150 I have (300ms MN3005 running on 18volts) which is almost impossible to overdrive.

The most recent one I've made isn't quite working properly, not sure at all about it... is very dark and overdriven, sounds like an overdrive pedal, which in the right hands can sound pretty cool, but its not subtle. Still a work in progress that one!

[gtr2]

Andy, what clock did you use for the v3205 double delay builds?

Madbean, is there any reason we couldn't run the mn3101 clock for the v3205's?

Josh

[jkokura]

Check the datasheets. They'll tell you.

Jacob

[gtr2]

I did already... I'm up to my ears in data sheets.

I think the power supply polarity should work but the cool audio data sheet on the v3102 is very vague and I'm not real clear on the clocks and what requirements need met for the BBD's.  From what I can tell I think it should work, but I'm at the end of my current understanding Jacob.  I don't really want to tie Brian down with this and I've been doing a lot of leg work, but I'd like to find a solution...

Josh

[jkokura]

They're expensive chips I know. I don't want you to fry them, but you could try it. I think it could work, and I imagine the worst being that it just doesn't work.

Jacob

[gtr2]

They're expensive chips I know. I don't want you to fry them, but you could try it. I think it could work, and I imagine the worst being that it just doesn't work.

Jacob

Yeah, it's not like their mn3005's.  The v3205's are easy to replace.  It's probably worth a try, but I'll have to find some other stuff to order as well or I'll get charged 5 bucks for shipping a tiny part.

The other option would be to buffer the clock outputs going to the double delay board, which would be easily accessible, but I have no idea on how to buffer a clock signal.  Would it be that much different than a standard buffer?  From what I gather the clock input pins on each BBD have input capacitance creating a "loading effect". When the total capacitance is summed between the two v3205's, the result is that it corrupts the clock pulses. I guess the input capacitance is like a fixed lowpass filter on the clock pulse. As long as the clock stays well below the frequency of that filter, the clock is received exactly as sent. Round off those rising and falling edges with the additional input capacitance, and the switching action within the BBD becomes less sharp, resulting in a serious decline in audio quality.  The v3102 could work if it's not "loaded down" I guess..

Josh

[k.rock!]

Hey Josh, I have no idea if this clock buffer would help you out or not, but you can check out the data sheet...it looks to me like a standard buffer though

http://www.national.com/ds/LM/LMH2180.pdf

Kaleb

[hoyager]

"One buffered 4047 drives 4 x MN 3005 in my Yamaha E1010"

You must have read this thread?

http://www.diystompboxes.com/smfforum/index.php?topic=87831.0

My guess is if we were using 2 3005's and an mn3102, it would sound much cleaner.

"The Yamaha E1010 delay which uses 4 x MN3005, has a low pass filter after each bbd, and each bbd has it's own bias trim. The clock to each bbd is also buffered by it's own TC4049, wired as 2 x 3 inverters in parallel."

It seems both 4047 and 4049 have been used as clock chips

http://www.4shared.com/file/30199724/5425cbd6/1010a.html
http://www.4shared.com/file/30199692/5f70dd1f/1010b.html

I've used v3102 (wouldn't know how or where to use anything else....)

Josh did you try a voltage regulator at R19?

[hoyager]

this thread too

http://www.diystompboxes.com/smfforum/index.php?topic=68582.0

sorry if you've been there already..

[gtr2]

Thanks for sharing guys.  I've been looking into the 4049 as a buffer, so thanks for the info    That was the first I saw of the yamaha with the 3005's.  Pretty cool!

I've just got to figure out the best way to try this without to much hassle.  My Double Dly add on board is sitting right above the aquaboy board soldered with old resistor leads and was meant to be pretty permanent (or so I thought).  I may just cut the clock leads there and tie into a breadboarded 4049ube.  I think this may even give a better clock signal than subbing in a mn3101 and cheaper too.    If it works I'll have to figure out a more permanent arrangement...  My build was pristine too, now it has some battle scars    O well...

I have not adjusted the voltage to the v3205's yet.  I think the major problem is with the clock driver right now and I want to sort that out first.  If that gets straightened, I'll move on to the operating voltage and input signal strength.  I'm not sure how much I'll get done tonight, if anything, but I'll keep working on it!

Josh

[gtr2]

I had more time than I thought.   PROGRESS MADE!!!  I've got a delay than has almost passable repeats now.  Pretty close to my carbon copy.  Not as clean as I'm aiming for yet, but I'm getting there.

I added in a CD4049UBE between the v3102 clock drivers CP1, CP2 outputs and the v3205's CP1,CP2 inputs.

The voltage to the 4049 is about 6.2v and I'm gonna take it to 5v. (I just used some resistors at hand for a quick voltage divider temporarily)  The clock signal does not pass right running at 9v.

The buffer mod is also increasing the available delay time.

I'm gonna start tweaking the v3201's input voltage and the input signal, but that's gonna happen in the next day or so.

Here's a pic of my mess.  The pots are just mounted in one of those cheap radio shack cases to help for testing.  I'm glad I opted for the 1590BB for my enclosure size.

Josh

[hoyager]

Awesome work man! This is great news

What do you think is the best way to implement this into the 'box'? A portion of proto-board?

I'm about to order some parts so may as well 2 birds... (actually probably about 6)

[gtr2]

Andy, don't get to exited yet.  Upon some "playing" after my post last night, I'm still noticing more of the distortion than I'd like.  The 4049 buffer did clean it up a little but not as much as I thought.

There are a couple things I don't know about the buffer.  I'm not really sure if the voltage applied to it effects the clock frequency if at all.  Like I said before, it didn't work when I was supplying 9v, but some of the examples I've seen it used were giving it 15v?  That was for a different bbd though.  If I had access to an oscilloscope I'd be able to see the clock signal.  So I'm just gonna run it at 5v and call it good I guess.

The other thing is the load impedance on the outputs of the v3205 bbd's.  I don't know enough about it to know if it is optimal for the two v3205's...

I tried adding a voltage divider to cut the signal again at c15.  I found once again that I was able to cut the signal but then I don't get any delay (calibration was tried after I did the voltage divider FWIW)

I then removed the voltage divider and just adjusted the pot I've got in for r15.  I can get a pretty good delay with little distortion that way, but I also loose all the higher frequencies to ground...

I can also get  cleaner delays turning down the guitar, which is obvious.  But when I "dig" in it responds with the "break up" like an overdrive.

Maybe changing out the Q2 mpsa18 to something lower gain would help?

Uhh, just when I thought I was getting somewhere too.  If anyone's got any suggestions feel free to share.

Josh