A/DA Flanger does TZF?

[RaceDriver205]

Awesome, glad you guys are getting into this.

New England

Where is 'New' England?

[sfr]

Awesome, glad you guys are getting into this.

New England

Where is 'New' England?

Since I can't add anything worthwhile to this topic other than I as well am very excited about this -

New England is the northeastern states in the U.S.; Maine, New Hampshire, Vermont, Connecticut, Rhode Island, Massachusetts. 

[analog kid]

Hey everyone, sorry to chime in hear with a dumb or obvious question but I've been looking for THIS version layout of the ADA for a real long time and think I have had everyone involved in creating the files and material (possibly anyone who's ever had it to ! : )  BUT my question is... is the only purpose of all the talk going on and the work Charlie doing for the layout , ONLY to get Fab'd boards done for folks?? meaning , though obviously the layout will be changed (double sided, large ground planes ,etc..) to take advantage of PCB fab services. ...
IS there known to be anything wrong with the NEWEST version Layout AS-IS???
I don't think I have much a problem with very tight traces , my etches are usually very clean down to very thin traces. So  I would really hate to put off building it asap , Unless there is going to be a very improved layout done, and also available to print,  "other than" as a manufactured board
  again sorry to hijack but to me a relevant question since this all looked to start after notice of tight traces.       Surely it's been built from that layout, and is verified? If so I for one an FINALLY, more than happy to build it from this layout as is!
 

[moosapotamus]

...is the only purpose of all the talk going on and the work Charlie doing for the layout , ONLY to get Fab'd boards done for folks??

There are a number of folks who also want to add some cool mods, like TZF, stereo outs, ... So, the other idea was to also create a layout for the (new) stock circuit that includes additional pads in all the right places to make experimentation and modifications easier.

... I for one an FINALLY, more than happy to build it from this layout as is!

Go for it!

~ Charlie

[markusw]

No sweat. I'm already on my way, but it might be almost that long before I have some images to proof, anyway. Might just need some feedback on where to include all those extra pads for the future mods.

Cool! 

Will try to modify Stephen's schem for the TZF and stereo mod. thanks again btw for sending the excel file! 

Had a look at the schem again and now I'm pretty sure that one additional opamp stage would be necessary for stereo out. Otherwise the even/odd switch would change its function to the opposite in stereo. Anyway, will do some sims.....


Markus

[StephenGiles]

This had gone quiet!

[markusw]

This had gone quiet!

Didn't find any time this weekend to do the schem mods. 
Hopefully will be able to post my first suggestions tomorrow.

[StephenGiles]

Let me know if you need any help with the excel symbols.

[markusw]

Let me know if you need any help with the excel symbols.

Thanks for the offer!! 

[moosapotamus]

I just realized that diode arrangement around IC1b in the input section (as shown in both the Rev4 scheme and Stephen's drawing) does not match the Rev4 PCB layout! It looks to me like it's done this way on the Rev4 PCB...
http://moosapotamus.net/IDEAS/ADAflanger/ADAinput.gif

Actually, I can't be absolutely positive about the orientation of the diodes, because that's not indicated on the Rev4 PCB layout. But, that's the general arrangement that I come up with when I trace the layout. Does that make sense?

Stephen, you have built yours per your drawing and verified it. So, I'm inclined to go that way with my layout. But, I still find it curious that ADA's documentation does not match.

Does anyone know if one way would be better, or different sounding, or anything?

Thanks
~ Charlie

[markusw]

Insert Quote
I just realized that diode arrangement around IC1b in the input section (as shown in both the Rev4 scheme and Stephen's drawing) does not match the Rev4 PCB layout! It looks to me like it's done this way on the Rev4 PCB...
http://moosapotamus.net/IDEAS/ADAflanger/ADAinput.gif

The inut section you've drawn looks exactly like in rev3. I believe the layout in the Power Point file is also rev3.

Markus

[StephenGiles]

This time in the morning - it's 7.45am here!!! I'll check out the various versions of original revs this evening. I have to do battle with mums taking their kids to school in 4x4 monsters in a minute!

[moosapotamus]

Thanks, Markus. I think I was using the Rev4 scheme to trace through the Rev3 (powerpoint) layout.

So, like I said, I'm planning to do it the way Stephen has it in his scheme.

Next question...
What about those opamps? Do they really need to be all different? Why couldn't they all be the same, like TL074 or something?

Thanks!
~ Charlie

[StephenGiles]

I remember Mike Irwin telling me that the MC3403 has better drive of something and also recommended the MC 33074 (I think). I'll look to see if I still have the thread. However, nothing to stop you using TL074s at all.

[markusw]

Here's the modded schem with my suggestions for mods. Actually, it's just the modded part. I simply was too stupid to get it all in a jpg. 
Anyway, the relevant parts of the schem are shown.
In addition, for ultra slow LFO When if TZF mode) another cap might be added switchable to the 33µ cap in the LFO. Could probably be 33µ too, don't know what value is necessary to divide the LFO rate by 2. Is there a linear correlation between LFO frequency and cap size, btw??

The second output for stereo could be taken directly from the output of IC1c. W/o the optional jumper delayed and "dry" signal would be send to the two output jacks separately with the feedback not active. Probably, it would be interesting to have the "optional jumper" added to see whether feedback would be possible in stereo mode this way. In this case the added 68k would just be needed for stereo (i.e. the mono/stereo switch would connect only in stereo mode).
Don't know if it is necessary to connect the neg input of the additional opamp output stage to e.g. Vb when in mono mode?  IIRC a not terminated opamp input may cause problems. Any ideas?



While drawing the schem I realised that for true-bypass-switching in stereo the second output probably also had to be swtiched (3PDT + millenium??).

I'm pretty confident that the stereo out w/o feedback should work. Don't know if feedback is possible this way though.

Comments are highly appreciated 

Markus

[StephenGiles]

To get the whole circuit in a jpg, highlight the cells it covers as if you are setting a print area, copy and paste into Paint, do Image/attributes and alter the sheet size, then save as whatever you want.

[markusw]

To get the whole circuit in a jpg, highlight the cells it covers as if you are setting a print area, copy and paste into Paint, do Image/attributes and alter the sheet size, then save as whatever you want.

Thanks for the tip!   

[markusw]

To get the whole circuit in a jpg, highlight the cells it covers as if you are setting a print area, copy and paste into Paint, do Image/attributes and alter the sheet size, then save as whatever you want.

BTW, do you think about the stereo out? Might it work??

[StephenGiles]

Provided that the levels are the same, it should work.

[moosapotamus]

That looks good, Markus. I don't think you need the extra 68K. You could just use the pad that the jumper goes to. In fact, maybe that would be the spot to put the switch. I think this might also be the spot to put in a wet/dry (vibrato) control option, replacing the two 68K's with a 150K pot, if desired. If you add the stereo mod, the two 68K's could perhaps optionally be replaced with a dual pot to control the balance between the two outputs, if you want.

Another option that would go well with the vibrato option would be to add a dry, direct output. Again, levels might have to be tweaked, but a switching jack that would break the connection on one side of the 68K thats attached to IC1b would do well (at Markus' TZF jumper). This would also be like an easy psudo-stereo type mod.

Here's another interesting read on making stereo...
http://www.diystompboxes.com/smfforum/index.php?topic=11254.0

And, I'm gonna dredge this up 'cause it's a really good discussion...
http://www.diystompboxes.com/smfforum/index.php?topic=25681.0
... and, there's some good info in there on opamp selection, among other things.

I've also come across a few posts in the archives that talk about a level change when the effect is active, versus bypassed. I'm going to guess that if the effect is modified for true bypass, this could be an issue? So, might it make sense to maybe replace the output buffer's 4K7 feedback resistor with a 10K trim pot, or some other means of adjustment for output level matching?

I've also found some talk about the configuration of those diodes in the input section... I'm sure y'all already knew their purpose, but I was very interested to learn that they act as a limiter that tames the regeneration (enhance) at extreme settings, or something like that. Anyway, it seems that the older ~Rev3 configuration is preferred.

Also, another interesting comment about the threshold control...

The "Threshold" control is designed to cut off the delay mix section wen you're not playing. Many flangers continue to "whoosh" when you are not playing, but the A/DA is dead quiet. If you run the threshold control all the way up, it takes a pretty hefty signal to kick the flange back in but I wouldn't say it's something you can play with like you could, say, an auto-wah. Not really in the same league as far as interactivity goes.

But, there's still lots of reports out there about how quiet this circuit is without the threshold control. It would certainly simplify the build to leave it out. And, I think it takes up too much space to leave as an option. So, I'm still mulling it over. Anyone have any other thoughts about this?

Yes, I have a variable capacitor in my ADA Flanger.
Stephen

Sorry, Stephen. I know that's a pretty old quote. But, it just made me curious... do you have any recollection?

Thanks!
~ Charlie