2010 rev.5 ADA Flanger Clone. Couple of questions.

Started by Skruffyhound, March 12, 2010, 06:03:24 PM

Previous topic - Next topic

Skruffyhound

Can anyone enlighten me as to why IN5817 in particular was chosen as reverse polarity protection, I'm interested in the theory if anyone knows, but it's also proving difficult to source from my usual suppliers in Europe and I would also like to know if there is an adequate sub that I might already have in stock.

Was a consensus of opinion ever reached on Q1, I don't have LS4393/2N4393, is a J201 or a 2N3819 a feasible sub, or not.

Generally, I'm having trouble sorting the wheat from the chaff in the numerous and long threads on this build. Can anyone tell me if the latest rev. has been changed to include the accumulated knowledge from earlier revisions or do I have to start combing my way through the suggested mods and cutting tracks/splicing components in on my shiny new boards. I'm particularly interested to know if the Bajaman mods were accepted as making a difference and if they are integrated. See this thread for details:                    http://www.diystompboxes.com/smfforum/index.php?topic=74367.0 

Thanks. I will continue to post my inevitable further questions in this thread in order to keep out of the "mire" of older threads. If anyone else has any 2010 rev. questions feel free to pile on.

12Bass

Are you planning to use it with a 9 V supply?  I'm guessing that the Schottky rectifiers are necessary due to the use of the charge pump, and are not needed if using 18 V.  Another similar Schottky might be fine... not too familiar, however.   
It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring. - Carl Sagan

oldschoolanalog

#2
Quote from: Skruffyhound on March 12, 2010, 06:03:24 PMCan anyone enlighten me as to why IN5817 in particular was chosen as reverse polarity protection, I'm interested in the theory if anyone knows, but it's also proving difficult to source from my usual suppliers in Europe and I would also like to know if there is an adequate sub that I might already have in stock.
The 1N4001/D7 is there for polarity protection; although it does nothing to protect the charge pump (if you choose to use it).
1N5817's D8&9 are used as part of the charge pump circuitry.
http://www.geofex.com/circuits/+9_to_33.htm
Probably chosen for their low voltage drop.
http://www.onsemi.com/pub_link/Collateral/1N5817-D.PDF
QuoteWas a consensus of opinion ever reached on Q1, I don't have LS4393/2N4393, is a J201 or a 2N3819 a feasible sub, or not.
If you want to experiment w/VC flanging; try any/all of those FET's 'till you find one that works (read the Baja text for more on that). If you want to use the "Threshold" only as a noise gate (a very good & well behaved one, at that...) a J201 will be fine.
QuoteCan anyone tell me if the latest rev. has been changed to include the accumulated knowledge from earlier revisions...
In a word, yes. The PCB has been altered to accept changes, if you wish to make any (except for the charge pump circuit, we are talking about one resistor here).
Quote...or do I have to start combing my way through the suggested mods and cutting tracks/splicing components in on my shiny new boards.
The "suggested mods" are all in the PDF's at Charlie's site. All the headaches (you have NO idea...) of the past Revs have been pretty much "ironed out". What you have is as close to a "paint by numbers" A/DA flanger project as you will ever see. Please don't mutilate the PCB.
QuoteI'm particularly interested to know if the Bajaman mods were accepted as making a difference and if they are integrated. See this thread for details:                    http://www.diystompboxes.com/smfforum/index.php?topic=74367.0
It appears they have been added to some extent. Cross reference the schematic w/his texts. Just to be sure.  :-X
Mystery lounge. No tables, chairs or waiters here. In fact, we're all quite alone.

moosapotamus

Um... everything that Dave said (wrote) 8), plus...

The complete "Bajahaman mods" include the following...

  • confirming that the clock frequency should be doubled in the calibration procedure
  • adding the 22K resistor (R73) to the BBD output (could be replaced with a jumper or other resistor value or a trim pot at the builder's discretion)
  • increased the value of R65 from 82K to 150K to allow greater tuning range from the clock range trim (T5)

~ Charlie
moosapotamus.net
"I tend to like anything that I think sounds good."

Skruffyhound

Thank you for taking the time gentlemen.
Charlie and Dave, you must be fairly tired of the same old questions  :icon_rolleyes:
I will try to get on as far as I can on my own before I ask any more dumb questions.
Your efforts on this project are much appreciated. Rest assured I was not intending to mutilate the PCB, and I have read all the threads and all the PDF material, there's just rather a lot of information out there to hold in mind while building. This is the first of four of these I'm intending to build, so I will probably work through all the variants.

Skruffyhound

OK, that Geo link was the answer to the diode question, thanks. I've built charge pumps before, but never found that article. Only the one on this use of the Max 1044 http://www.geofex.com/circuits/+9_to_-9.htm
Now I can finish this board and get a listen to it. :icon_biggrin: