Behringer VD400 analog delay - trimpot adjust and it's awesome!

[bolero]

 don't laugh too hard: I tried mapping out the area that I suspect may have something to do with the echo tone, before the output:



if the printing on the PCB is correct, there are some differences compared to the MN3205 DM2 schem:

  1. before the final output, they have a 1K resistor (R52) instead of a 470 ohm (R34) on the DM2

  2. after that little network above IC1 in the DM2 schem, there is an extra 1 uF 50v cap (C20)

  3. the order of that little network above IC1 seems different: Behr has the 100p over 47K combo ( C38/R36) before the 47K and 10K + 6n8 ( R53, R48+C43) where Boss had them all running parallel

although I have no idea what is going on inside IC5 ?

the question marks in the drawings may be ground, not sure where they went.

[bolero]

I think I know what happened: Behr moved the 1uF, 50V cap ( C31 in the DM2) from before to after that little network, and strapped the 100pF cap across the 470k resistor going in, instead of running it parallel to the others ( C28 in the DM2)

maybe to avoid legal action, if they had cloned the circuit 100% ?

[ElectricDruid]

maybe to avoid legal action, if they had cloned the circuit 100% ?

No, almost certainly not. There's basically no way to protect a circuit beyond patents and gloop. Whatever gloop you cover the circuit in can be scraped off if someone is determined, and patents run out. In this case, there would have been nothing patented anyway, and the circuit wasn't glooped. The only bit you can properly protect is the actual circuit diagram (and as we know even that is widely abused ). That falls under copyright. The circuit itself doesn't.

After all, there's an entire "boutique" industry of which 90+% is direct clones of earlier stuff. If legal action was possible, that wouldn't exist.

[Fancy Lime]

maybe to avoid legal action, if they had cloned the circuit 100% ?

No, almost certainly not. There's basically no way to protect a circuit beyond patents and gloop. Whatever gloop you cover the circuit in can be scraped off if someone is determined, and patents run out. In this case, there would have been nothing patented anyway, and the circuit wasn't glooped. The only bit you can properly protect is the actual circuit diagram (and as we know even that is widely abused ). That falls under copyright. The circuit itself doesn't.

After all, there's an entire "boutique" industry of which 90+% is direct clones of earlier stuff. If legal action was possible, that wouldn't exist.

Jupp, if you design a circuit, there is no protection for your hard work. But if you draw it on a piece of paper, that drawing is protected by copyright until 70 years or so after you shuffled off this mortal coil and you heirs can sue anyone who dares post it on a forum. It's one of the many slightly crazy sides of copyright. It may be worth noting that the PCB-design is also considered a drawing or work of art and is therefore also protected by copyright. So if you clone a circuit, you have to design your own PCB.

Andy

[PRR]

> that drawing is protected by copyright

But if I re-draw it on clean paper, that art is "mine".

While the concepts can be patented, nearly every patent can be broken (prior art) or evaded (do it different). Audio encourages some of the *worst* patents. Patents (not Design) which specify every value..... you say 0.27uF, I say 0.22uF, that's different.

Moreover patents are VERY expensive to file and to defend. Not just in court. If you sue the 800 Pound Gorilla for infringement, next day Guitar Wearhouse etc cancel orders for *your* product. Gorilla does $13million of business, Druid does $130 of sales, GC won't think twice who their best friend is. Likewise "Gorilla" has been known to stomp all over copyright and patent, even copying typos on spec-sheets, and saying "So??"

[Fancy Lime]

The other way round is easy, though. If you want to make sure you circuit gets copied, all you have to do is goop the board. Starting a few ridiculous rumors on gear forums about where you sourced your parts seems to help, too.

Andy

[ElectricDruid]

Gorilla does $13million of business, Druid does $130 of sales, GC won't think twice who their best friend is. Likewise "Gorilla" has been known to stomp all over copyright and patent, even copying typos on spec-sheets, and saying "So??"

This is one reason that Electric Druid puts all the IP out under an open source Creative Commons license. It's pretty hard for people to steal stuff that you're already sharing! The side effect is that it seems to encourage honesty in people, which is welcome.

The reason being: Why *try* and protect something that is basically unprotectable. You might as well admit as much and throw it out to other people to be honest. For me, the evidence thus far is that if you trust people, they're decent with you.  Not in every case, obviously, but the vast majority. That's a great thing to be able to say.

If I ever built something that Behringer decided to clone for half the price, I guess I might feel different, but at the same time, if I ever found myself in that position, I'd have achieved some degree of success beyond my wildest dreams anyway!! "imitation is the sincerest form of flattery" and all that! I should be so lucky!! lol!

[potul]

On the other side, if you design a digital pedal you get much more protection. The firmware gets protected by copyright, so no one can clone your pedal, unless they do the coding from scratch.
Laws are quite restrictive on the software side. Mooer some time ago had to stop production of a couple of pedals because they used part of the code of an EHX pedal.

[generalkustard]

Is there any way to use a single pot to combine the delay rate pot with the small trimmer to the left to make the whole range accessible without having to kep opening the pedal up?
Thanks in advance.

EDIT..I have tweaked the trimpot inside so I get pretty much the full range now (only slightly faster on longest settings)

[nillep]

I made mods for longer delay time on VD400.
Paralleled caps in pre and post filter for lower cutoff freq.
Paralleled cap in clock driver for longer delay time.
Made some adjustment on delay feedback cap and resistor for smoother repeats.