Melted Black Glue

[trem]

I have an amp from a very respected and expensive builder. A lot of the preamp is covered with melted glue. I imagine it is there to either hide component values, or some type of non-protected (as in patent) circuitry that the builder feels is unique to him. But the problem is, now the amp belongs to me, and it is a nightmare for me, or anybody else to deal with. I have scraped/chiseled away the area that I wanted access to, so I know what was there. Its not like there is an armed guard protecting the amp.
I was just wondering what some of you guys think of this practice. Maybe you do it yourselves when you build amps for sale. Off hand, I cannot think of another product like this. Imagine if you bought a car and you had to spend 5 hours un-gluing the spark plugs from the head so you could change them, just because the builder did not want you to know what "special" plugs he used in his motors. Is this unique to guitar amps?
Thanks

[jrfrond]

"Potting" circuitry to prevent nosey owners or techs from reverse-engineering/snooping is hardly anything new. I have seen it in amps as far back as the 60's. Old Standel amps come to mind. It is considered a legit, albeit sometimes-annoying practice.

[defaced]

This is very prominent in effects pedals. I'm kinda new to that scene, but there are alot of pedals, I imagine "boutique", that are gooped. I think it's lame and would use this as a reason not to buy something. If you're intent on removing it, I'm sure the effects guys have some techniques that work pretty well. Freestompboxes.org and diystompboxes.com are two places I'd start my search.

[Ronsonic]

I'm not a fan of the goop.

I have gooped, and may goop again. But not in amps.

[captntasty]

What arrangement of circuitry could one possibly engineer that would warrant goop in an amp? I haven't found a way to implement that spare super-secret flux-capacitor into a tone stack yet...

[jmaf]

Let's not name names, but suppose for a moment that a fictitious builder called Besa Moogie would clutter up extremely high gain, 120 panel controls and pots and 100 Watts power into a package normally recognized in 15 watts amps.... Yep, microphonic capacitors, cables and vibrating chassis require hot glue all over the place..... Not necessarily to hide anything, though.

[tedmich]

Patents are very expensive and only entitle the holder to sue infringers, who are often much better funded for such things. Secrecy is the only security for small builders, if they don't want to see a Bogera or Randull version anytime soon. Does it make the units harder to service? Yes. Harder to "clone"? Yes as can be seen in all the online hash about Dumble's "secret sauce"

Some electronics require potting; DC/DC converters and some delay relays come to mind, but they are sturdy and usually replaced whole.

The real insurance against amateur cloning is multi layered PCBs... just try to draw that schematic!

[Prairie Dawg]

Patents are very expensive and only entitle the holder to sue infringers, who are often much better funded for such things. Secrecy is the only security for small builders, if they don't want to see a Bogera or Randull version anytime soon. Does it make the units harder to service? Yes. Harder to "clone"? Yes as can be seen in all the online hash about Dumble's "secret sauce"

Some electronics require potting; DC/DC converters and some delay relays come to mind, but they are sturdy and usually replaced whole.

The real insurance against amateur cloning is multi layered PCBs... just try to draw that schematic!

Alex had it all wrong. On the Rob Livesay Band site you can see the terms and conditions for buying one of his amps, such as "thou shalt never disclose .....".

Had it been me, I wouldn't have sold the amp at all-just a license to use it under certain terms and conditions with an immediate repo if violated, or for any reason, good reason or no reason at all.

[Enzo]

Multilayer boards? POtting? It's a freaking guitar amp for god's sake. How novel or different is the circuit now really? A little 2meg local FB resistor here, maybe a cathode diode there, yes, there will be little odd details, but really, how many of us can;t sit down and draw a completely functional amp circuit on a piece of paper while sitting in a bar? If I had to trace out a four layer board full of DSP something, maybe not, but guitar amp? Going in, I got pretty good idea what 99% of it will be. Secrecy measures may be an annoyance, but little more. Maybe a pain in the ass for some individual in his basement, but if I am Fender or Marshall and want to know what some competitor built, that stuff won;t slow me down much.

[uvacom]

Multilayer boards? POtting? It's a freaking guitar amp for god's sake. How novel or different is the circuit now really? A little 2meg local FB resistor here, maybe a cathode diode there, yes, there will be little odd details, but really, how many of us can;t sit down and draw a completely functional amp circuit on a piece of paper while sitting in a bar? If I had to trace out a four layer board full of DSP something, maybe not, but guitar amp? Going in, I got pretty good idea what 99% of it will be. Secrecy measures may be an annoyance, but little more. Maybe a pain in the ass for some individual in his basement, but if I am Fender or Marshall and want to know what some competitor built, that stuff won;t slow me down much.

That's what annoys me a bit. It really only slows down the hobbyists and amateurs, people who are not really a threat to one's business. There's nothing wrong with trade secrets, don't get me wrong. But to hinder the serviceability of your equipment (which is probably not nearly as novel as the designer thinks it is - when was the last time anybody revealed anything truly ingenious underneath a glob of epoxy in an amp/pedal?) to achieve that end is something I find objectionable.

[captntasty]

It does get one's curiosity up though, doesn't it? Perhaps enough to have to go buy one to get in on the secret mojo...

[Alex R]

Isn't it mostly PR? Pour on the gloop and you're labelling your amp/pedal as mojo-imbued. Not telling you what's in here. Nope, it's too precious. If you knew what I'd put in here you'd put it in yours too then you'd be as rich as I'm gonna be. The aim is to create a magical mystery glow of dumblenosity around your brand. Then desirability will go up, along with demand, followed by prices, sales volume, and profits. Also with a bit of luck it will make your gear totally unrepairable so the poor suckers will have to buy another one if it breaks. By which time you'll have been able to put up your prices again. All that for the cost of a few cans of fence protector or tractor underseal or whatever it it.

[Dave Curtis, dB AudioTech]

Lemme guess...

Voodoo Amps.

[Chuck H]

Ok, there's really nothing new under the sun as tube guitar amps go. But I did have to submit a working model as a design to a MFG once.

As Enzo pointed out, a big MFG won't be stopped from learning what's under "goop". Knowing I had no real protection for my design I still didn't want to make it easy. So I used solvents to wipe all the markings off the components. Since most components need to be removed for accurate testing you still need to tear the thing down to know all the component values. Almost as effective as the goop and won't stop anyone from repairing the unit. Well, except the tech wouldn't know what value a bad component USED to be if it's fried. But a good tech shouldn't have too much trouble with a repair.

Chuck

[jrfrond]

Multilayer boards? POtting? It's a freaking guitar amp for god's sake. How novel or different is the circuit now really? A little 2meg local FB resistor here, maybe a cathode diode there, yes, there will be little odd details, but really, how many of us can;t sit down and draw a completely functional amp circuit on a piece of paper while sitting in a bar?

Yes, and the more Margaritas, the better!!!

It's true! WHAT rocket-science will you see in a typical tube amp? Ironically, I have noticed that most of the schematics for many newer tube amps are just a plain bitch to read, in the manner that they are drawn. A conspiracy to deter copycats? Probably not, but if you look at any issue of The Tube Amp Book, schematics were consistently drawn in a particular fashion.

Is it just me noticing this?