Making Reverb

[trialabc]

I wanna make a DIY guitar amplifier with reverb function built-in. However, when I search the web, it seems that reverb need a spring device in order to make the effect.

Is there any other method to make a reverb? Since I am very new to guitar also, I hardly able to distinguish delay and reverb.

Thanks for your attention!

[J M Fahey]

Short answer, you need a spring reverb tank to get that effect.
There are other ways, but they are more complicated and often out of reach from the average experimenter.

[teemuk]

There are also companies that sell small circuit boards that contain a digital signal processor (and other needed components), which are programmed produce basic audio effects (like echo, reverb, phaser, chorus etc.) All you need is to provide circuitry for input, output, proper power supply and usually also somekind of an interface to select effects and control their magnitude. All that tricky DSP processing stuff, A/D and D/A converters and other digital circuitry has already been designed and built so buying such a pre-made module is a major shortcut.

It's definitely not as easy option as doing something based on a spring reverb unit but still another sensible solution.

[phatt]

Hello trialabc,
                   Yep Reverb not as easy as it my seem, especially for the novice.
You may want to consider a seperate unit before onboard units.
Try the "Belton unit" Though I've not heard one in the flesh, I've read good reports.

BYOC make a whole kit based on the Belton digital rev unit.
all the DA stuff is done inside the black box the rest is simple analog circuitry. :tu:

Still not quite as cool as the real spring tank it maybe your best option.
Phil.

[trialabc]

Thanks for the comments!

To J M Fahey : Yes, that's my concern. I don't wanna spend a lot of time searching in the web

To teemuk : Do you have any suggestion of these ICs? Actually I would prefer components rather than modules. Yes modules are much easier, and probably produce less noise than hand-made board. However, they are much more expensive. Since ironing components like TSOP120 (120 pins, 14 x 14mm ICs) is not very difficult, i think i can handle it. If I have time, it is not a problem to even start from the beginning : writing code and programming MCU for selecting different effects.

To phatt : Thx for the suggestion. However, modules are expensive (to me), I will put it to my last resort. (Though I think it could be the only choice for the moment.

[teemuk]

To teemuk : Do you have any suggestion of these ICs?

Unfortunately not, aside from finding out that products like that are made today (even for individual consumers in small quantities) and checking out a couple of datasheets I haven't really made any effort to look more into it. Google search likely should reveal something and I have a faint memory that there used to be some discussion about them at http://www.diystompboxes.com/smfforum/ , mainly in the DSP section, if I remember correctly.

[crane]

I would recommend to use the FV-1 chip manufactured by http://www.spinsemi.com/
Really easy to apply in a SS schematic without a real reverb tank/spring/plate.
It includes ADC, uC and DAC in one chip. Has an internal ROM memory with reverb code already in it, but has the opportunity to add external ROM with your onw effect code.
It is not cheap (about 20 euros in europe I guess), but it's really a nice single chip solution to your problem.
I think tonepad has a reverb pedal based on this chip.
In europe it can be bought in www.banzaimusic.com - some other places as well I guess.
Hope this helps.

[trialabc]

Well, thanks for the suggestion, but that chip is just too expensive....

I think I will make it using MCU by myself in case that I have time to develop. Just wanna ask one thing more, what is the difference of Reverb and Echo? They seems to be the same....

[phatt]

Hi trialabc,
               Yes in basic terms they are the same thing, BUT (Always a but)
In bacis terms, Reverb is just very short delay/Echos and Echo is long delay times.

Reverberation of say a big Hall has multiple (usually short) delayed returns and they all tend to mass together. Also consider each one may have returned after being bounced of different surfaces and hence each path returns a slightly different sonic/tonal siganture.

Just check out the specs of your computers sound card and see how Reverbs can be played with to deliver different sound enviroments,, i.e. cave, bathroom, hall.

For the purpose of guitar the spring tank has been the most successful for adding colour to the sound.

Delay is more like standing between two mountains and a loud call will return a long delay of what you yell, often returning a complete phrase a good 1 or 2 seconds later.

For guitar,, digital reverbs and delays deliver outstanding broard freq response and it is debateable as to whether this is good or bad. (depends what you play also)

To much digital stuff can make you guitar sound ,,well TOO Perfect and this can lead to a lot of frustration. You might wish to ask the chaps that have gone back to some of the analog gear which although limited tends to be more realistic.

For me ,, I've never muched liked the Digital Reverb sound so I use a Spring tank for Reverb but often add a Digital delay for some songs.
Have fun, Phil.

[crane]

Well, thanks for the suggestion, but that chip is just too expensive....

I think I will make it using MCU by myself in case that I have time to develop. Just wanna ask one thing more, what is the difference of Reverb and Echo? They seems to be the same....

It is easy to make a reverb sounding algorythm, but it is hard to make it good sounding. I myself wanted to create an infinite reverb DIY pedal. I started by playing around in MATLAB. The result was quite... I'm looking for the right words. Well it was a reverb, but it sounded awful. Don't forget that I had MATLAB running on a PC having the computing power much better than an MCU. I'm not trying to persuade you not to try, I'm just warning you that it's not gonna be easy.
I've set it off for a while cause I'm a little busy right now. I think I ' ll try later again
Well, let us now how you're doing

[J M Fahey]

Yesterday I bought some 1.5x5mm perforated cylindric magnets ... you can imagine what for ...
Haven't made a reverb in ages; besides last year I lost all my dies (don't ask), but I think I can improvise some.
Let's see what comes out of this. :duh :loco

[phatt]

Yesterday I bought some 1.5x5mm perforated cylindric magnets ... you can imagine what for ...
Haven't made a reverb in ages; besides last year I lost all my dies (don't ask), but I think I can improvise some.
Let's see what comes out of this. :duh :loco

Wow!  So you want to make the Tank from scratch?

Humm? I think you you need medication.

Just kidding you    You are brave, an I wish you luck.
Phil.

[rowdy_riemer]

Hell, JM makes his own speakers.

[J M Fahey]

Hi Phatt, I DID make them for ages.
I still have some of them left, the economic amount to get into this is lots of 300 units or more.
I had the whole die set made by a die maker.
The cost?: same as a small car; yet much more useful to me.
I'll post the picture of one of them.
Rough looking, but it works.
The main problem (and I mean PROBLEM) were the pencil-lead sized cylindrical hollow magnets, magnetized perpendicularly to the axis, not along it.
I begged and begged and BEGGED until a magnet maker gave me 1 Kilo of grey magnet powder/dust, the same they press hydraulically and then cook until half-molten (sintering) to make regular magnets.
I pressed over two thousand in my own hand-cranked press (my right arm look Schwartzenegger's, my left one like Woody Allen's hehe) and gave them back to him, so he cooks them alongside any other "real customer" job.
Lighting the oven, slowly rising it to final temperature and letting it cool down takes *days*.
Just this operation costs a couple hundred U$S, no matter if I put 1 Kilo or 500 inside that oven.
All this happened in the early 90's; then we had 12 Years of *very* cheap dollar where even imported meat and wheat were cheaper than homegrown, imagine what that did to our Industry.
We ate Spanish tomatoes and Israeli oranges and grapes !!!!!
Now I'm trying to start again, with a new "simple " problem : my diemaker died less than one year ago and his family sold all dies by the Kilo/Pound  to a scrap iron merchant, because they rushed to sell his house before any distant relatives appear on the scene.
I could only rescue the strap handle set (Fender type) , the metal corner protector one (like the one that was used by Sunn, Acoustic, ARP, etc.), and the heavy rubber leg one, but I lost the full Reverb die set, both Knob ones (Fender with numbers around and unfinished Chicken Head), plastic Tweeter/horn driver (copy of Fostex 104) and many other small ones.
I visited the magnet maker to see if he had any small, cylinder magnet and he gave me samples of "metallic" ones, probably samarium-cobalt.
Still have to convince a spring-maker to make a few "samples", under illusion that I will next order some 5000 units.
All of this, which seems crazy, even to me (today), did work very well when Argentina was a closed market, importing was a nightmare, and *anything* you made sold well.
Today, "globalization" has killed every industry (unless you have unlimited access to slave workers) *everywhere*, even in good old USA (I guess in Australia too). Oh well.
We'd better start learning to eat rice with chopsticks, use conical straw hats and live on a U$S15 a month salary.

[phatt]

Hi Mr Fahey,
                 Well you certainly leave no stone unturned. 

In this digital age where every kind of effect known is accessed via a simple press of a button it might be sobering for some of the younger ones to realise how much work was involved just to make *one effect*.

Ouch! Bakin the ferrite just to form the mag is obviously no simple deal and it is the hardest part to source when they break.

I find that once the fine wire that passes through the magnet snaps off it's curtains unless you have an old tank laying around.
I always salvage any kind of spring tank (working or not) just to get those damn little magnets,, hopefully with the wire end bit still intact.

Thanks for the insight into the finer details.
Phil.