Reverb Pan - What makes it a long, medium or short delay?

[LooseChange]

I want to change the length of delay in a reverb pan.

I did mess with dwell but I always find the tone of the reverb will start to suffer as i'ts lowered and the length really does not change. I'm sure there is a mechanical trick.

So, how does Accutronics do this?

Thanks!

[plexi50]

I dont know if it is related but the 2 spring tank in my Classic 50 4x10  lacks some fullness and duration
On the other hand my Classic 50 head with a 3 spring tank is full and has a longer duration rate of decay
Maybe it's the springs

[Willabe]

It's supposed to be how they terminator the springs at there ends physically. The way they set the very ends gives more or less damping, effecting the springs ability to vibrate.

I'm not sure if you looked at the springs ends were they're mounted into that copper tube on different length of dwell tanks, if you could even see a difference?


                                    Brad  

[jjasilli]

Some cursory research suggests that you can't always get what you want   :  See:  http://www.online-discussion.com/SteveKimock/viewtopic.php?p=502 and http://www.amplifiedparts.com/tech_corner/spring_reverb_tanks_explained_and_compared

The point is that by its very nature reverb has a short delay, about 33mS, and a long decay. 

But if you try sometime you just might find you get what you need:  a delay effect, perhaps coupled with reverb, should get you where you want to go.

[LooseChange]

Accutronics calls it delay but you are right, its the decay I am talking about.

[Willabe]

I just read through the Steve Kimock article and now I remember how it works.          

I had read in a Gerald Weber book, years ago, where he was talking about how they set the length of decay. I couldn't find it in his books this morning.

It's the damping disk. It's like a flat washer that is strung/threaded on the end of the springs straight mounting wire/rod that is inserted into the cooper/brass tube that sets the decay time.

The bigger the diameter of the disc (and what it's made of) limits/restricts the springs movement ( just like a guitar strings movement) in the tube.
    

[jjasilli]

Yes, quoting from the Kimock article:  "What is Decay? The length of time required for a decrease in level by a certain amount is called the DECAY TIME. The decay time is usually defined as the time it takes a sound to decrease by 60 db.* Decay time is determined by the acoustical properties of the reflective surfaces.  What controls Decay? The DECAY TIME performance specification of a reverb unit is dependent on the choice of material type and thickness of the DAMPER DISC.  This is a customizable option when ordering an Accutronics tank, so it will be a variable when choosing which Reverb unit is right for you. When ordering a tank, one follows this guide when selecting the correct decay time:
DIGIT #4 - DECAY TIME
1 = Short (1.2 to 2.0 sec)
2 = Medium (1.75 to 3.0 sec)
3 = Long (2.75 to 4.0 sec)"

Dan:  Hopefully one of these choices will be satisfactory.  However, there's a rather large variable for each choice. IIRC reverb tanks cannot be modded internally, except maybe to carefully re-connect a wire lead.  Clearly, a delay effect gives finer control over delay & decay, maybe with a bit less reverb signal in the mix.

* Comment: a sound cannot be heard by human ears if it is 60db below another sound.

[kagliostro]

The only thing I can think as to modify the spring response

 is to use, very carefully, and with unpredictable results

one or more Lead fishing (there are of different weight)



Kagliostro

[RicharD]

Reverb tanks are funny birds.  Think acoustic coupling.  If you're shooting for more, bigger brighter reverb, slip a piece of masonite in the bag on the open side.  Move that thang closer to the speaker.  More springs, more decay.  If you're seeking to tame the tank, add some additional insulation and distance from the speaker.  Me, I like a short tank face up as close to the speaker as I can get it.  My amp will feedback through the tank with the reverb turned up full and nothing plugged it.  Of course I'm a bleeding edge kind-o-guy.

[HotBluePlates]

From the horse's mouth:

Accutronics  Click "How Reverb Works"

If you look closely on the main page, there is a picture of a 6-spring tank, which has 3 delay lines. 2 springs are connected with what appears like a brass rivet to make each delay line. The particular placement of each rivet is different on each delay line, to get a more complex mix of reflections and a higher quality delay.

A 2-spring, long delay tank is stock for a blackface, but I MUCH, much prefer a 6-spring medium delay tank. As you note, the dwell becomes much more usable.

If I had the time to spend to figure out the old Thunderfunk 12-spring reverb system, I might try it. It used 2 6-spring tanks. I think they had a custom tank for one or both. If I remember right, the inputs of both tanks were wired in series, the output was wired in parallel, and there were different placements of all rivets (it wasn't just 2 identical 6-spring tanks).

Dave Funk wrote Guitar Player a very nasty letter when they reviewed his amp, and just commented it was "Fendery enough." Even with a lack-luster review and after a mean letter, GP still acknowledged it was the best reverb in any amp they ever heard.