Spring Reverb Time

[MrJulius]

I showed the guy I take lessons from my Fuzz I made and told him I was wanting to a do Spring Reverb. He said he has a tank and he would be willing to give it to me.

Ok, now after some searching I found this page. But the schems images are no longer available (Screw you image shack) and the end result is never shown :-(.

http://www.diystompboxes.com/smfforum/index.php?topic=49528.0

Now here is where my questions come in. I am pretty much a straight beginner with a project under my belt, but my knowledge is still extremely limited. I saw the Stage Center Reverb (at GGG), but I am slightly inclined to stay away from PCB for the time being, and I just feel like doing this on Perf Board if possible haha :-).

Before I can start throwing down schems I know I will have to find the input imped of the tank, so I know what I need to design around.


Ok, now here we go.

Goal
- Perf Board Based Spring Reverb Unit
- Used at the end of a pedal chain before amplifier input
- Some form of Wet/Dry mix control
- Powered by any form of external source (I have no intention of using batteries)

Based on "KerryF's" Project Design (Thread above) Input->Op Amp Boost->Reverb Tank->Full 12ax7 Gain Stage->First Half 12ax7 Gain Stage->Fender ToneStack->Second Half 12ax7 Gain Stage->Output

and

http://www.accutronicsreverb.com/drive1.pdf

(See http://www.accutronicsreverb.com/schemat.htm for all the different (Might I add very simple) shcems for driving various imped tanks)

I am basing my idea like so. I am under the impression that I will have

1/4" Input -> Drive Circut -> Reverb Tank -> Make up gain stage -> 1/4" Output

I am correct in saying that this idea is the basis for the reverb? I am planning on omitting the tonestack (I have no interest in it) and thus omitting the second gain stage. Also, I am planning on going solid state for the make up gain. This idea is sound, correct?

Once you all have confirmed this basic idea, the next step is to figure out how I will adjust the wet to dry signal. I have no idea on how to do this hahaha. In the final project I just want to be able to turn one wet/dry knob. Any ideas?

But anyways, is my basic idea correct? Anyone know anything about the other Reverb project in the thread I posted at the beginning? Once y'all "approve" this, I'll start getting into specifics.

Thanks guys, you rock.

[Kearns892]

Sorry, I have to say I won't be of any help, but I just got the spring reverb on my amp repaired. I went to pick it up like a week ago and they gave me the broken tank. I was so stoked. It looks like one of the springs simply came loose, but honestly I haven't looked into it much at all. Hoping to eventually do something with it. Sorry I have nothing to contribute, just letting you know I'll be following your progress in hopes I can pick up a few things if I ever decide to tackle this. Good luck.

[theehman]

Kerry got a lot of crap from people about selling his Pink Verb that he designed w/ help from people here and at other forums.  I've asked him about the schematic before but he's not willing to reveal it.

[tiges_ tendres]

I think he used a JRC386 at the input of the circuit to drive the tank.

I bet whatever the circuit is, it's not too far away from something in the app notes for the chip.

[theehman]

He said he basically used the ROG Ruby to drive it.

http://www.runoffgroove.com/ruby.html

[kurtlives]

Kerry got a lot of crap from people about selling his Pink Verb that he designed w/ help from people here and at other forums.  I've asked him about the schematic before but he's not willing to reveal it.

He sent it to me.

Terrible design that sounds really bad imo.

ROG input buffer > LM386 driver > tank > 12AX7 running on 12V (yuck)...

[petemoore]

I'll crotique, piece by piece...
  Supply voltage...''higher'' seems to fit the power of the work that needs done.
  ROG input buffer
  A reverb's input is probably it's 'easiest' work for a chip or tube position.
  > LM386 driver
  I'm not sure if there's a 'better' chip choice [perhaps something with more power], LM386 sure is handy.
  > tank
  You already have this, which tank, makes a diff.
  > 12AX7 running on 12V (yuck)...
  Agreed, why mess with a 12vdc plate on a tube [will distort and tend to have weakness] when it's going to be an input that may see hot signals. Something else in the ''chip'' category can make the power supply and construction much simpler, and work with 12vdc.
  First of all, more voltage might be a good starting point, IIRC the SCR uses 9+/9-Vdc  supply, I wouldn't want go any lower.

[Mark Hammer]

I don't know the circuit in question, but I wonder what use the tube portion is on the recovery side.  One would think that the critical application of the tube is on the driver side.

[petemoore]

  Distortion after reverb seemed to tend toward mushy, un-intelligable sounds, but 
  I soon persued clean after reverb [including amp].
  Preferences vary...a reverb that is almost purely spring distortion seems a worthwhile approach suggestion, since distortion can easily be introduced anywhere in the chain.
  Put the 12v plate of a 12ax7 [very easily made to distort, just give it some input signal] as a distortion box, then try that out on the output of your otherwise clean reverb. [iow toss the LV-ax7 tube stage].
 

[MrJulius]

Ok, I got the tank. The guy said he ripped it out of a fender that he was overhauling.

Accutronics (Sweet right? haha)

Model Number - 8EB2C1B

http://www.michaeltone.com/Accutronics.htm

Ok, according to that site, my tanks =

Input - 800 ohm
Output- 2,575 ohm

Well shit...

None of the schems on the accu website account for an 800ohm  input tank...

...........

.............

One can be made for 600ohm

http://www.accutronicsreverb.com/drive1.pdf

I don't know enough about this stuff to straight up design my own, so what do I need to do? haha. Can I just lay it out like it was a 600ohm? If no, what do I need to change?

Thanks guys,

MrJulius

(ALso, anyone have a link to the "Standard" method of blending a wet/dry signal?)

[Uma Floresta]

4AB3C1B is the one in the Fender outboard tank. 8 ohm input impedance.

[sean k]

Just go for the accutronics 150-600ohms with the 2N3904 and 2N3906.

It's close enough I'd say.

[Vitrolin]

hi you could check out this splitter bender from ROG

use say GREEN for reverb, and connect RED SEND to RED RETURN

http://www.runoffgroove.com/splitter-blend.html

or maybe this one

http://seanm.ca/stomp/bblender.html

there is various dry/wet or blenders out there

or just put a buffer in parallel to your reverb chain (drive-reverb tank-recovery) and a mix pot between them

[MrJulius]

4AB3C1B is the one in the Fender outboard tank. 8 ohm input impedance.

And your point? That is not the tank I have......................

____

I completely understand this blender http://seanm.ca/stomp/bblender.html so looks like I will use it :-).

___

Ok, a couple more stupid noob questions.

Schem = http://www.accutronicsreverb.com/drive1.pdf

1) In relation to the drive circuit, the two circles with 15 in them (and a pos/neg sign), is this telling me I need a 15 volt input? If so, what kind of power supply do I need to pick up? Also, on the blender it says 12v or 18v will allow for more headroom, where can I pick up a power supply for it. I am not looking to use batteries on this.

2) On the Drive circuit, to the right of the op amp there is two resistors that are listed as "2.2" Can someone link me to the mouser part? I am assuming they do not mean 2.2k

Thanks guys, I'm going to order parts as soon as I get these little details figured out :-).


(Also, where do y'all buy cap's? Unless I am missing something, I can't find any of the coveted "Green Caps" on mouser, and a lot of the caps they do have are like 40 cents a pop??)

[petemoore]

Schem = http://www.accutronicsreverb.com/drive1.pdf
  ...doesn't show the PS. Easier to discuss PS's with a schematic..

1) In relation to the drive circuit, the two circles with 15 in them (and a pos/neg sign), is this telling me I need a 15 volt input?
  You need two 15v supplies, 15+/15-vdc.
  If so, what kind of power supply do I need to pick up?
  Something like this ?
  http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=137&Itemid=26
  Also, on the blender it says 12v or 18v will allow for more headroom, where can I pick up a power supply for it.
  Guitar Center sells 18vdc wallwarts.
  I am not looking to use batteries on this.
  2) On the Drive circuit, to the right of the op amp there is two resistors that are listed as "2.2" Can someone link me to the mouser part? I am assuming they do not mean 2.2k  
  2.2  ohms
  Thanks guys, I'm going to order parts as soon as I get these little details figured out :-).

[MrJulius]

Cool deal. And am I assuming correctly when I wire the bipolar output directly to each corresponding output on the board?

There is no mini circuit on each +/- input correct?

(Sorry for these newb questions, I am slowly but surely figuring this stuff out, thanks a lot guys, hopefully this project will help other people out as well)