Self contained small DIY spring reverb- wiring help..mostly

[glenn.b]

Hi folks!
    I saw THis:   http://www.diystompboxes.com/smfforum/index.php?topic=87780.0 / last night and was amazed! I've been wanting a reverb besides my ggg reverb.  As it is, I already have some 3 inch springs leftover from a reverb unit that was in my first car, a '69 Dart GT.  The springs are very light , and I also have transducers, though not completely certain at this point if I need them for this or not. (?? )

(I hope the pic comes out :icon_confused)
Anyhow I was hoping the wiring could be made a bit more clear.  Thanks in advance!

[joelindsey]

have some 3 inch springs leftover from a reverb unit that was in my first car, a '69 Dart GT.

Cars had built in reverb back then? That's amazing!

When you say you have transducers, do you mean the two yellow ones that are already on the spring assembly or other ones? I'm not really sure what your question is.

[glenn.b]

My first car was a '69, but I first drove it in'86!     But yes, what I am calling transducers ( perhaps even wrongly!) are the 2 little yellow things on the end of the springs.   As far as the reverb system in the car, the"audiophile" driver insisted on not only be 1 speaker in the dash, but a special extra speaker and the rear of the vehicle. If They were really into music They would have a reverb system installed in the back as well.  The amount of blend was controlled by a knob in the dash.

[glenn.b]

I just read my post, and it lacked clarity.   The below layout is where I want to employ my springs

[petey twofinger]

i wonder if that circuit would work with a "real" spring tank ?

[Earthscum]

I think the transducers are going to be needed. One drives the springs, and the other picks up the resulting reverberation. All you're gonna need to do is look up a spring reverb driver (LM386, as you're thinking, has been done, and should be a good option). Do the transducers or the unit have any numbers on it, any indication of any ratings?

[joelindsey]

For what it's worth, a few months ago I built the reverb circuit here: http://sound.westhost.com/project34.htm ... I cut out the mixing section (leaving nothing but wet signal) because I didn't need it and added a tone control. It's sounded very nice with guitar, organ and voice so far. I used an accutronics 4AB3C1B, which is an 8 ohm input impedance and 2250 ohm output impedance.



... One thing I will say is the lm386 will distort pretty easily if you don't keep tabs on the input level. I've wondered if instead of the 368 something like an FET booster going into one of those $3 audio output transformers from radio shack would be better.

http://www.radioshack.com/product/index.jsp?productId=2103254&CAWELAID=107597296

[Earthscum]

You could try a BTL with a TDA2822. It should be a pretty clean chip, and you're still only looking at an 8-pin DIP. And if you WANT it to distort, well... it does that, too. 

[glenn.b]

Thanks for all the ideas & comments!

Posted by: Earthscum
Insert Quote
I think the transducers are going to be needed. One drives the springs, and the other picks up the resulting reverberation. All you're gonna need to do is look up a spring reverb driver (LM386, as you're thinking, has been done, and should be a good option). Do the transducers or the unit have any numbers on it, any indication of any ratings?
Posted on: Yesterday at 10:21:09 PM Posted by: petey twofinger

Agreed on the need part.  No markings to speak of. So if I have transducers, it eliminates the need for a pieazo pickup, like in Top Tops' build?

Posted by: joelindsey
Insert Quote
For what it's worth, a few months ago I built the reverb circuit here: http://sound.westhost.com/project34.htm ... I cut out the mixing section (leaving nothing but wet signal) because I didn't need it and added a tone control. It's sounded very nice with guitar, organ and voice so far. I used an accutronics 4AB3C1B, which is an 8 ohm input impedance and 2250 ohm output impedance.

I did see that while searching the ends of the earth for a simple reverb, and there is no doubt that one is simple.   But of late money has gotten extremely tight in my household, which means, no ordering a Accutronics spring assembly(s).  So I'm trying to be very practical and get the most bang, er..I mean "boinggg" outta what springs  I have on hand.

Posted by: Earthscum
Insert Quote
You could try a BTL with a TDA2822. It should be a pretty clean chip, and you're still only looking at an 8-pin DIP. And if you WANT it to distort, well... it does that, too. 

    Noooo!  I want distortion from somewhere down the line of effects/and/or the amp, but not the reverb!   But then, you say it can run clean?  Cleaner the the 386?

...I'm still clueless about the wiring of the above posted "MiniSprings" reverb.   Shoot, maybe I'll post a pic of the whole reverb from my car-as it sits next to me on my kitchen table.  Maybe someone with some true experience would know how to retrofit it to a guitar effect...Need someone like R.G.

[Mark Hammer]

have some 3 inch springs leftover from a reverb unit that was in my first car, a '69 Dart GT.

Cars had built in reverb back then? That's amazing!

When you say you have transducers, do you mean the two yellow ones that are already on the spring assembly or other ones? I'm not really sure what your question is.

http://www.swtpc.com/mholley/PopularElectronics/Feb1966/PE_Feb1966.htm

[Earthscum]

Well, heck... Take a shot of the whole unit. I think you'd be fine running the driver that was in there. Think about it this way: battery driven reverb is going to suck some power, so you probably want a wall wart. A car's electrical system is 12V, and 12V adapters are quite common. You may find that you just have to apply juice and figure out how to squeeze it into a stompable enclosure.

[joelindsey]

I did see that while searching the ends of the earth for a simple reverb, and there is no doubt that one is simple.   But of late money has gotten extremely tight in my household, which means, no ordering a Accutronics spring assembly(s).  So I'm trying to be very practical and get the most bang, er..I mean "boinggg" outta what springs  I have on hand.

it's possible that your spring assembly would work if the impedance was close. I've tried a small 600 ohm input tank with it and it works, but it just doesn't sound as good as the larger tank.

[glenn.b]

Thank you Mark for the input!  That is going way back, but that is pretty close to what I have.  I wonder, if that was built, what more would be needed to use it for guitar playing?

Posted by: Earthscum
Insert Quote
Well, heck... Take a shot of the whole unit. I think you'd be fine running the driver that was in there. Think about it this way: battery driven reverb is going to suck some power, so you probably want a wall wart. A car's electrical system is 12V, and 12V adapters are quite common. You may find that you just have to apply juice and figure out how to squeeze it into a stompable enclosure.

Yeah Earthscum, I have several 12 V DC warts.  Thing is, I had posted this on another board, but struggled to figure out how in the world it worked.  I would be glad to use it as is, if I only knew how to make it work.  Here is what it looks like altogether:


And Please don't laugh, one of my weaknesses is schematics, so I did not understand this as I drew it, nonetheless I drew it out as best as I could, using AppleWorks.     The six lines at the bottom right represent all the lines in,  but I was at a loss which one was which. 

So I guess I figure out how this thing works (inputs/outputs/power/switchin/pots etc.., or scavenge the springs and use them to build the MiniSprings, if I knew the wiring for it..

it's possible that your spring assembly would work if the impedance was close. I've tried a small 600 ohm input tank with it and it works, but it just doesn't sound as good as the larger tank.
Posted on: Today at 11:34:45 AM Posted by: Earthscum

That's true, the Springs assy. that was in the link that Mark posted was 8 ohms input by 2000 ohms output.

[zambo]

has anyone tried a fet boost with the 3 dollar 1k to 8 ohm transformer?  I just built one with a set of lpb1's one as a buffer for the dry signal and one into a 1 or 2 watt vellman amp ( 9 dc) into a 8 ohm in  tank 2250k out . Output goes into a SHO and rejoins the dry signal. Would be nice to get rid of the amp in the front and just use a fet boost. could it be a SHO with that transformer?

[zambo]

here is what i got so far with this 8 ohm tank. The lpb1's that i am using for buffers are coloring the signal to much. losing a lot of highs . Its killin my high man.....yeah.. other than that i really like this thing. worth exploring more for sure. anyone got a cleaner boost or buffer? Ideas ?

http://www.youtube.com/watch?v=PldsLFUN0vQ&feature=youtu.be

[zambo]

no takers on this one?

[glenn.b]

 zambo!    Love it.... that's about what I'm talkin bout!  Reverb done easy... I am going to watch that again tomorrow when I'm not tired.  So far my mind is wrapping around that  pretty easily.  Got yur springs, 2/3 watt amp,a buffer,on the "other" side a SHO,(Gee wonder if a "crackle NOT ok" will work in lieu of an actual SHO circuit.    actually how to build a little two watt amp using a LM386??like a headphone amp I think.  More tomorrow ....nice catch!!!

[zambo]

well I plugged it into my hi gain amp today and got some really strange results. When the crackle ok knob is at its loudest I get a fuzzy, bad solder joint kind of sound. If I turn it down I can kind of tune it out to a degree but it sounds like I can hear white noise in the background. Also if I push the amp to hard I get a sound like a blown voic coil will sound sometimes. Like a rattly squeak sound that happens when you play a muted low note. I am thinking its starving for voltage? maybe? I dont know what the crackle pot is doing, That might be oscilations? I have no idea. Is not as affected on a clean amp though. The whole thing is out in the open and I am wondering if sheilding will take care of some of it. Maybe I need another buffer at the output side of the dry signal to seperate the outputs of the reverb recovery (sho) and the input dry signal buffer ( lpb1). I am a little clueless and would love some help. The lm386 amp configured as a constant current amp (?) I hear works with 8 ohm tanks. I chased around all the links in this and a few other threads. It says 9 volts isnt really enough to push a higher ohm tank. you can run it on 12 or so though and it does better. Its around 1/2 watt at 12 volts I think. I really would like to get this sorted. I love the reverb sound from that tank. so surfy!! I still cant get the highs to come through on the dry side either. More buffers?

[zambo]

glenn - did you figure out what ohms your tank is? thanks for reply btw. I really want to build these. I have like four tanks of various ohms etc.

[glenn.b]

Posted by: zambo
Insert Quote
well I plugged it into my hi gain amp today and got some really strange results. When the crackle ok knob is at its loudest I get a fuzzy, bad solder joint kind of sound. If I turn it down I can kind of tune it out to a degree but it sounds like I can hear white noise in the background. Also if I push the amp to hard I get a sound like a blown voic coil will sound sometimes. Like a rattly squeak sound that happens when you play a muted low note. I am thinking its starving for voltage? maybe? I dont know what the crackle pot is doing, That might be oscilations? I have no idea. Is not as affected on a clean amp though. The whole thing is out in the open and I am wondering if sheilding will take care of some of it. Maybe I need another buffer at the output side of the dry signal to seperate the outputs of the reverb recovery (sho) and the input dry signal buffer ( lpb1). I am a little clueless and would love some help. The lm386 amp configured as a constant current amp (?) I hear works with 8 ohm tanks. I chased around all the links in this and a few other threads. It says 9 volts isnt really enough to push a higher ohm tank. you can run it on 12 or so though and it does better. Its around 1/2 watt at 12 volts I think. I really would like to get this sorted. I love the reverb sound from that tank. so surfy!! I still cant get the highs to come through on the dry side either. More buffers?

Whew!!   Lots going on there,  but I think your correct, at least partially :   A little more power 12/18 volts, perhaps.  I say this because if I am not mistaken,   the " Hot Springs" that Paia offers are meant to / capable of running at 18v, where there is more headroom.  White noise?  Yeah, that should improve with the addition on an enclosure-no tellin how much radio Freq. your picking up....anyway these are my guesses
but YES, Surf stuff is what I am hoping for!  Gotta have it!

ummary
Posted on: Yesterday at 10:53:07 PM Posted by: zambo
Insert Quote
glenn - did you figure out what ohms your tank is? thanks for reply btw. I really want to build these. I have like four tanks of various ohms etc.

I'm pretty sure....  I say that because I have not measured it per se,   but I think have identified it : It is a Gibbs Type 5G or 7G Reverberation Unit, 8 ohms input, 2000 ohms output.  This things is like circa 1950-60...To be honest I have not ever measured the ohms on this or any other reverb, so if you know the procedure I am all ears.