That is correct.hansen said:
that is also correct. But don't forget that the junction of R14 and R15 goes to the center pin of the OUTPUT jack.
Spring Reverb from the 60's
- Thread starter hansen
- Start date
Help Support GroupDIY Audio Forum:
Ok thank you! But wait... is the INPUT and OUTPUT symbolised with concentric circles the SAME as where A and E are wired to then? The concentric circles are actual physical components (jacks), and A and E are connections from the pcb to the IN or OUT (jacks) symbolised with concentric circles.abbey road d enfer said:
scott2000
Well-known member
hansen said:
Yes???.....
"A" is the point/junction in between C1 and R14.....
"E" is the point/junction between the negative C5 side of cap and the un-grounded leg of the pot
You should have 4 actual connectors though if I'm reading it right?
maybe it would be nice if "B" and "C" could actually be shown somehow as the other two connectors ??? ..
Hopefully someone can correct me if I'm wrong.....
edit......... E just goes to the pot leg.....not the output......pot is mounted on chassis so there needs to be a wire to reach it from "E".. ..... edited pic......
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scott2000
Well-known member
Today I tested the reverb with a mic and preamp. I am so happy it worked all really well. Last step will be some additional knobs, and putting everything in a nice designed 19’ Rack. Update will follow soon.
When the pot meter is down, there is no reverb at all. Slowly opening it gives already lots of reverb. When the meter is at 12’o clock, it starts giving feedback already. For me this works really cool though, and I think I will keep it that way. A few things I do not understand:
Input of the circuit links directly to output. How does it come the signal misses lots of low, even though the Pot Meter is closed. Is that R14 that is responsible for that?
If I wanted to have feedback later then 12o’clock on the pot meter, on which component do I have to change the resistance?
Next I want to create a Dry signal potmeter and a mastergain potmeter. Can I replace the dry signal potmeter with R14, and does the Master potmeter come right before the output? How much Ohm on both pots would be right?
When the pot meter is down, there is no reverb at all. Slowly opening it gives already lots of reverb. When the meter is at 12’o clock, it starts giving feedback already. For me this works really cool though, and I think I will keep it that way. A few things I do not understand:
Input of the circuit links directly to output. How does it come the signal misses lots of low, even though the Pot Meter is closed. Is that R14 that is responsible for that?
If I wanted to have feedback later then 12o’clock on the pot meter, on which component do I have to change the resistance?
Next I want to create a Dry signal potmeter and a mastergain potmeter. Can I replace the dry signal potmeter with R14, and does the Master potmeter come right before the output? How much Ohm on both pots would be right?
As I wrote in the beginning of this post I found an article that was published somewhere in the 60’s in ‘Popular Electronics’ (all credits go to them). I just wanted to make a reverb rack with a basic circuit. I am not sure if I took the right circuit for this to learn, as everybody that knew a thing about electronics was saying that this was ‘ancient stuff’ and things could be done better these days. I would agree, but I still learnt so many new things and now I have my own working Spring Reverb. In this post I will show step by step what I have done for those interested in recreating. Also, I am not an engineer. Pictures and sound file attached for reference.
PCB
There are other ways to make a pcb. I’ve chosen to etch my own. Its harder to make different connections within the circuit, but etching is really cool. Materials will cost not more then €10
Materials: Copper epoxy plate - Fe3Cl - Photocopy machine - glossy photo paper - Iron (to apply heath) and a bucket of water.
The hardest thing about the pcb was that there was no real tutorial. Because every paper and Ferric chloride is different I spend two days to figure it out.
Make sure you work with glossy paper. Not every glossy paper is good. In the beginning I noticed that the first photocopies where on plastic glossy paper. Everything melted and it didn’t work out. Don't buy plastic paper! The second day I used thick glossy paper, printed with a laserprinter (just bring an usb to a photocopy shop, they’ll know what to use). The Iron was set to linnen (hottest), and I pressed the iron against the glossy paper, so that the print touched the copper pcb.
After ten minutes, I placed the copper with the glossy paper melted to its surface in boiled water with soap. After 5 minutes or so I was able to peel it off. It took me several tries to understand what happened. I had the feeling that the inkt was still fragile, so i didn’t rubbed it off too harsh. But the paper comes off quite smooth. Be sure to rip it off slower when you get closer to the inkt, or it doesn’t stick that well.
In the end you'll be having a inktprint of your circuit on the copper plate. The next step was quite easy; we need to make the Fe3Cl react with the copper. The copper underneath the inkt will not react! I boiled water in a plastic bowl, and on top of that I made another smaller plastic bowl with ferric chloride. I measured the temperature till it reached 40-50 degree. After that I placed the copper pcb on it, and within 5 minutes it was all done.
The inkt is still on the pcb obviously, so it needed to be cleaned with aceton and a sponge. Drilling the holes was easy too. If it doesn't work, don’t give up, but try different paper would be my tip. Also be careful with the Fe3Cl, wear a mask! Don’t pour it in the drain but bring it to the chemical deposit.
Components
Because this build is ancient, lots of the components are not existing anymore. Luckily the spring verb was still available for €30 or so (I believe Lee_M mentioned the right one). Try to find components as close as written in the article. I had the exact resistors, but I believe all my capacitors have slightly more uF then written. Also, all the resistors had 1% instead of 10%.
After I finished the build, a friend of me checked it for faults. It appeared (and I don't know why) that the FET was wrongly written in the article. So he placed the S and the D pin of the FET the other way around. Check the pictures how I placed the components. Pm me if you want to BOM.
PSU
Not much to say about it. I chose a 48V one, and wired the + and - to the pcb + and earth symbol.
Rack
Now I had to saw of a small part of the reverbtank. It was not made for a 19’ rack. Drilled some holes for input, output, wet and C13 cable.
Things to be done:
- Dry button
- Master button
- on/on Switch + LED
- Red metal plate as front
PCB
There are other ways to make a pcb. I’ve chosen to etch my own. Its harder to make different connections within the circuit, but etching is really cool. Materials will cost not more then €10
Materials: Copper epoxy plate - Fe3Cl - Photocopy machine - glossy photo paper - Iron (to apply heath) and a bucket of water.
The hardest thing about the pcb was that there was no real tutorial. Because every paper and Ferric chloride is different I spend two days to figure it out.
Make sure you work with glossy paper. Not every glossy paper is good. In the beginning I noticed that the first photocopies where on plastic glossy paper. Everything melted and it didn’t work out. Don't buy plastic paper! The second day I used thick glossy paper, printed with a laserprinter (just bring an usb to a photocopy shop, they’ll know what to use). The Iron was set to linnen (hottest), and I pressed the iron against the glossy paper, so that the print touched the copper pcb.
After ten minutes, I placed the copper with the glossy paper melted to its surface in boiled water with soap. After 5 minutes or so I was able to peel it off. It took me several tries to understand what happened. I had the feeling that the inkt was still fragile, so i didn’t rubbed it off too harsh. But the paper comes off quite smooth. Be sure to rip it off slower when you get closer to the inkt, or it doesn’t stick that well.
In the end you'll be having a inktprint of your circuit on the copper plate. The next step was quite easy; we need to make the Fe3Cl react with the copper. The copper underneath the inkt will not react! I boiled water in a plastic bowl, and on top of that I made another smaller plastic bowl with ferric chloride. I measured the temperature till it reached 40-50 degree. After that I placed the copper pcb on it, and within 5 minutes it was all done.
The inkt is still on the pcb obviously, so it needed to be cleaned with aceton and a sponge. Drilling the holes was easy too. If it doesn't work, don’t give up, but try different paper would be my tip. Also be careful with the Fe3Cl, wear a mask! Don’t pour it in the drain but bring it to the chemical deposit.
Components
Because this build is ancient, lots of the components are not existing anymore. Luckily the spring verb was still available for €30 or so (I believe Lee_M mentioned the right one). Try to find components as close as written in the article. I had the exact resistors, but I believe all my capacitors have slightly more uF then written. Also, all the resistors had 1% instead of 10%.
After I finished the build, a friend of me checked it for faults. It appeared (and I don't know why) that the FET was wrongly written in the article. So he placed the S and the D pin of the FET the other way around. Check the pictures how I placed the components. Pm me if you want to BOM.
PSU
Not much to say about it. I chose a 48V one, and wired the + and - to the pcb + and earth symbol.
Rack
Now I had to saw of a small part of the reverbtank. It was not made for a 19’ rack. Drilled some holes for input, output, wet and C13 cable.
Things to be done:
- Dry button
- Master button
- on/on Switch + LED
- Red metal plate as front
Attachments
scott2000
Well-known member
Thanks for sharing that! Very helpful....
kooma
Well-known member
JMFahey
Well-known member
Well, except mehansen said:
, who know a thing or two about Electronics, praised it, and in fact actually *built* them (about 100 of them) back in the day With very good results, as you now confirmed.
Congratulations.
As I described in the last post, I wanted to design a dry and master button and on/off switch with LED.
It did work after testing, at least most of it did. I will explain what I did for people interested to recreate;
ON/OFF switch+ LED
I bought a ON/ON switch with 6 poles at the bottom. The + and - wires that came from the PSU and went to the PCB were cut and reconnected to the upper two, and the middle two poles. Easy to do.
The LED was a bit more difficult. I had to calculate the amount of Ohm I had to place before the LED so that it wouldn't burn. As you can see, I designed it between Q2 and C6. I knew that the + pole gave 40V, but i wasn't sure how much volt would be at the LED. Easy solution; just measure the amount of voltage between Q2 and C6. I measured; 27,1V.
The LED is a 2V 30mA unit. So (if I am not wrong) I used Ohms law to calculate the right amount of resistance:
(27,1-2V)/0.03= 836,6 ohm. I think I placed a 1k resistor in the and, but it worked!
Master and Dry pods
I thought it'd be cool to have only the wet signal, so I placed the dry button directly between the input and the output. I thought that whenever you'd turn down the dry button, the signal would only go through the spring, and enters right before the output. Well the dry button works, as I am able to turn the dry signal louder or off. The only error (I don't understand why) is that whenever the dry knob is fully turned down, there is also no signal coming through the wet button. So I cant have a signal without the dry. I can turn him quite low, but not off without affecting the wet.
The Master was quite easy. I placed it right before the output.
Last step would be creating a nice design, with shiny knobs and stuff. After that my work is done here ;D
It did work after testing, at least most of it did. I will explain what I did for people interested to recreate;
ON/OFF switch+ LED
I bought a ON/ON switch with 6 poles at the bottom. The + and - wires that came from the PSU and went to the PCB were cut and reconnected to the upper two, and the middle two poles. Easy to do.
The LED was a bit more difficult. I had to calculate the amount of Ohm I had to place before the LED so that it wouldn't burn. As you can see, I designed it between Q2 and C6. I knew that the + pole gave 40V, but i wasn't sure how much volt would be at the LED. Easy solution; just measure the amount of voltage between Q2 and C6. I measured; 27,1V.
The LED is a 2V 30mA unit. So (if I am not wrong) I used Ohms law to calculate the right amount of resistance:
(27,1-2V)/0.03= 836,6 ohm. I think I placed a 1k resistor in the and, but it worked!
Master and Dry pods
I thought it'd be cool to have only the wet signal, so I placed the dry button directly between the input and the output. I thought that whenever you'd turn down the dry button, the signal would only go through the spring, and enters right before the output. Well the dry button works, as I am able to turn the dry signal louder or off. The only error (I don't understand why) is that whenever the dry knob is fully turned down, there is also no signal coming through the wet button. So I cant have a signal without the dry. I can turn him quite low, but not off without affecting the wet.
The Master was quite easy. I placed it right before the output.
Last step would be creating a nice design, with shiny knobs and stuff. After that my work is done here ;D
Attachments
That's because the 'Dry' pot shorts the wet signal. You have to put resistors at teh pots wipers so you can mix dry and wet without too much interaction.hansen said:
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