Author Topic: String Ringer build.  (Read 37869 times)

digi2t

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String Ringer build.
« on: April 20, 2012, 09:44:17 PM »
Having taken a break to work on some smaller circuits of late, I finally got everything to finish the String Ringer (Lovetone Ring Stringer clone). This thing is quite the box. I spent the better part of the day twiddling the knobs, and I'm sure that I'm barely starting to get my head around it. This sucker can just put out some jaw-dropping sounds  :icon_eek:.

I did run into two snags, but with some hardcore staring, I managed to get things sorted out. First, the LFO wasn't working, but then I realized that my LFO Depth jack was grounded to the chassis, thus killing the LFO. Luckily, I had some Switchcraft fiber washers from my Gristleizer build, so I pressed two of them into service, and presto!, problem solved. Here's a pic of the washers in action;



Second snag, I placed a wrong resistor in the R39 slot. Instead of the specified 1.2K, I put in a 2.2K. This made it impossible for me to find a sweet spot for the Vactrol with the 1K trimmer. To make things worse, everything was already bolted into place when I discovered this (THANKS Mr. Murphy  :icon_evil:). I was able to unsolder the 2.2K, and I simply soldered the 1.2K on the backside. Upon further reflection, I figured this might actually be a good thing for some. I used a VTL5C3 in here, but one could use a variety of different LDR/LED combinations. You could try different resistors here to find one that places the 1K trimmer into the zone. Just don't use anything smaller than say 470 Ohm, in case you bottom the trimmer, that way you won't burn the LED, or Vactrol. In my case, the 1.2K resistor works well with the Vactrol. To allow for future adjustment, I drilled a hole in the top, directly above the trimmer. This allows me to slip a screwdriver in to adjust the Vactro trimmer, and a nice little plastic cap finishes things up quite nicely (just above the Octave/Ringmod footswitch).

Considering the complexity of the build, I got away cheap with only two snags. This motivates me for the Ludwig Phase II build coming next  :icon_cool:.

The pots spec'd in the v1.2 pdf were just too rich for my blood, so I improvised. Regular 16mm pots were pressed into service. I measured the height of the rotary switches, and them used a small block of foam to jig each pot to the same height. Pieces of solid wire were then soldered between the poles and the board. Here are some more pics of the build. Sorry, the knobs haven't arrived yet  :icon_redface:...













And of course, the customary video. Mind you, although the video is 9 minutes and change, I'm barely scratching the tip of the iceberg here. You can twiddle knobs until your mind goes numb with this thing. It's a crazy machine. I figure a proper video, going through ALL the different control settings, would be very long indeed. Here you go...



Many thanks once again to all who have contributed information here on this baby. All the info came in handy, especially for the troubleshooting.

And most of all, very special, great big THANK YOU!! to John Lyon's. He went the extra mile and 7/8th's to help me out on this one. A true gentleman, through and through. Without his effort, this project wouldn't have happened. Thanks John!
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Strategy

Re: String Ringer build.
« Reply #1 on: April 20, 2012, 10:24:39 PM »
This is really helpful. I've been slowly filling a string ringer with 'spare' components over a long time and am actually getting close to completely populated. I was also considering using VTL5C3, glad to see it worked for you, I will probably do the same.

Now, I have some hitches/questions with this build:
- 2200k resistors: HUH? where to get these?
- where did you get the LT44 transformers?

Strategy

digi2t

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Re: String Ringer build.
« Reply #2 on: April 20, 2012, 10:58:09 PM »
Transformers and BAT48 diodes courtesy of here;

http://www.ebay.ca/itm/2X-LT44-Transformer-and-4-X-BAT48-Schottky-Diodes-Ring-Modulator-Kit-Parts-/120837040857?pt=UK_Guitar_Accessories&hash=item1c2272ead9

This is what I used, they work very well.

2.2M resistors... hmmm... I had them from some other project... oh yeah, Parallel Universe II, that's it! Mine are carbon 1/2 watters, but they fit just perfect in the space on the PCB. I think Tayda, or dipmicro was where I got them. Just took a look on the Bay, there's tons there.

As for the Vactrol, like I mentioned, you might want to fool around with R39 (1.2K). The less the resistance, the faster it will modulate at lower gains. As you lower the resistance, you'll here the modulation come in harder, so you can play around with the value here. Just be careful not to go too low.
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glops

Re: String Ringer build.
« Reply #3 on: April 21, 2012, 12:05:33 AM »
HOLY COW

glops

Re: String Ringer build.
« Reply #4 on: April 21, 2012, 12:20:45 AM »
I love that enclosure.  Is there string ring pcb artwork out there? I musta missed it. I'll go search.  Still need to get on those Ludwig boards I bought from you. A bit intimidated by that one, just the ordering of the parts seems like it would take up an afternoon. Love your projects, man. Good taste.

digi2t

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Re: String Ringer build.
« Reply #5 on: April 21, 2012, 07:59:56 AM »
Quote
Is there string ring pcb artwork out there?

The PCB layout is contained in the build paper. It also includes the schematic, BOM, PCB art work, parts layout, and tuning guide. The build paper can be found here;

http://www.scribd.com/doc/51501609/StringRingerv12r (need to log into Facebook)

or here;

homepage.ntlworld.com/paul.nelson666/StringRingerv12r.pdf  (direct download)

I might try and upload it to the Gallery as well. For some reason it's getting tougher to find.

*EDIT* - OK, I uploaded it to the Gallery. You can get it here as well;

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=47333&g2_GALLERYSID=6620e3dd40c9550a2e94aad4dd9d5203
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John Lyons

Re: String Ringer build.
« Reply #6 on: April 21, 2012, 10:09:20 AM »
Very nice Dino! Glad you got that one wrapped up. Thanks again for the trade.
Basic Audio Pedals
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garcho

Re: String Ringer build.
« Reply #7 on: April 21, 2012, 12:19:26 PM »
Pedals like this make me want to start new bands!
It's funny, some builds, like this one, are inspiring because I think of all the cool music I could make with one. Other builds are more about the satisfaction of gluing little thingies together with solder. Of course, both are valid, but I started this black hole of a 'hobby' for the former. Nice one digi2t!
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digi2t

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Re: String Ringer build.
« Reply #8 on: April 22, 2012, 11:01:41 AM »
Hmm, just noticed something peculiar.

Firstly, let me set the stage; The Octave/Ringmod footswitch has a green LED associated with it. LED OFF means Ocatve mode, LED ON means Ringmod mode. Also, I'm using 3PDT stompbox switches here, so I have a spare pole available on all three switches. With that said....

When in Octave mode, you can kick in/out the LFO. The LFO will modulate your octave signal. With the LFO on, the Octave footswitch LED will come on, and pulsate at the speed of the LFO. Here's the hitch... when you turn the LFO off, the LED will sometimes go off, or sometimes stay on, depending (I'm guessing) where in the LFO sweep/pulse you turned it off. If the IC's output is "high", it keeps the LED on, if it's "low", the LED is off. This is a bit confusing visually, because if it stays on, now you can lose track of whether the unit is in Octave, or Ringmod mode.

Looking at the schematic, the only thing I can figure is that IC3/3 can be on or off depending on where in the cycle I hit the LFO switch. If it's on, then it continues to send power to the LED, even though I turned off the LFO, thus keeping my LED (and Vactrol for that matter) lit. If this correct, then maybe the white jumper marked "Vactrol IN" should run through the unused pole of my LFO footswitch, before going to the Vactrol. That should kill the Octave LED, no matter where in the cycle the LFO is. Right? Here's the schematic;



This problem also messes with the DRIVE pot, since the LDR resistance (in parallel) can sometimes be high, or low, depending on where in the cycle you turned off the LFO.

The other thing is that in Ringmod mode, if you turn on the LFO, you have no rate indication, as you have in Octave mode (green footswitch LED flashes). I'm thinking that modding the white wire, and also running a fourth LED from the IC output, with the ground to the switch pole grounding the footswitch LED, should also give me a dedicated RATE LED, whenever I turn on the LFO.
I'm going to try this. If someone could take a quick look at the schem, and confirm my theory, I'd appreciate it.

In the meantime, I'm off to experiment.
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Strategy

Re: String Ringer build.
« Reply #9 on: April 22, 2012, 10:04:51 PM »
Another question for you Digi2T, do you know what part you used for the LFO depth external control jack? Thanks much!
Strategy

digi2t

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Re: String Ringer build.
« Reply #10 on: April 23, 2012, 07:09:20 AM »
Another question for you Digi2T, do you know what part you used for the LFO depth external control jack? Thanks much!
Strategy

For the jack, here is what I used;

http://www.stewmac.com/shop/Electronics,_pickups/Components:_Jacks/9-lug_Stereo_Jack.html

I've used it before on my Gristleizer build, and it works great, BUT.... you will need to isolate the jack from the chassis. If it's grounded in any way, it will kill the LFO. So, I also used these;

http://parts.digikey.com/1/parts/103859-washer-swedged-fiber-5-8-x3-8-s1029.html

These will take care of the grounding issue, perfectly.

Cheers,
Dino
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digi2t

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Re: String Ringer build.
« Reply #11 on: April 23, 2012, 12:28:32 PM »
OK, after some experimenting, I believe I've got the Vactrol / LFO problem licked.

-First, use a 3PDT switch for the LFO footswitch.
-Take the white jumper, that goes from IC3/pin8, to D15, and unsolder it at the D15 end.
-Connect this end of the white wire to the free pole that will be CLOSED to COM on the LFO 3PDT switch, when the LFO is engaged.
-Connect a new jumper from D15 to the free COM pole. This will sent LFO power to the Vactrol only when the LFO is engaged. If you wish, you may connect a second wire to the switch pole - white wire from IC3/pin8 - , add a 2.2K resistor to the positive side of an LED, and connect the LED negative to the COM marked "blue" on the schematic. Now, you'll have a handy RATE indicator, that will show you the LFO rate in any mode, anytime the LFO is on. Turning off the LFO, will also kill the RATE LED.

Also...

The 1.2K resistor specified for the LED/LDR combo is too big for the VTL5C3 Vactrol. I was not satisfied with the adjustment range of the 1K trimmer, so I ran some tests, replacing the 1.2K resistor with a 25K trimmer, to try and find what value would be more effective here with the 1K trimmer.

After some adjusting, I found that at 730 Ohms, I had a better sweep with the 1K trimmer. At one end of the 1K's sweep, the octave rang through louder, with the LFO modulation coming in on the decay. At the other end, the modualtion would be present all the time. Now, I could adjust at what point I want the LFO to come in with the 1K trimmer. If I turned the 25K trimmer any lower (below 300 Ohms), the LFO would start to slow down, since we're getting to close to ground. At this point, I decided to try something else. I replaced the 1K trimmer, with a 5K, and instead of the 1.2K resistor, I used a 680 Ohm.

Nirvana!!

With the 5K, I can sweep from modulation at the very, very end of the note decay, to almost constant modulation. The 680 Ohm resistor does the job of keeping the LFO far away from ground so as not to affect it's speed. I tested this by turning on the LFO, and switching between Octave, and Ringmod. I noticed no change in LFO speed between the two. The 5K trimmer give the best sweep results for the VTL5C3. I highly recommend this set up for the VLT5C3.

Next, I'm going to look at D13, and D14. Maybe I can incorporate a switch here to give me an up/down option as well, like the Uglyface, when modulating my Octave signal.
Stay tuned....
« Last Edit: April 23, 2012, 12:44:33 PM by digi2t »
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nelson

Re: String Ringer build.
« Reply #12 on: April 23, 2012, 06:23:33 PM »
Wow, I'm really surprised that project file is still hosted there. That's hosted on a defunct ISP storage that I had about 7 years ago. I'm no longer with that ISP. In fact, the ISP has been taken over by another company.

Crazy.

My project site
Winner of Mar 2009 FX-X

digi2t

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Re: String Ringer build.
« Reply #13 on: April 23, 2012, 07:02:18 PM »
Wow, I'm really surprised that project file is still hosted there. That's hosted on a defunct ISP storage that I had about 7 years ago. I'm no longer with that ISP. In fact, the ISP has been taken over by another company.

Crazy.

If you don't mind, I uploaded a copy to the Gallery. Just in case.

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nelson

Re: String Ringer build.
« Reply #14 on: April 23, 2012, 08:05:16 PM »
Wow, I'm really surprised that project file is still hosted there. That's hosted on a defunct ISP storage that I had about 7 years ago. I'm no longer with that ISP. In fact, the ISP has been taken over by another company.

Crazy.

If you don't mind, I uploaded a copy to the Gallery. Just in case.



I just hosted it back then for the person who did the project, Markus.

It's his IP.

 
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Winner of Mar 2009 FX-X

LaceSensor

Re: String Ringer build.
« Reply #15 on: April 23, 2012, 08:13:38 PM »
Nice Build

Ill watch this thread for the mod ideas.
can you tell me if you can hear the octave bleeding through to the bypass signal please?
I dont get any bleed in ring mode, but I can hear faint the oct fuzz in bypass with that option selected.

Also, why did you use BAT diodes and not 1n34a germaniums?

digi2t

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Re: String Ringer build.
« Reply #16 on: April 23, 2012, 09:41:44 PM »
Quote
can you tell me if you can hear the octave bleeding through to the bypass signal please?
I dont get any bleed in ring mode, but I can hear faint the oct fuzz in bypass with that option selected.

Let me look into this. I'm still exploring with this unit, and my mind is still too busy discovering. My ears haven't gone into "picky" mode yet  :icon_mrgreen:.

Quote
Also, why did you use BAT diodes and not 1n34a germaniums?

I read on the forum (it was Taylor that wrote about it) that Schottky diodes performed better, over silicons and germaniums, in ringmods. Her's Taylor's take on it;

"Diodes don't conduct until you cross their forward voltage threshold. That means that you will have no signal through the diode ring when the signal is smaller than the Vf of the diodes you're using. Germanium diodes have a lower forward V than silicon ( about .3v vs. about .6v) but Schottky diodes are even better, sometimes .15v or .2v. Using a matched quad Schottky array (TI part number UC3611) will give you the least gating and best matching, as the diodes are formed on the same wafer."

As I mentioned before in this thread, I purchased the LT44 transformers, and the BAT48 diodes, as a kit. They've worked out very well.

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LaceSensor

Re: String Ringer build.
« Reply #17 on: April 24, 2012, 06:24:03 AM »
Sounds good. I used the 1n34a and the octave fuzz is outstanding. I bought 10 to get a matched quad.

If you can get back to me on the bleed issue Id really appreciate it. Might mean I need to tweak a trimmer or somesuch...im not sure..

Here is my build for comparison sake :)
I havent labelled mine yet, either ;)




digi2t

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Re: String Ringer build.
« Reply #18 on: April 24, 2012, 10:30:05 PM »
Very nice! :icon_cool:

So, tonight I turned on my "picky" ears. You're right, there is bleed through. No doubt about it. Even with shielded wires. I don't think tweaking any trimmer will cure it. I scoped mine, and it's set up pretty nicely.

From what I can see, even in bypass, the audio signal is still running through the board. The input is split, one to the switch, and one to the board. I figure maybe it would be a good idea to ground the input going to the board when the effect is bypassed. Use a 3PDT switch for the Bypass, disconnect the input wire from the board and connect it to the COM of the third set of poles. Run a new wire from one side of switch (effect ON) to the board, and another to ground (effect BYPASS). That should kill any noise coming from the unit when bypassed. I had the same problem with my Gristleizer build (LFO bleed), and the grounding bypass setup was the ticket.

What thinks you?

*EDIT* - YEEEEHHHAAAWWW.... A guy on Ebay that has one for sale, was nice enough to scan and email me a nice, clear copy of the Ring Stinger manual. These suckers are hard to find! I've put it into pdf format, and you can get it here;

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=47408&g2_GALLERYSID=c2bb43554d90242cac910abf4c9bfb50

See folks, it's a wheel... sometimes yous helps the folks, and sometimes theys helps you  :icon_mrgreen:.
« Last Edit: April 24, 2012, 10:49:24 PM by digi2t »
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"gigantically smaller."  - pinkjimiphoton

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LaceSensor

Re: String Ringer build.
« Reply #19 on: April 25, 2012, 12:12:23 PM »
Very nice! :icon_cool:

So, tonight I turned on my "picky" ears. You're right, there is bleed through. No doubt about it. Even with shielded wires. I don't think tweaking any trimmer will cure it. I scoped mine, and it's set up pretty nicely.

From what I can see, even in bypass, the audio signal is still running through the board. The input is split, one to the switch, and one to the board. I figure maybe it would be a good idea to ground the input going to the board when the effect is bypassed. Use a 3PDT switch for the Bypass, disconnect the input wire from the board and connect it to the COM of the third set of poles. Run a new wire from one side of switch (effect ON) to the board, and another to ground (effect BYPASS). That should kill any noise coming from the unit when bypassed. I had the same problem with my Gristleizer build (LFO bleed), and the grounding bypass setup was the ticket.

What thinks you?

*EDIT* - YEEEEHHHAAAWWW.... A guy on Ebay that has one for sale, was nice enough to scan and email me a nice, clear copy of the Ring Stinger manual. These suckers are hard to find! I've put it into pdf format, and you can get it here;

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=47408&g2_GALLERYSID=c2bb43554d90242cac910abf4c9bfb50

See folks, it's a wheel... sometimes yous helps the folks, and sometimes theys helps you  :icon_mrgreen:.

Any chance you could scribble me a schematic of what you are referring to? Ive read it and not sure how to implement it. Sounds right whatever but its the wiring that confuses me.

Edit - by COM do you mean the middle common pole of the switch? then the top one goes back to the board, bottom one goes to ground?
« Last Edit: April 25, 2012, 12:20:54 PM by LaceSensor »