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bossarea
Forum Admin
United Kingdom
3652 Posts |
 Posted - 05/03/2009 : 19:51:41
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A long time ago I started thinking about creating a VB-2 clone. The idea was to take a BF-2 and replace the guts with a completely new PCB. When I looked at the scheamtic and realized that the VB-2 contained the unavailable Roland BA622A VCA chip, the whole project was put on the shelf but I started looking into it when I found out that the BA6110 VCA could be used instead of the BA622A. Gathering parts took several months with the 3 position switch being the hardest part to track down. A couple of months ago I finally had everything I needed and I started the build.
This is the starting point. A MIJ BF-2 that I picked up from Ebay for �20. It worked when I got it but cosmetically it was in a sad state with the bottom plate completely covered in glue.
I drew the PCB using PCB123 (http://www.pcb123.com/) by copying the picture in the schematic. That means I drew it the way it looks from the component side. The PCB is slightly modified because the switch from BA622A to BA6110 also required me to add 4 transistors.
I bought the StencilPro printing kit from www.cbridge.com and used it to print the component side of the PCB. It actually helped a lot when I soldered in the components. No need to double check the direction of diodes, polarity of caps or which way to turn transistors. More about the printing further down.
All the components are soldered in and the PCB is mounted in the housing for testing.
Naturally I had a few issues when I first connected it to power. I had forgotten to put in a jumper, one solder point was not soldered and there was one layout mistake on the PCB. Also, I wasn't aware that the BA6110 had a different pin layout so when I was finished with it, I ended up with two jumpers on the solder side of the PCB.
My workbench needs a good cleaning. I keep losing stuff all the time.  Notice the upside down original VB-2. I had to compare voltages when troubleshooting.
I removed the paint from the BF-2 enclosure using a combination of sanding and dremeling. The original finish is incredibly durable. I doubt that my new finish is anywhere close to the same quality.
Sprayed two coats of primer before applying the paint.
Before painting I searched the Internet for a suitable colour and found this.
That's Opel/Vauxhall Caribic blue. My local Halford's didn't have this paint so I came home with a can of Rover Caribian Blue instead. Sounded the same so I hoped it would be similar. The Rover paint turned out to be a very dark green. So dark in fact that the black labeling would be almost invisible. I ended up sanding it down again. I went back and got a can of Vauxhall Sapphire blue. Bad idea, this time it looked more like a CH-1.
Here's the painted housing with the PCB mounted.
Time to print the treadle and control plate. First I started by printing the artwork on transparent paper.
The StencilPro kit came with two types of material. Normal and high resolution. This is high res which should ideally give something like 200dpi resolution. Place the printout on top of the material and give it 30 seconds of UV.
After UV exposure, just put the stencil in water and wash off the areas that wasn't exposed. To the left is the finished "Vibrato" stencil.
I glued the stencil to the treadle using stencil adhesive. A non permanent glue that allows for repositioning of the stencil. I then applied the paint using a squeegee.
Here's the final result. I'm a bit rubbish at the painting process and make a lot of mistakes. I printed the treadle twice and the control plate 3 times. The word "Rate" on the control plate is a little blurred but since it was my third attempt, I decided to leave it that way.
The control plate is a cut out made from the plastic of an old DVD cover. This is not the perfect material because it is flexible. When the pot nuts are tightened, pressure is applied to the middle of the control plate with the result that the edges will lift up. It is also so tick that I was unable to use washers when tightening the nuts.
I mentioned that the BF-2 had the underside covered with glue. I tried to scrape it off but it took too long so I used the sander instead. I took a photo of a label and printed it with a slight modification.
The final result.
Naturally, the most important thing is, how does it sound? Is there an audible difference between this and the original?
The sound is exactly the same when the knobs are all around the middle position. When Rate or Rise time is decreased, there are differences. The clone is more suttle and doesn't give me the extremes that the original does. I will have to trobleshoot the oscillator circuit that controls the 3102 to see how it differs from the original.
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DasBeef
Gold Member
United Kingdom
704 Posts |
Posted - 05/03/2009 : 20:09:06
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| Ha ha! Thats some quality work! First UK made boss pedal! |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 05/03/2009 : 20:41:40
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The only thing I can say is this:  |
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verivorax
Platinum Member
Canada
1185 Posts |
Posted - 05/03/2009 : 22:15:48
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AMAZING work! So do we have to be careful of a spate of bossarea VB-2 clones out there?!?!
I'd say it's decidedly rarer than a real one.  |
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nathanscribe
Silver Member
United Kingdom
376 Posts |
Posted - 05/03/2009 : 22:20:07
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Nice work! I'll have to check out those stencils - I'm getting a bit bored of Dymo labels...
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FunkenGrooven
Silver Member
USA
360 Posts |
Posted - 05/04/2009 : 03:06:12
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I smell an "Ultra rare" vintage made in the UK E-bay listing I'm sure you could get at least 1500.00 for it |
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DeFrag
Moderator
USA
3409 Posts |
Posted - 05/04/2009 : 03:25:10
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A valiant effort to be sure,
& you're a Fluke man too!
(I have the 179, which model is yours?) |
Edited by - DeFrag on 05/04/2009 03:29:09 |
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sp-1
Platinum Member
Germany
1454 Posts |
Posted - 05/04/2009 : 11:14:41
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 That looks very professional 
Great job  |
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 05/04/2009 : 17:32:07
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You should find the right paint, find some cheap broken pedals and make those VB-2's in small quantities (just for us Bossarea members!)
Great, great work!! |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 05/04/2009 : 18:07:40
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Thanks for all the praise.
It was a fun project and I might just have another go. Maybe I'll make another VB-2 or maybe I'll turn a DS-1 into a DM-2. I still got some troubleshooting to do on the current project though.
quote:
Originally posted by DeFrag
A valiant effort to be sure,
& you're a Fluke man too!
(I have the 179, which model is yours?)
The yellow one is a Fluke 77. I've had it for a long time. It never goes wrong and the battery lasts practically forever. There's also a Fluke 8050A bench multimeter on top of the scope and signal generator. |
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nathanscribe
Silver Member
United Kingdom
376 Posts |
Posted - 05/04/2009 : 19:51:54
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| Have you thought about using a CA3080 instead of the BA662? |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 05/04/2009 : 20:32:52
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I was looking to see if I could find other compatible VCAs than the BA6110 but never considered the CA3080. Do you know if it's a drop-in replacement or if it needs the 4-transistor current mirror that the BA6110 requires. I'd replace the 6110 right away if it makes the circuit more similar to the original.
I've looked at the differences between the clone and the original today and found that the difference is the voltage out of the VCA. It's only half of what I get out of the BA622A. It's possible that my bias current is too small. I used different transistors than BYOC and the guys and Ladyada so I might try to replace them. |
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nathanscribe
Silver Member
United Kingdom
376 Posts |
Posted - 05/05/2009 : 00:17:07
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From what I know, the 3080 does the same job as the 662, except the 662 includes a buffer at the output (that can be bypassed by simply not wiring the pins in circuit) whereas the 3080 does not, and if you were of a mind to include that buffer you'd be using an external transistor (FET?), but it'd still be a lower part count than the 6110 route.
The LM13700 is a dual package OTA, with buffers - still in production and easily available. I've heard it doesn't perform as well as some other OTAs though. Even considering it's a 14- or 16-pin (can't recall) it might still take up less room than a single 6110 with all those transistors.
For what it's worth, I built a TR-909 clone using a 3080 in place of the clap circuit's original 662, and it works just fine. |
Edited by - nathanscribe on 05/05/2009 00:18:41 |
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Sray10
Silver Member
USA
150 Posts |
Posted - 05/05/2009 : 02:01:24
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| Sweet!!! I like the color too |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 05/05/2009 : 17:35:36
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quote:
Originally posted by nathanscribe
From what I know, the 3080 does the same job as the 662, except the 662 includes a buffer at the output (that can be bypassed by simply not wiring the pins in circuit) whereas the 3080 does not, and if you were of a mind to include that buffer you'd be using an external transistor (FET?), but it'd still be a lower part count than the 6110 route.
The LM13700 is a dual package OTA, with buffers - still in production and easily available. I've heard it doesn't perform as well as some other OTAs though. Even considering it's a 14- or 16-pin (can't recall) it might still take up less room than a single 6110 with all those transistors.
For what it's worth, I built a TR-909 clone using a 3080 in place of the clap circuit's original 662, and it works just fine.
Thanks, that's great info. I will have to research this and see if it's a better option. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 05/05/2009 : 18:02:30
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quote:
Originally posted by bossarea
quote:
Originally posted by nathanscribe
From what I know, the 3080 does the same job as the 662, except the 662 includes a buffer at the output (that can be bypassed by simply not wiring the pins in circuit) whereas the 3080 does not, and if you were of a mind to include that buffer you'd be using an external transistor (FET?), but it'd still be a lower part count than the 6110 route.
The LM13700 is a dual package OTA, with buffers - still in production and easily available. I've heard it doesn't perform as well as some other OTAs though. Even considering it's a 14- or 16-pin (can't recall) it might still take up less room than a single 6110 with all those transistors.
For what it's worth, I built a TR-909 clone using a 3080 in place of the clap circuit's original 662, and it works just fine.
Thanks, that's great info. I will have to research this and see if it's a better option.
This is getting really interesting... thanks fo the info!
The one thing it does tell us is that unless you can get an old-stock/pulled 662, you aren't going to be building a true clone  |
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My Fake VB-2
