Superb Boss FV500H mod

[Jacew]

I really like the construction of this volume pedal. Never really liked the taper however. Feels very clumsy compared to EB jr.

I've been trying to get used to it. But decided it's not working.

Not wanting to go switching pedals to no end I looked for replacement pot. Which turned out to be useless. Despite being cheap Alpha, there is no available replacements anywhere.

So I looked to replace wafer. Except that due to the construction of the lever, that alpha has half shorter slider any normal pot so that didn't work either.

So I replaced the exp wafer of the dual gang pot with 500k alpha with fullsize slider. And crosswired it's input and output lugs with orginal wafer.



Result was stunnigly good. As the second wafer in parallel now smoothens out the taper, it feels just as good as that EB jr. did. Without any of it's drawbacks...

[Alkerion]

Re: Superb Boss FV500H mod

Hi !

Could we have a bit more detail regarding the pot used (reference) and the wiring ?

Which pot did you change?

The volume dual pot is a 250k/500k, do you change it for a 500k/500k?
Or did you change the min volume pot we can adjust from outside ?

Thanks
Regards

[Jacew]

Re: Superb Boss FV500H mod

I didn't change the pot. Pot in Boss FV-500h is 25k/250k dual gang and has only 1/3 rotation of normal. I couldn't find replacement anywhere. If anyone knows where to find one I'd really like to know!

What I did was that I opened the pot and changed the slider part inside the pot to 500k. Then I wired it backwards in parallel with the other wafer, so the pedal acts less quickly when lowering volume.

[Alkerion]

Re: Superb Boss FV500H mod

Hi !
Sorry, I was wrong, mine is 10k for Exp and 250k for Vol, it's written on it...
When you write : "Then I wired it backwards in parallel with the other wafer", does it mean that you wired the Vol pot with Exp pot ?
How did you change it ? (I?ve opened it and it seems quite hard to remove the wafer without damaging anything)
You bought a new dual 500k pot ?
Linear, audio or log?
Can you still use Exp ?

To me the volume curve on this pedal is not good, the volume change too quickly in a too short foot amplitude, I would like to improve that.
BR

[Jacew]

Re: Superb Boss FV500H mod

Hi !
Sorry, I was wrong, mine is 10k for Exp and 250k for Vol, it's written on it...
When you write : "Then I wired it backwards in parallel with the other wafer", does it mean that you wired the Vol pot with Exp pot ?
How did you change it ? (I?ve opened it and it seems quite hard to remove the wafer without damaging anything)
You bought a new dual 500k pot ?
Linear, audio or log?
Can you still use Exp ?

To me the volume curve on this pedal is not good, the volume change too quickly in a too short foot amplitude, I would like to improve that.
BR

Yep, exp side is 10k. My bad.

I just used 500k pot wafer I had lying around. It's changeable. You bend the 4 tabs that hold the existing wafer and it should drop right out. Then put in other and bend tabs back to hold it in place.

I need to open it up to make sure as I don't fully remember which lug I connected with which, but basically I wired the exp side of the pot parallel with volume side.

Obviously it won't be usable as exp pedal after that.

[Alkerion]

Re: Superb Boss FV500H mod

I've opened my pot, but to replace the 250k wafer I've to remove the axis, something that will for sure damage the pot.

So you've replaced the 10k or the 250k ?

Why haven't you just replaced the dual pot by a single 500k ?

On my setup the volume is OFF at 160K, above 160 it's useless, and I can't ear any differences on high volume from 50K to 0. the usable range is quite poor.

I'll first try to replace the pot by a good 250k.

[Alkerion]

Re: Superb Boss FV500H mod

Something strange is that when the pedal is set to highest volume the Vol pot value is 2.7K, do you have the same value ?

I've ordered B250K and B500K to test.

I'll also remove the circuit boards and wire directly, and add a switch to select the impedance 250K, 100K and 25K an the volume pot.

I'll post a few pictures and keep you informed once done.

[Jacew]

Re: Superb Boss FV500H mod

Something strange is that when the pedal is set to highest volume the Vol pot value is 2.7K, do you have the same value ?

I've ordered B250K and B500K to test.

I'll also remove the circuit boards and wire directly, and add a switch to select the impedance 250K, 100K and 25K an the volume pot.

I'll post a few pictures and keep you informed once done.

I don't remember if it went all the way to 0, but it should and I recall it does. I'll check that too. If it doesn't it may have worn out or misaligned pot.

Those pots you've ordered are not going to work. I said it multiple times in this thread that pot in Boss FV-500 has unique rotation: It only rotates 1/3 of usual lenght so you need special pot for it.

EDIT: Unless you were going to gut that for the mod I mean...

[Alkerion]

Re: Superb Boss FV500H mod

I've modified a B250K pot to be a D shaft :


Then, wired it directly to the jacks the simplest way :


The feeling is way better than the original pedal, the only "issue" is that I still have a little volume when the pedal is down, it will probably be much better with the 500k pot.

To follow....

[Jacew]

Re: Superb Boss FV500H mod

The feeling is way better than the original pedal, the only "issue" is that I still have a little volume when the pedal is down, it will probably be much better with the 500k pot.

To follow....

I'm sure of that. They're nice if they just had better electronins inside. Nice to see others improving them as well.

You have volume when pedal is heel down because regular pot won't rotate to 0 due to the construction of the pedal. It also won't turn fully open. 500k or 250k won't change that.

Did you measure the load when fully open. I'd be interested to hear what you get?

[Alkerion]

Re: Superb Boss FV500H mod

Original pot : 237K -> 2K7

New B250K pot: 215K -> 16K2

I've my idea to solve these issues, already worked on it and obtained 190K -> 2R

I'll receive ma 500K pot in ~10 days, so I expect to have something around 400K -> 0R, and with a 600K resistor I'll reduce the 400K to around 240K, that way I'll have a 240K -> 0R perfect pot :-)

Will also add a switch to set the min volume to other values than 240K (I'll try 100K & 25K).

With high quality jack socket and minimum wiring the tone will be back and I'll have less interference, all that with perfect feeling under the foot to adjust the volume.

[Alkerion]

Re: Superb Boss FV500H mod

For those interested, here is my "schema" :


and first rewiring (original connections but min vol pot on VOL not connected):

[Jacew]

Re: Superb Boss FV500H mod

Original pot : 237K -> 2K7

New B250K pot: 215K -> 16K2

I've my idea to solve these issues, already worked on it and obtained 190K -> 2R

I'll receive ma 500K pot in ~10 days, so I expect to have something around 400K -> 0R, and with a 600K resistor I'll reduce the 400K to around 240K, that way I'll have a 240K -> 0R perfect pot :-)

Will also add a switch to set the min volume to other values than 240K (I'll try 100K & 25K).

With high quality jack socket and minimum wiring the tone will be back and I'll have less interference, all that with perfect feeling under the foot to adjust the volume.

How do you plan to get that 16k to 0 at heel down? I couldn't figure that out and would certainly be interested if it is possible.

Just heads up that you won't waste your time...

[Alkerion]

Re: Superb Boss FV500H mod

No rocket science, just a little hole :

[Jacew]

Re: Superb Boss FV500H mod

I meant how we're you planning to get the pedal all the way silent: You get sound because theres 16k load (as your measurements show) even when it should be silent. Also you don't get full output through pedal at the other end for same reason.

I don't know a way to fix that electrically. That's why I couldn't just replace the pot (and used the second wafer in parallel). Stock one has shorter rotation than any aftermarket pot.

EDIT: Well, I didn't quite got your previous post first. Sure moving the pot to close fully fixes that issue. But then your volume is not going fully open... Whether it's 250k or 500k doesn't really affect that.