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Racer X
Silver Member
USA
299 Posts |
 Posted - 10/07/2008 : 14:20:44
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Time for the propeller beenie wearing brain trust to get 'em spinning. We all know that adjusting trimmer pots in flangers,choruses and delays is not such a good idea. Clock syncing and the like ......
A fellow sonic adventurer posed the question of " What would it
sound like if I adjusted the timmers in my BF-2 ? "
I haven't got my head completely around this one yet this morning.
( Caffeine uptake is behind the curve )
So, at a minimum would you think that the signal would maintain
coherence ? At the extreme would there be any recognizable signal ?
My scope is tits up so I can't ride the traces right now.
Conjecture, proven science, conspiracy theorys and outright lies
will be carefully considered and evaluated.
In the end, the aforementioned aural explorer is not so much concerned with maintaining the integrity of the BF-2's known signal shaping. Producing a more " interesting " noise is the primary
concern.
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Edited by - Racer X on 10/07/2008 14:22:36 |
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happyplucker
Bronze Member
United Kingdom
126 Posts |
Posted - 10/07/2008 : 14:24:48
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| if thiats the case, why dont they just try it? |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/07/2008 : 14:31:57
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quote:
Originally posted by Racer X
Time for the propeller beenie wearing brain trust to get 'em spinning. We all know that adjusting trimmer pots in flangers,choruses and delays is not such a good idea. Clock syncing and the like ......
A fellow sonic adventurer posed the question of " What would it
sound like if I adjusted the timmers in my BF-2 ? "
I haven't got my head completely around this one yet this morning.
( Caffeine uptake is behind the curve )
So, at a minimum would you think that the signal would maintain
coherence ? At the extreme would there be any recognizable signal ?
My scope is tits up so I can't ride the traces right now.
Conjecture, proven science, conspiracy theorys and outright lies
will be carefully considered and evaluated.
In the end, the aforementioned aural explorer is not so much concerned with maintaining the integrity of the BF-2's known signal shaping. Producing a more " interesting " noise is the primary
concern.
 YES
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Racer X
Silver Member
USA
299 Posts |
Posted - 10/07/2008 : 15:38:55
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quote:
Originally posted by happyplucker
if thiats the case, why dont they just try it?
Because he is smart enough to realize that he could end up with
a purple paper weight. And should the experimental trimmer tweeking result in useless fecal matter he would like to have a properly functioning unit. Trimmer adjustments such as these pretty much nessecitate a scope to sync clock pulses.
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/07/2008 : 16:14:06
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Hi Racer X & Guys
As a great man (Laurie) once wrote:
(Well...... not his exact words)
Carefully pull out the original Trim Pots,
Measure them.
Label a small plastic bag or container.
Put them in a safe place.
Buy some replacement Trim Pots
Solder the replacements into place, & trim away.
If it all turns to fecal  matter...
You can then always replace the original pots.
Regards Dr. Bob
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Racer X
Silver Member
USA
299 Posts |
Posted - 10/07/2008 : 16:17:29
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That is intuitively obvious to even the most casual observer.
Why didn't I think of that ?
Laurie, you would have made a good Radar tech.
Thanks Dr. Bob. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/07/2008 : 16:34:56
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Prefer to fly underneath the radar
(but thank you!) |
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verivorax
Platinum Member
Canada
1185 Posts |
Posted - 10/07/2008 : 17:25:50
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so it was a bad idea for me to tweak the trims while I was playing through it?
I marked the original position, and moved them (just the clock, if I recall) just until the sound got mega-bendy - I'd say like a VB-2 but I haven't heard one yet...yet.. (but maybe soon...). I put the pots back to the marked positions and everything was, and is, AOK.
mind you, that was a few years ago when MIJ BF-2s were relatively everywhere..and cheapy too. |
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 10/07/2008 : 17:33:03
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I think the main limitation comes from the pcb, the BBDs and how fast you could clock them.
Theoretically you could convert a BF-2 to HF-2 just by overclocking. However, the BF-2 board is not built for signals in the MHz range.
At higher speeds the clock signal is heavily lowpass filtered and the clock transitions are not very well defined. This is how it looks on the BF2 with manual at 0%.
For the conversion to HF-2 you will need a clock speed of ~ 1 MHz, which might be possible if you use a buffer.
It is easier to change the BBD chip with one that has lower number of stages like the MN3004, if you could find one, that is. |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 10/07/2008 : 22:42:02
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quote:
Originally posted by cctsim
For the conversion to HF-2 you will need a clock speed of ~ 1 MHz, which might be possible if you use a buffer.
It is easier to change the BBD chip with one that has lower number of stages like the MN3004, if you could find one, that is.
If you swap out the BBD chip to a MN3204 (iirc mn3004 are out of production) you'll get something closer to a Bass Flanger. (followed by C7->.01, C6->.015)
The HF2 and BF2B has half the delay speed, making them more suitable for rhythm. Also the HF2 has an added second tone path for the octave up. A MN3209 has an even lower speed of 256, and a MN3308 has 2048.
Leave the trimpot in the lower corner alone and mark and twist away with the other two. Saw one mod with a pot mounted on the side |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/08/2008 : 06:18:54
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Just a word of caution Guys
If my old memory still serves me well?
I believe the Supply pins were swapped on some of the BBD devices.
Get the datasheets, & double check, to be 100% safe.
Regards Dr. Bob |
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Topic |
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Trimmer Fun
