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Goran
Double Platinum Member
Sweden
2203 Posts |
 Posted - 01/30/2006 : 10:43:27
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Many of the rarer delays, flangers, choruses have BBD-chips in them.
Are these replaceable if they broke?
Are the easily found?
Can we suspect this happen to the above pedals because of age (like electrolytics probably be dead after 15-20 years or so)?
This was actualised by a RBF10 I bought recently, the unaffected signal goes fine but the flanged signal is completely dead so I suspect that the BBD-chip is dead.
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 01/30/2006 : 11:52:33
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These very rarely break. Electrolytic capacitors die because they dry up but the BBDs (and any other transistor or integrated circuit) are Si-based devices that normally only break if they're exposed to excessive voltages.
Some of them will still break though. I think Matsushita/Panasonic still makes some variants like the MN3007 but it might be harder to find the older versions like the MN3002. In those cases I guess a bit of Internet searching will be required to find someone who still have NOS components laying around. |
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stinkfoot
Silver Member
Sweden
181 Posts |
Posted - 01/30/2006 : 12:12:00
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As bossarea said, BBD chips are becoming harder and harder to find, since most of them are no longer in production. Some of the smaller ones (with shorter delay times) are now being reproduced, thanks to a few companies like Maxon, Ibanez and Visual Sound starting to produce analog circuits in large enough numbers to make it worthwile for the chip producers. But in general, BBD chips (especially the larger chips with longer delay times) are quite scarce. And of course, the price reflects the diminishing supply...
For the average user who will only need one or two chips, combing the open market for stocks of NOS BBD chips is very rarely worth the effort - it is much easier to simply order the chips you need from someone who has already done the work for you, like Steve at Small Bear Electronics. You will of course pay a bit more for each one, but if it's for repairing a pedal you have, it will be worth it. If you plan on going into production, it's of course another story...
Luckily, BBD circuits usually don't die from age - what kills them is usually too much voltage or the wrong polarity, as well as static electricity. So there's no need to replace them as a precautionary measure.
For each BBD, there will also be a timing/clock chip that may or may not have to be replaced. Look in the schematic, and you'll see a second chip that is tied in to the main delay chip. For instance, in the first edition DM-2, the main delay chip is a MN3005 and the clock chip is a MN3101. Later versions had a MN3205 and MN3102, respectively.
/Andreas |
Edited by - stinkfoot on 01/30/2006 12:12:25 |
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BBD-chips
