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Forums - Synths & synthesis
Subject: Help! - TB-303 Sequencer Timing Not Perfect
Viewing all 9 messages - View by pages of 10: 1
Original Message 1/9 07-Nov-00 @ 07:14 AM - Help! - TB-303 Sequencer Timing Not Perfect
Can anyone advise me?
I've just bought a TB-303 and at first I thought everything was OK.
The sequencer timing seems to drift slightly(whether running it by itself OR syncing it with a MIDI-Sync 24 converter) and then right itself after a couple of bars. But the timing glitch seems so small I'm not sure whether or not I have a problem or if all 303's do the same thing.
I spoke to the enginner of the company I bought it from and he reckons that it's a common thing with analogue sequencers from the 1980's.
Can anyone let me know if they've encountered similar problems with their 303?
Many Thanks,
DAN
I've just bought a TB-303 and at first I thought everything was OK.
The sequencer timing seems to drift slightly(whether running it by itself OR syncing it with a MIDI-Sync 24 converter) and then right itself after a couple of bars. But the timing glitch seems so small I'm not sure whether or not I have a problem or if all 303's do the same thing.
I spoke to the enginner of the company I bought it from and he reckons that it's a common thing with analogue sequencers from the 1980's.
Can anyone let me know if they've encountered similar problems with their 303?
Many Thanks,
DAN
Message 2/9 07-Nov-00 @ 10:03 AM - RE: Help! - TB-303 Sequencer Timing Not Perfect
I have had no problems like this, well actually once... but I programmed a really wierd pattern which gave a slight impression it was off sync.Oh well, next....
Message 3/9 07-Nov-00 @ 04:34 PM - RE: Help! - TB-303 Sequencer Timing Not Perfect
The one i got to play with for a day didn't drift at all.Dude practically had to beat me up to get me away from the thing.
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Osc drift but seq usually dont.Are you talking milleseconds of drift?If you are used to a computer sequencer w/384ppq resolution and swith to 24ppq you might think it's drifting,never heard of this.
ASK TREV
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Osc drift but seq usually dont.Are you talking milleseconds of drift?If you are used to a computer sequencer w/384ppq resolution and swith to 24ppq you might think it's drifting,never heard of this.ASK TREV
Message 4/9 07-Nov-00 @ 06:36 PM - RE: Help! - TB-303 Sequencer Timing Not Perfect
If the sequencer timing is drifting so much that it's quite noticable, then you do have a problem with your 303 - and the people you bought it from are bullshitting you. Just because it's analogue it doesn't mean it's going to drift about all over the place.
The timing pulses for the sequencer are generated from a little clock circuit near the microprocessor. This could be faulty. Maybe the tempo pot is scratchy / noisy. This would cause the sequencer timing to wobble about. Or bad joint / loose component on the board. Something intermittent. Dirty switch contacts inside the sync socket.
In fact there's a whole load of factors that could be the cause that I can think of, starting as far back as the power supply.
I'd have to listen to it.
I'd be happy to take a look at this 303 and repair it for you if necessary. I'm in the uk also (Manchester).
Trev
The timing pulses for the sequencer are generated from a little clock circuit near the microprocessor. This could be faulty. Maybe the tempo pot is scratchy / noisy. This would cause the sequencer timing to wobble about. Or bad joint / loose component on the board. Something intermittent. Dirty switch contacts inside the sync socket.
In fact there's a whole load of factors that could be the cause that I can think of, starting as far back as the power supply.
I'd have to listen to it.
I'd be happy to take a look at this 303 and repair it for you if necessary. I'm in the uk also (Manchester).
Trev
Message 5/9 07-Nov-00 @ 06:38 PM - RE: Help! - TB-303 Sequencer Timing Not Perfect
oh, you say it does it when synced with a MIDI - sync converter? Oh, shit, didn't read that first time. Uh not quite sure then. Not without listening to it.
Trev
Trev
Message 6/9 07-Nov-00 @ 06:45 PM - RE: Help! - TB-303 Sequencer Timing Not Perfect
I can say that, due to the fact that the microprocessor checks the state of the tempo clock only about 500 times a second (the frequency of it's interrupt clock) you will get a very, VERY slight 'swing' to the sequence. Only a few mS mind, probably not noticable.
But it won't go out of sync.
trev (complete sad bastard, I know)
But it won't go out of sync.
trev (complete sad bastard, I know)
Message 7/9 07-Nov-00 @ 10:01 PM - RE: Help! - TB-303 Sequencer Timing Not Perfect
are you making any progress on my midi clock box?
-;) Drop the clone clown.
-;) Drop the clone clown.
Message 8/9 08-Nov-00 @ 05:39 AM - RE: Help! - TB-303 Sequencer Timing Not Perfect
Hi Trev,
Thanks for the reply...
Please bear in mind the 303 never loses Sync, it just sounds like it varying tempo by a very small amount. But I CAN hear something happening.
I just don't know whether it's my "sharp" perception and therefore I'd find it happenning on all 303's, or if I have a problem that's so slight that it's difficult to prove there is actually something wrong.
I phoned 10+ music equipment servicing companies and this is roughly what they said:
Panic Music: They do all definitely drift a bit. Try turning the Tempo control to both extremes a few times otherwise it might need cleaning. But reassured me that they do ALL drift.
Service Zone: They shouldn't drift at all
Music Control: Most 303's drift slightly and can sound worse the higher the BPM
Synthesiser Service Centre: (First Bloke) Yes they do drift by a very small amount. Then asks someone else. (Second bloke) No they don't drift?????
Cimple Solution: Guy speaks with his boss and they both reckon it's probably inherent in the bad spec/design of the 303, and it wouldn't surprise them.
Engineer Reccomended by Roland: No they shouldn't drift. But also reckons it's just a coincidence that the sequencer seems to drift by the same amount regardless of whether it's being run stand-alone or being synced.
Some Other Engineer: It's probably your Doepfer MAUSI CV Converter/MIDI-Sync 24 box as I don't think they're made to a very high spec????
So as you can see I got really pissed off with all these conflicting opinions.
But on listening closer I'm not convinced that the problem is a timing drift. Is it possible that the VCA isn't opening quick enough.
I now think that the problem actually sounds like the attack is slower (being lengthened). I know the 303 doesn't have an attack control but that's what it sounds like.
Sounds seem to become less percussive and then more prercussive which is what I think is giving me the impression of speeding up and slowing down.
Does THIS happen on all 303's bearing in mind that the problem is very small?
Cheers,
DAN
PS. What a day. I'm fucking worn out worrying about whether I've been sold a dud 303.
Thanks for the reply...
Please bear in mind the 303 never loses Sync, it just sounds like it varying tempo by a very small amount. But I CAN hear something happening.
I just don't know whether it's my "sharp"
perception and therefore I'd find it happenning on all 303's, or if I have a problem that's so slight that it's difficult to prove there is actually something wrong.I phoned 10+ music equipment servicing companies and this is roughly what they said:
Panic Music: They do all definitely drift a bit. Try turning the Tempo control to both extremes a few times otherwise it might need cleaning. But reassured me that they do ALL drift.
Service Zone: They shouldn't drift at all
Music Control: Most 303's drift slightly and can sound worse the higher the BPM
Synthesiser Service Centre: (First Bloke) Yes they do drift by a very small amount. Then asks someone else. (Second bloke) No they don't drift?????
Cimple Solution: Guy speaks with his boss and they both reckon it's probably inherent in the bad spec/design of the 303, and it wouldn't surprise them.
Engineer Reccomended by Roland: No they shouldn't drift. But also reckons it's just a coincidence that the sequencer seems to drift by the same amount regardless of whether it's being run stand-alone or being synced.
Some Other Engineer: It's probably your Doepfer MAUSI CV Converter/MIDI-Sync 24 box as I don't think they're made to a very high spec????
So as you can see I got really pissed off with all these conflicting opinions.
But on listening closer I'm not convinced that the problem is a timing drift. Is it possible that the VCA isn't opening quick enough.
I now think that the problem actually sounds like the attack is slower (being lengthened). I know the 303 doesn't have an attack control but that's what it sounds like.
Sounds seem to become less percussive and then more prercussive which is what I think is giving me the impression of speeding up and slowing down.
Does THIS happen on all 303's bearing in mind that the problem is very small?
Cheers,
DAN
PS. What a day. I'm fucking worn out worrying about whether I've been sold a dud 303.
Message 9/9 08-Nov-00 @ 09:10 AM - RE: Help! - TB-303 Sequencer Timing Not Perfect
Put it this way, I would really, really have to listen to your 303 first before I could make any conclusions. You're in the
UK, so where about are you? Could you record a .wav or mp3 file for me? Or are you very far from me? The problem is that
it's very difficult to give you a straight answer without hearing how your particular 303 actually sounds.
The simple answer is YES, the 303's internal sequencer clock WILL quite naturally drift to some extent; it doesn't use a
crystal reference, rather it relies on simple resistor / capacitor timing, and it will therefore be quite succeptable
to temperature variations. It's absolute nonsense to say that it won't drift. HOWEVER, it should NOT drift to the extent
that you'd actually be able to hear the variations. So the answer is technically 'yes', but actually 'no' because the drift
is actually so small that you won't notice it!!! Unless, of course, your 303 is faulty in some way, and the clock is drifting
quite a lot, possibly due to a scratchy tempo potentiometer.
Anyway, the fact that it also does it when you're syncing it to something else rules out a faulty / drifting tempo clock.
No, there won't be anything wrong with your midi/sync converter. The fact that it does it both of it's internal clock and
from midi clock tells us that it's not either clock source that's to blame. Yes, it sounds like it's something in the analoge voice section itself. If the 303 came out of sync, i.e. if it skipped/lagged on a note, it would NOT correct itself. For it to 'appear to lose sync momentarily', but NOT actually go out of sync, some notes are maybe not sounding as they should for some reason. Like you say, the sound becoming less percussive and then more percussive. No, I don't think this should happen. Depends how servere it is. I'd need to hear it.
Hang on... are you absolutely sure that all the six voice pots along the top are in good nick? You may say yes, but are you positive? I actually had my 303 for a few months before realising that the decay pot was going faulty. A tiny hairline crack
on the carbon track inside the pot was losing contact intermittently, and this caused the sound to jump suddenly from a slow to fast decay. This sounded most irritating, and sounded very similar to what you describe. A dodgy filter env mod pot could cause the attack to appear to vary. When your 303 is running, touch each control knob very lightly and see if each one has any effect. Believe me, this is a very likely cause because those six pots are one of the first set of components to fail, they are pretty cheap and nasty, get dirty, and after a lot of heavy-handed use the little tracks inside them can be worn or become split. I had to replace all six on mine.
Trev
UK, so where about are you? Could you record a .wav or mp3 file for me? Or are you very far from me? The problem is that
it's very difficult to give you a straight answer without hearing how your particular 303 actually sounds.
The simple answer is YES, the 303's internal sequencer clock WILL quite naturally drift to some extent; it doesn't use a
crystal reference, rather it relies on simple resistor / capacitor timing, and it will therefore be quite succeptable
to temperature variations. It's absolute nonsense to say that it won't drift. HOWEVER, it should NOT drift to the extent
that you'd actually be able to hear the variations. So the answer is technically 'yes', but actually 'no' because the drift
is actually so small that you won't notice it!!! Unless, of course, your 303 is faulty in some way, and the clock is drifting
quite a lot, possibly due to a scratchy tempo potentiometer.
Anyway, the fact that it also does it when you're syncing it to something else rules out a faulty / drifting tempo clock.
No, there won't be anything wrong with your midi/sync converter. The fact that it does it both of it's internal clock and
from midi clock tells us that it's not either clock source that's to blame. Yes, it sounds like it's something in the analoge voice section itself. If the 303 came out of sync, i.e. if it skipped/lagged on a note, it would NOT correct itself. For it to 'appear to lose sync momentarily', but NOT actually go out of sync, some notes are maybe not sounding as they should for some reason. Like you say, the sound becoming less percussive and then more percussive. No, I don't think this should happen. Depends how servere it is. I'd need to hear it.
Hang on... are you absolutely sure that all the six voice pots along the top are in good nick? You may say yes, but are you positive? I actually had my 303 for a few months before realising that the decay pot was going faulty. A tiny hairline crack
on the carbon track inside the pot was losing contact intermittently, and this caused the sound to jump suddenly from a slow to fast decay. This sounded most irritating, and sounded very similar to what you describe. A dodgy filter env mod pot could cause the attack to appear to vary. When your 303 is running, touch each control knob very lightly and see if each one has any effect. Believe me, this is a very likely cause because those six pots are one of the first set of components to fail, they are pretty cheap and nasty, get dirty, and after a lot of heavy-handed use the little tracks inside them can be worn or become split. I had to replace all six on mine.
Trev
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