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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Tascam DR-05 ticking noises
I have two Tascam DR-05 recorders and they both exhibit the same
phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. The noise only occurs if the recording gain is set low; as soon as it is advanced, the noise floor of the pre-amp is enough to stop the effect (it doesn't need to be high enough to mask it). it isn't audible on the headphone monitoring port, even if that is connected to the input of a high gain amplifier; it only shows up when the recording is played back. Can anyone suggest why this is occurring (bearing in mind that it only affects the left channel) and can anyone suggest a cure? -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#2
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Tascam DR-05 ticking noises
This is a SWAG - and based on personal history.
Back in the day, I had a Tandberg 10" machine, TOL for its day. However, and despite two trips to their Armonk, NY service location, it would 'tick' as you describe on the left channel, and in Fast Forward in a dry room, would shoot sparks from static electricity from the tape to the tape head. I actually drove to Armonk and demonstrated the phenomenon that they stated was impossible. Did not matter which tape was used either. I traded it in on a Revox and never looked back. So, check all your grounding, your patch cords and so forth. That is the best I can suggest off-hand. Best of luck! Peter Wieck Melrose Park, PA |
#4
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Tascam DR-05 ticking noises
In article d.invalid,
Adrian Tuddenham wrote: I've had similar experiences with static electricity on the drive belts of some tape machines, but this is a hand-held digital recorder with no moving parts. It makes the noises even with a short double-ended 3.5mm stereo jack lead in the input socket and nothing connected to the far end. If the lead is plugged into a passive mixer, the result is just the same and if it is connected to a grounded mains-powered mixer, the result is still the same. I don't think static electricity or anything to do with grounding can be the problem. Is it possible to download the resulting digital recording, and examine the waveform with Audacity or a similar tool? A ticking sound might be the result of a one-sample error - either a single bad sample (which would show up as a vertical "tick" on the waveform), or a missing or duplicated sample (which would show up as a vertical jump in the waveform, or a sudden flat spot). In either case, "clocking errors" are what comes to mind for me... a synchronization problem in the analog-to-digital/storage process. Years ago, there used to be a fairly common problem of this sort with long-distance phone calls, where the calls were being transmitted in digital format between phone switches whose internal clocks/oscillators were not properly synchronized. One would be running faster than the other, and occasionally (every few seconds) the difference between the clocks would cause one audio sample to be dropped or duplicated. This resulted in an almost-inaudible "tick" sound. Not a problem for voice calls, really. However, for modem connections (e.g. V.32) which were sensitive to signal phase, it was enough to cause a one-bit error in the data, resulting in a spurious character appearing (most commonly "}" if I recall correctly). If V.42 error control was turned on, the error was detected and the data packet re-sent, so you wouldn't see the bad data, but the retransmission slowed down the connection significantly. |
#5
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Tascam DR-05 ticking noises
AUTO LEVEL
Using this function, the recording level is automatically increased when the input sound is too quiet or decreased when it is too loud. This function is useful for recording meetings, for example. In this mode, the recording level cannot be changed manually. Precautions for placement and use * The environmental temperature operating range of this unit is 0€“40°C (32€“104°F). * Do not install this unit in the following types of locations. Doing so could degrade the sound quality and/or cause malfunctions. Places with significant vibrations Near windows or other places exposed to direct sunlight Near heaters or other extremely hot places Extremely cold places Places with bad ventilation or high humidity Very dusty locations. * If this unit is placed near a power amplifier or other device with a large transformer, it could cause a hum. If this occurs, increase the distance between this unit and the other device. * This unit could cause color irregularities on a TV screen or noise from a radio if used nearby. If this occurs, use this unit farther away. * This unit might produce noise if a mobile phone or other wireless device is used nearby to make calls or send or receive signals. If this occurs, increase the distance between this unit and those devices or turn them off. * To enable good heat dissipation, do not place anything on top of this unit. * Do not place this unit on top of a power amplifier or other device that generates heat. Beware of condensation If the unit is moved from a cold to a warm place, or used after a sudden temperature change, there is a danger of condensation; vapor in the air could condense on the internal mechanism, making correct operation impossible. To prevent this, or if this occurs, let the unit sit for one or two hours at the new room temperature before using it. __________________________________________________ __________ All of the above suggests that this is an acutely sensitive device. You mention that the ticking happens only when something is plugged in, even if that something is inactive or not plugged in itself. Again, just for giggles, try shorting the inputs, left and right (not left to right). The internal architecture may cause these artifacts to favor the left channel over the right, and I actually find it encouraging that both units display identical behavior. But, what it comes down to if a problem is associated with a specific set of conditions - avoid those conditions moving forward. If shorting the not-otherwise-connected input cord make a change, then you have found the problem. If the problem is associated with the AGC (when the mics are off), you have found the problem. And so forth. Best of luck, again. Peter Wieck Melrose Park, PA |
#6
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Tascam DR-05 ticking noises
On 12-11-2018 17:50, Adrian Tuddenham wrote:
I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. The noise only occurs if the recording gain is set low; as soon as it is advanced, the noise floor of the pre-amp is enough to stop the effect (it doesn't need to be high enough to mask it). it isn't audible on the headphone monitoring port, even if that is connected to the input of a high gain amplifier; it only shows up when the recording is played back. Can anyone suggest why this is occurring (bearing in mind that it only affects the left channel) and can anyone suggest a cure? Oscillating a bit somewhere? |
#7
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Tascam DR-05 ticking noises
Sjouke Burry wrote:
On 12-11-2018 17:50, Adrian Tuddenham wrote: I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. The noise only occurs if the recording gain is set low; as soon as it is advanced, the noise floor of the pre-amp is enough to stop the effect (it doesn't need to be high enough to mask it). it isn't audible on the headphone monitoring port, even if that is connected to the input of a high gain amplifier; it only shows up when the recording is played back. Can anyone suggest why this is occurring (bearing in mind that it only affects the left channel) and can anyone suggest a cure? Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#8
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Tascam DR-05 ticking noises
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#9
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Tascam DR-05 ticking noises
On 13-11-2018 0:18, Adrian Tuddenham wrote:
Sjouke Burry wrote: On 12-11-2018 17:50, Adrian Tuddenham wrote: I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. The noise only occurs if the recording gain is set low; as soon as it is advanced, the noise floor of the pre-amp is enough to stop the effect (it doesn't need to be high enough to mask it). it isn't audible on the headphone monitoring port, even if that is connected to the input of a high gain amplifier; it only shows up when the recording is played back. Can anyone suggest why this is occurring (bearing in mind that it only affects the left channel) and can anyone suggest a cure? Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. |
#10
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Tascam DR-05 ticking noises
In article ,
Sjouke Burry wrote: On 13-11-2018 0:18, Adrian Tuddenham wrote: Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. |
#11
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Tascam DR-05 ticking noises
Dave Platt wrote:
In article , Sjouke Burry wrote: On 13-11-2018 0:18, Adrian Tuddenham wrote: Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. That could be the sort of thing that is happening - but I wonder why it comes on after about a second's delay? Demonstration at: www.wrightshardware.co.uk/Other/DR0002_0276.wav ....beware loud clicks! -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#12
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Tascam DR-05 ticking noises
On 13/11/2018 10:59, Adrian Tuddenham wrote:
Dave Platt wrote: In article , Sjouke Burry wrote: On 13-11-2018 0:18, Adrian Tuddenham wrote: Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. That could be the sort of thing that is happening - but I wonder why it comes on after about a second's delay? Demonstration at: www.wrightshardware.co.uk/Other/DR0002_0276.wav ....beware loud clicks! Any chance of cutting a couple of traces and jumpering/swapping left and right to see if the problem swaps channel or stays the same? The mystery ticking noise I had long ago was with magnetic tape car cassette player, no record function, would overlay ticks on pre-recorded tapes. A small bit of ferrite/magnet buried in the pinchwheel rubber was the cause there. |
#13
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Tascam DR-05 ticking noises
On Monday, November 12, 2018 at 11:50:19 AM UTC-5, Adrian Tuddenham wrote:
I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. The noise only occurs if the recording gain is set low; as soon as it is advanced, the noise floor of the pre-amp is enough to stop the effect (it doesn't need to be high enough to mask it). it isn't audible on the headphone monitoring port, even if that is connected to the input of a high gain amplifier; it only shows up when the recording is played back. Can anyone suggest why this is occurring (bearing in mind that it only affects the left channel) and can anyone suggest a cure? -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk Is there a Tascam specific web group? With two of these doing the exact same *weird* and specific problem, sounds like a design issue. |
#14
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Tascam DR-05 ticking noises
On Mon, 12 Nov 2018 16:50:02 +0000,
lid (Adrian Tuddenham) wrote: Can anyone suggest why this is occurring (bearing in mind that it only affects the left channel) and can anyone suggest a cure? I would guess(tm) that the "ticks" are coming from something outside of the recorder. Try testing it again at a different location. If the "ticks" go away, look around at your original location for suitable culprit. Periodic noises are fairly easy, but random is difficult. For example, I just found a similar problem that was caused by RF noise from an ultrasonic mouse and rat repeller: http://www.victorpest.com/store/rat-control/ultrasonics The device produces random ultrasonic noises and whatever was doing the randomizing was also producing random bursts of RF noise. You might have something similar happening. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#15
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Tascam DR-05 ticking noises
Jeff Liebermann wrote:
On Mon, 12 Nov 2018 16:50:02 +0000, lid (Adrian Tuddenham) wrote: Can anyone suggest why this is occurring (bearing in mind that it only affects the left channel) and can anyone suggest a cure? I would guess(tm) that the "ticks" are coming from something outside of the recorder. Try testing it again at a different location. I first noticed it when I was recording a brass band in a school hall and subsequently a radio play in a small studio - the test recordings were made on the kitchen table at home. It doesn't appear to be location-specific. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#16
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Tascam DR-05 ticking noises
N_Cook wrote:
On 13/11/2018 10:59, Adrian Tuddenham wrote: Dave Platt wrote: In article , Sjouke Burry wrote: On 13-11-2018 0:18, Adrian Tuddenham wrote: Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. That could be the sort of thing that is happening - but I wonder why it comes on after about a second's delay? Demonstration at: www.wrightshardware.co.uk/Other/DR0002_0276.wav ....beware loud clicks! Any chance of cutting a couple of traces and jumpering/swapping left and right to see if the problem swaps channel or stays the same? I really don't want to go butchering it, I'mrelying on it quite a bit for location recordings. The mystery ticking noise I had long ago was with magnetic tape car cassette player, no record function, would overlay ticks on pre-recorded tapes. A small bit of ferrite/magnet buried in the pinchwheel rubber was the cause there. I've had that happen with a car cassette player, the tapes got worse and worse until one day I found the cause. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#17
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Tascam DR-05 ticking noises
On Monday, November 12, 2018 at 11:50:19 AM UTC-5, Adrian Tuddenham wrote:
I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. To be clear, this doesn't happen when using the internal mics? What sort of "external circuit" are we talking about? If it only happens when recording silence, wouldn't that be easily mitigated with post production software? But if it's a design problem, I would try adding an osc signal above audible frequencies at low levels right at the input jack. Should have no effect on the recorded audio and may be enough to keep the phenomenon from happening. If there's no room inside the Tascam, maybe you can add it to the external circuit. |
#18
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Tascam DR-05 ticking noises
On 13/11/2018 18:00, Adrian Tuddenham wrote:
N_Cook wrote: On 13/11/2018 10:59, Adrian Tuddenham wrote: Dave Platt wrote: In article , Sjouke Burry wrote: On 13-11-2018 0:18, Adrian Tuddenham wrote: Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. That could be the sort of thing that is happening - but I wonder why it comes on after about a second's delay? Demonstration at: www.wrightshardware.co.uk/Other/DR0002_0276.wav ....beware loud clicks! Any chance of cutting a couple of traces and jumpering/swapping left and right to see if the problem swaps channel or stays the same? I really don't want to go butchering it, I'mrelying on it quite a bit for location recordings. The mystery ticking noise I had long ago was with magnetic tape car cassette player, no record function, would overlay ticks on pre-recorded tapes. A small bit of ferrite/magnet buried in the pinchwheel rubber was the cause there. I've had that happen with a car cassette player, the tapes got worse and worse until one day I found the cause. Do you use batteries or what used to be oddly called "battery eliminators" to power the recorders? |
#19
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Tascam DR-05 ticking noises
On 13/11/2018 19:17, John-Del wrote:
On Monday, November 12, 2018 at 11:50:19 AM UTC-5, Adrian Tuddenham wrote: I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. To be clear, this doesn't happen when using the internal mics? What sort of "external circuit" are we talking about? If it only happens when recording silence, wouldn't that be easily mitigated with post production software? But if it's a design problem, I would try adding an osc signal above audible frequencies at low levels right at the input jack. Should have no effect on the recorded audio and may be enough to keep the phenomenon from happening. If there's no room inside the Tascam, maybe you can add it to the external circuit. Even if it had to be sub 20K , then it could be knotched out quite easily as only low level anyway and doubtful whether anyone would know. |
#20
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Tascam DR-05 ticking noises
In article .invalid, Adrian Tuddenham wrote: That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. That could be the sort of thing that is happening - but I wonder why it comes on after about a second's delay? Demonstration at: www.wrightshardware.co.uk/Other/DR0002_0276.wav ...beware loud clicks! Looking at that file, I see three sets of noisy impulses... two negative-going and one positive-going. They're present in both channels - similar but not identical waveforms in the two channels. There's a very sharp leading edge (rise time is two or three samples) and then a much slower fall, with some ringing. The signal takes about 40 milliseconds to fall back to zero, and then overshoots. This doesn't look like a one-sample error on the digital-storage side of things - it's not just a brief impulse. It appears to me that something is spiking the input to the ADC pretty hard, and that this glitch is getting into both ADC inputs. The fact that the pulse and ringing is slightly different, between the two channels, suggests that it's not just a single sample of bad data in the ADC being blurred out by the ADC's filters. Is this .WAV exactly as it came out of the recorder, or did you adjust it (e.g. gain-boost for visibility) in any way? |
#21
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Tascam DR-05 ticking noises
N_Cook wrote:
On 13/11/2018 18:00, Adrian Tuddenham wrote: N_Cook wrote: On 13/11/2018 10:59, Adrian Tuddenham wrote: Dave Platt wrote: In article , Sjouke Burry wrote: On 13-11-2018 0:18, Adrian Tuddenham wrote: Oscillating a bit somewhere? That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. That could be the sort of thing that is happening - but I wonder why it comes on after about a second's delay? Demonstration at: www.wrightshardware.co.uk/Other/DR0002_0276.wav ....beware loud clicks! Any chance of cutting a couple of traces and jumpering/swapping left and right to see if the problem swaps channel or stays the same? I really don't want to go butchering it, I'mrelying on it quite a bit for location recordings. The mystery ticking noise I had long ago was with magnetic tape car cassette player, no record function, would overlay ticks on pre-recorded tapes. A small bit of ferrite/magnet buried in the pinchwheel rubber was the cause there. I've had that happen with a car cassette player, the tapes got worse and worse until one day I found the cause. Do you use batteries or what used to be oddly called "battery eliminators" to power the recorders? Two AA cells, recharged in a separate charger. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#22
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Tascam DR-05 ticking noises
Dave Platt wrote:
In article .invalid, Adrian Tuddenham wrote: That's what I was thinking, but why only on the left channel? Both recorders behave the same way. Spread in components, differences in layout causing parasitic caps an inductances to vary, take your pic. Possibly there's some occasional switching noise on a digital or power trace, which is coupled more effectively into the left-channel analog trace going to the ADC? The left-channel trace might actually be acting to shield the right-channel trace from some of the noise. That could be the sort of thing that is happening - but I wonder why it comes on after about a second's delay? Demonstration at: www.wrightshardware.co.uk/Other/DR0002_0276.wav ...beware loud clicks! Looking at that file, I see three sets of noisy impulses... two negative-going and one positive-going. They're present in both channels - similar but not identical waveforms in the two channels. There's a very sharp leading edge (rise time is two or three samples) and then a much slower fall, with some ringing. The signal takes about 40 milliseconds to fall back to zero, and then overshoots. This doesn't look like a one-sample error on the digital-storage side of things - it's not just a brief impulse. It appears to me that something is spiking the input to the ADC pretty hard, and that this glitch is getting into both ADC inputs. The fact that the pulse and ringing is slightly different, between the two channels, suggests that it's not just a single sample of bad data in the ADC being blurred out by the ADC's filters. Is this .WAV exactly as it came out of the recorder, or did you adjust it (e.g. gain-boost for visibility) in any way? Exactly as downloaded. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#23
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Tascam DR-05 ticking noises
John-Del wrote:
On Monday, November 12, 2018 at 11:50:19 AM UTC-5, Adrian Tuddenham wrote: I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. To be clear, this doesn't happen when using the internal mics? That is correct - or at least I have never noticed it. I'm guessing it is because: 1) I never use the internal mics for professional work and rarely use them at all. 2) When I do use the mics, nowhere is quiet enough to show up the effect. 3) I would record from the mics with the gain at a level where just the pre-amp noise floor prevented the effect. What sort of "external circuit" are we talking about? I tried it with a 'double-ender' 3.5mm screened jack lead about a foot long, with nothing connected to the far end. The effect also happens with the same lead plugged into a passive mixer and also on a longer lead with a built-in 12dB attenuator, fed from a powered mixer I have also used a passive distribution box with separate L and R inputs (P.O. 315 jacks) taking line level from the mic pre-amp (floating and battery-powered) and delivering signals to two 3.5mm output plugs, one attenuated by 12 dB and one by 24 dB for the two recorders. If it only happens when recording silence, wouldn't that be easily mitigated with post production software? I had to do that on one occasion, but it is time-consuming taking out the clicks by hand. I would rather tackle the problem at source if at all possible. But if it's a design problem, I would try adding an osc signal above audible frequencies at low levels right at the input jack. Should have no effect on the recorded audio and may be enough to keep the phenomenon from happening. If there's no room inside the Tascam, maybe you can add it to the external circuit. ....or add a bit of hiss to dither it. ....or add a sub-audio signal. ....or never turn the recording gain right down and let the pre-amp noise floor take care of it.. I haven't looked to see if new software is downloadable for that model - but I suspect this is more likely to be a hardware fault. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#24
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Tascam DR-05 ticking noises
On Tuesday, November 13, 2018 at 6:31:29 PM UTC-5, Adrian Tuddenham wrote:
John-Del wrote: On Monday, November 12, 2018 at 11:50:19 AM UTC-5, Adrian Tuddenham wrote: I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. To be clear, this doesn't happen when using the internal mics? That is correct - or at least I have never noticed it. I'm guessing it is because: 1) I never use the internal mics for professional work and rarely use them at all. 2) When I do use the mics, nowhere is quiet enough to show up the effect. 3) I would record from the mics with the gain at a level where just the pre-amp noise floor prevented the effect. What sort of "external circuit" are we talking about? I tried it with a 'double-ender' 3.5mm screened jack lead about a foot long, with nothing connected to the far end. The effect also happens with the same lead plugged into a passive mixer and also on a longer lead with a built-in 12dB attenuator, fed from a powered mixer I have also used a passive distribution box with separate L and R inputs (P.O. 315 jacks) taking line level from the mic pre-amp (floating and battery-powered) and delivering signals to two 3.5mm output plugs, one attenuated by 12 dB and one by 24 dB for the two recorders. If it only happens when recording silence, wouldn't that be easily mitigated with post production software? I had to do that on one occasion, but it is time-consuming taking out the clicks by hand. I would rather tackle the problem at source if at all possible. But if it's a design problem, I would try adding an osc signal above audible frequencies at low levels right at the input jack. Should have no effect on the recorded audio and may be enough to keep the phenomenon from happening. If there's no room inside the Tascam, maybe you can add it to the external circuit. ...or add a bit of hiss to dither it. ...or add a sub-audio signal. ...or never turn the recording gain right down and let the pre-amp noise floor take care of it.. \ That's true, but if my solution works, it won't require any intervention to prevent that spurious noise. Years ago, I had a customer with a Vizio flat TV that would start, run five seconds, and shut down. Turns out it was set to the PC input awaiting a timing signal, and when finding none, shut down as most computer monitors will. There was no way to change the input during the short time it was on. I connected a PC to it, it stayed on, and I put it back on "TV" mode and sent it back with instructions to be careful about switching inputs. A month later, it was back with the same problem. Seems when switching inputs to watch a DVD, they again paused over the PC input and the TV shut down. |
#25
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Tascam DR-05 ticking noises
I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. try connecting an audio signal generator do create say a 1 kHz sine tone. slowly drop the level. at some level the clicks will start. observe the tone during the clicks for clues. Does the tone change in anyway due to the clicks? Also with the external input connected to nothing, do the clicks change depending on if the external input is open vs shorted or terminated? These recorders often apply a few volts of DC power to the input to power mics. Put a scope on the input line and see if the spikes are actually present on the input line. Or connect the input to another audio input that you can listen to , do the spikes come OUT the audio input? If you apply a small DC signal to the input through a current limiting resistor , will that stop the spikes? Try both polarities? Is there a schematic available? mark |
#26
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Tascam DR-05 ticking noises
On Wednesday, November 14, 2018 at 10:23:52 AM UTC-5, wrote:
I have two Tascam DR-05 recorders and they both exhibit the same phenomenon: when they are recording complete silence, there are faint irregular ticking noises on the left channel. This occurs when using an external circuit which disconnects the internal mics, but the circuit only needs to be plugged in, not connected to anything, for it to happen. If there is any sound on the channel, the noise immediately stops, but re-starts about one second after complete silence returns. try connecting an audio signal generator do create say a 1 kHz sine tone. slowly drop the level. at some level the clicks will start. observe the tone during the clicks for clues. Does the tone change in anyway due to the clicks? Also with the external input connected to nothing, do the clicks change depending on if the external input is open vs shorted or terminated? These recorders often apply a few volts of DC power to the input to power mics. Put a scope on the input line and see if the spikes are actually present on the input line. Or connect the input to another audio input that you can listen to , do the spikes come OUT the audio input? If you apply a small DC signal to the input through a current limiting resistor , will that stop the spikes? Try both polarities? Is there a schematic available? mark also, the wave file posted shows clicks in both L and R, is it bot or just L? Also the clicks in the wav file are alternating polarity, up then down then up etc. might mean something to you mark |
#27
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Tascam DR-05 ticking noises
Can you read the IC numbers relating to preamps, then perhaps find a
generic operational problem with it, outside of Tascam. A datasheet would let you find the main rails and perhaps there is some space to add some chip caps across the rails in that arra. |
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