Motorboating; what is it, 'why?', and how to fix it?
Motorboating is a low frequency oscillation, often due to feedback though the power supply. Coupling caps shouldn't be too big, power supply filters may have to be larger if your supply has more droop than Fender's original.
analog
Here's what causes the motorboating: The resistive divider that biases your input amplifier is coupling power supply fluctuations into the amplifier. The output amplifier draws heavy currents from the power supply, creating voltage fluctuations on the power supply, and so you have a positive feedback loop at some low frequency.
Motorboating (electronics)
Motorboating (electronics) In electronics, motorboating is a type of low frequency parasitic oscillation (unwanted cyclic variation of the output voltage) that sometimes occurs in audio and radio equipment and often manifests itself as a sound similar to an idling motorboat engine, a "put-put-put", in audio output from speakers or earphones. [1 ...
best way to diagnose motorboating?
Re: best way to diagnose motorboating? by Alexo » Mon Sep 08, 2008 8:31 pm Motorboating can be caused by having resistors of too low a value in the B+ supply. I.e. if you have a 1K5 between two preamp stages' filter caps, you may get motorboating that could go away if that R was increased to 10K.
Motorboating: What exactly is it?
Motorboating is a low frequency oscillation. There are numerous causes. Many are related to capacitors or high impedance power supplies (flat batteries). You need to look at the supply rails to see if they are fluctuating in time to with the motorboating because one cause is coupling between the amplifier and the power supply -- this can ...
Is this motorboating and how do I control it
Nov 17, 2012. #3. if you have an esr meter check the other power supply caps,I had a Scott amp that had a bad power supply cap that would motorboat at line voltage,but when lowered it otherwise worked well,if you don't have an esr meter,or cap tester,you can measure the ac voltage across the caps to check them.
Tube Amp Motorboating
Thanks Aart!This video includes a sound clip of motor-boating and discusses how to fix the problem. The problem is generally found in single-ended tube amps ...
Motorboating; what is it, 'why?', and how to fix it?
Hello all, Thank you for this fantastic thread. I had some quiet motor boating going on in my revisioned el84/6SN7 amp and could not figure out the problem till I found this thread mention separating the pre and g screen power supply nodes . I inserted 15k resistor and 47uF cap on the plates of...
Putt-putting sound or motorboating
Putt-putting sound or motorboating. In an amplifier that has ever worked correctly once, motorboating is almost always a signal that the decoupling capacitors in the B+ lines of the preamp section are going high impedance, not decoupling properly. Replace the B+ decoupling capacitors at least for the preamp. Since the other capacitors are old ...
When Good Amps Go Bad
This can result in increased hum, loss of low frequency response, low gain, and sometime a phenomenon known as motorboating, in which the amp makes a continued popping or putting sound.
Amplifier Stability
Amplifier Stability. An amplifier is only an oscillator waiting for the chance. Definitions of amplifier stability are the inverse of conditions for oscillation. Oscillations can take the form of sustained audible signals, very low frequency 'motorboating', or supersonic 'thud-hiss (distortion)'. These are frequently sensitive to control ...
Avoiding op amp "motor boating" (also known as "inadvertent positive
Haven't heard it for a while, but old audio amps used to "motorboat" when you didn't bypass things well enough and got inadvertent positive feedback. Dr. T : So they called it "motor boating" because it "sunk" the amp?
Motor Boating Caused by SS Preamp. Help!?
The MA12 input does not seem to have capacitive coupling. Personally, I would consider using this on tube amps connected to the audio lab. Especially so if the motorboating stay with the left channel output of the 8000A and the pre-amp out and power amp in of your 8000A has not been separated as per tech. manual.
Problem with amplifier.... "motorboating" noise?
The voltage from the pot is presented at the op-amp's noninverting input, the feedback resistors tell the op-amp how much gain you want, and the op-amp puts out what you gave it magnified by that gain.
Solving Tube Amplifier Motorboating with B+ Decoupling Resistors
A quick demonstration of the role power supply decoupling resistance and capacitance plays in suppressing low-frequency oscillations (motorboating). Video on this amplifier: • Designing a ...
"Motorboating" Pre Amp
Variations of current in the power amp causes the supply voltage to jump up and down. The very simple biasing of the preamp amplifies the jumping voltage causing motorboating PUT, PUT, PUT sounds. Filter the biasing of the preamp better, filter the supply voltage better or regulate the supply voltage to the preamp.
source of ''motorboating''?
What is generally considered to be the cause or source of motorboating? On my scope I see the outputs, one normal amplitude the other shorter and both traces are ''pulsing'' like motorboating. the short trace only wants to go positive and barely negative. any ideas? thanks
Solid-State Power Amplifiers
The term motorboating is used because the amplifier will produce an output that literally sounds like an idling motor boat. Motorboating is usually caused by excessive resistance in the power supply ground returns of an amplifier.
What causes "Motorboating"????
The cause of "classic" motorboating, is impedance of the power supply being too high (cap too low can do this). The theory is, that as the audio signal swings, the power supply voltage swings as well.
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A massive pipeline explosion that shot a pillar of flame toward the sky after a vehicle drove through a fence and struck an above-ground valve on Monday was not terror-related, authorities said.
Weird "Motor-boating" Problem
I'm guessing that subsonic info sets off an oscillation in a marginally stable amp which keeps going. So I'm thinking you probably have two problems here, the obvious one is the amp motorboating, but the less obvious one is whatever is producing that subsonic nonsense in the first place.
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One of the final messages from the five-person crew of the Titan submersible before it imploded, killing all inside, was "all good here", a hearing has revealed.
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Nine people, including a child, have been killed after handheld pagers used by members of the armed group Hezbollah to communicate exploded across Lebanon, the country's health minister says.
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Tito Jackson, an original member of the Jackson 5 pop group and brother of the late Michael Jackson, has died aged 70, US media report. An official cause of death is yet to be determined.
FOUND: Cause of motorboating on Stromberg-Carlson ASR-433 phono stage
Well, it took long enough- but I found it. I have a Stromberg-Carlson ASR-433 that I've been tinkering with for quite a while- and it's always had a problem with phono stage- if the volume and bass were cranked above a certain point, the phono stage would start to motorboat (at about 4Hz or so...
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Motorboating is a low frequency oscillation, often due to feedback though the power supply. Coupling caps shouldn't be too big, power supply filters may have to be larger if your supply has more droop than Fender's original.
Here's what causes the motorboating: The resistive divider that biases your input amplifier is coupling power supply fluctuations into the amplifier. The output amplifier draws heavy currents from the power supply, creating voltage fluctuations on the power supply, and so you have a positive feedback loop at some low frequency.
Motorboating (electronics) In electronics, motorboating is a type of low frequency parasitic oscillation (unwanted cyclic variation of the output voltage) that sometimes occurs in audio and radio equipment and often manifests itself as a sound similar to an idling motorboat engine, a "put-put-put", in audio output from speakers or earphones. [1 ...
Re: best way to diagnose motorboating? by Alexo » Mon Sep 08, 2008 8:31 pm Motorboating can be caused by having resistors of too low a value in the B+ supply. I.e. if you have a 1K5 between two preamp stages' filter caps, you may get motorboating that could go away if that R was increased to 10K.
Motorboating is a low frequency oscillation. There are numerous causes. Many are related to capacitors or high impedance power supplies (flat batteries). You need to look at the supply rails to see if they are fluctuating in time to with the motorboating because one cause is coupling between the amplifier and the power supply -- this can ...
Nov 17, 2012. #3. if you have an esr meter check the other power supply caps,I had a Scott amp that had a bad power supply cap that would motorboat at line voltage,but when lowered it otherwise worked well,if you don't have an esr meter,or cap tester,you can measure the ac voltage across the caps to check them.
Thanks Aart!This video includes a sound clip of motor-boating and discusses how to fix the problem. The problem is generally found in single-ended tube amps ...
Hello all, Thank you for this fantastic thread. I had some quiet motor boating going on in my revisioned el84/6SN7 amp and could not figure out the problem till I found this thread mention separating the pre and g screen power supply nodes . I inserted 15k resistor and 47uF cap on the plates of...
Putt-putting sound or motorboating. In an amplifier that has ever worked correctly once, motorboating is almost always a signal that the decoupling capacitors in the B+ lines of the preamp section are going high impedance, not decoupling properly. Replace the B+ decoupling capacitors at least for the preamp. Since the other capacitors are old ...
This can result in increased hum, loss of low frequency response, low gain, and sometime a phenomenon known as motorboating, in which the amp makes a continued popping or putting sound.
Amplifier Stability. An amplifier is only an oscillator waiting for the chance. Definitions of amplifier stability are the inverse of conditions for oscillation. Oscillations can take the form of sustained audible signals, very low frequency 'motorboating', or supersonic 'thud-hiss (distortion)'. These are frequently sensitive to control ...
Haven't heard it for a while, but old audio amps used to "motorboat" when you didn't bypass things well enough and got inadvertent positive feedback. Dr. T : So they called it "motor boating" because it "sunk" the amp?
The MA12 input does not seem to have capacitive coupling. Personally, I would consider using this on tube amps connected to the audio lab. Especially so if the motorboating stay with the left channel output of the 8000A and the pre-amp out and power amp in of your 8000A has not been separated as per tech. manual.
The voltage from the pot is presented at the op-amp's noninverting input, the feedback resistors tell the op-amp how much gain you want, and the op-amp puts out what you gave it magnified by that gain.
A quick demonstration of the role power supply decoupling resistance and capacitance plays in suppressing low-frequency oscillations (motorboating). Video on this amplifier: • Designing a ...
Variations of current in the power amp causes the supply voltage to jump up and down. The very simple biasing of the preamp amplifies the jumping voltage causing motorboating PUT, PUT, PUT sounds. Filter the biasing of the preamp better, filter the supply voltage better or regulate the supply voltage to the preamp.
What is generally considered to be the cause or source of motorboating? On my scope I see the outputs, one normal amplitude the other shorter and both traces are ''pulsing'' like motorboating. the short trace only wants to go positive and barely negative. any ideas? thanks
The term motorboating is used because the amplifier will produce an output that literally sounds like an idling motor boat. Motorboating is usually caused by excessive resistance in the power supply ground returns of an amplifier.
The cause of "classic" motorboating, is impedance of the power supply being too high (cap too low can do this). The theory is, that as the audio signal swings, the power supply voltage swings as well.
A massive pipeline explosion that shot a pillar of flame toward the sky after a vehicle drove through a fence and struck an above-ground valve on Monday was not terror-related, authorities said.
I'm guessing that subsonic info sets off an oscillation in a marginally stable amp which keeps going. So I'm thinking you probably have two problems here, the obvious one is the amp motorboating, but the less obvious one is whatever is producing that subsonic nonsense in the first place.
One of the final messages from the five-person crew of the Titan submersible before it imploded, killing all inside, was "all good here", a hearing has revealed.
Nine people, including a child, have been killed after handheld pagers used by members of the armed group Hezbollah to communicate exploded across Lebanon, the country's health minister says.
Tito Jackson, an original member of the Jackson 5 pop group and brother of the late Michael Jackson, has died aged 70, US media report. An official cause of death is yet to be determined.
Well, it took long enough- but I found it. I have a Stromberg-Carlson ASR-433 that I've been tinkering with for quite a while- and it's always had a problem with phono stage- if the volume and bass were cranked above a certain point, the phono stage would start to motorboat (at about 4Hz or so...