Followup ...can't seem to be able to edit my original post...
Why it works? Like I said...dunno but just try it yourself! I did not say to you that your el cheapo chokes could not possibly work because of their limited bandwith.
So just take my word for it. Or try it yourself.
Why would Marantz, Luxman et al use a seperate filament supply do you think? Because it did not matter? To make tha amp heavier? To make it more expensive?
Don't think so!
Why it works? Like I said...dunno but just try it yourself! I did not say to you that your el cheapo chokes could not possibly work because of their limited bandwith.
So just take my word for it. Or try it yourself.
Why would Marantz, Luxman et al use a seperate filament supply do you think? Because it did not matter? To make tha amp heavier? To make it more expensive?
Don't think so!
Whilst I have not tried this and so offer no comment. Lynn Olsen has found the same. See his notes on his web site
Aloha Audio
ciao
James
Aloha Audio
ciao
James
Joel,
the problem is the interwinding capacitance between the HT winding and any adjacent heater winding. It's typically 1nF, so the spikes as the diodes switch on and off are capacitively coupled to the heater circuit. I've observed these spikes on a 6.3V AC heater. Heater/cathode capacitance can then couple these spikes into the audio department.
Sadly, it really is worth using a separate transformer for the HT...
the problem is the interwinding capacitance between the HT winding and any adjacent heater winding. It's typically 1nF, so the spikes as the diodes switch on and off are capacitively coupled to the heater circuit. I've observed these spikes on a 6.3V AC heater. Heater/cathode capacitance can then couple these spikes into the audio department.
Sadly, it really is worth using a separate transformer for the HT...
EC8010 said:
This is called "listening to your scope". I can pick up radio waves from Jupiter as well - does that mean all broadcasts I listen to are somehow tainted? How are you gaurding your amp against sun spot emisson?
Answer this one question EC8010: are you saying you can hear diode switching when listening to your system?
Yes. That was the reason that the scope came out. There was hum, and it had a nasty buzz on it. First, I thought it was HT line hum, but then I found a nasty waveform leaving the driver stage which didn't relate to the waveform on the HT supply, so I looked at the heaters. After replacing a valve and adding some capacitors, the hum was significantly reduced, and the buzz had gone.
Bear in mind that these spikes occurred at 100Hz rate and were visible when the scope was set to display a 6.3V RMS sinewave. We're not talking about cosmic noise here, this was audio frequency hash with RF harmonics, and with significant amplitude.
Bear in mind that these spikes occurred at 100Hz rate and were visible when the scope was set to display a 6.3V RMS sinewave. We're not talking about cosmic noise here, this was audio frequency hash with RF harmonics, and with significant amplitude.
7N7 said:
There! I've done it again, made a fool of myself on the Forum. I promise to be good in future; thank you so much for pointing out the error of my ways.
Hey, don't be so hard on yourself. You're just being an ordinary human being. You should celebrate it! Imagine the weight of all that extra responsibility that the superhumans must bear saving us ordinary human beings from ourselves.
se
He Who Laughs Last, Laughs Best.
Let's get things into perspective.
The rating of 136dBA peak, is for a single frequency (in this case undefined), and that is a whole different thing to broadband music signal.
Yes, the system was going into soft self-limiting, but despite this, realistically the achieved SPL will not be 136dBA continuous on music - simple.
So, you can rest assured that my hearing is not damaged.
Spectral content is mission critical to ear survival when running at the levels attained - ear physiology is the reason here.
The resultant sound that we did get was the smoothest sound that any of us have ever heard, and this factor is important as regards hearing damage - harsh sound will break your ears, and in my experience smooth (the smoothness that we had Sat night) sound is relatively inoccuous.
You guys can scoff all you like, but this treatment really does work (and with video and RF signals too), and very clearly so, and moreover, all who have heard this (pro-audio or consumer) treatment want it for their own systems - simple as that.
Eric.
Let's get things into perspective.
The rating of 136dBA peak, is for a single frequency (in this case undefined), and that is a whole different thing to broadband music signal.
Yes, the system was going into soft self-limiting, but despite this, realistically the achieved SPL will not be 136dBA continuous on music - simple.
So, you can rest assured that my hearing is not damaged.
Spectral content is mission critical to ear survival when running at the levels attained - ear physiology is the reason here.
The resultant sound that we did get was the smoothest sound that any of us have ever heard, and this factor is important as regards hearing damage - harsh sound will break your ears, and in my experience smooth (the smoothness that we had Sat night) sound is relatively inoccuous.
You guys can scoff all you like, but this treatment really does work (and with video and RF signals too), and very clearly so, and moreover, all who have heard this (pro-audio or consumer) treatment want it for their own systems - simple as that.
Eric.
Tubes and distortion
I have heard many comments about tubes producing 1 percent distortion. That figure is a myth. It is not uncommon to see less that 0.1 percent from a vacuum tube amplifier running at full power.
3 percent distortion is the limit for most loudspeakers. Keep in mind that harmonic distortion in most cases additive.
Where the solid state amplifier hurts is at low levels. Transistors tend to be non-linear devices. The sonic artifacts are really noticable with brass instruments.
If you are a rock.n.role fan it really doesn' make much difference what you reproduce your music with. The fact is that most modern music is recorded to be played on CD Players: Boom-Boom, Tweet Tweet or worse; FM radio
I have heard many comments about tubes producing 1 percent distortion. That figure is a myth. It is not uncommon to see less that 0.1 percent from a vacuum tube amplifier running at full power.
3 percent distortion is the limit for most loudspeakers. Keep in mind that harmonic distortion in most cases additive.
Where the solid state amplifier hurts is at low levels. Transistors tend to be non-linear devices. The sonic artifacts are really noticable with brass instruments.
If you are a rock.n.role fan it really doesn' make much difference what you reproduce your music with. The fact is that most modern music is recorded to be played on CD Players: Boom-Boom, Tweet Tweet or worse; FM radio
What Noise Annoys An Oyster ?.
Sorry, I cannot agree with that statement.
Good quality replay equipment is just as important for R'n'R as it is for any other genre in my opinion, and even more so.
R'n'R typically contains a lot of 'noise' type signals, and if the replay gear is not up to the task, then a truckload more of noise and imd products are the result.
Nice clean simple recordings can sound very nice on 'bad' replay gear, but when this 'bad' replay gear is fed complex or dirty signals, the in-roon resultant goes downhill real fast ime.
A good replay system should only tell you what is on the recording, and not be reactive, nor modify or subtract information.
When the replay system is good enough, items like micophones, guitars and preamps become clearly audible.
As for live sound reinforcement systems and instrument amplifiers, clarity is mission critical too.
When done correctly, items like harmonica can sound great, and no ear bleeding.
Ditto, items like National Steel guitar, or Dobro guitars can sound great, but without the earbleeding harshness that is unfortunately the usual standard.
Live and recording microphones are unfortunately usually pretty rough sounding, and this is revealed in both live work, and replay systems, but can be cured.
I understand that speakers are typically relatively high in distortion, but it is notable that the source recording, and replay equipment are still clearly discernable despite this.
Eric.
Sorry, I cannot agree with that statement.
Good quality replay equipment is just as important for R'n'R as it is for any other genre in my opinion, and even more so.
R'n'R typically contains a lot of 'noise' type signals, and if the replay gear is not up to the task, then a truckload more of noise and imd products are the result.
Nice clean simple recordings can sound very nice on 'bad' replay gear, but when this 'bad' replay gear is fed complex or dirty signals, the in-roon resultant goes downhill real fast ime.
A good replay system should only tell you what is on the recording, and not be reactive, nor modify or subtract information.
When the replay system is good enough, items like micophones, guitars and preamps become clearly audible.
As for live sound reinforcement systems and instrument amplifiers, clarity is mission critical too.
When done correctly, items like harmonica can sound great, and no ear bleeding.
Ditto, items like National Steel guitar, or Dobro guitars can sound great, but without the earbleeding harshness that is unfortunately the usual standard.
Live and recording microphones are unfortunately usually pretty rough sounding, and this is revealed in both live work, and replay systems, but can be cured.
I understand that speakers are typically relatively high in distortion, but it is notable that the source recording, and replay equipment are still clearly discernable despite this.
Eric.
Re: Re: Tubes and distortion
You are correct. I should have been more specific:
Looking at the manufacture specification on said amplifier. A review of the tube specification is considered as well. When I test an amplifier, I look of a point where the amp shows a radical increase in harmonic distortion. Most of the time the radical increase in distortion occurs above the output tube specification.
My test method:
The unit under test is connected to a non-reactive 8-ohm load. Utilizing an audio volt meter and distortion analyzer I look for distortion products in 1-decibel steps. The test is conducted with a pure sine-wave source between 16 Hz and 10,000 Hz.
Power is determined with a true RMS voltmeter. The derived voltage, across the load is used to calculate power.
Circlotron said:
You are correct. I should have been more specific:
Looking at the manufacture specification on said amplifier. A review of the tube specification is considered as well. When I test an amplifier, I look of a point where the amp shows a radical increase in harmonic distortion. Most of the time the radical increase in distortion occurs above the output tube specification.
My test method:
The unit under test is connected to a non-reactive 8-ohm load. Utilizing an audio volt meter and distortion analyzer I look for distortion products in 1-decibel steps. The test is conducted with a pure sine-wave source between 16 Hz and 10,000 Hz.
Power is determined with a true RMS voltmeter. The derived voltage, across the load is used to calculate power.
Re: What Is The Point ?.
When loudspeaker manufacturers all make their loudspeakers to a common standard having identical impedance against frequency, we can start testing with that known load. Until then, an 8 ohm resistive load is as good a starting point as any, and shows the amplifier's best voltage performance. Having established that, we can be more unpleasant to the amplifier and impulse test it to determine current delivery. None of these tests relates to music, but they do allow testing of known engineering design faults.
What would you suggest as a test, given that a loudspeaker could be moving coil, electrostatic, ribbon, piezo-electric, or any combination of these?
mrfeedback said:
When loudspeaker manufacturers all make their loudspeakers to a common standard having identical impedance against frequency, we can start testing with that known load. Until then, an 8 ohm resistive load is as good a starting point as any, and shows the amplifier's best voltage performance. Having established that, we can be more unpleasant to the amplifier and impulse test it to determine current delivery. None of these tests relates to music, but they do allow testing of known engineering design faults.
What would you suggest as a test, given that a loudspeaker could be moving coil, electrostatic, ribbon, piezo-electric, or any combination of these?
Re: Re: What Is The Point ?.
I wonder what he wants; perhaps a square wave test? Output transformers will show ringing and overshoot. Negative feedback can increase or decrease the overshoot with respect to square waves.
There is no such thing as a perfect speaker. Without some parameters we cannot design a good amplifier. A 3 way sepaker can fluctuate between 2 and 20 ohms. 8 ohms is a good value for test purposes.
I have a calibrated microphone but I have no distortion tables to go with it. I have an Altec spectrum real-time analyzer.
How far do we need to go with this?
EC8010 said:
I wonder what he wants; perhaps a square wave test? Output transformers will show ringing and overshoot. Negative feedback can increase or decrease the overshoot with respect to square waves.
There is no such thing as a perfect speaker. Without some parameters we cannot design a good amplifier. A 3 way sepaker can fluctuate between 2 and 20 ohms. 8 ohms is a good value for test purposes.
I have a calibrated microphone but I have no distortion tables to go with it. I have an Altec spectrum real-time analyzer.
How far do we need to go with this?
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