JSmith
Master Contributor
Indeed...
Does anyone know what the final count was supporting the CTA petition?
When submitting, I don't recall seeing any figure of how many submissions had been received.
JSmith
-
WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Buckeye Purifi Eigentakt 1ET9040BA monoblock power amplifier Stereophile Measurements
- Thread starter pma
- Start date
- Status
Does anyone know what the final count was supporting the CTA petition?
When submitting, I don't recall seeing any figure of how many submissions had been received.
JSmith
restorer-john
Grand Contributor
The petition is funny as they are pretending all this is new and will cause undue burdens of testing, compliance and costs when the rule has been in place since 1974 with pretty much the same requirements. We have a saying in Australia- "suffer in your jocks".
Sokel
Master Contributor
- Joined
- Sep 8, 2021
- Messages
- 8,785
- Likes
- 9,302
The strange thing with CTA is that they don't mention the measuring protocol at all other than the 8 Ohm spec.
What do they know that we don't?Doesn't seem peachy to me.
On the other hand this nice,round $500 billion figure can give lots of motive.
What do they know that we don't?Doesn't seem peachy to me.
On the other hand this nice,round $500 billion figure can give lots of motive.
Vladimir Filevski
Addicted to Fun and Learning
- Joined
- Mar 22, 2020
- Messages
- 699
- Likes
- 991
Yes, they can handle more than 5W. How much more? I don't know, but I can make an educated guess - no more than 50 W (@8 ohm amp power)/Now I'm confused.The whole subject of my post is pure power handling,more than 5W to be precise.
Regardless anything else.
So,they can or they can't?And by how much?
(don't want to think that this lamp makes them glow too,I hope it doesn't )
Lamp is inside the body and can't be seen.
Edit: 50W
Last edited:
restorer-john
Grand Contributor
(don't want to think that this lamp makes them glow too
Plenty of loudspeakers used incandescent globes as limiters. JBL control ones IIRC. Realistic Mach Twos used two, one for the tweeter and one for the midrange. They were 12V automotive 'festoon' style globes. And yes, I lit them up- back in the day. The bright flash came out the reflex port. LOL.
Here you go, Mach two crossovers:
restorer-john
Grand Contributor
That is actually a pretty compelling argument.
I do take the view it's a lot easier to produce an amplifier that has a flat power response vs frequency than a loudspeaker, but the point is well taken.
Sokel
Master Contributor
- Joined
- Sep 8, 2021
- Messages
- 8,785
- Likes
- 9,302
If I ever get speakers like that they had better tell that in prior.
Or else I could get a heart attack with big brass ascending after a quiet part
It's been 2 months since comments closed. I haven't seen anything from the FTC in response. Looks like 123 comments.
Regulations.gov
www.regulations.gov
Old_School_Brad
Major Contributor
- Joined
- Sep 10, 2024
- Messages
- 1,462
- Likes
- 1,901
If I ever get speakers like that they had better tell that in prior.
Or else I could get a heart attack with big brass ascending after a quiet part
It's been 2 months since comments closed. I haven't seen anything from the FTC in response. Looks like 123 comments.
Regulations.gov
Thanks. Is this the new thread for the FTC regulation discussion?
Not as far as I'm concerned. I answered one question and that's it for me.Thanks. Is this the new thread for the FTC regulation discussion?
Its not as easy as you make it to be ...
Look at the 9040 power curve below ... where is the knee at 8 ohms (thick black line)? There's a large flat plateau between 40W and 200W. What power level are you going to pick then? This amp is super clean, into 8ohms, up to ~ 390W with under -120dB THD+N.
I ask the same questions for the 4 ohms (thick red line). Flat plateaus with under -120dB THD+N up to 700W... will you pick the 400W rating at -125dB THD+N as your knee point?
Spec'ing amplifier power using the 'knee' method is fraud with problems and very subjective inaccuracies. Those amps with sharp knees will still be able to distort to 0.1% at the least. If the resolution is low and can't visually point to the 0.1% or 1%, the AP system can (or should) easily interpolate for you to get the desired power level for the distortion you are seeking for.
- Joined
- Jun 30, 2022
- Messages
- 238
- Likes
- 119
Buckeye has been a great seller/manufacturer. They took care of my SMPS issue during the late December. They wanted to work on it ASAP (on the 23rd) but I figured it is not a good idea for them to work during the holidays. I'm excited to receive my Purifi 1ET7040SA mono block back.
Also, we all have some clarification to do w.r.t rating amplifiers (especially class D). This forum is so dead set on SINAD, multi tone, and various other numbers very much past the human hearing limitations...I think that the same rule should apply to all amplifiers (and all classes). If a class D can't drive 1000watts/8ohms@15khz then it must be displayed in the specifications. You can always write a footnote about..how 1000watts/8ohms at 15khz is not really needed. I think that the same footnote should apply to the SINAD numbers that we chase here. I'm expecting full transparency from the industry and reviewers. Let the buyer make the decision. Also, note that some SMPS in class D will have Bus Pumping issues too. A well built class AB will have none of these issues except that it will weigh 50 kilos and cost $10k. One can buy a vintage amp and refurbish it, I tend to refurbish Yamaha M80s and they don't sweat it when driving my Thiel CS3.6s. I went with class D even when I knew that the power limitations/pumping could happen because...I know that these are extremes (btw, with my speakers my Buckeye Amps had bus pumping and Dylan sent me extra filtercaps and it fixed that issue).
Also, we all have some clarification to do w.r.t rating amplifiers (especially class D). This forum is so dead set on SINAD, multi tone, and various other numbers very much past the human hearing limitations...I think that the same rule should apply to all amplifiers (and all classes). If a class D can't drive 1000watts/8ohms@15khz then it must be displayed in the specifications. You can always write a footnote about..how 1000watts/8ohms at 15khz is not really needed. I think that the same footnote should apply to the SINAD numbers that we chase here. I'm expecting full transparency from the industry and reviewers. Let the buyer make the decision. Also, note that some SMPS in class D will have Bus Pumping issues too. A well built class AB will have none of these issues except that it will weigh 50 kilos and cost $10k. One can buy a vintage amp and refurbish it, I tend to refurbish Yamaha M80s and they don't sweat it when driving my Thiel CS3.6s. I went with class D even when I knew that the power limitations/pumping could happen because...I know that these are extremes (btw, with my speakers my Buckeye Amps had bus pumping and Dylan sent me extra filtercaps and it fixed that issue).
- Joined
- Dec 12, 2019
- Messages
- 13,871
- Likes
- 31,003
dude. two light bulbs. cool.
Irrelevant aside: A pair of Mach Twos passed through here years back. They were not bad. Way better than the Mach One to my ear(s).
For those, like me, who had no idea what the term "Bus Pumping" means, here is good explanation.
EDIT: Further reading states that bus pumping is only an issue with single ended amplifier designs and not differential output designs such as the Purifi modules. Just don't ground any of its positive or negative outputs.
EDIT: Further reading states that bus pumping is only an issue with single ended amplifier designs and not differential output designs such as the Purifi modules. Just don't ground any of its positive or negative outputs.
Last edited:
KSTR
Major Contributor
For any engineer the answer is clear: I look at the actual waveform and find the point where the waveform starts to clip, starting to crop off the tops of the sine (or show any other drastic deformation like slew-limiting, or protection kicking in even for short bursts). I read the voltage from the oscilloscope and calculate the power. And state that with no more than 2 significant digits.
Because that is what we want to know, the hard-clipping level as that's where things really fall apart in practical application. Distortion just below this point is irrelevant, especially if it is intentional distortion like from a tube amp or a soft-clipper.
In those typical THD+N vs Power plots, I'd use the point where the distortion starts to explode, for your example that would be 0.40kW@8R, 0.80kW@4R and 1.5kW@2R or whatever we could read from the plot if it had proper subdivisions.
KSTR
Major Contributor
0.3%...1% distortion from clipping is easily spotted by the experienced eye and using a good analog scope.
Any rise below hard clipping from 0.000x% to, say 0.3% in the last 10% or so of the output voltage range is completely irrelevant in practice.
And like I said a few posts back, when somebody showed IMD plots at 1W and 100W:
1. The plots look remarkable similar, almost identical. There's nothing one can glean off the 100W plot that can't be seen in the 1W plot.
2. I also said, the lower power 1W plot stresses the input buffer more than the 100W plot. Low input voltages reveal noise and THDN issues in buffer stages that are hidden or don't exist at large voltage inputs. That's why you see noise floor issues in the 1W IMD plot but don't see them in the 100W IMD plot.
- Thread Starter
- #780
No. Have you ever done such measurement and observing distortion?
- Status
Similar threads
- Locked
