[Bonehead7171]

Sadly, I know what happened to my Kyocera DA-01 CD Player. It broke under warranty. I sent it to Kyocera for repair, they repaired it and sent it back. It had the same problem as when I sent it to them. I sent it back (again) and they said "unrepairable, so sorry, here take this new model worth half as much instead." I was annoyed, but what could I do? The original was pretty interesting, it had a pop-out mechanism like a cassette player to load the disc.

The one they replaced it with was this one, the DA-610:

That one lasted quite a bit longer and though I don't think it was as nice as the model I purchased, the sound was quite good and I was pleased with it. I think I replaced it in 1994 or 1995 when it broke. Now, keep in mind I was in college at the time I bought the DA-01, which I believe may have been the first announced CD player ever. Discs cost a fortune and there were very few available (I absolutely recall the two I bought when I got the player were Donald Fagan's The Nightfly and Depeche Mode's Construction Time Again.) To say I was an early adopter would be to underplay it. I still bought a lot more vinyl than CDs for several years just due to the fact that the music I wanted wasn't even available on CD!

The DA 610 looks exactly like the KLH she got me! I thought it was a great piece at the time. I never had 1 issue...why did I ditch it? Who knows...It goes in the same column with a million other bad decisions....

 

[tincanear]

Now I know why the Schiit Freya burns through tubes so fast, their lead engineer can't do math.

You don't push 80v into an 8 ohm load to get 100w. You push 28-29v. Class A in its "purest form" is about 25% efficient, give or take a little for overhead -- so 400wpc to generate 100wpc. Not 800wpc. And you can improve this by a factor of two by using inductive coupling (though most people don't like the sound).

Jason is correct about the rail voltage needed. For 100w rms into 8 ohms -> 28v rms means 40v above bias point, 40v below bias point so 80v across the power supply.

 

[Andrew Randle]

Toaster options could be balanced (toasts both sides) or single-ended.

I like ones that are good at imaging, i.e the ones that imprint iconography.

Certain other hi-fi branded toasters would have a perfectly even cook, within 0.00001%, but taste burnt. They might even be adept at burning the house down.

Andrew

 

[zoidbb]

Jason is correct about the rail voltage needed. For 100w rms into 8 ohms -> 28v rms means 40v above bias point, 40v below bias point so 80v across the power supply.

Except he didn't call it rail voltage. Here's the quote:

I know you guys hate math, but let’s do a simple calculation. Let’s say you want to make a Class A amp that does 100 watts into 8 ohms. To do that, you need to swing 80 volts across those 8 ohms.

And 80V into 8 ohms means you need to swing 10 amps.


Aside: I = V/R is the equation you’re looking at.

“So?” you ask, all innocent and non-engineeringy.

Sooooooo…your Class A amp, in its most pure form, needs to run 10 amps across 80V all the time. Which runs us into another equation: P = VI

Or, power = voltage x current.

Or, to put a really sharp point on it, your 100W Class A into 8 ohm amplifier has to dissipate 800 watts at idle.

Firstly, he doesn't say anything about rail voltage. He says you need 80 volts across 8 ohms. This is not how we talk about AC signals firstly, we talk in terms of RMS, Vp (Voltage-Peak), and Vpp (Voltage-Peak-to-Peak). RMS is, roughly speaking, the average voltage of the /absolute/ value of the waveform (functionally, signs removed from the amplitudes). Vp is the total differential from 0 amplitude to the peak of the waveform (usually positive), so the amplitude of one side of the wave. Vpp is the total swing from peak to trough.

So for 100wpc RMS into 8 ohms we have:

Vrms = 28v
Vp = 40v
Vpp = 80v
R = 8 ohms

Does that mean the load is drawing 800w? Absolutely not. The power draw is actually based on Vp, not Vpp. At peak positive, you're pulling 200w (Vp = 40v, R = 8 ohms, I = Vp/R = 40v / 8 ohms = 5 amps, P = Vp * I = 40v * 5 a = 200w). At peak negative you're pulling 200w as well. That's 400wpc total power dissipation, as I noted earlier.

 

[US Blues]

RIP David Crosby.

Music Is Love.

 

[Andrew Randle]

I could have owned the sign off of this particular building after the new sign was put in its place. It was huge and I had no way to store it at the time. When I was hired the plant consisted of 80% women, maybe 6,000 employees. That ratio of women to men was often mentioned by the headhunters looking for new employees.

Typical RCA employee:

 

[rkw]

We are weird. We're considering a solar house with rainwater capture (for all house water, no well) in Texas.

Not weird, considering the water shortage in Corpus Christi.
https://arstechnica.com/tech-policy...on-and-is-losing-its-big-bet-on-desalination/

 

[Paladin79]

Typical RCA employee:

Many were new hires ages 18 to 25 because of the expansion that occurred at the time, many were right out of college, as I was. I was also single, so I might actually know something about the eligible women there.

 

[tincanear]

Except he didn't call it rail voltage. Here's the quote:

Firstly, he doesn't say anything about rail voltage. He says you need 80 volts across 8 ohms. This is not how we talk about AC signals firstly, we talk in terms of RMS, Vp (Voltage-Peak), and Vpp (Voltage-Peak-to-Peak). RMS is, roughly speaking, the average voltage of the /absolute/ value of the waveform (functionally, signs removed from the amplitudes). Vp is the total differential from 0 amplitude to the peak of the waveform (usually positive), so the amplitude of one side of the wave. Vpp is the total swing from peak to trough.

So for 100wpc RMS into 8 ohms we have:

Vrms = 28v
Vp = 40v
Vpp = 80v
R = 8 ohms

Does that mean the load is drawing 800w? Absolutely not. The power draw is actually based on Vp, not Vpp. At peak positive, you're pulling 200w (Vp = 40v, R = 8 ohms, I = Vp/R = 40v / 8 ohms = 5 amps, P = Vp * I = 40v * 5 a = 200w). At peak negative you're pulling 200w as well. That's 400wpc total power dissipation, as I noted earlier.

yes. perhaps Jason is trying to simplify things for non EE's (it would take another chapter to explain differences between Vrms, Vp, Vpp, etc).

yes, at least 400W idle dissipation for each amplifier channel, 800W for a stereo amp (like the sumo Nine and Ten were). plus design allowances to hit required RMS output power spec with low AC mains, and keeping the output devices in a fairly linear operating region (min Vce / Vds), beta droop), emitter / source resistor drop, etc. all of which would increase the total power dissipation.

 

[adydula]

Peak power, music power, RMS power, my head hurts..

,707
1.414
Leading or lagging and all that gorp.

But what I did today has left me smiling alot or big time..

D8000 Pros with the MMB2...and the sound here was as good as it gets...
Absolutely wonderful multi bit dac..
Even when switching to my other dacs costing ALOT more, this little machine just does the job so very well.

Just loving it.
Alex

 

[zoidbb]

yes. perhaps Jason is trying to simplify things for non EE's (it would take another chapter to explain differences between Vrms, Vp, Vpp, etc).

yes, at least 400W idle dissipation for each amplifier channel, 800W for a stereo amp (like the sumo Nine and Ten were). plus design allowances to hit required RMS output power spec with low AC mains, and keeping the output devices in a fairly linear operating region (min Vce / Vds), beta droop), emitter / source resistor drop, etc. all of which would increase the total power dissipation.

Perhaps, but he should at least use numbers that make sense. The numbers and math presented are completely nonsensical, and serve no purpose other than to confuse the layman. It would have been /simple/ for him to use the correct numbers and quote the correct heat dissipation, instead of making everything suddenly fear that their 100w class A amp is going to blow a breaker by pulling a more power than a microwave.

EDIT: You'd also have to go /way/ out of your way to design an amp that consumes literally double the gain stage's power dissipation. Like... by adding 200w light bulbs or something.

 

[tincanear]

reminds me of a project posted by Nelson Pass (of Threshold, FirstWatt, etc.) check out fig. 16 and page 8

aside: IIRC, there were some Audible Illusions pre-amps that would burn out tubes faster than you could replace and break-in a new set.

 

[Pondoro]

Toaster options could be balanced (toasts both sides) or single-ended.

I like ones that are good at imaging, i.e the ones that imprint iconography.

Certain other hi-fi branded toasters would have a perfectly even cook, within 0.00001%, but taste burnt. They might even be adept at burning the house down.

Andrew

But can I get two and use them as monoblocks?

 

[Timster]

Great!!

How about an ad for my first "cans".



Honest. I used them on a Crystal radio that was attached to my bedpost. I even took them apart and they still worked.


And, the rest, as they say, is history.

Here's an interesting read about these headsets!

https://earlyradiohistory.us/1922brn.htm

 

[roncruiser]

I thought I'd post up here for some quick answers, thoughts and opinions.
I'm looking to pull the trigger on the Vidar 2 or Aegir.

Room is untreated: (l x w x h) 25'x13'x9'
One end of the length(l) opens and widens to the kitchen and the other end of the length(l) opens and widens to a stairway.
It's an odd shaped room. Not quite a rectangular box but "close" in general.
I share a wall with a neighbor on the kitchen side of the length(l). In other words I cannot play music blaringly loud.
Loud enough to enjoy though!

I want to make the right speaker amp choice right off the bat: Vidar 2 or Aegir.

My speakers:
Speaker pair 1: Denton Wharfedale 85th Anniversary (4 ohms: 88db @ 2.0V @ 1m)
Speaker pair 2: Klipsch RP-600M (8 ohms: 96dB @ 2.83V / 1m)
I switch between the two speaker sets often. Currently they are driven by a Marantz Rx SR8012.

Which amp would you recommend for the Speakers and Setup?
If I can only get one amp. Which amp?
If I reach deep into my pockets, easily but reluctantly but happily, which amps? 2x Vidar's or 2x Aegir's or another amp? Given the budget is $1600. The price of two Aegir's. Max.

Bifrost 2 -> Freya + -> Amp -> Speakers