[Tjj226 Angel]

It all boils down to E=IR (E)voltage = (I)current x (R)resistance.
I measure the voltage, both peak and average and use the R of 32Ω to figure the current for those voltages.
Then I multiply the voltage x current to determine the wattage.

This calculates numbers that are representative of the conditions as music is playing.

And really trying to condense the dynamic that is music into a snap shot of a single number is like herding cats, its kinda shows what is happening but is not completely inclusive nor truly representative of what is truly happening in real time.

JJ

You could also do W = (V^2)/R it saves you a step. However you have to also figure that the current on the secondary is split between your resistor and your headphones. So your calculation need to incorporate how much power is being put out vs how much power your headphones themselves are receiving.

 

[johnjen]

Yes indeed there is a 'bleed off' into the higher Ω load (the cans) but I was just figuring the output power the amp delivers at 32Ω to make the point that the power we actually use is so small it points directly at those small signal dynamics.

And if I were to napkin math it again and the jump from 32Ω to 320Ω (a x 10 multiplier) this would reduce those already minuscule wattage numbers and add another 0 between the decimal point and the calculated number, and in some cases divide it in ≈ 1/2 again (at 640Ω).
These reflect the Ω range of the HD800 (≈325 - 680Ω).

And I'm 'old skewl', so that thar new math of using squares is for you young'ns always trying to skip steps and such…
hahahahahahahahahahahahahahaha

Not to mention I use 1.414 and invert it, adding yet another step in the conversion from p-p to rms.
Yep 'old skewl' fer sure.

JJ

 

[bcowen]

Yes indeed there is a 'bleed off' into the higher Ω load (the cans) but I was just figuring the output power the amp delivers at 32Ω to make the point that the power we actually use is so small it points directly at those small signal dynamics.

And if I were to napkin math it again and the jump from 32Ω to 320Ω (a x 10 multiplier) this would reduce those already minuscule wattage numbers and add another 0 between the decimal point and the calculated number, and in some cases divide it in ≈ 1/2 again (at 640Ω).
These reflect the Ω range of the HD800 (≈325 - 680Ω).

And I'm 'old skewl', so that thar new math of using squares is for you young'ns always trying to skip steps and such…
hahahahahahahahahahahahahahaha

Not to mention I use 1.414 and invert it, adding yet another step in the conversion from p-p to rms.
Yep 'old skewl' fer sure.

JJ

Yeah, but the 32 ohms you're calculating with is impedance, not resistance. Whether that makes any difference or not is unknown....I already fessed up that I suck at math. LOL!

 

[johnjen]

Yes that's all true, but the additional capacitance and inductance are also minuscule and so add a minimal amount of additional load that the amp sees.

And actually I have a fixed 35Ω resistor across the output xfmr which is in parallel to the HD800's (320-680Ω) which results in a 32Ω load ≈±1Ω.
So really the vast majority of the load is predominantly resistive.

JJ

 

[johnjen]

So I'm now playing around with varying the amount of 'matched' filament voltage that is being applied to the 71A output tubes.

I started out with 5.001 thru 5.009vdc as a range.
Then moved to the range of 5.02 thru 5.09vdc.
And now I've worked up to 5.11 to 5.19vdc range and will continue to slowly increase the filament supply voltage up to a 'safe' upper limit of ≈ 4-5% (5.2 to 5.25vdc).

I'm listening for SQ and tube noise changes, as I adjust the B+ to stay in the 170VDC sweet spot.

I must say that thus far the SQ has seemed to further stabilize and has added a bit more resolution - inner detail - focus.
But I'm not done running the full range of voltages so there may be more acoustic changes in store.

JJ

 

[gefski]

So I'm now playing around with varying the amount of 'matched' filament voltage that is being applied to the 71A output tubes.

I started out with 5.001 thru 5.009vdc as a range.
Then moved to the range of 5.02 thru 5.09vdc.
And now I've worked up to 5.11 to 5.19vdc range and will continue to slowly increase the filament supply voltage up to a 'safe' upper limit of ≈ 4-5% (5.2 to 5.25vdc).

I'm listening for SQ and tube noise changes, as I adjust the B+ to stay in the 170VDC sweet spot.

I must say that thus far the SQ has seemed to further stabilize and has added a bit more resolution - inner detail - focus.
But I'm not done running the full range of voltages so there may be more acoustic changes in store.

JJ

JJ are you still listening to the HEDD? Don’t see it listed in your stuff.

 

[johnjen]

Say there gefski.

No I don't have them anymore.
HEDD wanted them sent to Jude as a 'demonstrator' pair for the headfi community…

JJ

 

[johnjen]

So it just occurred to me that I never connected a few dots between the meaning of a few of the 'special' words I use to describe 'beneficial' sonic and acoustic attributes, and how I relate them together into a 'tool' to use during evaluation of the net effect of mods and experiments.

It's really simple, and it's like this.
How loud can I crank it till it gets uncomfortable and I HAVE to turn it down?
Then I figure how long can I listen at that lowered SPL.
And I keep lowering the MOAR knob until the irritation aka tLFF (the Listener Fatigue Factor) is not a factor any more.

I then keep track of what the 'high water mark' was and see if it has been increased, or not.
There are particular 'test tracks' that are especially helpful for these types of tests.

This testing has revealed a truism, that being louder is better, IF tLFF has been minimized for the entire system.
This is yet another D'oh, forehead slap moment, I mean D'uh YEAH!!!!

There is a great deal of low level inner detail that can be heard IF it is sufficiently elevated in SPL and when combined with our ears rising sensitivity to the very bottom end low frequencies, can make for 'engaging' musical experiences.
BUT this 'trick' only really works IF the tLFF doesn't rattle our teeth, so to speak.

IOW IF we can remain at 'elevated' levels without tLFF raising it's ugly voice, THEN the brain will re-train itself and the system will settle into that range of operation and the SQ can become sublime and fully engaging.

In short, when you can crank it, and not let tLFF get in your face, the SQ can simply be marvelous.

JJ

 

[johnjen]

So I've achieved Pluckyness.
My latest fussing's with filament voltage settings, and keeping everything else dialed in, has revealed a degree of leading edge plosiveness to any plucked or picked or struck strings, or beat or struck upon drum head.

It's a subtle yet appreciated additional aspect to the 'REALNESS' aspect of SQ of those instruments that can get plucked or picked or struck, or beat upon…

This is directly related to LEDI (Leading Edge Dynamic Impact) but is more focused upon the instruments ability to deliver punch with power instead of just delivering speed and adroitness with resolution.

As in 'My, that sure sounds Plucky to me!!!!
hahahahahahahahahahha

JJ

 

[bcowen]

So I've achieved Pluckyness.
My latest fussing's with filament voltage settings, and keeping everything else dialed in, has revealed a degree of leading edge plosiveness to any plucked or picked or struck strings, or beat or struck upon drum head.

It's a subtle yet appreciated additional aspect to the 'REALNESS' aspect of SQ of those instruments that can get plucked or picked or struck, or beat upon…

This is directly related to LEDI (Leading Edge Dynamic Impact) but is more focused upon the instruments ability to deliver punch with power instead of just delivering speed and adroitness with resolution.

As in 'My, that sure sounds Plucky to me!!!!
hahahahahahahahahahha

JJ

At some point someone needs to create a 'Johnjen Translator' iPhone app that automatically opens when something like LEDI appears.

 

[johnjen]

I'll get right on that, well at least I'll put it at the end of my to-do-list and jump right into all of that as soon as that list rolls around to it.

In the mean time the 1st post of this thread does contain links to all of my Boldened nifty terms and their definitions, which is shown in the first line of my sig line.
But for now everyone will just have to use this backup for convenience and such… hahahahahahahahahaha

JJ

 

[johnjen]

Yet another status report.

The Purp-Amp has continued to improve as I fuss with finding the 'best' filament voltage to run this amp.
Thus far while making small (0.01v) steps up from 5.1 vdc to the filament voltage for the 71A output tubes, I've wound up in the range of 5.19 to 5.20vdc while keeping the B+ voltage across the tubes to 170vdc.

This has yielded improvements in multiple ways.
#1 The amount and types/kinds of noise of these 80yr old tubes have, has been reduced and significantly so.

#2 The SQ has risen yet again with more dynamic impact (LEDI (Leading Edge Dynamic Impact) & Pluckyness) everywhere. There is more 'aliveness' or REALNESS which makes for a more engaging T3 (Toe Tapping Time) and HB&W (Head Bobbing & Weaving) listening experience, and even 'Air Piano' has taken a step up.

#3 Overall operational stability has also improved, with a narrower window of adjustment needed to keep these key voltages in their sweet spot.

It's taken a while to dial all of this in but thus far the end results are most gratifying across the board.

And for those who are wondering why I pursued this course of action in the 1st place…
These 71A tubes like all the other DHT tubes I'm going to be using (26 & 45 & 300B) use the filament as THE direct source of electrons, so small voltage changes at this input of the tube has a much more direct effect upon the operation of these tubes vs. indirectly heated tubes (ones with a separate cathode).
Another way of viewing this is, I'm supplying an optimal amount of voltage which then becomes the amplified signal, and so the voltage inputs can meet the needed output power requirements because they are more closely matched.

Sorta like Momma Bear, not to much nor to little, but just right…
hahahahahahahahahaha

JJ

 

[johnjen]

My new current project is building a power distribution box with 3 duplex receptacles to power the new inbound gear.

I'll need at least 6 plug capacity for all of the new tube gear that will be showing up soon-ish.

I've mentioned the 2 monoblock speaker amps, the WE-124 variant/derivative (ƒ'124), (2 plugs).
The 26 pre-amp with 2) #26 tubes (1 plug).
The 45 HP amp with 2) #45 tubes (1 plug).
The 300B HP amp with 2) #300B tubes (1 plug).
The Purp-Amp with #71A and 6BQ7 tubes (1 plug).

And of course I'll need to make up additional interconnects and power cables to accommodate all of this.
This of course also means I'll be fussing and dialing in these circuits to optimize everything, like the tubes and their operating voltages, adding my secret sauce(s), getting everything all settled in and stable etc.

I am especially intrigued with the 26 pre-amp driving the 45 HP amp, as there will only be 2 tubes/ch for this entire chain.
This setup is all Class A SET design using DHT's, and with a collection of matched 'vintage' tubes from the 1930's and 40's to choose from as well as some new production matched sets as well.

And of course the 300B amp should be a 'contendah' as well.
And to be able to compare each of these 3 HP amps to each other from the same source(s) will be a treat as well.

I'm especially pleased, as the Purp-Amp has reached such an enticing SQ plateau, it makes for an elevated SQ target to shoot for, by any of these other HP amps.

JJ

 

[Zachik]

My new current project is building a power distribution box with 3 duplex receptacles to power the new inbound gear.

Are you planning to have any sort of filtering or power conditioning? I assume you'd post more as you start making decisions and progress...

And of course I'll need to make up additional interconnects and power cables to accommodate all of this.

I need to replace couple stock black power cords, so hope you'd provide more info on this mini-project as well. Being a newb with DIY - always better to learn from others' experiences.

 

[johnjen]

Are you planning to have any sort of filtering or power conditioning? I assume you'd post more as you start making decisions and progress...

All of my power conditioning (isolation xfmrs etc.) will be feeding this distribution box.
https://www.partsconnexion.com/CONXKIT-81353.html
And I'll swap out the 'stock' duplex receptacles with 2 of the SR 'orange' (the outrageously/stupid expensive) duplex receptacles.

I need to replace couple stock black power cords, so hope you'd provide more info on this mini-project as well. Being a newb with DIY - always better to learn from others' experiences.

My latest cable builds use 2) single conductor THHN 16awg copper wires for each conductor, so there are 6 wires in a light twist which terminate in cryo'd rhodium plated plugs and IEC connectors. The cable is then covered in braided sleeving.

Yes they are stiff and need to be shaped to fit, but are effectively 13awg ac power cables and are low cost (≈$40 each).
And I of course, as is my modus operendi, will apply additional 'conditioning' tweaks etc. to give them that extra touch of euphonic goodness.
Just because I can…
hahahahahahahahahaha

JJ