The sound of H2 using a 19V main PSU
Hello dewdrop and my best wishes to you for 2020.
My post #472 was incomplete because it missed the subject information; which I derived a couple of days ago. Here are the key findings due to using a 19 V main PSU [SMPS]:
1. It works; meaning the resultant subjective impressions [attributes] of H2 negative phase [H2np] are like those described by Mr. Pass. Except, they are more enhanced or pronounced.
2. Bass energy is increased.
3. The overall character of this new and different sound is one of heightened "warmth".The localization attribute of [H2np] is still present except its contributors were embalmed by this warmth![/B]
4. The sound was not offensive at all after an hour or so of playing diverse music.
I 'll use the flexibity of my main PSU to vary on the fly its output from +24 V to +19.5V by simply adjusting its variac knob. There is more to learn by this upcoming sound impressions experiment.
I suggest to newdrop [and others] that you not shy away from doing this experiment of using a 19V5 PSU.
Best
Anton
Hello dewdrop and my best wishes to you for 2020.
My post #472 was incomplete because it missed the subject information; which I derived a couple of days ago. Here are the key findings due to using a 19 V main PSU [SMPS]:
1. It works; meaning the resultant subjective impressions [attributes] of H2 negative phase [H2np] are like those described by Mr. Pass. Except, they are more enhanced or pronounced.
2. Bass energy is increased.
3. The overall character of this new and different sound is one of heightened "warmth".The localization attribute of [H2np] is still present except its contributors were embalmed by this warmth![/B]
4. The sound was not offensive at all after an hour or so of playing diverse music.
I 'll use the flexibity of my main PSU to vary on the fly its output from +24 V to +19.5V by simply adjusting its variac knob. There is more to learn by this upcoming sound impressions experiment.
I suggest to newdrop [and others] that you not shy away from doing this experiment of using a 19V5 PSU.
Best
Anton
Finally got an hour spare to put the H2 together 
3.5mm In and Out with a 24v pass through to power other 24v devices, and a screened, shielded 3.5mm cable.
Very pleased with the sound so far. I'll give it a good listen over the next few weeks and see how it goes.
I took some measurements with the voltages set at 16.00 at T2, giving 1% on the graph:
[H2 THD]
Definitely a dominant H2
[H2 Noise]
Noise floor is a little high
[H2 Frequency Response]
I wish I could travel with the Korg B1 that I am using as a headphone amp, so I'm going to try using this to produce the H2 and then feed into the inverting opamp buffer that I made using the samples from Burson (thread here https://www.diyaudio.com/forums/parts/346728-burson-supreme-sound-projects.html):
3.5mm In and Out with a 24v pass through to power other 24v devices, and a screened, shielded 3.5mm cable.
Very pleased with the sound so far. I'll give it a good listen over the next few weeks and see how it goes.
I took some measurements with the voltages set at 16.00 at T2, giving 1% on the graph:
[H2 THD]
Definitely a dominant H2
[H2 Noise]
Noise floor is a little high
[H2 Frequency Response]
I wish I could travel with the Korg B1 that I am using as a headphone amp, so I'm going to try using this to produce the H2 and then feed into the inverting opamp buffer that I made using the samples from Burson (thread here https://www.diyaudio.com/forums/parts/346728-burson-supreme-sound-projects.html):
Attachments
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For someone myself with no electronics training (self taught or otherwise), having a part spec (which might be arbitrary to cognescenti
) works for me particularly when I do not have a warehouse like yourself or a parts bin like many of the posters to this thread. I certainly do not have the skill set to measure and post great charts like those just created by <avtech23> or do a deep dive into the circuit intricacies like <antoinel>
One item I would like to mention is that for a newbie like myself having someone like Nelson offer at no charge a prebuilt board like the H2 Original or a kit like the H2 Rev1 (2?) is wonderful. Thanks for that!
With the little bit of DIYing that I do, it has become quickly obvious that buying small quantities (1, 2, <5) of anything becomes a question of whether you can live with the high S/H charged by vendors of these parts. I DO understand that there are costs associated with inventory, labor, shipping, etc. but it seems like some use it as a profit center.
To my offer of 33 ohm resistors above, it was cheaper to buy 100 pieces
of 33 ohm, 1W, 1% tolerance from Amazon Prime than to buy the 2 pieces I needed from Mouser, etc...plus I had them in 2 days. Same with the 1000 uf electrolytics tho' I did not have to buy 100! Another look at 19V5 SMPS main PSU for H2 Ptreamp V1.
The revised measurement which is relevant to the following discussion is T2 =14.7 V for either channel. It resulted from the use of a 19V5 SMPS main PSU instead of the recommended 24 V. The attached graph is/shows:
1. A copy of the original and last graph in the second article on H2.
2. The trends of the data-driven plots by Mr. Pass for Null, 1%H2 and 2%H2 suggested that I can add a couple "theoretical" graphs below the aforementioned ones. They are X% and Y%; noting that the suggested magnitude of Y% is greater than X% which is greater than 2%.
3. I next used the coordinates of T2 = 14.7 V and Vpinch = 2.8V to generate the red dot. It is >X%. Operation of the H2 generator is contraindicated at this distortion level which is >>2% [excessive!].
4. But wait! I know from the first gragh on page 7 of either article that % Distortion is Directly Proportional to Vout at the drain of the FET. So I arbitrarily lowered the FETs' Vout from 1 Vp-p to 150 mVp-p.
5. The resultant sound impression at this FETs' Vout = 150 mVp-p is the same as that described by Mr. Pass in his articles for H2 negative phase; meaning recessed, and localized where it fit.
6. This lowered FETs' Vout may allow for a better "Volume Control" than for say a must 1 Vp-p inside the downrange equipment of preamp and power amp.
In conclusion, H2 Preamp V1 is flexible in using either a 24 V or 19V5 SMPS.
The revised measurement which is relevant to the following discussion is T2 =14.7 V for either channel. It resulted from the use of a 19V5 SMPS main PSU instead of the recommended 24 V. The attached graph is/shows:
1. A copy of the original and last graph in the second article on H2.
2. The trends of the data-driven plots by Mr. Pass for Null, 1%H2 and 2%H2 suggested that I can add a couple "theoretical" graphs below the aforementioned ones. They are X% and Y%; noting that the suggested magnitude of Y% is greater than X% which is greater than 2%.
3. I next used the coordinates of T2 = 14.7 V and Vpinch = 2.8V to generate the red dot. It is >X%. Operation of the H2 generator is contraindicated at this distortion level which is >>2% [excessive!].
4. But wait! I know from the first gragh on page 7 of either article that % Distortion is Directly Proportional to Vout at the drain of the FET. So I arbitrarily lowered the FETs' Vout from 1 Vp-p to 150 mVp-p.
5. The resultant sound impression at this FETs' Vout = 150 mVp-p is the same as that described by Mr. Pass in his articles for H2 negative phase; meaning recessed, and localized where it fit.
6. This lowered FETs' Vout may allow for a better "Volume Control" than for say a must 1 Vp-p inside the downrange equipment of preamp and power amp.
In conclusion, H2 Preamp V1 is flexible in using either a 24 V or 19V5 SMPS.
Attachments
The Introduction in the two articles by Mr. Pass which are entitled "H2 Harmonic Generatior" shows this statement:
"Looking back at the glory days of tube sound, some speculate that the 2nd harmonic character of single-ended tube amplifier circuits is an important element of the sound quality they want."
The attached schematic reinforces the above speculation by demonstrating a facet or more of tube amplifiers' sound.
1. The schematic is for an assembled Class aP mono-power amplifier. I'll explain its works in a follow-up post with links to posts in the thread "Class aP amplifiers.
2. It is is essentially a Class AB push-pull amp with added operational flexibilty. It has components which resemble those in vacuum tube amps. Namely, an output power transformer [OPT], and an NPN which has Electrical Characteristics which resemble those for a pentode [meaning a voltage-variable current source].
3. An aP generator [not shown] is a precision rectifier. Its has two output pulses which are positive-going [in phase], of equal amplitude and which are diplaced in time as shown under the pulses [0 to t and t to t1] from the parent music signal at the left of the view.
4. The secondary output of [OPT] drives the two inputs of Threshold S/150 which drives two ADS L730 loudspeakers.
Its Sound Impressions:
Very pleasing and likeable. It is as articulated by Mr. Pass: "a deeper soundstage and improved localization than otherwise" . Achieved by simply decreasing the amplitude of the input pulse [t to t1] from +Vp to 0.99Vp relative to the other pulse [0 to t].
1. As shown in the schematic, its power amp/loudspeakers combo has the sound of H2 negative phase [H2np]/its attributes.
2. Shorting [on the fly] the value of the input resistor [68 Ohm] for the pulse [t to t1] generates the sound of the fundamental which is void of the above [H2np] attributes. Unmistakable.
3. The localization attribute of [H2np] is readily discernible for this mono power sound output. The instruments are found in a "layered" fashion behing the loudspeakers and in front of me.
Best
Anton
"Looking back at the glory days of tube sound, some speculate that the 2nd harmonic character of single-ended tube amplifier circuits is an important element of the sound quality they want."
The attached schematic reinforces the above speculation by demonstrating a facet or more of tube amplifiers' sound.
1. The schematic is for an assembled Class aP mono-power amplifier. I'll explain its works in a follow-up post with links to posts in the thread "Class aP amplifiers.
2. It is is essentially a Class AB push-pull amp with added operational flexibilty. It has components which resemble those in vacuum tube amps. Namely, an output power transformer [OPT], and an NPN which has Electrical Characteristics which resemble those for a pentode [meaning a voltage-variable current source].
3. An aP generator [not shown] is a precision rectifier. Its has two output pulses which are positive-going [in phase], of equal amplitude and which are diplaced in time as shown under the pulses [0 to t and t to t1] from the parent music signal at the left of the view.
4. The secondary output of [OPT] drives the two inputs of Threshold S/150 which drives two ADS L730 loudspeakers.
Its Sound Impressions:
Very pleasing and likeable. It is as articulated by Mr. Pass: "a deeper soundstage and improved localization than otherwise" . Achieved by simply decreasing the amplitude of the input pulse [t to t1] from +Vp to 0.99Vp relative to the other pulse [0 to t].
1. As shown in the schematic, its power amp/loudspeakers combo has the sound of H2 negative phase [H2np]/its attributes.
2. Shorting [on the fly] the value of the input resistor [68 Ohm] for the pulse [t to t1] generates the sound of the fundamental which is void of the above [H2np] attributes. Unmistakable.
3. The localization attribute of [H2np] is readily discernible for this mono power sound output. The instruments are found in a "layered" fashion behing the loudspeakers and in front of me.
Best
Anton
Attachments
FYI: On understanding the sound of vacuum tube amplifiers
Please visit my last post in the thread "Class aP amplification". I show the schematic of the current bench-prototype power amp which uses SemiSouth SJDP120R085 instead of NPN which I showed in the previous post of this "H2" thread. Works great, sounded better than the NPN prototype. Its music is commensurate with the findings of Mr. Pass due to H2 negative phase.
Here are promised cherry-picked posts from the orchard thread "Class aP amplification". Post#200 [schematic and build of the Class aP Generator], plus 203, 170, 151, and 149.
Best
Anton
Please visit my last post in the thread "Class aP amplification". I show the schematic of the current bench-prototype power amp which uses SemiSouth SJDP120R085 instead of NPN which I showed in the previous post of this "H2" thread. Works great, sounded better than the NPN prototype. Its music is commensurate with the findings of Mr. Pass due to H2 negative phase.
Here are promised cherry-picked posts from the orchard thread "Class aP amplification". Post#200 [schematic and build of the Class aP Generator], plus 203, 170, 151, and 149.
Best
Anton
