To whom had interest in my Babo Zen:
Do you remember?
The reason why I gave the name as "Babo (Dumb)"?
The reason was that I used strange complement sets of Jfets
and Mosfets. I used a strange combo of J310 (U5) and 2SJ108GR
(U6) and an odd combo of IRFP250N (Q1) and IRFP240 (Q2) of IR.
Nevertheless, the sound was very good.
By the way, recently I built the “first-watt” F4 using 2SK170BL,
2SJ74V, IRFP240 (Samsung) and IRFP9240 (Fairchild). And,
after this still I had left-over of these FETs. Therefore, I replaced
the old FETs with these new ones. After the renewal, I adjusted
the bias at 1A per channel and the output dc offset to the level
lower than 20mV when the amp was reached to the steady-state
heat balance.
I jumped into my CD player and threw in Taj Mahal, “Ain’t
Gwine Whistle Dixie (Anymo’) (8:37)”.
The sound changed from the 2nd harmonic character slightly to
the 3rd harmonic sound. The sound was improved
I felt like enjoying the whistle, electric strings, drums,
percussions, brasses, and their rich and natural harmonies under
the bright and warm sunshine shining from the blue sky at the sea
side. The sound was really cool. I raised volume up, but the sound
didn’t go hard. It was still easy and cool . . .
I can’t call this “Babo Zen” anymore.
I should call this “Papa’s Zen5 with Input JFETs”. The real name.
(I still love the nick name, Babo Zen, tho . . .)
I’d like recommend you to try to build not only F4, but also Papa’s
Zen5 having the JFET inputs. You can’t regret. I’m 99% sure
Do you remember?
The reason why I gave the name as "Babo (Dumb)"?
The reason was that I used strange complement sets of Jfets
and Mosfets. I used a strange combo of J310 (U5) and 2SJ108GR
(U6) and an odd combo of IRFP250N (Q1) and IRFP240 (Q2) of IR.
Nevertheless, the sound was very good.
By the way, recently I built the “first-watt” F4 using 2SK170BL,
2SJ74V, IRFP240 (Samsung) and IRFP9240 (Fairchild). And,
after this still I had left-over of these FETs. Therefore, I replaced
the old FETs with these new ones. After the renewal, I adjusted
the bias at 1A per channel and the output dc offset to the level
lower than 20mV when the amp was reached to the steady-state
heat balance.
I jumped into my CD player and threw in Taj Mahal, “Ain’t
Gwine Whistle Dixie (Anymo’) (8:37)”.
The sound changed from the 2nd harmonic character slightly to
the 3rd harmonic sound. The sound was improved
I felt like enjoying the whistle, electric strings, drums,
percussions, brasses, and their rich and natural harmonies under
the bright and warm sunshine shining from the blue sky at the sea
side. The sound was really cool. I raised volume up, but the sound
didn’t go hard. It was still easy and cool . . .
I can’t call this “Babo Zen” anymore.
I should call this “Papa’s Zen5 with Input JFETs”. The real name.
(I still love the nick name, Babo Zen, tho . . .)
I’d like recommend you to try to build not only F4, but also Papa’s
Zen5 having the JFET inputs. You can’t regret. I’m 99% sure
Babowana said:
Papa,
I'm sorry for having given up the J-Low.
Today, I found the two Pass DIY logos taken from the J-Low.
I re-used one of them to complete my new F4.
I promise that I will never give up both "Zen5 with Input JFETs"
(Babo Zen) and "F4"
Cheers,
:darkside"
Attachments
Zen Mod said:
I found a red-colour paper box I got when I bought mountain-hiking shoes.
The size was very fit for keeping the pair of Jordan. I put the pair into it
and filled in the void space with old news papers to arrest them into no
movement, and put the box on the invisible place. I’m going to use them
for a certain future project (I have no idea of what and when) . . .
My living room space is 70m^3.
It is the half space of Cotton Club in Shanghai where the international
jazz players: drum, lead guitar, bass guitar, trumpet and saxphone:
often play Grant Green, Sookie Sookie.
Mmm . . .
What a heat!
How come from this small 85dB speaker . . . so loudly and lively.
I am sure that the "Zen5 with Input Jfets" is a fancy monster.
I wonder why Pass diyers are ignorant about this amp . . .
It is the half space of Cotton Club in Shanghai where the international
jazz players: drum, lead guitar, bass guitar, trumpet and saxphone:
often play Grant Green, Sookie Sookie.
Mmm . . .
What a heat!
How come from this small 85dB speaker . . . so loudly and lively.
I am sure that the "Zen5 with Input Jfets" is a fancy monster.
I wonder why Pass diyers are ignorant about this amp . . .
Attachments
OK, now I completed a new set up for my new living space where
I am free alone.
The pre is Chinese product of one 6N6 diode tube and two 6N3
amplifier tubes. I did not see inside yet. But, I guess that the
circuit must be resembling the old but famous vintage tube pre,
e.g. Maranz 7 or . . .
Spec says input sensitivity of 1V, voltage gain of 20dB and frequency
band of 5Hz to 100KHz at -1dB . . .
The power is my F4 of 8W+8W. Do you need any info about F4?
The speakers are again ATC SCM7. I had to buy one more pair as
wife and children forced me to leave the same pair at home.
Wow . . . the F4 delivers big tube sound to the speakers almost
without adding or deleting the tube charactors. Fantastic!
I am listening to Bob Marley, One Love, "4. Lively Up Yourself".
The sound is really really nice . . . and loud . . .
Bass notes are very clear, tightly supporting upper melodies.
The next one is the one I always like without feeling the sickness
even if I repeatedly listen. "5. No woman No cry" . . . mmm . . .
It's a master piece of Bob Marley, I think . . .
Different taste . . . but I also like my MOSFET pre with F4.
The reason why I am using tube pre here is due to eye attraction . . .
I do not know when I return myself to the MOSFET pre tho . . .
I am free alone.
The pre is Chinese product of one 6N6 diode tube and two 6N3
amplifier tubes. I did not see inside yet. But, I guess that the
circuit must be resembling the old but famous vintage tube pre,
e.g. Maranz 7 or . . .
Spec says input sensitivity of 1V, voltage gain of 20dB and frequency
band of 5Hz to 100KHz at -1dB . . .
The power is my F4 of 8W+8W. Do you need any info about F4?
The speakers are again ATC SCM7. I had to buy one more pair as
wife and children forced me to leave the same pair at home.
Wow . . . the F4 delivers big tube sound to the speakers almost
without adding or deleting the tube charactors. Fantastic!
I am listening to Bob Marley, One Love, "4. Lively Up Yourself".
The sound is really really nice . . . and loud . . .
Bass notes are very clear, tightly supporting upper melodies.
The next one is the one I always like without feeling the sickness
even if I repeatedly listen. "5. No woman No cry" . . . mmm . . .
It's a master piece of Bob Marley, I think . . .
Different taste . . . but I also like my MOSFET pre with F4.
The reason why I am using tube pre here is due to eye attraction . . .
I do not know when I return myself to the MOSFET pre tho . . .
Attachments
I love Richard Bona's CD album, Reverence.
The songs are lyrical and always help me to calm down.
I heard that Richard Bona was influenced by Jaco Pastorious
as a bassist - a stunning bassist.
I picked up 6. Reverence (The Story of a Miracle) and powered
up this song with F4. The bass was really stunning, not only
as rhythmic and harmonic foundations, but also as part of melodies.
Great!
The songs are lyrical and always help me to calm down.
I heard that Richard Bona was influenced by Jaco Pastorious
as a bassist - a stunning bassist.
I picked up 6. Reverence (The Story of a Miracle) and powered
up this song with F4. The bass was really stunning, not only
as rhythmic and harmonic foundations, but also as part of melodies.
Great!
Attachments
Yeah . .. . who I am . . . ?
I opened cover plate of my tube pre to rip off the circuit.
As I expected, the circuit is the copy of Marantz 7's line stage.
It has two stages, and the output has current feedback to the
Kathode of the first stage. But, it has no output buffer of Marantz
7 so that the output impedace is high, about 10k, providing the
voltage gain of about 20dB.
High output impedance . . . 10K . . . so what . . . ?
F4 has input impedance of 47K as a load, and is a good coupling
power with this tube pre with respect to the sound. If the output
impedance is higher than normal, couldn't it be a bit better current
source in another word . . . ?
I opened cover plate of my tube pre to rip off the circuit.
As I expected, the circuit is the copy of Marantz 7's line stage.
It has two stages, and the output has current feedback to the
Kathode of the first stage. But, it has no output buffer of Marantz
7 so that the output impedace is high, about 10k, providing the
voltage gain of about 20dB.
High output impedance . . . 10K . . . so what . . . ?
F4 has input impedance of 47K as a load, and is a good coupling
power with this tube pre with respect to the sound. If the output
impedance is higher than normal, couldn't it be a bit better current
source in another word . . . ?
Hi Papa,
I have a question with F4.
As you might have read, my tube pre has the output impedance
of 10K. Meanwhile, I have a tube buffer amp that could be located
between the pre and F4. But, as F4 has the Jfet input buffer, I do
not want to add the external additional buffer if I could increase
the input impedance of F4 somewhat.
Question: Considering the 10K output impedance of the pre, I
would like to increase the 48K input impedance of F4, increasing
the ground reference resistor at the Jfet input side to 200K. Will
this affect the sound quality of F4? If not, until how big could I
increase it without losing the sound quality?
Many thanks,
I have a question with F4.
As you might have read, my tube pre has the output impedance
of 10K. Meanwhile, I have a tube buffer amp that could be located
between the pre and F4. But, as F4 has the Jfet input buffer, I do
not want to add the external additional buffer if I could increase
the input impedance of F4 somewhat.
Question: Considering the 10K output impedance of the pre, I
would like to increase the 48K input impedance of F4, increasing
the ground reference resistor at the Jfet input side to 200K. Will
this affect the sound quality of F4? If not, until how big could I
increase it without losing the sound quality?
Many thanks,
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