Hi Kokorianz, don't be mad. I'm not trying to highjack this thread, and i dont think i can, because i'm using the floating ground for output so same slice of pie but just with different flavour... The guys have to know whats tested with the floating output and what not. For instance i tested the coil +40 ohm resistor instead of the 140 ohm resistor, and want to report that each way you put it, a suplimentary resistor in series with the coil is not good because it limits the swings that the coil can do(the sound has less pressence, feels less relaxed and the bass is not as deep), so i use only one coil of 100 ohm and soldered it dirrectly to the Vcc+ of the PSU and to the bias pot. Beware to keep it in phase. Keeping it in phase will give a more relaxed and present sound+ deeper and puncier bass than out of phase.
With the coil in this position and mounted like this i have tons of bass, an extraordinary presence, depth of field, roundness, dinamics and INCREDIBLE clarity. The 1k2 bias is now 220r/4w (its barelly warm) resistor giving me a 1.5A bias.
I compared the coil to a150 ohm metal film 2w resistor and the resistor seems to sound muddy now and have a fuzzy sound. I highly recommend trying an inductor there.
Today I applied the 3k3 from the base of 2n1711 to ground, the cascode (made from bc413b) and the 8k2 from V+ and got full 28V on the output instead of half Vcc. Have any ideea? Do i have modify everything as you did to work, or i can modify only that part?
Also when putting the floating ground center to GND (through ground loop breaker) it shorts one cap. How do you connect the floating point to GND? My star ground is also connected there to clean the ripple out. Or you dont have a ground loop breaker?
Thanks in advance
With the coil in this position and mounted like this i have tons of bass, an extraordinary presence, depth of field, roundness, dinamics and INCREDIBLE clarity. The 1k2 bias is now 220r/4w (its barelly warm) resistor giving me a 1.5A bias.
I compared the coil to a150 ohm metal film 2w resistor and the resistor seems to sound muddy now and have a fuzzy sound. I highly recommend trying an inductor there.
Today I applied the 3k3 from the base of 2n1711 to ground, the cascode (made from bc413b) and the 8k2 from V+ and got full 28V on the output instead of half Vcc. Have any ideea? Do i have modify everything as you did to work, or i can modify only that part?
Also when putting the floating ground center to GND (through ground loop breaker) it shorts one cap. How do you connect the floating point to GND? My star ground is also connected there to clean the ripple out. Or you dont have a ground loop breaker?
Thanks in advance
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I suppose what you call cascode with bc413 is the current mirror 2xbc413. You made the amp function without speaker neither 3.9k pull up resistor , so the input transistor pulled the 3ma current from the upper capacitor . Plug in the speaker and re adjust the Vcc/2 . The precedent ground is now called -14V . The only ground, non floating, is the joint of the two capacitors which must be used as the star point . The speaker the emitter resistor of the input and the input reference ground are taken from the common joint of the two capacitors. In the picture these capacitors are near the circuit , they must be upon the output transistors with the leads of the capacitors link directly without wires the collector and the emitter . You can fix the joining leads to the heat sink . Without this procedure you louse lot of bass .
What is ground loop bracker?
What is ground loop bracker?
Thank you . The 3.3k is good for driving the outputs by low impedance. Your transistors need high impedance. Replace the 3.3k by 100k adjust and by listening decide the value. By the way , you wanted to try germanium . Why not try for the input stage as the famous ACY23, In your country must have a lot of Soviet ones .
I would try if they were awailable.. I have on hand ADZ 12, EFT250, ASZ18 as power, ac180,181 as drivers, some OC71 (just 3pcs) , EFT323,319 and thats all. In the old comunist Romania only the EFT, AC and ASZ where found and the same today.
The adz and oc are very hard to find here. I buyed them from an old electronic store long time ago...
The adz and oc are very hard to find here. I buyed them from an old electronic store long time ago...
Now I just setled to a version that I liked most after allot of listening hours. 
Next week I will try the current mirror again with your advice of course.
I gounded everithing to float as you did and what do you know, the little hum that I had (10cm from speaker) dissapeared completely. The conclusion is that that when you go with floating supply everything has to ground there. Is just like a diff PSU, only that the float point is equivallent to 0V.
Cant wait to test some germaniums. They have low gain and I think that I have to start with 12v for the output stage at max 1A bias then we'll see.
Next week I will try the current mirror again with your advice of course.I gounded everithing to float as you did and what do you know, the little hum that I had (10cm from speaker) dissapeared completely. The conclusion is that that when you go with floating supply everything has to ground there. Is just like a diff PSU, only that the float point is equivallent to 0V.
Cant wait to test some germaniums. They have low gain and I think that I have to start with 12v for the output stage at max 1A bias then we'll see.
What I can say now is that the JLH now is extremely close to the 30w Hiraga wich has almost all upgrades possible including some exotic parts... The jlh is made from the monkey box (only the outputs are now new) ... ) Interesting stuff. If I knew 6 years ago about this....
Even the heat dissipation is almost the same.
) Interesting stuff. If I knew 6 years ago about this....Even the heat dissipation is almost the same.
The Jlh has its own voice signature, thats the only difference. The Hiraga is a bit more forgiving for the quality of the song that you are playing. And that is all my friends.
Luckily for me I found another 2sc3611 in my monkey box, this gives even more bass and more roundness to the voice. Will have to listen to it again next week.
Now I will go to sleep like a baby. I listened all day to Diana Krall, Norah Johnes, Ryu Miho, Liu Zi Ling, Jacintah and so on.
Good night to everyone.
Luckily for me I found another 2sc3611 in my monkey box, this gives even more bass and more roundness to the voice. Will have to listen to it again next week.
Now I will go to sleep like a baby. I listened all day to Diana Krall, Norah Johnes, Ryu Miho, Liu Zi Ling, Jacintah and so on.
Good night to everyone.
Qoute Kokoriantz
https://www.youtube.com/watch?v=1PdcmFvZvuI&t=570s. from 9:40 to13:50
These are the main sound sources I used to tune this amp for perfect reproduction .
Try to be pleased by these two musical pieces on any other amp than this one .
Thanks for sharing this. I have to say though, that I was pleased listening to it with my lowly superlux 668b on my cellphone.
https://www.youtube.com/watch?v=1PdcmFvZvuI&t=570s. from 9:40 to13:50
These are the main sound sources I used to tune this amp for perfect reproduction .
Try to be pleased by these two musical pieces on any other amp than this one .
Thanks for sharing this. I have to say though, that I was pleased listening to it with my lowly superlux 668b on my cellphone.
Hy Kokoriantz,
I tweaked the sublimed jlh to my taste and listen to it allot and now i'm ready to test the current mirror, and later the germaniums, BUT couldnt listen extensivelly nore compare the current mirror vs the classic one, because i have a hum that its making the comparison task dificult.. Did you have any hum?
If i remove the curent mirror the hum dissapeares.
Thanks
Ok i tested the current mirror tyded to float gnd instead of the psu gnd. It doesnt work at all.. With the current mirror joint to psu gnd its humming badly....
I'll stick to non current mirror.. Now i swapped mj21194 to mjl4281a. Will test them and listem to them this week.
Will try germaniums soon.
Cheers
I'll stick to non current mirror.. Now i swapped mj21194 to mjl4281a. Will test them and listem to them this week.
Will try germaniums soon.
Cheers
I swapped the mj21194 with mjl4281a and came back to 21194... The 4281a has more gain indeed but it lacks the finesse a bit. The mids are abit muddy, not so clear; the overall speed has improved but i'm not after the speed.. in rest everything remains the same. I suspect the cob has something to do with this.
I have also the mjl21194 (plastic case) and listened to it also and didnt sense any difference so i sticked to them for more convenient cpu xeon radiators.
Anyway, today i swapped the input with germanium, the ASY77. The gain has decreased, BUT WHAT A SOUND. Will listen more and report back soon.
Cheers
Sergiu
I have also the mjl21194 (plastic case) and listened to it also and didnt sense any difference so i sticked to them for more convenient cpu xeon radiators.
Anyway, today i swapped the input with germanium, the ASY77. The gain has decreased, BUT WHAT A SOUND. Will listen more and report back soon.
Cheers
Sergiu
This kit came with ST micro 2n3055 transistors, ordered some time ago, received today. Don't buy the kit if you look for the Motorola transistors
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