Vix said:
omit everything after DAC coupling caps ;
replace them with 470n - 1uF solid caps
make Jfet BOZ with input imp of at least 100K
make it also with no more than gain of 4 (12db)
place one cap in parallel to drain resistor of BOZ ; calculate it for ,
say , 40KHz
listen
vary value of caps
also - bypass elko caps connected from EXTL and EXTR with solid caps
let us know what's happening
Zen Mod said:
Hi ZM,
I'm quiet but busy, components have arrived, well most of them and i'm busy building the balanced version, also have pcb for single ended...but that can wait.
Right now i don't have decent output caps but i'll use the ones i tested with until the sonicraft and obligato i sent for arrive.
Should test tomorrow or wednesday, my schedule is quite tight so i don't have as much time as i would wish....weekend was for resting after a hellish work week at oostende.
As for the issue of how quickly i get tired...well, i haven't noticed it.
I haven't listened for extended periods with the test setup but you do raise a question i should test, so i will.
I should refer that I'm still on the honeymoon stage with my speakers, they are so far ahead of what i've heard before that it's a bit hard to be completely objective .
They are so transparent and sound stage so clear that i do not get tired with them, it's because of this that the Shanling now sounds like S...., whereas before i thought it sounded ok ( I didn't know better ).
In short they have revealed the Shanling as the weak link.
As i said before, taking out the op-amp I/V output stage of the
Shanling and taking the signal direct from the DAC chip with the basic passive I/V test set up gives me a cleaner ( so less tiring ) and better top end tone ( before it was dull and lifeless ).
I have yet to do the extended listening with this set-up, it is important to see if output staright from the DAC is tiring or not,...although i would be surprised if it is, i'll report on this ASAP.
😎 🙂
Carlos & Sasha : very nice and interesting thread ...
(Thanks for link, ZM, I would have missed it otherwise....)
Manu
(Thanks for link, ZM, I would have missed it otherwise....)
Manu
Hi Guys,
Sorry for long "pause" in proceedings but i was waiting for my coupling caps.
Got some very nice sonicrafts this morning so i hope i can test today.
Will report ofcourse and post a picture of the setup.😎
Sorry for long "pause" in proceedings but i was waiting for my coupling caps.
Got some very nice sonicrafts this morning so i hope i can test today.
Will report ofcourse and post a picture of the setup.😎
Hi Zen Mod,
Almost finished building both boards, tested one yesterday.
Will report asap, thing is in a hurry to test i botched the protoboard version, now i built with pcb !
I'm sure i'll need to tweak output cap/resistors but that's expected.
I also replaced top resistance with a 200R pot to adjust offset for center value.
😉
Almost finished building both boards, tested one yesterday.
Will report asap, thing is in a hurry to test i botched the protoboard version, now i built with pcb !
I'm sure i'll need to tweak output cap/resistors but that's expected.
I also replaced top resistance with a 200R pot to adjust offset for center value.
😉
Also trying to design the final pcb, how is this for a start....haven´t done one in many many years ?
Of course this will only have a final form when we settle on final values and cap type after testing.
Coupling caps can be in or outboard, for example the sonicrafts and the Obligatos i have are too big for inboard.
Of course this will only have a final form when we settle on final values and cap type after testing.
Coupling caps can be in or outboard, for example the sonicrafts and the Obligatos i have are too big for inboard.
Attachments
Hi ZM,
It's tweaking time...tested both channels on the Shanling.
Fantastic sound, detail on top end with not a hint of harshness....lovely natural voice tone.
....but Bass is gone....well not completely but it does not go down to say ....room shaking 30hz, tight controlled 30hz i have usually.
I'm using values in the last schematic i posted here, except for output resistor value, i'm using 3k3....but that gives me too much gain, i'll go back to 1k5.
Should i lower the 10u cap to say 4u7....if i can get bass then sound will be gorgeous.😀
Edit: all pots are adjusted to 7.5 V dc offset at output
It's tweaking time...tested both channels on the Shanling.
Fantastic sound, detail on top end with not a hint of harshness....lovely natural voice tone.
....but Bass is gone....well not completely but it does not go down to say ....room shaking 30hz, tight controlled 30hz i have usually.
I'm using values in the last schematic i posted here, except for output resistor value, i'm using 3k3....but that gives me too much gain, i'll go back to 1k5.
Should i lower the 10u cap to say 4u7....if i can get bass then sound will be gorgeous.😀
Edit: all pots are adjusted to 7.5 V dc offset at output
give me voltage potential on DAC outputs WITHOUT I/V stage connected , and same potential with I/V connected .
tell me one more time ( sorry if you did that already ) - what's input impedance of your dreky UGS ?
tell me one more time ( sorry if you did that already ) - what's input impedance of your dreky UGS ?
pot is 200R adjusted to give mid offset.
Just a detail, i used a 220u/25v Panasonic FM on each board on supply inputs, should i take it out ? might be messing up power supply output impedance?
Voltages are:
With I/V : all 4 outputs are: 3.04V Dc
Without I/V : 1.6 V, 3.04V, 2.9V, 1.6V DC
Just a detail, i used a 220u/25v Panasonic FM on each board on supply inputs, should i take it out ? might be messing up power supply output impedance?
Voltages are:
With I/V : all 4 outputs are: 3.04V Dc
Without I/V : 1.6 V, 3.04V, 2.9V, 1.6V DC
CeeVee said:
sorry I meant on volume pot on input of UGS
?
I need to figure out what is exact input impedance of your UGS thingie
anyway - just for test - increase these 10uF caps on output of I/V stage ; maybe input impedance of UGS is too low ......
you can use even lousy elkos for test ; 20uF is adequate ; so - C1 and C2 , each 20uF
let me know what's happening 😉
OK,
It seems input impedance of UGS is in the order of 10K, out put 300R, as Flat says.
I can make it higher by increasing Rin.....but i think that is working at the wrong end no ?
So i should have a lower cut-of off....
Cf = 1/(2*pi*R*C)
Cf= 1/ (2*pi*10OOO*0.00001)
Cf= 1,59Hz
using the 10u on the I/V.
...if someone wasn't taking my bass away.
🙄
It seems input impedance of UGS is in the order of 10K, out put 300R, as Flat says.
I can make it higher by increasing Rin.....but i think that is working at the wrong end no ?
So i should have a lower cut-of off....
Cf = 1/(2*pi*R*C)
Cf= 1/ (2*pi*10OOO*0.00001)
Cf= 1,59Hz
using the 10u on the I/V.
...if someone wasn't taking my bass away.
🙄
...hehe ..i would if i was at home.
That is why i have a little time for theory.
I'll test that this evening.
But i can tell you this: sound is extreemly good, so much so that i ended up listening to it like that until about 2 in the morning.
It's clear that the solution is this way...with bass WOW, can hardly wait.
😎
That is why i have a little time for theory.
I'll test that this evening.
But i can tell you this: sound is extreemly good, so much so that i ended up listening to it like that until about 2 in the morning.
It's clear that the solution is this way...with bass WOW, can hardly wait.
😎
CeeVee said:
in any case - when you finish that thingie ...... you can send that Drekling to me , for proper disposal .......
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