Hello everyone,
I'm new to the forum*and*I apologize*for my English*unclear.
I*am passionate*discussions*about this*wonderful project*of*siberian*preamplifier.
My question*concerns the*simulation,*with*a*resistance*of*4P1L*filament.
My doubt is*the value that*has been calculated,*of 0.33*ohms,*but*if*the*filament voltage*is about*1,*9v*and the current*passing through it,*as has been*suggested,is about*620ma, the resistance*to use*should*be,*approximately,*of*3*ohms and not of 0,33.
I ask you,*please,*a confirmation*or not*about this*my*doubt.
Thanks*and congratulations*for all your*interventions,
Regards,
andrea
I'm new to the forum*and*I apologize*for my English*unclear.
I*am passionate*discussions*about this*wonderful project*of*siberian*preamplifier.
My question*concerns the*simulation,*with*a*resistance*of*4P1L*filament.
My doubt is*the value that*has been calculated,*of 0.33*ohms,*but*if*the*filament voltage*is about*1,*9v*and the current*passing through it,*as has been*suggested,is about*620ma, the resistance*to use*should*be,*approximately,*of*3*ohms and not of 0,33.
I ask you,*please,*a confirmation*or not*about this*my*doubt.
Thanks*and congratulations*for all your*interventions,
Regards,
andrea
Hello
As you know,my first build of the 4P1L give me to much noise
now i have finished my sekund build ,and have used all the good advice from you,in this tread
short wire ,,shilded wire..2 trafoes to Coleman reg,,caps the right places on trafoes,,star ground mounted on a CU rail,,lead bitumen on the alu plate for the tubes
and the best --the noise is now much lower, and is at a level, where is do not disturb the music,,so i am very happy with the result
one question.....my star ground have no connection to chassis ,,,is this ok ?????
Many thanks to you all,,for helping me to get a super result..
now it is time to discuss the sound...later on.
Best Regards Bjarne
As you know,my first build of the 4P1L give me to much noise
now i have finished my sekund build ,and have used all the good advice from you,in this tread
short wire ,,shilded wire..2 trafoes to Coleman reg,,caps the right places on trafoes,,star ground mounted on a CU rail,,lead bitumen on the alu plate for the tubes
and the best --the noise is now much lower, and is at a level, where is do not disturb the music,,so i am very happy with the result
one question.....my star ground have no connection to chassis ,,,is this ok ?????
Many thanks to you all,,for helping me to get a super result..
now it is time to discuss the sound...later on.
Best Regards Bjarne
Bjarne, please connect 0V (star) to chassis at one point only, located near to the input socket.
Hej Rod
will try to connect my star ground to chassic
can you tell me why it is the best thing to do.??
i have very little hum..now
best Bjarne
will try to connect my star ground to chassic
can you tell me why it is the best thing to do.??
i have very little hum..now
best Bjarne
Bjarne, if the chassis is not connected, it will be influenced by electromagnetic fields (from CD players, computers, other power-trafos, lighting, power cables), and so on. In other words the chassis will act to collect and re-radiate noise.
Connecting the chassis to system-0V (ground) keeps the chassis from re-radiating, at east up to fairly high frequencies. With a good ground connexion, the chassis acts as a shield, to protect signal wiring from the EM fields.
Connecting the chassis to system-0V (ground) keeps the chassis from re-radiating, at east up to fairly high frequencies. With a good ground connexion, the chassis acts as a shield, to protect signal wiring from the EM fields.
Hello Rod
just connected the star earth to chassic
this remove the last bit of noise totally--absolute noise free
i am so thankfully for your help
Best Bjarne
just connected the star earth to chassic
this remove the last bit of noise totally--absolute noise free
i am so thankfully for your help
Best Bjarne
Maybe you will also hear improved sound ... the EM noise will corrupt the smallest music signals, too.
I'm pleased you now have a good design!
I'm pleased you now have a good design!
I am just now sitting and hear some music..i am not shure that i ever had better sound from a pre--
my last build was a Aleph 1.7..before that a Tram2.and Borbely pre
have own a Pass Labs x02--whits i prefer to a Conrad Johnson act2
but for now i am super happy with this marveled preamp
best Bjarne
my last build was a Aleph 1.7..before that a Tram2.and Borbely pre
have own a Pass Labs x02--whits i prefer to a Conrad Johnson act2
but for now i am super happy with this marveled preamp
best Bjarne
Hi Bjarne,
Great to hear you sorted things out.
Would be great to share your comments about the sound. Take your time to listen to it first 🙂
Enjoy!
Ale
Great to hear you sorted things out.
Would be great to share your comments about the sound. Take your time to listen to it first 🙂
Enjoy!
Ale
Do you have an example of Gm and Rp with what you'd consider a good range to operate the filaments?
I've been thinking about a single stage 4p1l headphone amp in parafeed since the headphones I want to use are very efficient (I could use input step up transformer if necessary). And it's a bonus that it can easily be CCS loaded and run in filament bias. LL1930 reflects 9600 ohms with 300 ohm load, LL1674 reflects 4800.
edit: I just looked through your Siberian Gen 3 article. With starved filaments 163 v on plate and 32 ma Ia, Rp is 5093 ohms. This is significantly higher than what the data sheet says isn't it?
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Hello
I have a high frekvent noise (about 7 to 9khz i think) goes a little op and down in strange
no hum or hiss (very little) just this high noise
just mount a bigger gridstopper 27k
the noise is a bit lesser
How big value of gridstopper is ok to use ???
What value shall i use to gread leak resistor ,,my potmeter is 50k
I use Gen3 4P1L pre
Best Bjarne
I have a high frekvent noise (about 7 to 9khz i think) goes a little op and down in strange
no hum or hiss (very little) just this high noise
just mount a bigger gridstopper 27k
the noise is a bit lesser
How big value of gridstopper is ok to use ???
What value shall i use to gread leak resistor ,,my potmeter is 50k
I use Gen3 4P1L pre
Best Bjarne
hi Bjarne,
27K is enough, do not go higher for the stopper, or the grid-leak value may be compromised.
7-9 kHz is maybe microphonics..... it is unusual for a single-stage to oscillate electrically so low.
Try a different 4P1L. If it is not that, you will need an oscilloscope to look at the power supplies.
27K is enough, do not go higher for the stopper, or the grid-leak value may be compromised.
7-9 kHz is maybe microphonics..... it is unusual for a single-stage to oscillate electrically so low.
Try a different 4P1L. If it is not that, you will need an oscilloscope to look at the power supplies.
If a 1k grid stopper doesn't stop oscillation, your problem is elsewhere. Could be a bad tube, or could be the filament supply or could be a CCS elsewhere.
4p1l microphonic noise is around 1 to 2 kHz band and only manifests as a "ding" when you tap the valve if not well damped 🙂
Ale
Ale
You are very helpfull---greetings to you
i stick to my 1.3k for gridstopper
i have just finished to change to my russian socket...
same tube ..must see what that brings--just now .no highfrekvent noise..funny
what value off grid leak resistor is right for me ..i use 50k pot ????
Best Bjarne
i stick to my 1.3k for gridstopper
i have just finished to change to my russian socket...
same tube ..must see what that brings--just now .no highfrekvent noise..funny
what value off grid leak resistor is right for me ..i use 50k pot ????
Best Bjarne
Hello
just an update on the high frekvent noise..after i have change to russian socket ,,this noise
is gone...strange
Ang i must find another fault ,when i sit and hear music,,came suddenly hum and noise in one channel --not much but i could hear it--
it was a cap on myColeman reg who loose the connection to a little transistor ..i must make a wire to get the connection stable
A funny thing i hear with the new socket ..the music is more clear in the top,,strange ^¨```
Best Bjarne
just an update on the high frekvent noise..after i have change to russian socket ,,this noise
is gone...strange
Ang i must find another fault ,when i sit and hear music,,came suddenly hum and noise in one channel --not much but i could hear it--
it was a cap on myColeman reg who loose the connection to a little transistor ..i must make a wire to get the connection stable
A funny thing i hear with the new socket ..the music is more clear in the top,,strange ^¨```
Best Bjarne
Hi...
My first nearly six month of living with my 4P1L.
First I'll like to post a picture of the "latest" tweaked 4P1L and try to describe what
I have found as great improvement for this fantastic pre-amp.
Just to clarify I'm "still" on a slightly tweaked version 1, as I has managed to tweak this
from very good, to quite amazing.
What I have found is the most important tweaks for the "Cap version of 4P1L" is.
1. Output Coupling Caps , from best to worse 🙂
1) Vcap Cuft(0.1uf) + Vcap Tftf(0.1uf) - Wau but have a lot of clicks and pops, due too not enought capacitor values.
2) Vcap Cuft(0.1uf) + Rike S.cap(0.33uf) - Breaking in right now very very nice.
3) Vcap Cuft (0.1uf) + Clarity MR(0.33uf) - this is my third best combination.
4) Clarity MR (0.33uf) - very nice cap but lack of a lot of things.
5) Vcap Cuft (0.1uf) + Russian K75 pio(0.22uf) - what a joke.
6) Russian K75 pio(0.22uf) - a very big joke.
Remarks.
The V-cap Cuft cost a fortune but this is a real winner.
Rike S-Cap in combination with V-cap Cuft, this is very very nice.
2. The Last capacitor in my power supply, now using Clarity TC 20uf.
Chancing from Panasonic 2uF PIO to Clarity TC huge huge difference.
Just adding the Clarity TC 20uf gives a huge difference.
Everything seems to clear up, widther soundstage, more deep, more black.
Less noise floor, this is one of the best upgrade and only 15£.
3. Grid leak resistor going from 47K to 68K amazing improvement.
Very happy with Koa Spear (Metal oxide resistor).
As all schematics (version 1,2) shows 47K, this was when I rather prefered
to keep my 6922. make it higher in my case 68K and this will make a huge
improvement to the sound of the 4P1L.
4. Grid Stopper, Tried Kiwame Carbon (too granny), Koa Spear Metal Oxide (too Noisy), Takman REX carbon (very nice), Takman REY metal (best choice so far).
For sure I would try other high cost Resistors here, and for sure do not go under
Takman REX carbon.. for 0.66£ it's a very good start.
Just Remeber Takman REY metal, does not has a metal sound at all.. Very nice.
5. Cathode Resistor.. I'm very very satisfied with the mills 12watt. Better in any way
compared to my first Vishay Dale 10w. Use non magnetic here.
6. The operation point has been tried from between 20-30mA, this is the 8 Ohm Cathode version I'm on. Depending upon your power amp, I have a 2a3DC and Speaker
you can easily fine adjust for your own desired taste.
I hope my impressions was a form of inspiration too other 4P1L builders.
It's a little hard to express what I feel, english is not my native language...
/Best Michael.
My first nearly six month of living with my 4P1L.
First I'll like to post a picture of the "latest" tweaked 4P1L and try to describe what
I have found as great improvement for this fantastic pre-amp.
Just to clarify I'm "still" on a slightly tweaked version 1, as I has managed to tweak this
from very good, to quite amazing.
What I have found is the most important tweaks for the "Cap version of 4P1L" is.
1. Output Coupling Caps , from best to worse 🙂
1) Vcap Cuft(0.1uf) + Vcap Tftf(0.1uf) - Wau but have a lot of clicks and pops, due too not enought capacitor values.
2) Vcap Cuft(0.1uf) + Rike S.cap(0.33uf) - Breaking in right now very very nice.
3) Vcap Cuft (0.1uf) + Clarity MR(0.33uf) - this is my third best combination.
4) Clarity MR (0.33uf) - very nice cap but lack of a lot of things.
5) Vcap Cuft (0.1uf) + Russian K75 pio(0.22uf) - what a joke.
6) Russian K75 pio(0.22uf) - a very big joke.
Remarks.
The V-cap Cuft cost a fortune but this is a real winner.
Rike S-Cap in combination with V-cap Cuft, this is very very nice.
2. The Last capacitor in my power supply, now using Clarity TC 20uf.
Chancing from Panasonic 2uF PIO to Clarity TC huge huge difference.
Just adding the Clarity TC 20uf gives a huge difference.
Everything seems to clear up, widther soundstage, more deep, more black.
Less noise floor, this is one of the best upgrade and only 15£.
3. Grid leak resistor going from 47K to 68K amazing improvement.
Very happy with Koa Spear (Metal oxide resistor).
As all schematics (version 1,2) shows 47K, this was when I rather prefered
to keep my 6922. make it higher in my case 68K and this will make a huge
improvement to the sound of the 4P1L.
4. Grid Stopper, Tried Kiwame Carbon (too granny), Koa Spear Metal Oxide (too Noisy), Takman REX carbon (very nice), Takman REY metal (best choice so far).
For sure I would try other high cost Resistors here, and for sure do not go under
Takman REX carbon.. for 0.66£ it's a very good start.
Just Remeber Takman REY metal, does not has a metal sound at all.. Very nice.
5. Cathode Resistor.. I'm very very satisfied with the mills 12watt. Better in any way
compared to my first Vishay Dale 10w. Use non magnetic here.
6. The operation point has been tried from between 20-30mA, this is the 8 Ohm Cathode version I'm on. Depending upon your power amp, I have a 2a3DC and Speaker
you can easily fine adjust for your own desired taste.
I hope my impressions was a form of inspiration too other 4P1L builders.
It's a little hard to express what I feel, english is not my native language...
/Best Michael.